Re: Topband: Shunt feeding AB-577/621

[k8gg]

Hi All,

A couple of thoughts:

I used an aluminum powder filled version of Permatex or similar anti-seize
compound the last time I put up an aluminum tower (Heights or Universal). 
No continuity problems.

Also with a rigid galvanized free-standing tower (Probably American Tower
or Pyrod) I used zinc filled anti-seize compound on the face of the
flanges between sections.  No conductivity problems for the 16 years it
was up with a shunt feed for 160 meters.

The AB-577 is probably resonant near 3.5 MHz with the C-3 antenna on top
if one wants to shunt feed it for 80 or 75 meters.

So, I vote for an inverted-L for 160 either supported from the top of the
mast or from a separate tree.

GL & 73,

George, K8GG


> Hi Pete,
>
> Good question. I haven't done it with any of my three AB-577s, but I've
> seen recommendations from others that the sections be electrically bonded.
>
> I'm not sure about the case for that. I just measured continuity on the
> flat portion of a spare tube and it showed zero ohms. If the contact areas
> are clean when the mast is assembled, they should make good contact with
> zero resistance. The clamp should act to keep the flat areas in contact,
> as should the downward pressure from the guys. I guess it may be possible
> that dirt carried by rain water might seep into the clamp and get between
> the sections as they rock back and forth in the wind, even if it's just by
> nanometers.
>
> If you buy that possibility, I think it can be overcome pretty easily by
> attaching right-angle tabs to the top and bottom of each section with
> screws/nuts, and running a section of copper strap between them, also
> secured with screws and nuts, or perhaps you can find some sort of clamp
> that would let you quickly connect/disconnect the strap as you raise/lower
> the mast.
>
> Hope this helps.
>
> 73, Dick WC1M
>
> -Original Message-
> From: N4ZR 
> Sent: Monday, October 1, 2018 11:48 AM
> To: topband reflector 
> Subject: Topband: Shunt feeding AB-577/621
>
> I have an AB-577 with a C-3E on top, and am interested in the possibility
> of shunt-feeding it for 160 - 100 watts only.  Anyone have any experience
> with doing this?  Are the section-to-section joints adequately conductive?
>  I would plan to use an omega match, because I'm guessing it would be well
> short of a quarter wave.
>
> My other option is an inverted L.  Should I maybe just go ahead with that?
>
> --
>
> 73, Pete N4ZR
> Check out the Reverse Beacon Network
> at <http://reversebeacon.net>, now
> spotting RTTY activity worldwide.
> For spots, please use your favorite
> "retail" DX cluster.
>
>
>
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>


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Re: Topband: Shunt feeding AB-577/621

[Dick Green WC1M]

Hi Pete,

Good question. I haven't done it with any of my three AB-577s, but I've seen 
recommendations from others that the sections be electrically bonded. 

I'm not sure about the case for that. I just measured continuity on the flat 
portion of a spare tube and it showed zero ohms. If the contact areas are clean 
when the mast is assembled, they should make good contact with zero resistance. 
The clamp should act to keep the flat areas in contact, as should the downward 
pressure from the guys. I guess it may be possible that dirt carried by rain 
water might seep into the clamp and get between the sections as they rock back 
and forth in the wind, even if it's just by nanometers.

If you buy that possibility, I think it can be overcome pretty easily by 
attaching right-angle tabs to the top and bottom of each section with 
screws/nuts, and running a section of copper strap between them, also secured 
with screws and nuts, or perhaps you can find some sort of clamp that would let 
you quickly connect/disconnect the strap as you raise/lower the mast.

Hope this helps.

73, Dick WC1M

-Original Message-
From: N4ZR  
Sent: Monday, October 1, 2018 11:48 AM
To: topband reflector 
Subject: Topband: Shunt feeding AB-577/621

I have an AB-577 with a C-3E on top, and am interested in the possibility of 
shunt-feeding it for 160 - 100 watts only.  Anyone have any experience with 
doing this?  Are the section-to-section joints adequately conductive?  I would 
plan to use an omega match, because I'm guessing it would be well short of a 
quarter wave.

My other option is an inverted L.  Should I maybe just go ahead with that?

-- 

73, Pete N4ZR
Check out the Reverse Beacon Network
at <http://reversebeacon.net>, now
spotting RTTY activity worldwide.
For spots, please use your favorite
"retail" DX cluster.



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Re: Topband: Shunt feeding AB-577/621

[donovanf]

Hi Pete, 


I'd suggest you proceed with an inverted-L 


73 
Frank 
W3LPL 

- Original Message -

From: "N4ZR"  
To: "topband reflector"  
Sent: Monday, October 1, 2018 3:47:37 PM 
Subject: Topband: Shunt feeding AB-577/621 

I have an AB-577 with a C-3E on top, and am interested in the 
possibility of shunt-feeding it for 160 - 100 watts only. Anyone have 
any experience with doing this? Are the section-to-section joints 
adequately conductive? I would plan to use an omega match, because I'm 
guessing it would be well short of a quarter wave. 

My other option is an inverted L. Should I maybe just go ahead with that? 

-- 

73, Pete N4ZR 
Check out the Reverse Beacon Network 
at <http://reversebeacon.net>, now 
spotting RTTY activity worldwide. 
For spots, please use your favorite 
"retail" DX cluster. 

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Re: Topband: Shunt feeding AB-577/621

[Joe Subich, W4TV]

On 2018-10-01 11:47 AM, N4ZR wrote:
> I have an AB-577 with a C-3E on top, and am interested in the
> possibility of shunt-feeding it for 160 - 100 watts only.  Anyone have
> any experience with doing this?  Are the section-to-section joints
> adequately conductive?

The section joints should be adequately conductive given the surface
area.  The big questions would be an adequate connection at the top
and conductivity through the "launcher."


My other option is an inverted L. Should I maybe just go ahead with
that?

Since the standard AB-577 is 48' tall, even with the boom of your
C-3E you are only about 1/8 wave tall on 160.  It will take a good
deal of additional top loading to make the standard AB-577 reasonable
on 160 meters ... I'd consider hanging an inverted L off the side.
Probably easier in the long run.

73,

   ... Joe, W4TV


On 2018-10-01 11:47 AM, N4ZR wrote:
I have an AB-577 with a C-3E on top, and am interested in the 
possibility of shunt-feeding it for 160 - 100 watts only.  Anyone have 
any experience with doing this?  Are the section-to-section joints 
adequately conductive?  I would plan to use an omega match, because I'm 
guessing it would be well short of a quarter wave.


My other option is an inverted L.  Should I maybe just go ahead with that?


_
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Topband: Shunt feeding AB-577/621

[N4ZR]

I have an AB-577 with a C-3E on top, and am interested in the 
possibility of shunt-feeding it for 160 - 100 watts only.  Anyone have 
any experience with doing this?  Are the section-to-section joints 
adequately conductive?  I would plan to use an omega match, because I'm 
guessing it would be well short of a quarter wave.


My other option is an inverted L.  Should I maybe just go ahead with that?

--

73, Pete N4ZR
Check out the Reverse Beacon Network
at , now
spotting RTTY activity worldwide.
For spots, please use your favorite
"retail" DX cluster.

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Topband: Shunt feeding

[HAROLD SMITH JR]

If anyone needs some info, drop me an email and I will send you some info. It 
has worked on towers from 55 to 80 ft with or with out a stack of antennas. 
73 de  Price w0riw0ri...@sbcglobal.net
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Re: Topband: Shunt feeding tower

[Pete Smith N4ZR]

Reading about 3-wire cages and the like, I feel a serious case of shunt 
envy.  Mine is a single wire about 18 inches from one corner of my Rohn 
25, connected to the tower at about 50 feet.  I used an omega match with 
a couple of 3 KV transmitting variables, because my tower is quite tall 
for 160 (97 feet with 3 yagis, 2 on top) and I could not find a 50-ohm 
point.It was absurdly easy to adjust and seems to work quite well at 100 
watts.  I'm sure there are better solutions (including Herb's), but this 
was really simple.


73, Pete N4ZR
Check out the Reverse Beacon Network at
http://reversebeacon.net,
blog at reversebeacon.blogspot.com.
For spots, please go to your favorite
ARC V6 or VE7CC DX cluster node.

On 8/26/2014 5:12 PM, Don wrote:

I would like to get on 160 this question most likely has been asked a 1000 time 
but I need information as how or can I shunt feed my 55 ft rohn 45 .

Don
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Re: Topband: Shunt feeding tower

[LB3RE LJ3RE Stein-Roar Brobakken]

How is inteference on rotor or relay boxes?I thinking 1kw generate magnetic 
radiation into cables ???  How u solve this guys ??  Tnx

---Sent by iphoneLB3RE LJ3RE K3RAG ex: LA6FJAwww.lb3re.com ~ Rag ~ Stein Roar 
Brobakken e-mail:post@lb3re.comhttp://la5o.wordpress.comwww.contesting.no

Reading about 3-wire cages and the like, I feel a serious case of shunt  
envy.  Mine is a single wire about 18 inches from one corner of my Rohn  
25, connected to the tower at about 50 feet.  I used an omega match with  
a couple of 3 KV transmitting variables, because my tower is quite tall  
for 160 (97 feet with 3 yagis, 2 on top) and I could not find a 50-ohm  
point.It was absurdly easy to adjust and seems to work quite well at 100  
watts.  I'm sure there are better solutions (including Herb's), but this  
was really simple.



73, Pete N4ZR

Check out the Reverse Beacon Network at

http://reversebeacon.net,

blog at reversebeacon.blogspot.com.

For spots, please go to your favorite

ARC V6 or VE7CC DX cluster node.



On 8/26/2014 5:12 PM, Don wrote:

 I would like to get on 160 this question most likely has been asked a 1000 
 time but I need information as how or can I shunt feed my 55 ft rohn 45 .



 Don

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 Topband Reflector Archives - http://www.contesting.com/_topband





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Re: Topband: Shunt feeding tower

[Herbert Schoenbohm]

I place all rotor wires and other cable through a few 3 Ferrite rings 
at the base of the tower with as many turns as I can squeeze on.  Before 
doing this I had a slight deflection in the rotor indicator at the shack 
when I was on 160. Now I have none. The most sensitive item may be the 
heavy bare wire indicator pot inside the rotor case.  Yet I have never 
lost one to burn out from RF.



Herb, KV4FZ


On 8/27/2014 8:35 AM, LB3RE LJ3RE Stein-Roar Brobakken wrote:

How is inteference on rotor or relay boxes?I thinking 1kw generate magnetic 
radiation into cables ???  How u solve this guys ??  Tnx

---Sent by iphoneLB3RE LJ3RE K3RAG ex: LA6FJAwww.lb3re.com ~ Rag ~ Stein Roar 
Brobakken e-mail:post@lb3re.comhttp://la5o.wordpress.comwww.contesting.no

Reading about 3-wire cages and the like, I feel a serious case of shunt
envy.  Mine is a single wire about 18 inches from one corner of my Rohn
25, connected to the tower at about 50 feet.  I used an omega match with
a couple of 3 KV transmitting variables, because my tower is quite tall
for 160 (97 feet with 3 yagis, 2 on top) and I could not find a 50-ohm
point.It was absurdly easy to adjust and seems to work quite well at 100
watts.  I'm sure there are better solutions (including Herb's), but this
was really simple.



73, Pete N4ZR

Check out the Reverse Beacon Network at

http://reversebeacon.net,

blog at reversebeacon.blogspot.com.

For spots, please go to your favorite

ARC V6 or VE7CC DX cluster node.



On 8/26/2014 5:12 PM, Don wrote:


I would like to get on 160 this question most likely has been asked a 1000 time 
but I need information as how or can I shunt feed my 55 ft rohn 45 .
Don
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Re: Topband: Shunt feeding tower

[Carl]

Which is the same height as the one I had in the 80's at another home. With 
stacked 10-15-20 W2PV-4's it resonated somewhere around 1530 KHz if I 
remember and an Omega was the only thing that worked well.


The gamma rod was 3/4 CATV hardline running thru PVC plumbing T's and pipe 
then tied of to the tower. Spacing was 24 and the sweet spot to connect was 
60' up.


Once I found out how poorly 60 mostly 120-130' on ground radials worked I 
added 4 spokes of 4' x 50' rabbit cage wire mesh from the base and it was an 
all new antenna that really kicked butt. The soil there was glacial sand 
better used for mixing concrete! That tower helped win a 160M contest on the 
second try, going from 600 to 1200W might have helped a bit (-;


Pretty soon others started using mesh as I was talking it up often on 160 
SSB after the DX faded out on CW.


Carl
KM1H



- Original Message - 
From: Pete Smith N4ZR n...@contesting.com

To: topband@contesting.com
Sent: Wednesday, August 27, 2014 6:28 AM
Subject: Re: Topband: Shunt feeding tower


Reading about 3-wire cages and the like, I feel a serious case of shunt 
envy.  Mine is a single wire about 18 inches from one corner of my Rohn 
25, connected to the tower at about 50 feet.  I used an omega match with a 
couple of 3 KV transmitting variables, because my tower is quite tall for 
160 (97 feet with 3 yagis, 2 on top) and I could not find a 50-ohm 
point.It was absurdly easy to adjust and seems to work quite well at 100 
watts.  I'm sure there are better solutions (including Herb's), but this 
was really simple.


73, Pete N4ZR
Check out the Reverse Beacon Network at
http://reversebeacon.net,
blog at reversebeacon.blogspot.com.
For spots, please go to your favorite
ARC V6 or VE7CC DX cluster node.

On 8/26/2014 5:12 PM, Don wrote:
I would like to get on 160 this question most likely has been asked a 
1000 time but I need information as how or can I shunt feed my 55 ft rohn 
45 .


Don
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No virus found in this message.
Checked by AVG - www.avg.com
Version: 2014.0.4716 / Virus Database: 4007/8110 - Release Date: 08/27/14



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Re: Topband: Shunt feeding tower

[Carl]

All I had on my tower were the 3 coax cables and rotator wire which were all 
taped to the tower about every 5' which apparently decoupled them. The coax 
also had about 15 of large 43 mix ferrite beads over them right at the 
feedpoint a few years before I was on 160. That was for TVI prevention.


Carl
KM1H


- Original Message - 
From: LB3RE LJ3RE Stein-Roar Brobakken p...@lb3re.com

To: Pete Smith N4ZR n...@contesting.com
Cc: topband@contesting.com
Sent: Wednesday, August 27, 2014 8:35 AM
Subject: Re: Topband: Shunt feeding tower


How is inteference on rotor or relay boxes?I thinking 1kw generate 
magnetic radiation into cables ???  How u solve this guys ??  Tnx


---Sent by iphoneLB3RE LJ3RE K3RAG ex: LA6FJAwww.lb3re.com ~ Rag ~ Stein 
Roar Brobakken 
e-mail:post@lb3re.comhttp://la5o.wordpress.comwww.contesting.no


Reading about 3-wire cages and the like, I feel a serious case of shunt
envy.  Mine is a single wire about 18 inches from one corner of my Rohn
25, connected to the tower at about 50 feet.  I used an omega match with
a couple of 3 KV transmitting variables, because my tower is quite tall
for 160 (97 feet with 3 yagis, 2 on top) and I could not find a 50-ohm
point.It was absurdly easy to adjust and seems to work quite well at 100
watts.  I'm sure there are better solutions (including Herb's), but this
was really simple.



73, Pete N4ZR

Check out the Reverse Beacon Network at

http://reversebeacon.net,

blog at reversebeacon.blogspot.com.

For spots, please go to your favorite

ARC V6 or VE7CC DX cluster node.



On 8/26/2014 5:12 PM, Don wrote:

I would like to get on 160 this question most likely has been asked a 
1000 time but I need information as how or can I shunt feed my 55 ft rohn 
45 .







Don



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Checked by AVG - www.avg.com
Version: 2014.0.4716 / Virus Database: 4007/8110 - Release Date: 08/27/14



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Re: Topband: Shunt feeding tower

[James Wolf]

Pete, et al.

It really helps if you know the self-resonant frequency of the tower.
ON4UN goes into a fair amount of detail in his Low-Band DXing book.  There
are examples and graphs that may or may not fit your exact configuration,
but you will get an idea of what affects tap point, bandwidth, gamma wire
diameter and spacing.  If I put it this information together, it seems to be
very close to what I already have installed.  
In my case, the tower is 120 ft.  however a 24' triibander at 100' ft likely
dominates the top loading.  There is a 2 el 40 at 115' but since the
elements are insulated and only the boom is at tower potential, it likely
isn't in play much.
My gamma spacing is about 30 inches,  tapped at 70', and the gamma-wire
diameter is just a single #10 wire.   However, according to ON4UN, the wider
spacing of the gamma-wire decreases the height of the tap point somewhat.
My VSWR isn't flat, but about 1.25:1, which is close enough.  I strongly
expect that if I raised the tap point I could lower it.
I am using a single series C for the match.

Jim - KR9U


- Original Message -
From: Pete Smith N4ZR n...@contesting.com
To: topband@contesting.com
Sent: Wednesday, August 27, 2014 6:28 AM
Subject: Re: Topband: Shunt feeding tower


 Reading about 3-wire cages and the like, I feel a serious case of shunt 
 envy.  Mine is a single wire about 18 inches from one corner of my Rohn 
 25, connected to the tower at about 50 feet.  I used an omega match with a

 couple of 3 KV transmitting variables, because my tower is quite tall for 
 160 (97 feet with 3 yagis, 2 on top) and I could not find a 50-ohm 
 point.It was absurdly easy to adjust and seems to work quite well at 100 
 watts.  I'm sure there are better solutions (including Herb's), but this 
 was really simple.

 73, Pete N4ZR
 Check out the Reverse Beacon Network at
 http://reversebeacon.net,
 blog at reversebeacon.blogspot.com.
 For spots, please go to your favorite
 ARC V6 or VE7CC DX cluster node.

 On 8/26/2014 5:12 PM, Don wrote:
 I would like to get on 160 this question most likely has been asked a 
 1000 time but I need information as how or can I shunt feed my 55 ft rohn

 45 .

 Don
 

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Topband Reflector Archives - http://www.contesting.com/_topband

Topband: Shunt feeding tower

[Don]

I would like to get on 160 this question most likely has been asked a 1000 time 
but I need information as how or can I shunt feed my 55 ft rohn 45 .

Don 
_
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Re: Topband: Shunt feeding tower

[Carl]

The first info needed is are the guy wires insulated from the tower and what 
is on top including mast?


Carl
KM1H


- Original Message - 
From: Don w4...@truvista.net

To: topband@contesting.com
Sent: Tuesday, August 26, 2014 5:12 PM
Subject: Topband: Shunt feeding tower


I would like to get on 160 this question most likely has been asked a 1000 
time but I need information as how or can I shunt feed my 55 ft rohn 45 .


Don
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Re: Topband: Shunt feeding tower

[Herbert Schoenbohm]

Don,  Build a three or 4 wire cage around the tower from top to ground 
out 24 inches #10 or 12 bar copper is fine.   A few standoff PVC or 
fiberglass will lessen changes in high wind conditions. Measure the cage 
to ground and build the required matching unit with the appropriate 
series capatiance to tune out the measured inductive reactance and 
adjust the impedence with a large diameter taped coil to ground on the 
coax side of the feed. Normally it doesn't take much to have a good 
working system if care is given to having at least 16 radials either on 
the ground or in the ground a few inches. Also having some top loading 
with a beam on top of the tower makes everything even easier.



Herb Schoenbohm, KV4FZ

On 8/26/2014 5:12 PM, Don wrote:

I would like to get on 160 this question most likely has been asked a 1000 time 
but I need information as how or can I shunt feed my 55 ft rohn 45 .

Don
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Re: Topband: Shunt feeding the Skyneedle - new developments

[JC N4IS]

I'm sure it will play well in terms of keeping your transmitter happy but
the relatively large bandwidth you are measuring is indicative of
substantial loss in the system somewhere.
This would be a large bandwidth even if you did not have the bandwidth
narrowing effects of a shunt feed.


Hi guys, the 3 wires is actually a transmission line and the antenna is well
known as Folded Unipole with 200 ohms impedance. My antenna is a Folded
Unipole as well and has the same broadband SWR measurement's. The loss is
the same for any tuning circuit it has nothing to do with the bandwidth. The
ground plane does, and in this case it is the same, right?

73's
JC
N4IS

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Re: Topband: Shunt feeding the Skyneedle - new developments

[Charlie Cunningham]

Good morning, JC

Well, in its present configuration, Carl's antenna is not really a folded
monopole, although it did start our as one when he had his gamma match
connected at full height of 90'.  At present he has his gamma attached at
67' - about 2/3 of the way up the tower. But that's sort of a nit-pick -
otherwise, I do agree that the gamma match (with its 3-wire cage, is a
shorted transmission line section. Since it's less than 1/4 wavelength it
will have inductive reactance that needs to be canceled with the series
tuning capacitor. 

Carl should have a good topband transmit antenna! As he builds out his
radial field, the efficiency will hopefully improve some more. I hope he had
fun with it last night, but 160 conditions of late have been rather poor -
apparently because of the sun's coronal mass ejection a few days ago.

Have a good day!\

73,
Charlie, K4OTV


-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of JC N4IS
Sent: Sunday, February 23, 2014 7:20 AM
To: 'Richard (Rick) Karlquist'; 'Carl Braun'; 'Carl'; '160'
Cc: w...@att.net; ad...@arrl.net
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments


I'm sure it will play well in terms of keeping your transmitter happy but
the relatively large bandwidth you are measuring is indicative of
substantial loss in the system somewhere.
This would be a large bandwidth even if you did not have the bandwidth
narrowing effects of a shunt feed.


Hi guys, the 3 wires is actually a transmission line and the antenna is well
known as Folded Unipole with 200 ohms impedance. My antenna is a Folded
Unipole as well and has the same broadband SWR measurement's. The loss is
the same for any tuning circuit it has nothing to do with the bandwidth. The
ground plane does, and in this case it is the same, right?

73's
JC
N4IS

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Re: Topband: Shunt feeding the Skyneedle - new developments

[Carl Braun]

Tom

I assume the system has reactance since the MFJ is reading the X and I'm 
seeing the resulting SWR on the analyzer AND at the rig.

The swr at my given freq as tuned with the variable cap is 1.3:1 or 
less...outside the enclosure the system had 1.0:1 swr readings and X=O over 
what appeared to be a broader bandwidth...even with 42 ohms at the feed point. 

I'm having fun in the contest and the antenna seems to be transmitting well and 
the amp hasn't blown up yet.  I have a very short run of RG58 from the panel to 
my switching network so I'm keeping the amplifier below 500W.

I'm definitely ready to get the RX loop up as listening on the needle is rough.

Thanks Tom

Carl AG6X

-Original Message-
From: Tom W8JI [mailto:w...@w8ji.com] 
Sent: Saturday, February 22, 2014 12:17 AM
To: Carl Braun
Cc: 160
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

The j11 ohms is the best I can get period. I was able to get j0 when the cap 
was outside of the steel enclosure with a better bandwidth. Maybe I should 
throw my $400 enclosure and find a fibergla$$ enclosure. But as others have 
indicated I should probably just live with it.

1.) How do you know the system really has some reactance?

2.) What is the SWR, that is more accurate.

3.) The SWR is meaningless anyway for control settings when  it is below 
maybe 1.3, and is typically meaningless for system losses when below 4.0:1 
for short cables on 160 meters. A 40 j10 load (if it is that) is around 
1.3:1, so it falls in the meaningless category


Do you think a smaller (physically) vacuum cap would have less interaction 
with the steel enclosure.  The one I have is only 3 round and 6 long. The 
air variable I'm using is 13 long and 7 round at mesh

RF behavior with chassis and cabinets and wiring can be complicated. Some 
people who work around it all their life never actually get a feel for how 
simple systems work, let alone things that might get colex like high 
impedance lines and physically large components inside close spaced boxes.

The interaction depends on the circuit impedance and the impedance of any 
components and wiring at various points in the system inside the box. You'll 
probably never get a meaningful answer because the problem is small, an 
answer requires knowing the actual impedances of everything, and at a 
minimum a feel for how the box and wiring *you* have interacts with the 
impedances.

The important thing at this point is how the equipment in the shack behaves 
with what you have, because any actual losses are meaningless.

73 Tom 

_
Topband Reflector Archives - http://www.contesting.com/_topband

Re: Topband: Shunt feeding the Skyneedle - new developments

[Carl Braun]

Charlie

Thanks for the tip.  I may play with a bit of inductance just to see how the 
system reacts. 

Not sure if I can post a pic here but I'm including a shot of the panel and the 
cap...hope you all can see it.  The static bleed choke has been removed and I'm 
awaiting PL 259 connectors from my friends at RF parts.


My crazy dog gets pretty loopy when we play with the Frisbee so I'm considering 
a trial cut in the asphalt to see how easy or ugly the process is.  I hear the 
secret is all in the blade that's used. You Tube has some videos showing the 
procedure for cutting asphalt...we'll see.

Thanks again

Carl AG6X

-Original Message-
From: Charlie Cunningham [mailto:charlie-cunning...@nc.rr.com] 
Sent: Friday, February 21, 2014 8:18 PM
To: Carl Braun; 'ZR'; '160'
Subject: RE: Topband: Shunt feeding the Skyneedle - new developments

Hi, Carl

Well, I think that what you are doing with your radials should be OK. I
guess I'd rather get them under the asphalt if  I could where they wouldn't
get torn up or b a trip hazard.

BTW I I was playing with your match on the Smith Chart and if you'll add
about 1 uHy inductance in series with the connector (SO-239?) where  you
feedline leaves the enclosure, that will take you to 45 +j0, but I'd be
concerned about incurring more losses in the inductor than any tiny mismatch
loss from the -j11 term. I probably wouldn't do it.

73,
Charlie, K4OTV


-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl
Braun
Sent: Friday, February 21, 2014 10:56 PM
To: Charlie Cunningham; 'ZR'; '160'
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

I'm working on the radial field weekly.  

Here is a theoretical question that results from my particular QTH.  The
Skyneedle is situated near a secondary blacktop driveway that is in the back
of my property.  I have to run radials over the blacktop to the rest of the
property and, in order to keep things kind of neat, I'm using
multi-conductor rotor cable as radials that travel over the blacktop.  I
have both 6 conductor and 3 conductor control cable that I'm using.  I strip
back the jacket at the radial ring...fan out the wires 3 apart and attach
them to the 1 1/2 copper pipe I'm using as a radial ring around the base of
the 'Needle'.  Then the radial wires converge back into the cable jacket
then travel across the 10' blacktop driveway and then they are removed from
the cable jacket where they fan out into the dirt and are buried.  Most of
these radial wires are 60' to 100' once they leave the jacket.

Any problem with what I'm doing here?  I understand that it would be better
if they fanned out directly from the base but I can have 50+ wires traveling
over the blacktop.

I was even considering getting an asphalt blade and cutting some channels
into the blacktop...burying the jacketed cable into the asphalt and then
sealing then in so I'm not running over them or tripping over them when
playing Frisbee with the hound.

My Guatemalan yard worker has been burying radial wires for the last month
and thinks that I'm LOCO but he likes getting paid at the end of the day.

As we speak I have a total of 34 radials with the shortest being 30' with
the longest at 100'.  Most of them are 60-70'.  Four of them are tied into
my 40m phased array radial field comprised of 90-100 radials under each
antenna ranging from 40' to 80'.  I can change the height of these verticals
from 33' for 40m to 66' for 80m.  1/2 wl spacing on 40 and 1/4 wl spacing on
80.

Carl AG6X

-Original Message-
From: Charlie Cunningham [mailto:charlie-cunning...@nc.rr.com]
Sent: Friday, February 21, 2014 7:36 PM
To: 'ZR'; Carl Braun; '160'
Subject: RE: Topband: Shunt feeding the Skyneedle - new developments

Well, if I recall correctly, Carl, Carl said his  feedline was about 70' of
LMR-400, so even at 2 2:1 or 2.5:1 VSWR, the excess losses in 70' of LMR-400
at 1.8 MHz are almost 0, so if he can match it OK at the transmitter end of
the line- no real point in making heroic efforts to achieve a perfect
match!  He'd gain more by working on his radial field, and he really should
do that before doing any more tuning because improving the radials WILL
affect the antenna impedance.

73,
Charlie, K4OTV

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of ZR
Sent: Friday, February 21, 2014 10:11 PM
To: Charlie Cunningham; 'Carl Braun'; '160'
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

The only benefit of getting it better would be a bit more 2:1 VSWR bandwidth
to keep the amp happy but even then there is sometimes a gotcha when tuning
an antenna.

Carl
KM1H



Subject: Re: Topband: Shunt feeding the Skyneedle - new developments


Well, you can do all that, Carl

But if your series variable capacitor is not maxed out (fully meshed) if you
can increase the capacitance enough  to get to j0, you would be at 45
+j0 and on a 1.1:1  VSWR circle

Re: Topband: Shunt feeding the Skyneedle - new developments

[Charlie Cunningham]

Hi, Carl

Well, paying with your load on a Smith Chart, tuning out the -j11 only
improved the VSWR from 1.3:1 to 1.1 - not really worth doing! Also, you
would need a fairly large inductor to obtain 1 uHy of inductance with low
loss, and I expect that you would incur more loss in the inductor (that
would subtract directly from your transmitted power) than you would gain in
improved mismatch loss by improving the VSWR from 1.3 t 1.1!! Keep in mind
also that the inductor would also have stray capacitance to the enclosure
walls that will lower its Q !  I wouldn't do it! 1.3:1 is great!!  Enjoy!!

You will help your overall performance much more by building a terminated
receiving loop - a KAZ, flag or pennant configuration to help your HEARING!!
MY KAZ loop did wonders for me!!

GL and have fun!

73,
Charlie, K4OTV


-Original Message-
From: Carl Braun [mailto:carl.br...@lairdtech.com] 
Sent: Saturday, February 22, 2014 7:23 AM
To: Charlie Cunningham; 'ZR'; '160'
Subject: RE: Topband: Shunt feeding the Skyneedle - new developments

Charlie

Thanks for the tip.  I may play with a bit of inductance just to see how the
system reacts. 

Not sure if I can post a pic here but I'm including a shot of the panel and
the cap...hope you all can see it.  The static bleed choke has been removed
and I'm awaiting PL 259 connectors from my friends at RF parts.


My crazy dog gets pretty loopy when we play with the Frisbee so I'm
considering a trial cut in the asphalt to see how easy or ugly the process
is.  I hear the secret is all in the blade that's used. You Tube has some
videos showing the procedure for cutting asphalt...we'll see.

Thanks again

Carl AG6X

-Original Message-
From: Charlie Cunningham [mailto:charlie-cunning...@nc.rr.com]
Sent: Friday, February 21, 2014 8:18 PM
To: Carl Braun; 'ZR'; '160'
Subject: RE: Topband: Shunt feeding the Skyneedle - new developments

Hi, Carl

Well, I think that what you are doing with your radials should be OK. I
guess I'd rather get them under the asphalt if  I could where they wouldn't
get torn up or b a trip hazard.

BTW I I was playing with your match on the Smith Chart and if you'll add
about 1 uHy inductance in series with the connector (SO-239?) where  you
feedline leaves the enclosure, that will take you to 45 +j0, but I'd be
concerned about incurring more losses in the inductor than any tiny mismatch
loss from the -j11 term. I probably wouldn't do it.

73,
Charlie, K4OTV


-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl
Braun
Sent: Friday, February 21, 2014 10:56 PM
To: Charlie Cunningham; 'ZR'; '160'
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

I'm working on the radial field weekly.  

Here is a theoretical question that results from my particular QTH.  The
Skyneedle is situated near a secondary blacktop driveway that is in the back
of my property.  I have to run radials over the blacktop to the rest of the
property and, in order to keep things kind of neat, I'm using
multi-conductor rotor cable as radials that travel over the blacktop.  I
have both 6 conductor and 3 conductor control cable that I'm using.  I strip
back the jacket at the radial ring...fan out the wires 3 apart and attach
them to the 1 1/2 copper pipe I'm using as a radial ring around the base of
the 'Needle'.  Then the radial wires converge back into the cable jacket
then travel across the 10' blacktop driveway and then they are removed from
the cable jacket where they fan out into the dirt and are buried.  Most of
these radial wires are 60' to 100' once they leave the jacket.

Any problem with what I'm doing here?  I understand that it would be better
if they fanned out directly from the base but I can have 50+ wires traveling
over the blacktop.

I was even considering getting an asphalt blade and cutting some channels
into the blacktop...burying the jacketed cable into the asphalt and then
sealing then in so I'm not running over them or tripping over them when
playing Frisbee with the hound.

My Guatemalan yard worker has been burying radial wires for the last month
and thinks that I'm LOCO but he likes getting paid at the end of the day.

As we speak I have a total of 34 radials with the shortest being 30' with
the longest at 100'.  Most of them are 60-70'.  Four of them are tied into
my 40m phased array radial field comprised of 90-100 radials under each
antenna ranging from 40' to 80'.  I can change the height of these verticals
from 33' for 40m to 66' for 80m.  1/2 wl spacing on 40 and 1/4 wl spacing on
80.

Carl AG6X

-Original Message-
From: Charlie Cunningham [mailto:charlie-cunning...@nc.rr.com]
Sent: Friday, February 21, 2014 7:36 PM
To: 'ZR'; Carl Braun; '160'
Subject: RE: Topband: Shunt feeding the Skyneedle - new developments

Well, if I recall correctly, Carl, Carl said his  feedline was about 70' of
LMR-400, so even at 2 2:1 or 2.5:1 VSWR, the excess losses in 70' of LMR-400
at 1.8 MHz

Re: Topband: Shunt feeding the Skyneedle - new developments

[Tom W8JI]

Thanks for the tip.  I may play with a bit of inductance just to see how the 
system reacts. 


This is way more problematic than it needs to be.

First, no one even knows if the reactance is real or a false reading caused 
by a bit error from calibration or noise.


Second, no one knows the sign of the reactance if it is there. It might be 
already be inductive.


Third, if the capacitor is not maxed out or at minimum and still has range 
left, which yours does, the capacitor will adjust out any reactance without 
adding anything else.


There are certain bridge voltages that with even one or two bits error, 
which is 2/256 bits or less than 1% error in voltages, where 10 ohms might 
be calculated. The algoryth tries to take that error out by watching SWR 
near bridge balance instead of bridge arm voltages, but I have no idea how 
the unit is calibrated or if the antenna system has noise causing a bit 
error.


All of this is pretty much meaningless. Even if it is a 1.3 :1 SWR, it is 
not going to be a problem. Also, if the real part is near 40 ohms and you 
have a high Q antenna system and losses, you might find lowest SWR is not 
X=0 because of interactions between resistance and reactance as things are 
tuned.


I would not even guess at a cure for something with a bunch of unknowns that 
might not even be a problem. I think this is a bigger worry and more complex 
than it should be.


73 Tom 


_
Topband Reflector Archives - http://www.contesting.com/_topband

Re: Topband: Shunt feeding the Skyneedle - new developments

[Carl]

Im not concerned by what is measured at the matching unit or a miniscule 
cable loss; just what is transformed back to the amp and its ability to load 
at full power without arcing, running out of or having too much fixed padder 
C during QSY's. Contests do not stay just in the narrow CW 50 KHz  window 
and not having to use an external tuner is a big plus.


Ive always modified my amps to work with my antennas on 160 and 80/75.

Carl
KM1H


- Original Message - 
From: Charlie Cunningham charlie-cunning...@nc.rr.com
To: 'ZR' z...@jeremy.mv.com; 'Carl Braun' carl.br...@lairdtech.com; 
'160' topband@contesting.com

Sent: Friday, February 21, 2014 10:35 PM
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments


Well, if I recall correctly, Carl, Carl said his  feedline was about 70' of
LMR-400, so even at 2 2:1 or 2.5:1 VSWR, the excess losses in 70' of LMR-400
at 1.8 MHz are almost 0, so if he can match it OK at the transmitter end of
the line- no real point in making heroic efforts to achieve a perfect
match!  He'd gain more by working on his radial field, and he really should
do that before doing any more tuning because improving the radials WILL
affect the antenna impedance.

73,
Charlie, K4OTV

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of ZR
Sent: Friday, February 21, 2014 10:11 PM
To: Charlie Cunningham; 'Carl Braun'; '160'
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

The only benefit of getting it better would be a bit more 2:1 VSWR bandwidth
to keep the amp happy but even then there is sometimes a gotcha when tuning
an antenna.

Carl
KM1H



Subject: Re: Topband: Shunt feeding the Skyneedle - new developments


Well, you can do all that, Carl

But if your series variable capacitor is not maxed out (fully meshed) if you
can increase the capacitance enough  to get to j0, you would be at 45
+j0 and on a 1.1:1  VSWR circle. No point int trying to do better than
that!!
Otherwise, just increase the series capacitance to bring that -j11  as
close to j0 as possible and take that! You'd be so near perfect that there
would be no real point in going further!

Your time and efforts might be better spent working on  your radial field!

73,
Charlie, K4OTV


-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl
Braun
Sent: Friday, February 21, 2014 8:46 PM
To: Charlie Cunningham; 'Tom W8JI'; '160'
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

Thanks to all who replied

Tom W8JI, your comments on the metallic panel and the static bleed choke
make sense.  I was so pleased with the FLAT SWR reading with the variable
cap outside the panel but I guess I can live with the slight SWR.  (Thanks
Charlie K4OTV).  I have a Nye Viking monster tuner but I hate to use it as
my Henry amp seems to load strangely when I have it inline so I think I'll
just live without it.

Can I add some coax (coiled) to bring the X down on the -j11 reading? I did
this with the old Telrex and brought the X right down and out of the pic.
I'm sure Ill need much more than I would on 14MHz but I think I'd like to
try anyway.

I'm still going to drop the tower down and add two more gamma wires to
create a cage and I still have the option of pulling the gamma wire(s) away
from the tower another 8-10 inches to add a few more ohms to the equation.

I'm having fun with the experiment.

Right now I'm hearing the beginnings of the SSB contest with N7GP, WD5COV,
W6YI with the big signals so far.  XE is the only DX I've heard.

Lots of stateside calling stateside

Carl AG6X

-Original Message-
From: Charlie Cunningham [mailto:charlie-cunning...@nc.rr.com]
Sent: Friday, February 21, 2014 5:21 PM
To: 'Tom W8JI'; Carl Braun; '160'
Subject: RE: Topband: Shunt feeding the Skyneedle - new developments

Well, Carl

I plotted your 45-j11 load on a Smith Chart (normalized to 50 ohms) and it's
very near the origin on a 1.3:1 VSWR circle. Since you have a relatively
short feedline of LMR-400, You should be able to just tune it out at the
transmitter end of the line, and the LMR-400 line will be operating at such
a very low SWR (around 1.3:1 that the excess loss from a 1.3:1 VSWR at 160
is completely trivial and negligible! It may not be completely
intellectually satisfying to have -j11 of reactance at the load, but it
should match easily and the antenna should work very well!  Enjoy!

Sounds like that Array solutions static bleed is not as high in impedance as
we might wish! A large resistance might give you more satisfactory results!

GL!  Enjoy!

73,
Charlie, K4OTV





-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Tom W8JI
Sent: Friday, February 21, 2014 8:02 PM
To: Carl Braun; '160'
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

Since then I've moved the variable capacitor inside the panel and mounted it

to a ¾ think Plexiglas

Re: Topband: Shunt feeding the Skyneedle - new developments

[Charlie Cunningham]

I completely agree with Tom. Carl!  I'd leave it alone(for the reasons that
I stated previously)!  I expect that you would lose more than you would gain
by adding an inductor!!  If it ain't broke don't fix it!!

You might want to put some  effort into a good terminated receiving loop!

73,
Charlie, K4OTV

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Tom W8JI
Sent: Saturday, February 22, 2014 9:09 AM
To: Carl Braun; '160'
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

Thanks for the tip.  I may play with a bit of inductance just to see how the
system reacts. 

This is way more problematic than it needs to be.

First, no one even knows if the reactance is real or a false reading caused
by a bit error from calibration or noise.

Second, no one knows the sign of the reactance if it is there. It might be
already be inductive.

Third, if the capacitor is not maxed out or at minimum and still has range
left, which yours does, the capacitor will adjust out any reactance without
adding anything else.

There are certain bridge voltages that with even one or two bits error,
which is 2/256 bits or less than 1% error in voltages, where 10 ohms might
be calculated. The algoryth tries to take that error out by watching SWR
near bridge balance instead of bridge arm voltages, but I have no idea how
the unit is calibrated or if the antenna system has noise causing a bit
error.

All of this is pretty much meaningless. Even if it is a 1.3 :1 SWR, it is
not going to be a problem. Also, if the real part is near 40 ohms and you
have a high Q antenna system and losses, you might find lowest SWR is not
X=0 because of interactions between resistance and reactance as things are
tuned.

I would not even guess at a cure for something with a bunch of unknowns that
might not even be a problem. I think this is a bigger worry and more complex
than it should be.

73 Tom 

_
Topband Reflector Archives - http://www.contesting.com/_topband

_
Topband Reflector Archives - http://www.contesting.com/_topband

Re: Topband: Shunt feeding the Skyneedle - new developments

[Charlie Cunningham]

I don't expect that ANY of those are valid concerns at 1.3:1 VSWR!!

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl
Sent: Saturday, February 22, 2014 9:14 AM
To: Charlie Cunningham; 'Carl Braun'; '160'
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

Im not concerned by what is measured at the matching unit or a miniscule 
cable loss; just what is transformed back to the amp and its ability to load

at full power without arcing, running out of or having too much fixed padder

C during QSY's. Contests do not stay just in the narrow CW 50 KHz  window 
and not having to use an external tuner is a big plus.

Ive always modified my amps to work with my antennas on 160 and 80/75.

Carl
KM1H


- Original Message - 
From: Charlie Cunningham charlie-cunning...@nc.rr.com
To: 'ZR' z...@jeremy.mv.com; 'Carl Braun' carl.br...@lairdtech.com; 
'160' topband@contesting.com
Sent: Friday, February 21, 2014 10:35 PM
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments


Well, if I recall correctly, Carl, Carl said his  feedline was about 70' of
LMR-400, so even at 2 2:1 or 2.5:1 VSWR, the excess losses in 70' of LMR-400
at 1.8 MHz are almost 0, so if he can match it OK at the transmitter end of
the line- no real point in making heroic efforts to achieve a perfect
match!  He'd gain more by working on his radial field, and he really should
do that before doing any more tuning because improving the radials WILL
affect the antenna impedance.

73,
Charlie, K4OTV

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of ZR
Sent: Friday, February 21, 2014 10:11 PM
To: Charlie Cunningham; 'Carl Braun'; '160'
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

The only benefit of getting it better would be a bit more 2:1 VSWR bandwidth
to keep the amp happy but even then there is sometimes a gotcha when tuning
an antenna.

Carl
KM1H



Subject: Re: Topband: Shunt feeding the Skyneedle - new developments


Well, you can do all that, Carl

But if your series variable capacitor is not maxed out (fully meshed) if you
can increase the capacitance enough  to get to j0, you would be at 45
+j0 and on a 1.1:1  VSWR circle. No point int trying to do better than
that!!
 Otherwise, just increase the series capacitance to bring that -j11  as
close to j0 as possible and take that! You'd be so near perfect that there
would be no real point in going further!

Your time and efforts might be better spent working on  your radial field!

73,
Charlie, K4OTV


-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl
Braun
Sent: Friday, February 21, 2014 8:46 PM
To: Charlie Cunningham; 'Tom W8JI'; '160'
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

Thanks to all who replied

Tom W8JI, your comments on the metallic panel and the static bleed choke
make sense.  I was so pleased with the FLAT SWR reading with the variable
cap outside the panel but I guess I can live with the slight SWR.  (Thanks
Charlie K4OTV).  I have a Nye Viking monster tuner but I hate to use it as
my Henry amp seems to load strangely when I have it inline so I think I'll
just live without it.

Can I add some coax (coiled) to bring the X down on the -j11 reading? I did
this with the old Telrex and brought the X right down and out of the pic.
I'm sure Ill need much more than I would on 14MHz but I think I'd like to
try anyway.

I'm still going to drop the tower down and add two more gamma wires to
create a cage and I still have the option of pulling the gamma wire(s) away
from the tower another 8-10 inches to add a few more ohms to the equation.

I'm having fun with the experiment.

Right now I'm hearing the beginnings of the SSB contest with N7GP, WD5COV,
W6YI with the big signals so far.  XE is the only DX I've heard.

Lots of stateside calling stateside

Carl AG6X

-Original Message-
From: Charlie Cunningham [mailto:charlie-cunning...@nc.rr.com]
Sent: Friday, February 21, 2014 5:21 PM
To: 'Tom W8JI'; Carl Braun; '160'
Subject: RE: Topband: Shunt feeding the Skyneedle - new developments

Well, Carl

I plotted your 45-j11 load on a Smith Chart (normalized to 50 ohms) and it's
very near the origin on a 1.3:1 VSWR circle. Since you have a relatively
short feedline of LMR-400, You should be able to just tune it out at the
transmitter end of the line, and the LMR-400 line will be operating at such
a very low SWR (around 1.3:1 that the excess loss from a 1.3:1 VSWR at 160
is completely trivial and negligible! It may not be completely
intellectually satisfying to have -j11 of reactance at the load, but it
should match easily and the antenna should work very well!  Enjoy!

Sounds like that Array solutions static bleed is not as high in impedance as
we might wish! A large resistance might give you more satisfactory results!

GL!  Enjoy!

73,
Charlie, K4OTV

Re: Topband: Shunt feeding the Skyneedle - new developments

[Carl]

That 1.3 is only at ONE frequency Charlie, he is not crystal controlled. 
What is the 2:1 bandwidth at the amp?


Carl
KM1H


- Original Message - 
From: Charlie Cunningham charlie-cunning...@nc.rr.com
To: 'Carl' k...@jeremy.mv.com; 'Carl Braun' 
carl.br...@lairdtech.com; '160' topband@contesting.com

Sent: Saturday, February 22, 2014 9:23 AM
Subject: RE: Topband: Shunt feeding the Skyneedle - new developments


I don't expect that ANY of those are valid concerns at 1.3:1 VSWR!!

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl
Sent: Saturday, February 22, 2014 9:14 AM
To: Charlie Cunningham; 'Carl Braun'; '160'
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

Im not concerned by what is measured at the matching unit or a miniscule
cable loss; just what is transformed back to the amp and its ability to load

at full power without arcing, running out of or having too much fixed padder

C during QSY's. Contests do not stay just in the narrow CW 50 KHz  window
and not having to use an external tuner is a big plus.

Ive always modified my amps to work with my antennas on 160 and 80/75.

Carl
KM1H


- Original Message - 
From: Charlie Cunningham charlie-cunning...@nc.rr.com

To: 'ZR' z...@jeremy.mv.com; 'Carl Braun' carl.br...@lairdtech.com;
'160' topband@contesting.com
Sent: Friday, February 21, 2014 10:35 PM
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments


Well, if I recall correctly, Carl, Carl said his  feedline was about 70' of
LMR-400, so even at 2 2:1 or 2.5:1 VSWR, the excess losses in 70' of LMR-400
at 1.8 MHz are almost 0, so if he can match it OK at the transmitter end of
the line- no real point in making heroic efforts to achieve a perfect
match!  He'd gain more by working on his radial field, and he really should
do that before doing any more tuning because improving the radials WILL
affect the antenna impedance.

73,
Charlie, K4OTV

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of ZR
Sent: Friday, February 21, 2014 10:11 PM
To: Charlie Cunningham; 'Carl Braun'; '160'
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

The only benefit of getting it better would be a bit more 2:1 VSWR bandwidth
to keep the amp happy but even then there is sometimes a gotcha when tuning
an antenna.

Carl
KM1H



Subject: Re: Topband: Shunt feeding the Skyneedle - new developments


Well, you can do all that, Carl

But if your series variable capacitor is not maxed out (fully meshed) if you
can increase the capacitance enough  to get to j0, you would be at 45
+j0 and on a 1.1:1  VSWR circle. No point int trying to do better than
that!!
Otherwise, just increase the series capacitance to bring that -j11  as
close to j0 as possible and take that! You'd be so near perfect that there
would be no real point in going further!

Your time and efforts might be better spent working on  your radial field!

73,
Charlie, K4OTV


-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl
Braun
Sent: Friday, February 21, 2014 8:46 PM
To: Charlie Cunningham; 'Tom W8JI'; '160'
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

Thanks to all who replied

Tom W8JI, your comments on the metallic panel and the static bleed choke
make sense.  I was so pleased with the FLAT SWR reading with the variable
cap outside the panel but I guess I can live with the slight SWR.  (Thanks
Charlie K4OTV).  I have a Nye Viking monster tuner but I hate to use it as
my Henry amp seems to load strangely when I have it inline so I think I'll
just live without it.

Can I add some coax (coiled) to bring the X down on the -j11 reading? I did
this with the old Telrex and brought the X right down and out of the pic.
I'm sure Ill need much more than I would on 14MHz but I think I'd like to
try anyway.

I'm still going to drop the tower down and add two more gamma wires to
create a cage and I still have the option of pulling the gamma wire(s) away
from the tower another 8-10 inches to add a few more ohms to the equation.

I'm having fun with the experiment.

Right now I'm hearing the beginnings of the SSB contest with N7GP, WD5COV,
W6YI with the big signals so far.  XE is the only DX I've heard.

Lots of stateside calling stateside

Carl AG6X

-Original Message-
From: Charlie Cunningham [mailto:charlie-cunning...@nc.rr.com]
Sent: Friday, February 21, 2014 5:21 PM
To: 'Tom W8JI'; Carl Braun; '160'
Subject: RE: Topband: Shunt feeding the Skyneedle - new developments

Well, Carl

I plotted your 45-j11 load on a Smith Chart (normalized to 50 ohms) and it's
very near the origin on a 1.3:1 VSWR circle. Since you have a relatively
short feedline of LMR-400, You should be able to just tune it out at the
transmitter end of the line, and the LMR-400 line will be operating at such
a very low SWR (around 1.3:1 that the excess loss from a 1.3

Re: Topband: Shunt feeding the Skyneedle - new developments

[Charlie Cunningham]

Well, Carl the looses in 70' or even 200' of LMR-400 are so low at 1.8 MHz,
even at 2.0:1 or 3.0 :1, if he can match it at the transmitter  end of the
line, it really doesn't matter!

Charlie, K4OTV

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl
Sent: Saturday, February 22, 2014 9:46 AM
To: Charlie Cunningham; 'Carl Braun'; '160'
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

That 1.3 is only at ONE frequency Charlie, he is not crystal controlled. 
What is the 2:1 bandwidth at the amp?

Carl
KM1H


- Original Message - 
From: Charlie Cunningham charlie-cunning...@nc.rr.com
To: 'Carl' k...@jeremy.mv.com; 'Carl Braun' 
carl.br...@lairdtech.com; '160' topband@contesting.com
Sent: Saturday, February 22, 2014 9:23 AM
Subject: RE: Topband: Shunt feeding the Skyneedle - new developments


I don't expect that ANY of those are valid concerns at 1.3:1 VSWR!!

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl
Sent: Saturday, February 22, 2014 9:14 AM
To: Charlie Cunningham; 'Carl Braun'; '160'
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

Im not concerned by what is measured at the matching unit or a miniscule
cable loss; just what is transformed back to the amp and its ability to load

at full power without arcing, running out of or having too much fixed padder

C during QSY's. Contests do not stay just in the narrow CW 50 KHz  window
and not having to use an external tuner is a big plus.

Ive always modified my amps to work with my antennas on 160 and 80/75.

Carl
KM1H


- Original Message - 
From: Charlie Cunningham charlie-cunning...@nc.rr.com
To: 'ZR' z...@jeremy.mv.com; 'Carl Braun' carl.br...@lairdtech.com;
'160' topband@contesting.com
Sent: Friday, February 21, 2014 10:35 PM
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments


Well, if I recall correctly, Carl, Carl said his  feedline was about 70' of
LMR-400, so even at 2 2:1 or 2.5:1 VSWR, the excess losses in 70' of LMR-400
at 1.8 MHz are almost 0, so if he can match it OK at the transmitter end of
the line- no real point in making heroic efforts to achieve a perfect
match!  He'd gain more by working on his radial field, and he really should
do that before doing any more tuning because improving the radials WILL
affect the antenna impedance.

73,
Charlie, K4OTV

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of ZR
Sent: Friday, February 21, 2014 10:11 PM
To: Charlie Cunningham; 'Carl Braun'; '160'
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

The only benefit of getting it better would be a bit more 2:1 VSWR bandwidth
to keep the amp happy but even then there is sometimes a gotcha when tuning
an antenna.

Carl
KM1H



Subject: Re: Topband: Shunt feeding the Skyneedle - new developments


Well, you can do all that, Carl

But if your series variable capacitor is not maxed out (fully meshed) if you
can increase the capacitance enough  to get to j0, you would be at 45
+j0 and on a 1.1:1  VSWR circle. No point int trying to do better than
that!!
 Otherwise, just increase the series capacitance to bring that -j11  as
close to j0 as possible and take that! You'd be so near perfect that there
would be no real point in going further!

Your time and efforts might be better spent working on  your radial field!

73,
Charlie, K4OTV


-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl
Braun
Sent: Friday, February 21, 2014 8:46 PM
To: Charlie Cunningham; 'Tom W8JI'; '160'
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

Thanks to all who replied

Tom W8JI, your comments on the metallic panel and the static bleed choke
make sense.  I was so pleased with the FLAT SWR reading with the variable
cap outside the panel but I guess I can live with the slight SWR.  (Thanks
Charlie K4OTV).  I have a Nye Viking monster tuner but I hate to use it as
my Henry amp seems to load strangely when I have it inline so I think I'll
just live without it.

Can I add some coax (coiled) to bring the X down on the -j11 reading? I did
this with the old Telrex and brought the X right down and out of the pic.
I'm sure Ill need much more than I would on 14MHz but I think I'd like to
try anyway.

I'm still going to drop the tower down and add two more gamma wires to
create a cage and I still have the option of pulling the gamma wire(s) away
from the tower another 8-10 inches to add a few more ohms to the equation.

I'm having fun with the experiment.

Right now I'm hearing the beginnings of the SSB contest with N7GP, WD5COV,
W6YI with the big signals so far.  XE is the only DX I've heard.

Lots of stateside calling stateside

Carl AG6X

-Original Message-
From: Charlie Cunningham [mailto:charlie-cunning...@nc.rr.com]
Sent: Friday, February 21, 2014 5:21 PM
To: 'Tom W8JI'; Carl

Re: Topband: Shunt feeding the Skyneedle - new developments

[Carl]

Charlie youre continually missing the point; ignore cable loss period.

The only issue is what impedance does the amp see from lets say 1800 to 1900 
KHz? AND can the amp load into it without a problem at full power? This is a 
system issue, not just what is measured at the antenna and needs to be 
addressed that way.


Put all that info into your program and post the results. Saying that a 1.3 
VSWR at reasonance at the antenna is sufficient is too simplistic. Compute 
the VSWR at the amp with whatever length of coax is actually used over the 
lower 100 KHz with a range of  at resonance VSWR's.


Carl
KM1H


- Original Message - 
From: Charlie Cunningham charlie-cunning...@nc.rr.com
To: 'Carl' k...@jeremy.mv.com; 'Carl Braun' 
carl.br...@lairdtech.com; '160' topband@contesting.com

Sent: Saturday, February 22, 2014 9:57 AM
Subject: RE: Topband: Shunt feeding the Skyneedle - new developments


Well, Carl the looses in 70' or even 200' of LMR-400 are so low at 1.8 MHz,
even at 2.0:1 or 3.0 :1, if he can match it at the transmitter  end of the
line, it really doesn't matter!

Charlie, K4OTV

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl
Sent: Saturday, February 22, 2014 9:46 AM
To: Charlie Cunningham; 'Carl Braun'; '160'
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

That 1.3 is only at ONE frequency Charlie, he is not crystal controlled.
What is the 2:1 bandwidth at the amp?

Carl
KM1H


- Original Message - 
From: Charlie Cunningham charlie-cunning...@nc.rr.com

To: 'Carl' k...@jeremy.mv.com; 'Carl Braun'
carl.br...@lairdtech.com; '160' topband@contesting.com
Sent: Saturday, February 22, 2014 9:23 AM
Subject: RE: Topband: Shunt feeding the Skyneedle - new developments


I don't expect that ANY of those are valid concerns at 1.3:1 VSWR!!

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl
Sent: Saturday, February 22, 2014 9:14 AM
To: Charlie Cunningham; 'Carl Braun'; '160'
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

Im not concerned by what is measured at the matching unit or a miniscule
cable loss; just what is transformed back to the amp and its ability to load

at full power without arcing, running out of or having too much fixed padder

C during QSY's. Contests do not stay just in the narrow CW 50 KHz  window
and not having to use an external tuner is a big plus.

Ive always modified my amps to work with my antennas on 160 and 80/75.

Carl
KM1H


- Original Message - 
From: Charlie Cunningham charlie-cunning...@nc.rr.com

To: 'ZR' z...@jeremy.mv.com; 'Carl Braun' carl.br...@lairdtech.com;
'160' topband@contesting.com
Sent: Friday, February 21, 2014 10:35 PM
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments


Well, if I recall correctly, Carl, Carl said his  feedline was about 70' of
LMR-400, so even at 2 2:1 or 2.5:1 VSWR, the excess losses in 70' of LMR-400
at 1.8 MHz are almost 0, so if he can match it OK at the transmitter end of
the line- no real point in making heroic efforts to achieve a perfect
match!  He'd gain more by working on his radial field, and he really should
do that before doing any more tuning because improving the radials WILL
affect the antenna impedance.

73,
Charlie, K4OTV

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of ZR
Sent: Friday, February 21, 2014 10:11 PM
To: Charlie Cunningham; 'Carl Braun'; '160'
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

The only benefit of getting it better would be a bit more 2:1 VSWR bandwidth
to keep the amp happy but even then there is sometimes a gotcha when tuning
an antenna.

Carl
KM1H



Subject: Re: Topband: Shunt feeding the Skyneedle - new developments


Well, you can do all that, Carl

But if your series variable capacitor is not maxed out (fully meshed) if you
can increase the capacitance enough  to get to j0, you would be at 45
+j0 and on a 1.1:1  VSWR circle. No point int trying to do better than
that!!
Otherwise, just increase the series capacitance to bring that -j11  as
close to j0 as possible and take that! You'd be so near perfect that there
would be no real point in going further!

Your time and efforts might be better spent working on  your radial field!

73,
Charlie, K4OTV


-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl
Braun
Sent: Friday, February 21, 2014 8:46 PM
To: Charlie Cunningham; 'Tom W8JI'; '160'
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

Thanks to all who replied

Tom W8JI, your comments on the metallic panel and the static bleed choke
make sense.  I was so pleased with the FLAT SWR reading with the variable
cap outside the panel but I guess I can live with the slight SWR.  (Thanks
Charlie K4OTV).  I have a Nye Viking monster tuner but I hate to use it as
my Henry amp seems

Re: Topband: Shunt feeding the Skyneedle - new developments

[Charlie Cunningham]

Well, I agree with all that, Carl. But Carl Braun, was reading dead-flat
1:1 at the transmitter end of his cable. I believe he is done!! The antenna
Q is what it is! As for improving his 2:1 VSWR bandwidth he could reduce
his radial field and increase his ground losses to improve his 2:1 BW -
but I believe that to be self-defeating!! I'm not missing your point - I
just don't see what you'd change to improve on a flat line! Carl is well
past the point of diminishing returns!

The math doesn't lie!

Charlie, K4OTV


-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl
Sent: Saturday, February 22, 2014 10:41 AM
To: Charlie Cunningham; 'Carl Braun'; '160'
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

Charlie youre continually missing the point; ignore cable loss period.

The only issue is what impedance does the amp see from lets say 1800 to 1900

KHz? AND can the amp load into it without a problem at full power? This is a

system issue, not just what is measured at the antenna and needs to be 
addressed that way.

Put all that info into your program and post the results. Saying that a 1.3 
VSWR at reasonance at the antenna is sufficient is too simplistic. Compute 
the VSWR at the amp with whatever length of coax is actually used over the 
lower 100 KHz with a range of  at resonance VSWR's.

Carl
KM1H


- Original Message - 
From: Charlie Cunningham charlie-cunning...@nc.rr.com
To: 'Carl' k...@jeremy.mv.com; 'Carl Braun' 
carl.br...@lairdtech.com; '160' topband@contesting.com
Sent: Saturday, February 22, 2014 9:57 AM
Subject: RE: Topband: Shunt feeding the Skyneedle - new developments


Well, Carl the looses in 70' or even 200' of LMR-400 are so low at 1.8 MHz,
even at 2.0:1 or 3.0 :1, if he can match it at the transmitter  end of the
line, it really doesn't matter!

Charlie, K4OTV

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl
Sent: Saturday, February 22, 2014 9:46 AM
To: Charlie Cunningham; 'Carl Braun'; '160'
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

That 1.3 is only at ONE frequency Charlie, he is not crystal controlled.
What is the 2:1 bandwidth at the amp?

Carl
KM1H


- Original Message - 
From: Charlie Cunningham charlie-cunning...@nc.rr.com
To: 'Carl' k...@jeremy.mv.com; 'Carl Braun'
carl.br...@lairdtech.com; '160' topband@contesting.com
Sent: Saturday, February 22, 2014 9:23 AM
Subject: RE: Topband: Shunt feeding the Skyneedle - new developments


I don't expect that ANY of those are valid concerns at 1.3:1 VSWR!!

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl
Sent: Saturday, February 22, 2014 9:14 AM
To: Charlie Cunningham; 'Carl Braun'; '160'
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

Im not concerned by what is measured at the matching unit or a miniscule
cable loss; just what is transformed back to the amp and its ability to load

at full power without arcing, running out of or having too much fixed padder

C during QSY's. Contests do not stay just in the narrow CW 50 KHz  window
and not having to use an external tuner is a big plus.

Ive always modified my amps to work with my antennas on 160 and 80/75.

Carl
KM1H


- Original Message - 
From: Charlie Cunningham charlie-cunning...@nc.rr.com
To: 'ZR' z...@jeremy.mv.com; 'Carl Braun' carl.br...@lairdtech.com;
'160' topband@contesting.com
Sent: Friday, February 21, 2014 10:35 PM
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments


Well, if I recall correctly, Carl, Carl said his  feedline was about 70' of
LMR-400, so even at 2 2:1 or 2.5:1 VSWR, the excess losses in 70' of LMR-400
at 1.8 MHz are almost 0, so if he can match it OK at the transmitter end of
the line- no real point in making heroic efforts to achieve a perfect
match!  He'd gain more by working on his radial field, and he really should
do that before doing any more tuning because improving the radials WILL
affect the antenna impedance.

73,
Charlie, K4OTV

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of ZR
Sent: Friday, February 21, 2014 10:11 PM
To: Charlie Cunningham; 'Carl Braun'; '160'
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

The only benefit of getting it better would be a bit more 2:1 VSWR bandwidth
to keep the amp happy but even then there is sometimes a gotcha when tuning
an antenna.

Carl
KM1H



Subject: Re: Topband: Shunt feeding the Skyneedle - new developments


Well, you can do all that, Carl

But if your series variable capacitor is not maxed out (fully meshed) if you
can increase the capacitance enough  to get to j0, you would be at 45
+j0 and on a 1.1:1  VSWR circle. No point int trying to do better than
that!!
 Otherwise, just increase the series capacitance to bring that -j11  as
close to j0 as possible and take that! You'd

Re: Topband: Shunt feeding the Skyneedle - new developments

[Roger D Johnson]

It may not be obvious but often you can get better bandwidth by NOT tuning
for 1:1 at the desired frequency! Those familiar with the Smith chart probably
already know this.

A narrow band antenna will produce a curve between a U and a V on the
Smith chart. If you tune for a 1:1 SWR, you bring the nose of the curve to the
center of the chart. This often leaves the tails outside the desired SWR
circle. If you continue until the nose goes to the opposite side of the SWR
circle, it brings more of the tails into the circle. The resulting SWR curve is
a W shape. It won't be 1:1 at any frequency but more of the curve will lie
within the chosen SWR circle.

73, Roger


On 2/22/2014 11:03 AM, Charlie Cunningham wrote:

Well, I agree with all that, Carl. But Carl Braun, was reading dead-flat
1:1 at the transmitter end of his cable. I believe he is done!! The antenna
Q is what it is! As for improving his 2:1 VSWR bandwidth he could reduce
his radial field and increase his ground losses to improve his 2:1 BW -
but I believe that to be self-defeating!! I'm not missing your point - I
just don't see what you'd change to improve on a flat line! Carl is well
past the point of diminishing returns!

The math doesn't lie!

Charlie, K4OTV





_
Topband Reflector Archives - http://www.contesting.com/_topband

Re: Topband: Shunt feeding the Skyneedle - new developments

[Carl]

I suppose I missed that part while doing things around here but this is the 
only pertinent info I can find from him. Nowhere does it say he has a 1:1 
anywhere with the cap in the cabinet.  Granted some of the posts are very 
confusing as to where things are being measured.



--
The j11 ohms is the best I can get period. I was able to get j0 when the cap 
was outside of the steel enclosure with a better bandwidth. Maybe I should 
throw my $400 enclosure and find a fibergla$$ enclosure. But as others have 
indicated I should probably just live with it.


The swr at my given freq as tuned with the variable cap is 1.3:1 or 
less...outside the enclosure the system had 1.0:1 swr readings and X=O over 
what appeared to be a broader bandwidth...even with 42 ohms at the feed 
point.
-- 

So maybe you can explain where the 1.0 at the transmitter end with the cap 
in the box came from?
Additionally the VSWR may/will change with added radials and ground moisture 
conditions.


Im going out for several hours so no rush on the answers.

Carl
KM1H


- Original Message - 
From: Charlie Cunningham charlie-cunning...@nc.rr.com
To: 'Carl' k...@jeremy.mv.com; 'Carl Braun' 
carl.br...@lairdtech.com; '160' topband@contesting.com

Sent: Saturday, February 22, 2014 11:03 AM
Subject: RE: Topband: Shunt feeding the Skyneedle - new developments


Well, I agree with all that, Carl. But Carl Braun, was reading dead-flat
1:1 at the transmitter end of his cable. I believe he is done!! The antenna
Q is what it is! As for improving his 2:1 VSWR bandwidth he could reduce
his radial field and increase his ground losses to improve his 2:1 BW -
but I believe that to be self-defeating!! I'm not missing your point - I
just don't see what you'd change to improve on a flat line! Carl is well
past the point of diminishing returns!

The math doesn't lie!

Charlie, K4OTV


-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl
Sent: Saturday, February 22, 2014 10:41 AM
To: Charlie Cunningham; 'Carl Braun'; '160'
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

Charlie youre continually missing the point; ignore cable loss period.

The only issue is what impedance does the amp see from lets say 1800 to 1900

KHz? AND can the amp load into it without a problem at full power? This is a

system issue, not just what is measured at the antenna and needs to be
addressed that way.

Put all that info into your program and post the results. Saying that a 1.3
VSWR at reasonance at the antenna is sufficient is too simplistic. Compute
the VSWR at the amp with whatever length of coax is actually used over the
lower 100 KHz with a range of  at resonance VSWR's.

Carl
KM1H


- Original Message - 
From: Charlie Cunningham charlie-cunning...@nc.rr.com

To: 'Carl' k...@jeremy.mv.com; 'Carl Braun'
carl.br...@lairdtech.com; '160' topband@contesting.com
Sent: Saturday, February 22, 2014 9:57 AM
Subject: RE: Topband: Shunt feeding the Skyneedle - new developments


Well, Carl the looses in 70' or even 200' of LMR-400 are so low at 1.8 MHz,
even at 2.0:1 or 3.0 :1, if he can match it at the transmitter  end of the
line, it really doesn't matter!

Charlie, K4OTV

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl
Sent: Saturday, February 22, 2014 9:46 AM
To: Charlie Cunningham; 'Carl Braun'; '160'
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

That 1.3 is only at ONE frequency Charlie, he is not crystal controlled.
What is the 2:1 bandwidth at the amp?

Carl
KM1H


- Original Message - 
From: Charlie Cunningham charlie-cunning...@nc.rr.com

To: 'Carl' k...@jeremy.mv.com; 'Carl Braun'
carl.br...@lairdtech.com; '160' topband@contesting.com
Sent: Saturday, February 22, 2014 9:23 AM
Subject: RE: Topband: Shunt feeding the Skyneedle - new developments


I don't expect that ANY of those are valid concerns at 1.3:1 VSWR!!

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl
Sent: Saturday, February 22, 2014 9:14 AM
To: Charlie Cunningham; 'Carl Braun'; '160'
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

Im not concerned by what is measured at the matching unit or a miniscule
cable loss; just what is transformed back to the amp and its ability to load

at full power without arcing, running out of or having too much fixed padder

C during QSY's. Contests do not stay just in the narrow CW 50 KHz  window
and not having to use an external tuner is a big plus.

Ive always modified my amps to work with my antennas on 160 and 80/75.

Carl
KM1H


- Original Message - 
From: Charlie Cunningham charlie-cunning...@nc.rr.com

To: 'ZR' z...@jeremy.mv.com; 'Carl Braun' carl.br...@lairdtech.com;
'160' topband@contesting.com
Sent: Friday, February

Re: Topband: Shunt feeding the Skyneedle - new developments

[Charlie Cunningham]

Wel, I agree with all of that, Roger.  I plotted Carl's 45-j11 load on a 50
ohm Smith Chart, and it's right near the origin of the chart on a 1.3:1 VSWR
circle. I'd need some more data points at some other frequencies to plot to
get a better picture of what's going on, But his VSWR is so low that the
losses in 70' of LMR-400 on 160 are completely negligible!  As long as he
can match it at the transmitter end - no problem! And at one point, he was
measuring dead-flat 1:1at the tranmitterend of the cable. His Henry amp
should handle that just fine without a tuner!

73,
Charlie, K4OTV

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Roger D
Johnson
Sent: Saturday, February 22, 2014 11:16 AM
To: '160'
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

It may not be obvious but often you can get better bandwidth by NOT tuning
for 1:1 at the desired frequency! Those familiar with the Smith chart
probably already know this.

A narrow band antenna will produce a curve between a U and a V on the
Smith chart. If you tune for a 1:1 SWR, you bring the nose of the curve to
the center of the chart. This often leaves the tails outside the desired
SWR circle. If you continue until the nose goes to the opposite side of the
SWR circle, it brings more of the tails into the circle. The resulting SWR
curve is a W shape. It won't be 1:1 at any frequency but more of the curve
will lie within the chosen SWR circle.

73, Roger


On 2/22/2014 11:03 AM, Charlie Cunningham wrote:
 Well, I agree with all that, Carl. But Carl Braun, was reading dead-flat
 1:1 at the transmitter end of his cable. I believe he is done!! The 
 antenna Q is what it is! As for improving his 2:1 VSWR bandwidth he 
 could reduce his radial field and increase his ground losses to 
 improve his 2:1 BW - but I believe that to be self-defeating!! I'm 
 not missing your point - I just don't see what you'd change to 
 improve on a flat line! Carl is well past the point of diminishing
returns!

 The math doesn't lie!

 Charlie, K4OTV




_
Topband Reflector Archives - http://www.contesting.com/_topband

_
Topband Reflector Archives - http://www.contesting.com/_topband

Re: Topband: Shunt feeding the Skyneedle - new developments

[Carl Braun]

The measurements are being taken, and have been taken, at the same point since 
the beginning of the antenna experiment.  The ONLY difference is that the 
variable cap is now mounted inside the steel panel as described in my previous 
posts, instead of outside the panel, as described in previous posts.  Same 
length of wire each scenario. 

I believe Tom W8JI called it when he stated that a change was likely when the 
cap is enclosed in a metallic enclosure vs sitting on a 5 gal plastic jug. 

The Henry amp seems to be OK with a little reactance so I'm going to 
concentrate on my gamma cage and radial system while waiting for RF Parts to 
deliver some necessary connectors. Once I get the PL259s installed I can 
replace my temp RG 58 jumper with the good stuff and then hit it with the 
Henry. Ive kept the power below 500w during the contest so as not to stress the 
small coaxial cable. 

73

Carl

Sent from my iPhone

 On Feb 22, 2014, at 8:42 AM, Carl k...@jeremy.mv.com wrote:
 
 I suppose I missed that part while doing things around here but this is the 
 only pertinent info I can find from him. Nowhere does it say he has a 1:1 
 anywhere with the cap in the cabinet.  Granted some of the posts are very 
 confusing as to where things are being measured.
 
 
 --
 The j11 ohms is the best I can get period. I was able to get j0 when the cap 
 was outside of the steel enclosure with a better bandwidth. Maybe I should 
 throw my $400 enclosure and find a fibergla$$ enclosure. But as others have 
 indicated I should probably just live with it.
 
 The swr at my given freq as tuned with the variable cap is 1.3:1 or 
 less...outside the enclosure the system had 1.0:1 swr readings and X=O over 
 what appeared to be a broader bandwidth...even with 42 ohms at the feed point.
 -- 
 So maybe you can explain where the 1.0 at the transmitter end with the cap in 
 the box came from?
 Additionally the VSWR may/will change with added radials and ground moisture 
 conditions.
 
 Im going out for several hours so no rush on the answers.
 
 Carl
 KM1H
 
 
 - Original Message - From: Charlie Cunningham 
 charlie-cunning...@nc.rr.com
 To: 'Carl' k...@jeremy.mv.com; 'Carl Braun' carl.br...@lairdtech.com; 
 '160' topband@contesting.com
 Sent: Saturday, February 22, 2014 11:03 AM
 Subject: RE: Topband: Shunt feeding the Skyneedle - new developments
 
 
 Well, I agree with all that, Carl. But Carl Braun, was reading dead-flat
 1:1 at the transmitter end of his cable. I believe he is done!! The antenna
 Q is what it is! As for improving his 2:1 VSWR bandwidth he could reduce
 his radial field and increase his ground losses to improve his 2:1 BW -
 but I believe that to be self-defeating!! I'm not missing your point - I
 just don't see what you'd change to improve on a flat line! Carl is well
 past the point of diminishing returns!
 
 The math doesn't lie!
 
 Charlie, K4OTV
 
 
 -Original Message-
 From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl
 Sent: Saturday, February 22, 2014 10:41 AM
 To: Charlie Cunningham; 'Carl Braun'; '160'
 Subject: Re: Topband: Shunt feeding the Skyneedle - new developments
 
 Charlie youre continually missing the point; ignore cable loss period.
 
 The only issue is what impedance does the amp see from lets say 1800 to 1900
 
 KHz? AND can the amp load into it without a problem at full power? This is a
 
 system issue, not just what is measured at the antenna and needs to be
 addressed that way.
 
 Put all that info into your program and post the results. Saying that a 1.3
 VSWR at reasonance at the antenna is sufficient is too simplistic. Compute
 the VSWR at the amp with whatever length of coax is actually used over the
 lower 100 KHz with a range of  at resonance VSWR's.
 
 Carl
 KM1H
 
 
 - Original Message - From: Charlie Cunningham 
 charlie-cunning...@nc.rr.com
 To: 'Carl' k...@jeremy.mv.com; 'Carl Braun'
 carl.br...@lairdtech.com; '160' topband@contesting.com
 Sent: Saturday, February 22, 2014 9:57 AM
 Subject: RE: Topband: Shunt feeding the Skyneedle - new developments
 
 
 Well, Carl the looses in 70' or even 200' of LMR-400 are so low at 1.8 MHz,
 even at 2.0:1 or 3.0 :1, if he can match it at the transmitter  end of the
 line, it really doesn't matter!
 
 Charlie, K4OTV
 
 -Original Message-
 From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl
 Sent: Saturday, February 22, 2014 9:46 AM
 To: Charlie Cunningham; 'Carl Braun'; '160'
 Subject: Re: Topband: Shunt feeding the Skyneedle - new developments
 
 That 1.3 is only at ONE frequency Charlie, he is not crystal controlled.
 What is the 2:1 bandwidth at the amp?
 
 Carl
 KM1H
 
 
 - Original Message - From: Charlie Cunningham 
 charlie-cunning...@nc.rr.com
 To: 'Carl' k...@jeremy.mv.com; 'Carl Braun'
 carl.br...@lairdtech.com; '160' topband

Re: Topband: Shunt feeding the Skyneedle - new developments

[Carl Braun]

Carl and Topbanders

Here are the latest details and I will try and be as thorough as possible.

Good news!  I built my gamma cage and the antenna now performs MUCH better.

Here's where I stand:

90' Tri Ex Skyneedle shunt fed with the gamma arm at 67' and a three wire gamma 
cage with 10 separation between wires.

My tower is grounded at the base via three 1 copper strap 1/8th inch thick and 
tied to a 1 1/2 copper pipe radial ring that measures 4' x 8'. The radial ring 
is also bonded to three 8' ground rods via 1 copper strap.

Currently I have approx 30 ground radials screwed to the radial ring with 
copper clad stainless screws and then painted with copper paste.  Some of the 
radials are formed from heavy control cable (similar to rotor cable) that are 
fanned out at the radial ring...converge into the Cable jacket, cross the 10' 
blacktop driveway and then emerge from the jacket and fan out across the 
property.  The radials vary from 30' long to 100' long with three of them tying 
directly into the radial field of my 40m phased array.

The three-wire gamma cage is made of 14ga stranded wire and converges into a 
cone with a single brass bolt holding all three ring lugs together 1.5' off of 
the ground at the base.  An additional 14ga wire is also connected to the brass 
bolt and bolts to a porcelain feed through insulator that brings the feed into 
the metallic (STEEL) panel.  A 14ga wire then bolts to the other end of the 
feed thru insulator and taps onto the input of the Cardwell air variable 
capacitor.  The output of the capacitor connects to a SO 239 connector that is 
mounted to a 2 copper strap that travels down the enclosure where two brass 
bolts bolt the strap to the bottom of the panel.  Under the panel, where the 
brass bolts emerge from the panel, two 2 copper straps connect to the brass 
bolts and then travel to the copper radial ring where they are terminated. 

Before the gamma cage I used a single 14ga wire dropped down from the gamma arm 
where it connected to the variable cap that was mounted outside my steel 
enclosure and sat on a plastic 5 gal pail.  The gamma wire connected to the 
variable cap and then it was wired to the same standoff insulator I mentioned 
above and into an empty steel panel where I had the same SO 239 connector 
mounted to the copper strap and then to my grounding system.  This config 
netted me 41 + j0 ohms.

I was pretty satisfied with this scenario so I mounted my variable cap on a 
3/4 thick piece of Plexiglas to the backplane via Teflon bolts inside the 
steel enclosure.  When I did this I saw my analyzer jump to 45 -j11 ohms.  No 
matter how much tweaking was done the lowest X on the analyzer was 11.  
Figuring I could live with that after making 24 contacts this morning I decided 
to move ahead with my gamma cage.  When I completed the cage per the info above 
I left my analyzer set on the previous frequency setting of 1825 and saw the 
resistance jump and the X go out of site.  Adjusting my variable cap (from 
approx 140 pf to 420 pf) rewarded me with a 42 + j0 reading.

Inside the shack on the 1000D and the BIRD I see 1.1:1 Vswr at 1.800 MHz, FLAT 
1.0:1 from 1.810 to 1.860 and 1.5:1 at 1.895 MHz.

I'm eager to get back on the air tonight and tomorrow morning to see how it 
plays

73

Carl AG6X



-Original Message-
From: Carl [mailto:k...@jeremy.mv.com] 
Sent: Saturday, February 22, 2014 1:22 PM
To: Carl Braun
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments


Subject: Re: Topband: Shunt feeding the Skyneedle - new developments


The measurements are being taken, and have been taken, at the same point 
since the beginning of the antenna experiment.

**  How about refreshing my merory about those details Carl? Frequency also. 
I wasnt involved in the early parts and deleted them already.


The ONLY difference is that the variable cap is now mounted inside the steel 
panel as described in my previous posts, instead of outside the panel, as 
described in previous posts.  Same length of wire each scenario.

I believe Tom W8JI called it when he stated that a change was likely when 
the cap is enclosed in a metallic enclosure vs sitting on a 5 gal plastic 
jug.

** No discussion needed there, thats been known for 100 years. It would also 
help to be more specific when presenting details, what does metallic really 
mean?

The Henry amp seems to be OK with a little reactance so I'm going to 
concentrate on my gamma cage and radial system while waiting for RF Parts to 
deliver some necessary connectors. Once I get the PL259s installed I can 
replace my temp RG 58 jumper with the good stuff and then hit it with the 
Henry. I've kept the power below 500w during the contest so as not to stress 
the small coaxial cable.

** Good move.

Carl
KM1H


73

Carl

Sent from my iPhone

 On Feb 22, 2014, at 8:42 AM, Carl k...@jeremy.mv.com wrote:

 I suppose I missed that part while doing things around here but this is 
 the only

Re: Topband: Shunt feeding the Skyneedle - FB!

[Charlie Cunningham]

Wow!!  Sounds like you r gamma cage worked out really well, Carl!!  The
fact that  you are running so much more series C now says that you removed a
lot of inductive reactance from your gamma section. Therefore the Q has
dropped significantly, I expect. Your VSWR bandwidth is great!  I would
think that even Carl, KM1H would agree - perhaps grudgingly! It seems that
all you hard work has really paid off!! Now enjoy your antenna and finish up
your radial work and get to work on the receiving loops!  I expect that you
are likely to have a really good transmitting antenna for Topband!!
Congrats!  Enjoy!

73,
Charlie, K4OTV

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl
Braun
Sent: Saturday, February 22, 2014 7:16 PM
To: Carl; '160'
Cc: w...@att.net; ad...@arrl.net
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

Carl and Topbanders

Here are the latest details and I will try and be as thorough as possible.

Good news!  I built my gamma cage and the antenna now performs MUCH better.

Here's where I stand:

90' Tri Ex Skyneedle shunt fed with the gamma arm at 67' and a three wire
gamma cage with 10 separation between wires.

My tower is grounded at the base via three 1 copper strap 1/8th inch thick
and tied to a 1 1/2 copper pipe radial ring that measures 4' x 8'. The
radial ring is also bonded to three 8' ground rods via 1 copper strap.

Currently I have approx 30 ground radials screwed to the radial ring with
copper clad stainless screws and then painted with copper paste.  Some of
the radials are formed from heavy control cable (similar to rotor cable)
that are fanned out at the radial ring...converge into the Cable jacket,
cross the 10' blacktop driveway and then emerge from the jacket and fan out
across the property.  The radials vary from 30' long to 100' long with three
of them tying directly into the radial field of my 40m phased array.

The three-wire gamma cage is made of 14ga stranded wire and converges into a
cone with a single brass bolt holding all three ring lugs together 1.5' off
of the ground at the base.  An additional 14ga wire is also connected to the
brass bolt and bolts to a porcelain feed through insulator that brings the
feed into the metallic (STEEL) panel.  A 14ga wire then bolts to the other
end of the feed thru insulator and taps onto the input of the Cardwell air
variable capacitor.  The output of the capacitor connects to a SO 239
connector that is mounted to a 2 copper strap that travels down the
enclosure where two brass bolts bolt the strap to the bottom of the panel.
Under the panel, where the brass bolts emerge from the panel, two 2 copper
straps connect to the brass bolts and then travel to the copper radial ring
where they are terminated. 

Before the gamma cage I used a single 14ga wire dropped down from the gamma
arm where it connected to the variable cap that was mounted outside my steel
enclosure and sat on a plastic 5 gal pail.  The gamma wire connected to the
variable cap and then it was wired to the same standoff insulator I
mentioned above and into an empty steel panel where I had the same SO 239
connector mounted to the copper strap and then to my grounding system.  This
config netted me 41 + j0 ohms.

I was pretty satisfied with this scenario so I mounted my variable cap on a
3/4 thick piece of Plexiglas to the backplane via Teflon bolts inside the
steel enclosure.  When I did this I saw my analyzer jump to 45 -j11 ohms.
No matter how much tweaking was done the lowest X on the analyzer was 11.
Figuring I could live with that after making 24 contacts this morning I
decided to move ahead with my gamma cage.  When I completed the cage per the
info above I left my analyzer set on the previous frequency setting of 1825
and saw the resistance jump and the X go out of site.  Adjusting my variable
cap (from approx 140 pf to 420 pf) rewarded me with a 42 + j0 reading.

Inside the shack on the 1000D and the BIRD I see 1.1:1 Vswr at 1.800 MHz,
FLAT 1.0:1 from 1.810 to 1.860 and 1.5:1 at 1.895 MHz.

I'm eager to get back on the air tonight and tomorrow morning to see how it
plays

73

Carl AG6X



-Original Message-
From: Carl [mailto:k...@jeremy.mv.com] 
Sent: Saturday, February 22, 2014 1:22 PM
To: Carl Braun
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments


Subject: Re: Topband: Shunt feeding the Skyneedle - new developments


The measurements are being taken, and have been taken, at the same point 
since the beginning of the antenna experiment.

**  How about refreshing my merory about those details Carl? Frequency also.

I wasnt involved in the early parts and deleted them already.


The ONLY difference is that the variable cap is now mounted inside the steel

panel as described in my previous posts, instead of outside the panel, as 
described in previous posts.  Same length of wire each scenario.

I believe Tom W8JI called it when he stated that a change was likely when

Re: Topband: Shunt feeding the Skyneedle - new developments

[Richard (Rick) Karlquist]

On 2/22/2014 4:15 PM, Carl Braun wrote:


Inside the shack on the 1000D and the BIRD I see 1.1:1 Vswr at 1.800 MHz, FLAT 
1.0:1 from 1.810 to 1.860 and 1.5:1 at 1.895 MHz.

I'm eager to get back on the air tonight and tomorrow morning to see how it 
plays


I'm sure it will play well in terms of keeping your transmitter
happy but the relatively large bandwidth you are measuring
is indicative of substantial loss in the system somewhere.
This would be a large bandwidth even if you did not have
the bandwidth narrowing effects of a shunt feed.

Does your 1000D SWR meter agree with your Bird meter?
I am somewhat skeptical of the SWR meter on my 1000D.
I suspect it reads on the low side.  Either that or my
Alpha 9500 reads on the high side.



73

Carl AG6X



Rick N6RK
_
Topband Reflector Archives - http://www.contesting.com/_topband

Re: Topband: Shunt feeding the Skyneedle - new developments

[Tom W8JI]

I was pretty satisfied with this scenario so I mounted my variable cap on a 
3/4 thick piece of Plexiglas to the backplane via Teflon bolts inside the 
steel enclosure.  When I did this I saw my analyzer jump to 45 -j11 ohms. 
No matter how much tweaking was done the lowest X on the analyzer was 11. 
Figuring I could live with that after making 24 contacts this morning I 
decided to move ahead with my gamma cage.  When I completed the cage per the 
info above I left my analyzer set on the previous frequency setting of 1825 
and saw the resistance jump and the X go out of site.  Adjusting my variable 
cap (from approx 140 pf to 420 pf) rewarded me with a 42 + j0 reading.


Inside the shack on the 1000D and the BIRD I see 1.1:1 Vswr at 1.800 MHz, 
FLAT 1.0:1 from 1.810 to 1.860 and 1.5:1 at 1.895 MHz.


I would expect you to have that bandwidth. It does NOT indicate loss.

Your shunt system now has an operating Q of around 4, because you now have 
200 ohms of series C.


With a thick radiator and a large yagi on top, and so much capacitance, you 
are exactly on target.


While I don't fully trust the FT1000 meter, no matter what, never 
automatically assume modest bandwidth like you have indicates loss. It 
doesn't. There are a whole lot of things that go into bandwidth beside loss!


73 Tom 


_
Topband Reflector Archives - http://www.contesting.com/_topband

Re: Topband: Shunt feeding the Skyneedle - new developments

[Charlie Cunningham]

Exactly!  All true and Tom is right on point!  You have removed a lot of
series reactance with that gamma cage, Carl -as  indicated by the required
tuning C changing.from 160 pF ot over 400 pF. OF COURSE the Q was reduced as
the series reactance was reduced and the real part stayed fairly constant.
That does not imply increased or excessive loss!

Regards
Charlie

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Tom W8JI
Sent: Saturday, February 22, 2014 9:07 PM
To: Carl Braun; '160'
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

I was pretty satisfied with this scenario so I mounted my variable cap on a 
3/4 thick piece of Plexiglas to the backplane via Teflon bolts inside the 
steel enclosure.  When I did this I saw my analyzer jump to 45 -j11 ohms. 
No matter how much tweaking was done the lowest X on the analyzer was 11. 
Figuring I could live with that after making 24 contacts this morning I 
decided to move ahead with my gamma cage.  When I completed the cage per the

info above I left my analyzer set on the previous frequency setting of 1825 
and saw the resistance jump and the X go out of site.  Adjusting my variable

cap (from approx 140 pf to 420 pf) rewarded me with a 42 + j0 reading.

Inside the shack on the 1000D and the BIRD I see 1.1:1 Vswr at 1.800 MHz, 
FLAT 1.0:1 from 1.810 to 1.860 and 1.5:1 at 1.895 MHz.

I would expect you to have that bandwidth. It does NOT indicate loss.

Your shunt system now has an operating Q of around 4, because you now have 
200 ohms of series C.

With a thick radiator and a large yagi on top, and so much capacitance, you 
are exactly on target.

While I don't fully trust the FT1000 meter, no matter what, never 
automatically assume modest bandwidth like you have indicates loss. It 
doesn't. There are a whole lot of things that go into bandwidth beside loss!

73 Tom 

_
Topband Reflector Archives - http://www.contesting.com/_topband

_
Topband Reflector Archives - http://www.contesting.com/_topband

Re: Topband: Shunt feeding the Skyneedle - new developments

[Carl]

That is the type of report I really like to hear Carl. All that work has 
paid off in spades.


As you increase the number of radials the VSWR bandwidth might decrease 
along with the R which is normal as the ground resistance decreases. Since 
it appears to work so well you might just leave it alone for awhile, operate 
and get a feel of how your signal compares with others.


With the top loading Id say the tower is close to being a 1/4 wave and the 
perfect world impedance about 35-36 Ohms with the remainder as ground 
resistance. That will result in very decent efficiency.


That cage you connected this morning sure changed the numbers from the 
single wire I was responding to.


OK on the steel panel. The usual rule of thumb there is to space coils and 
variables at least their width away. There were some amps and tuners on the 
market that would have radically different tuning, and more power out in the 
amplifier examples, with the cover removed.


Take a bow, Im impressed!!

Carl
KM1H


- Original Message - 
From: Carl Braun carl.br...@lairdtech.com

To: Carl k...@jeremy.mv.com; '160' topband@contesting.com
Cc: ad...@arrl.net; w...@att.net
Sent: Saturday, February 22, 2014 7:15 PM
Subject: RE: Topband: Shunt feeding the Skyneedle - new developments


Carl and Topbanders

Here are the latest details and I will try and be as thorough as possible.

Good news!  I built my gamma cage and the antenna now performs MUCH better.

Here's where I stand:

90' Tri Ex Skyneedle shunt fed with the gamma arm at 67' and a three wire 
gamma cage with 10 separation between wires.


My tower is grounded at the base via three 1 copper strap 1/8th inch thick 
and tied to a 1 1/2 copper pipe radial ring that measures 4' x 8'. The 
radial ring is also bonded to three 8' ground rods via 1 copper strap.


Currently I have approx 30 ground radials screwed to the radial ring with 
copper clad stainless screws and then painted with copper paste.  Some of 
the radials are formed from heavy control cable (similar to rotor cable) 
that are fanned out at the radial ring...converge into the Cable jacket, 
cross the 10' blacktop driveway and then emerge from the jacket and fan out 
across the property.  The radials vary from 30' long to 100' long with three 
of them tying directly into the radial field of my 40m phased array.


The three-wire gamma cage is made of 14ga stranded wire and converges into a 
cone with a single brass bolt holding all three ring lugs together 1.5' off 
of the ground at the base.  An additional 14ga wire is also connected to the 
brass bolt and bolts to a porcelain feed through insulator that brings the 
feed into the metallic (STEEL) panel.  A 14ga wire then bolts to the other 
end of the feed thru insulator and taps onto the input of the Cardwell air 
variable capacitor.  The output of the capacitor connects to a SO 239 
connector that is mounted to a 2 copper strap that travels down the 
enclosure where two brass bolts bolt the strap to the bottom of the panel. 
Under the panel, where the brass bolts emerge from the panel, two 2 copper 
straps connect to the brass bolts and then travel to the copper radial ring 
where they are terminated.


Before the gamma cage I used a single 14ga wire dropped down from the gamma 
arm where it connected to the variable cap that was mounted outside my steel 
enclosure and sat on a plastic 5 gal pail.  The gamma wire connected to the 
variable cap and then it was wired to the same standoff insulator I 
mentioned above and into an empty steel panel where I had the same SO 239 
connector mounted to the copper strap and then to my grounding system.  This 
config netted me 41 + j0 ohms.


I was pretty satisfied with this scenario so I mounted my variable cap on a 
3/4 thick piece of Plexiglas to the backplane via Teflon bolts inside the 
steel enclosure.  When I did this I saw my analyzer jump to 45 -j11 ohms. 
No matter how much tweaking was done the lowest X on the analyzer was 11. 
Figuring I could live with that after making 24 contacts this morning I 
decided to move ahead with my gamma cage.  When I completed the cage per the 
info above I left my analyzer set on the previous frequency setting of 1825 
and saw the resistance jump and the X go out of site.  Adjusting my variable 
cap (from approx 140 pf to 420 pf) rewarded me with a 42 + j0 reading.


Inside the shack on the 1000D and the BIRD I see 1.1:1 Vswr at 1.800 MHz, 
FLAT 1.0:1 from 1.810 to 1.860 and 1.5:1 at 1.895 MHz.


I'm eager to get back on the air tonight and tomorrow morning to see how it 
plays


73

Carl AG6X



-Original Message-
From: Carl [mailto:k...@jeremy.mv.com]
Sent: Saturday, February 22, 2014 1:22 PM
To: Carl Braun
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments


Subject: Re: Topband: Shunt feeding the Skyneedle - new developments


The measurements are being taken, and have been taken, at the same point
since the beginning of the antenna experiment

Re: Topband: Shunt feeding the Skyneedle - new developments

[Charlie Cunningham]

I'm impressed, too!  I believe Carl has it whipped!! Should be a really good
transmit antenna for Topband!!b Changing to that multi-wire gamma cage
really eliminated a lot of series reactance and lowered the Q of the
matching section and antenna combination!  Good stuff!

73,
Charlie,K4OTV

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl
Sent: Saturday, February 22, 2014 10:08 PM
To: Carl Braun; '160'
Cc: w...@att.net; ad...@arrl.net
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

That is the type of report I really like to hear Carl. All that work has
paid off in spades.

As you increase the number of radials the VSWR bandwidth might decrease
along with the R which is normal as the ground resistance decreases. Since
it appears to work so well you might just leave it alone for awhile, operate
and get a feel of how your signal compares with others.

With the top loading Id say the tower is close to being a 1/4 wave and the
perfect world impedance about 35-36 Ohms with the remainder as ground
resistance. That will result in very decent efficiency.

That cage you connected this morning sure changed the numbers from the
single wire I was responding to.

OK on the steel panel. The usual rule of thumb there is to space coils and
variables at least their width away. There were some amps and tuners on the
market that would have radically different tuning, and more power out in the
amplifier examples, with the cover removed.

Take a bow, Im impressed!!

Carl
KM1H


- Original Message -
From: Carl Braun carl.br...@lairdtech.com
To: Carl k...@jeremy.mv.com; '160' topband@contesting.com
Cc: ad...@arrl.net; w...@att.net
Sent: Saturday, February 22, 2014 7:15 PM
Subject: RE: Topband: Shunt feeding the Skyneedle - new developments


Carl and Topbanders

Here are the latest details and I will try and be as thorough as possible.

Good news!  I built my gamma cage and the antenna now performs MUCH better.

Here's where I stand:

90' Tri Ex Skyneedle shunt fed with the gamma arm at 67' and a three wire 
gamma cage with 10 separation between wires.

My tower is grounded at the base via three 1 copper strap 1/8th inch thick 
and tied to a 1 1/2 copper pipe radial ring that measures 4' x 8'. The 
radial ring is also bonded to three 8' ground rods via 1 copper strap.

Currently I have approx 30 ground radials screwed to the radial ring with 
copper clad stainless screws and then painted with copper paste.  Some of 
the radials are formed from heavy control cable (similar to rotor cable) 
that are fanned out at the radial ring...converge into the Cable jacket, 
cross the 10' blacktop driveway and then emerge from the jacket and fan out 
across the property.  The radials vary from 30' long to 100' long with three

of them tying directly into the radial field of my 40m phased array.

The three-wire gamma cage is made of 14ga stranded wire and converges into a

cone with a single brass bolt holding all three ring lugs together 1.5' off 
of the ground at the base.  An additional 14ga wire is also connected to the

brass bolt and bolts to a porcelain feed through insulator that brings the 
feed into the metallic (STEEL) panel.  A 14ga wire then bolts to the other 
end of the feed thru insulator and taps onto the input of the Cardwell air 
variable capacitor.  The output of the capacitor connects to a SO 239 
connector that is mounted to a 2 copper strap that travels down the 
enclosure where two brass bolts bolt the strap to the bottom of the panel. 
Under the panel, where the brass bolts emerge from the panel, two 2 copper 
straps connect to the brass bolts and then travel to the copper radial ring 
where they are terminated.

Before the gamma cage I used a single 14ga wire dropped down from the gamma 
arm where it connected to the variable cap that was mounted outside my steel

enclosure and sat on a plastic 5 gal pail.  The gamma wire connected to the 
variable cap and then it was wired to the same standoff insulator I 
mentioned above and into an empty steel panel where I had the same SO 239 
connector mounted to the copper strap and then to my grounding system.  This

config netted me 41 + j0 ohms.

I was pretty satisfied with this scenario so I mounted my variable cap on a 
3/4 thick piece of Plexiglas to the backplane via Teflon bolts inside the 
steel enclosure.  When I did this I saw my analyzer jump to 45 -j11 ohms. 
No matter how much tweaking was done the lowest X on the analyzer was 11. 
Figuring I could live with that after making 24 contacts this morning I 
decided to move ahead with my gamma cage.  When I completed the cage per the

info above I left my analyzer set on the previous frequency setting of 1825 
and saw the resistance jump and the X go out of site.  Adjusting my variable

cap (from approx 140 pf to 420 pf) rewarded me with a 42 + j0 reading.

Inside the shack on the 1000D and the BIRD I see 1.1:1 Vswr at 1.800 MHz, 
FLAT 1.0

Topband: Shunt feeding the Skyneedle - new developments

[Carl Braun]

All


Topband list

If you've followed my efforts to shunt feed my Skyneedle tower you'll know that 
I settled with a tap point of 67' and 30 or so of spacing with my feed point 
reading 42 + j0 ohms.  This reading was taken at the interior of my 20 x 30 x 
8 steel Hoffman enclosure with the variable cap located outside the enclosure 
sitting on a plastic 5 gal jug.  The output of the variable cap fed into a 
ceramic feed thru insulator thru the panel to a copper L bracket that mounts 
the SO 239 connector that I hooked my coax cable to.

Since then I've moved the variable capacitor inside the panel and mounted it to 
a ¾ think Plexiglas sheet mounted to the back plane with nylon bolts and 
washers.  There is a 1 air gap between the Plexiglas and the backplane.  I now 
have seen the 42+j0 ohms change to 45 - j11 ohms...that's the lowest reactance 
I can tune the capacitor for. Not really sure if its +j11 ohms or - j11 ohms 
but I assume if the reading was + j11 I could continue to tune it out with the 
capacitor but I cant.

Does the capacitor not play well with a steel enclosure?

The other strange situation I'm experiencing is when I connect my Array 
Solutions static bleed choke to the feed thru insulator at the outside of the 
panel to ground the resonant frequency jumps to 2.014 MHz at 25 +j0 
ohms...remove it entirely and I'm back to my 45 - j11 ohms.

I use 1 meg ohm from the feed point to ground on my other verticals with NO 
change in MFJ analyzer readings.

Any comments from the list on these problems?

Thanks


Carl AG6X

_
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Re: Topband: Shunt feeding the Skyneedle - new developments

[Tom W8JI]

Since then I've moved the variable capacitor inside the panel and mounted it 
to a ¾ think Plexiglas sheet mounted to the back plane with nylon bolts and 
washers.  There is a 1 air gap between the Plexiglas and the backplane.  I 
now have seen the 42+j0 ohms change to 45 - j11 ohms...that's the lowest 
reactance I can tune the capacitor for. Not really sure if its +j11 ohms 
or - j11 ohms but I assume if the reading was + j11 I could continue to tune 
it out with the capacitor but I cant.


Does the capacitor not play well with a steel enclosure?

Any enclosure will change things, especially a metallic enclosure. Just 
readjust the cap.


The other strange situation I'm experiencing is when I connect my Array 
Solutions static bleed choke to the feed thru insulator at the outside of 
the panel to ground the resonant frequency jumps to 2.014 MHz at 25 +j0 
ohms...remove it entirely and I'm back to my 45 - j11 ohms.


The choke is completely unnecessary with a shunt feed tower. It won't help a 
thing, so leave it out.


73 Tom 


_
Topband Reflector Archives - http://www.contesting.com/_topband

Re: Topband: Shunt feeding the Skyneedle - new developments

[Charlie Cunningham]

Well, Carl

I plotted your 45-j11 load on a Smith Chart (normalized to 50 ohms) and it's
very near the origin on a 1.3:1 VSWR circle. Since you have a relatively
short feedline of LMR-400, You should be able to just tune it out at the
transmitter end of the line, and the LMR-400 line will be operating at such
a very low SWR (around 1.3:1 that the excess loss from a 1.3:1 VSWR at 160
is completely trivial and negligible! It may not be completely
intellectually satisfying to have -j11 of reactance at the load, but it
should match easily and the antenna should work very well!  Enjoy!

Sounds like that Array solutions static bleed is not as high in impedance as
we might wish! A large resistance might give you more satisfactory results!

GL!  Enjoy!

73,
Charlie, K4OTV





-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Tom W8JI
Sent: Friday, February 21, 2014 8:02 PM
To: Carl Braun; '160'
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

Since then I've moved the variable capacitor inside the panel and mounted it

to a ¾ think Plexiglas sheet mounted to the back plane with nylon bolts and

washers.  There is a 1 air gap between the Plexiglas and the backplane.  I 
now have seen the 42+j0 ohms change to 45 - j11 ohms...that's the lowest 
reactance I can tune the capacitor for. Not really sure if its +j11 ohms 
or - j11 ohms but I assume if the reading was + j11 I could continue to tune

it out with the capacitor but I cant.

Does the capacitor not play well with a steel enclosure?

Any enclosure will change things, especially a metallic enclosure. Just 
readjust the cap.

The other strange situation I'm experiencing is when I connect my Array 
Solutions static bleed choke to the feed thru insulator at the outside of 
the panel to ground the resonant frequency jumps to 2.014 MHz at 25 +j0 
ohms...remove it entirely and I'm back to my 45 - j11 ohms.

The choke is completely unnecessary with a shunt feed tower. It won't help a

thing, so leave it out.

73 Tom 

_
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_
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Re: Topband: Shunt feeding the Skyneedle - new developments BTW

[Charlie Cunningham]

BTW. Carl

I agree completely with Tom that there's no point in having a static-bleed
choke on a grounded shunt fed tower!

73,
Charlie, K4OTV






-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Tom W8JI
Sent: Friday, February 21, 2014 8:02 PM
To: Carl Braun; '160'
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

Since then I've moved the variable capacitor inside the panel and mounted it
to a ¾ think Plexiglas sheet mounted to the back plane with nylon bolts and
washers.  There is a 1 air gap between the Plexiglas and the backplane.  I
now have seen the 42+j0 ohms change to 45 - j11 ohms...that's the lowest
reactance I can tune the capacitor for. Not really sure if its +j11 ohms or
- j11 ohms but I assume if the reading was + j11 I could continue to tune it
out with the capacitor but I cant.

Does the capacitor not play well with a steel enclosure?

Any enclosure will change things, especially a metallic enclosure. Just
readjust the cap.

The other strange situation I'm experiencing is when I connect my Array
Solutions static bleed choke to the feed thru insulator at the outside of
the panel to ground the resonant frequency jumps to 2.014 MHz at 25 +j0
ohms...remove it entirely and I'm back to my 45 - j11 ohms.

The choke is completely unnecessary with a shunt feed tower. It won't help a
thing, so leave it out.

73 Tom 

_
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_
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Re: Topband: Shunt feeding the Skyneedle - new developments

[Carl Braun]

Thanks to all who replied

Tom W8JI, your comments on the metallic panel and the static bleed choke make 
sense.  I was so pleased with the FLAT SWR reading with the variable cap 
outside the panel but I guess I can live with the slight SWR.  (Thanks Charlie 
K4OTV).  I have a Nye Viking monster tuner but I hate to use it as my Henry amp 
seems to load strangely when I have it inline so I think I'll just live without 
it.  

Can I add some coax (coiled) to bring the X down on the -j11 reading? I did 
this with the old Telrex and brought the X right down and out of the pic.  I'm 
sure Ill need much more than I would on 14MHz but I think I'd like to try 
anyway.

I'm still going to drop the tower down and add two more gamma wires to create a 
cage and I still have the option of pulling the gamma wire(s) away from the 
tower another 8-10 inches to add a few more ohms to the equation.  

I'm having fun with the experiment.

Right now I'm hearing the beginnings of the SSB contest with N7GP, WD5COV, W6YI 
with the big signals so far.  XE is the only DX I've heard.

Lots of stateside calling stateside

Carl AG6X

-Original Message-
From: Charlie Cunningham [mailto:charlie-cunning...@nc.rr.com] 
Sent: Friday, February 21, 2014 5:21 PM
To: 'Tom W8JI'; Carl Braun; '160'
Subject: RE: Topband: Shunt feeding the Skyneedle - new developments

Well, Carl

I plotted your 45-j11 load on a Smith Chart (normalized to 50 ohms) and it's
very near the origin on a 1.3:1 VSWR circle. Since you have a relatively
short feedline of LMR-400, You should be able to just tune it out at the
transmitter end of the line, and the LMR-400 line will be operating at such
a very low SWR (around 1.3:1 that the excess loss from a 1.3:1 VSWR at 160
is completely trivial and negligible! It may not be completely
intellectually satisfying to have -j11 of reactance at the load, but it
should match easily and the antenna should work very well!  Enjoy!

Sounds like that Array solutions static bleed is not as high in impedance as
we might wish! A large resistance might give you more satisfactory results!

GL!  Enjoy!

73,
Charlie, K4OTV





-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Tom W8JI
Sent: Friday, February 21, 2014 8:02 PM
To: Carl Braun; '160'
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

Since then I've moved the variable capacitor inside the panel and mounted it

to a ¾ think Plexiglas sheet mounted to the back plane with nylon bolts and

washers.  There is a 1 air gap between the Plexiglas and the backplane.  I 
now have seen the 42+j0 ohms change to 45 - j11 ohms...that's the lowest 
reactance I can tune the capacitor for. Not really sure if its +j11 ohms 
or - j11 ohms but I assume if the reading was + j11 I could continue to tune

it out with the capacitor but I cant.

Does the capacitor not play well with a steel enclosure?

Any enclosure will change things, especially a metallic enclosure. Just 
readjust the cap.

The other strange situation I'm experiencing is when I connect my Array 
Solutions static bleed choke to the feed thru insulator at the outside of 
the panel to ground the resonant frequency jumps to 2.014 MHz at 25 +j0 
ohms...remove it entirely and I'm back to my 45 - j11 ohms.

The choke is completely unnecessary with a shunt feed tower. It won't help a

thing, so leave it out.

73 Tom 

_
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_
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Re: Topband: Shunt feeding the Skyneedle - new developments BTW-P.S.

[Charlie Cunningham]

By the way, Carl. it sounds like you might have eliminated a bit of series
inductance when you moved the variable capacitor into the enclosure and you
may have picked up a bit of shunt-C by moving it into the metallic
enclosure, but you are so close to dead-flat 1:1, that it really doesn't
matter. You could just tweak the variable C to minimize the reactance at the
load, but -j11 is just fine! As I said earlier your 45-j11 resides near the
origin of the chart on a 1.3:1 VSWR circle!

Enjoy and have fun!

73,
Charlie, K4OTV


-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Charlie
Cunningham
Sent: Friday, February 21, 2014 8:30 PM
To: 'Tom W8JI'; 'Carl Braun'; '160'
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments BTW

BTW. Carl

I agree completely with Tom that there's no point in having a static-bleed
choke on a grounded shunt fed tower!

73,
Charlie, K4OTV






-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Tom W8JI
Sent: Friday, February 21, 2014 8:02 PM
To: Carl Braun; '160'
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

Since then I've moved the variable capacitor inside the panel and mounted it
to a ¾ think Plexiglas sheet mounted to the back plane with nylon bolts and
washers.  There is a 1 air gap between the Plexiglas and the backplane.  I
now have seen the 42+j0 ohms change to 45 - j11 ohms...that's the lowest
reactance I can tune the capacitor for. Not really sure if its +j11 ohms or
- j11 ohms but I assume if the reading was + j11 I could continue to tune it
out with the capacitor but I cant.

Does the capacitor not play well with a steel enclosure?

Any enclosure will change things, especially a metallic enclosure. Just
readjust the cap.

The other strange situation I'm experiencing is when I connect my Array
Solutions static bleed choke to the feed thru insulator at the outside of
the panel to ground the resonant frequency jumps to 2.014 MHz at 25 +j0
ohms...remove it entirely and I'm back to my 45 - j11 ohms.

The choke is completely unnecessary with a shunt feed tower. It won't help a
thing, so leave it out.

73 Tom 

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Re: Topband: Shunt feeding the Skyneedle - new developments

[Charlie Cunningham]

I'd think your Henry would match that just fine WITHOUT the Nye Viking
tuner!!

73,

Charlie. K4OTV

-Original Message-
From: Carl Braun [mailto:carl.br...@lairdtech.com] 
Sent: Friday, February 21, 2014 8:46 PM
To: Charlie Cunningham; 'Tom W8JI'; '160'
Subject: RE: Topband: Shunt feeding the Skyneedle - new developments

Thanks to all who replied

Tom W8JI, your comments on the metallic panel and the static bleed choke
make sense.  I was so pleased with the FLAT SWR reading with the variable
cap outside the panel but I guess I can live with the slight SWR.  (Thanks
Charlie K4OTV).  I have a Nye Viking monster tuner but I hate to use it as
my Henry amp seems to load strangely when I have it inline so I think I'll
just live without it.  

Can I add some coax (coiled) to bring the X down on the -j11 reading? I did
this with the old Telrex and brought the X right down and out of the pic.
I'm sure Ill need much more than I would on 14MHz but I think I'd like to
try anyway.

I'm still going to drop the tower down and add two more gamma wires to
create a cage and I still have the option of pulling the gamma wire(s) away
from the tower another 8-10 inches to add a few more ohms to the equation.  

I'm having fun with the experiment.

Right now I'm hearing the beginnings of the SSB contest with N7GP, WD5COV,
W6YI with the big signals so far.  XE is the only DX I've heard.

Lots of stateside calling stateside

Carl AG6X

-Original Message-
From: Charlie Cunningham [mailto:charlie-cunning...@nc.rr.com] 
Sent: Friday, February 21, 2014 5:21 PM
To: 'Tom W8JI'; Carl Braun; '160'
Subject: RE: Topband: Shunt feeding the Skyneedle - new developments

Well, Carl

I plotted your 45-j11 load on a Smith Chart (normalized to 50 ohms) and it's
very near the origin on a 1.3:1 VSWR circle. Since you have a relatively
short feedline of LMR-400, You should be able to just tune it out at the
transmitter end of the line, and the LMR-400 line will be operating at such
a very low SWR (around 1.3:1 that the excess loss from a 1.3:1 VSWR at 160
is completely trivial and negligible! It may not be completely
intellectually satisfying to have -j11 of reactance at the load, but it
should match easily and the antenna should work very well!  Enjoy!

Sounds like that Array solutions static bleed is not as high in impedance as
we might wish! A large resistance might give you more satisfactory results!

GL!  Enjoy!

73,
Charlie, K4OTV





-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Tom W8JI
Sent: Friday, February 21, 2014 8:02 PM
To: Carl Braun; '160'
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

Since then I've moved the variable capacitor inside the panel and mounted it

to a ¾ think Plexiglas sheet mounted to the back plane with nylon bolts and

washers.  There is a 1 air gap between the Plexiglas and the backplane.  I 
now have seen the 42+j0 ohms change to 45 - j11 ohms...that's the lowest 
reactance I can tune the capacitor for. Not really sure if its +j11 ohms 
or - j11 ohms but I assume if the reading was + j11 I could continue to tune

it out with the capacitor but I cant.

Does the capacitor not play well with a steel enclosure?

Any enclosure will change things, especially a metallic enclosure. Just 
readjust the cap.

The other strange situation I'm experiencing is when I connect my Array 
Solutions static bleed choke to the feed thru insulator at the outside of 
the panel to ground the resonant frequency jumps to 2.014 MHz at 25 +j0 
ohms...remove it entirely and I'm back to my 45 - j11 ohms.

The choke is completely unnecessary with a shunt feed tower. It won't help a

thing, so leave it out.

73 Tom 

_
Topband Reflector Archives - http://www.contesting.com/_topband


_
Topband Reflector Archives - http://www.contesting.com/_topband

Re: Topband: Shunt feeding the Skyneedle - new developments

[ZR]

The only benefit of getting it better would be a bit more 2:1 VSWR bandwidth 
to keep the amp happy but even then there is sometimes a gotcha when tuning 
an antenna.


Carl
KM1H



Subject: Re: Topband: Shunt feeding the Skyneedle - new developments


Well, you can do all that, Carl

But if your series variable capacitor is not maxed out (fully meshed) if
you can increase the capacitance enough  to get to j0, you would be at 45
+j0 and on a 1.1:1  VSWR circle. No point int trying to do better than
that!!
Otherwise, just increase the series capacitance to bring that -j11  as
close to j0 as possible and take that! You'd be so near perfect that there
would be no real point in going further!

Your time and efforts might be better spent working on  your radial field!

73,
Charlie, K4OTV


-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl
Braun
Sent: Friday, February 21, 2014 8:46 PM
To: Charlie Cunningham; 'Tom W8JI'; '160'
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

Thanks to all who replied

Tom W8JI, your comments on the metallic panel and the static bleed choke
make sense.  I was so pleased with the FLAT SWR reading with the variable
cap outside the panel but I guess I can live with the slight SWR.  (Thanks
Charlie K4OTV).  I have a Nye Viking monster tuner but I hate to use it as
my Henry amp seems to load strangely when I have it inline so I think I'll
just live without it.

Can I add some coax (coiled) to bring the X down on the -j11 reading? I did
this with the old Telrex and brought the X right down and out of the pic.
I'm sure Ill need much more than I would on 14MHz but I think I'd like to
try anyway.

I'm still going to drop the tower down and add two more gamma wires to
create a cage and I still have the option of pulling the gamma wire(s) away
from the tower another 8-10 inches to add a few more ohms to the equation.

I'm having fun with the experiment.

Right now I'm hearing the beginnings of the SSB contest with N7GP, WD5COV,
W6YI with the big signals so far.  XE is the only DX I've heard.

Lots of stateside calling stateside

Carl AG6X

-Original Message-
From: Charlie Cunningham [mailto:charlie-cunning...@nc.rr.com]
Sent: Friday, February 21, 2014 5:21 PM
To: 'Tom W8JI'; Carl Braun; '160'
Subject: RE: Topband: Shunt feeding the Skyneedle - new developments

Well, Carl

I plotted your 45-j11 load on a Smith Chart (normalized to 50 ohms) and it's
very near the origin on a 1.3:1 VSWR circle. Since you have a relatively
short feedline of LMR-400, You should be able to just tune it out at the
transmitter end of the line, and the LMR-400 line will be operating at such
a very low SWR (around 1.3:1 that the excess loss from a 1.3:1 VSWR at 160
is completely trivial and negligible! It may not be completely
intellectually satisfying to have -j11 of reactance at the load, but it
should match easily and the antenna should work very well!  Enjoy!

Sounds like that Array solutions static bleed is not as high in impedance as
we might wish! A large resistance might give you more satisfactory results!

GL!  Enjoy!

73,
Charlie, K4OTV





-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Tom W8JI
Sent: Friday, February 21, 2014 8:02 PM
To: Carl Braun; '160'
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

Since then I've moved the variable capacitor inside the panel and mounted it

to a ¾ think Plexiglas sheet mounted to the back plane with nylon bolts and

washers.  There is a 1 air gap between the Plexiglas and the backplane.  I
now have seen the 42+j0 ohms change to 45 - j11 ohms...that's the lowest
reactance I can tune the capacitor for. Not really sure if its +j11 ohms
or - j11 ohms but I assume if the reading was + j11 I could continue to tune

it out with the capacitor but I cant.

Does the capacitor not play well with a steel enclosure?

Any enclosure will change things, especially a metallic enclosure. Just
readjust the cap.

The other strange situation I'm experiencing is when I connect my Array
Solutions static bleed choke to the feed thru insulator at the outside of
the panel to ground the resonant frequency jumps to 2.014 MHz at 25 +j0
ohms...remove it entirely and I'm back to my 45 - j11 ohms.

The choke is completely unnecessary with a shunt feed tower. It won't help a

thing, so leave it out.

73 Tom

_
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_
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-
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Checked by AVG - www.avg.com
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Re: Topband: Shunt feeding the Skyneedle - new developments

[Charlie Cunningham]

Well, if I recall correctly, Carl, Carl said his  feedline was about 70' of
LMR-400, so even at 2 2:1 or 2.5:1 VSWR, the excess losses in 70' of LMR-400
at 1.8 MHz are almost 0, so if he can match it OK at the transmitter end of
the line- no real point in making heroic efforts to achieve a perfect
match!  He'd gain more by working on his radial field, and he really should
do that before doing any more tuning because improving the radials WILL
affect the antenna impedance.

73,
Charlie, K4OTV

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of ZR
Sent: Friday, February 21, 2014 10:11 PM
To: Charlie Cunningham; 'Carl Braun'; '160'
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

The only benefit of getting it better would be a bit more 2:1 VSWR bandwidth
to keep the amp happy but even then there is sometimes a gotcha when tuning
an antenna.

Carl
KM1H



Subject: Re: Topband: Shunt feeding the Skyneedle - new developments


Well, you can do all that, Carl

But if your series variable capacitor is not maxed out (fully meshed) if you
can increase the capacitance enough  to get to j0, you would be at 45
+j0 and on a 1.1:1  VSWR circle. No point int trying to do better than
that!!
 Otherwise, just increase the series capacitance to bring that -j11  as
close to j0 as possible and take that! You'd be so near perfect that there
would be no real point in going further!

Your time and efforts might be better spent working on  your radial field!

73,
Charlie, K4OTV


-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl
Braun
Sent: Friday, February 21, 2014 8:46 PM
To: Charlie Cunningham; 'Tom W8JI'; '160'
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

Thanks to all who replied

Tom W8JI, your comments on the metallic panel and the static bleed choke
make sense.  I was so pleased with the FLAT SWR reading with the variable
cap outside the panel but I guess I can live with the slight SWR.  (Thanks
Charlie K4OTV).  I have a Nye Viking monster tuner but I hate to use it as
my Henry amp seems to load strangely when I have it inline so I think I'll
just live without it.

Can I add some coax (coiled) to bring the X down on the -j11 reading? I did
this with the old Telrex and brought the X right down and out of the pic.
I'm sure Ill need much more than I would on 14MHz but I think I'd like to
try anyway.

I'm still going to drop the tower down and add two more gamma wires to
create a cage and I still have the option of pulling the gamma wire(s) away
from the tower another 8-10 inches to add a few more ohms to the equation.

I'm having fun with the experiment.

Right now I'm hearing the beginnings of the SSB contest with N7GP, WD5COV,
W6YI with the big signals so far.  XE is the only DX I've heard.

Lots of stateside calling stateside

Carl AG6X

-Original Message-
From: Charlie Cunningham [mailto:charlie-cunning...@nc.rr.com]
Sent: Friday, February 21, 2014 5:21 PM
To: 'Tom W8JI'; Carl Braun; '160'
Subject: RE: Topband: Shunt feeding the Skyneedle - new developments

Well, Carl

I plotted your 45-j11 load on a Smith Chart (normalized to 50 ohms) and it's
very near the origin on a 1.3:1 VSWR circle. Since you have a relatively
short feedline of LMR-400, You should be able to just tune it out at the
transmitter end of the line, and the LMR-400 line will be operating at such
a very low SWR (around 1.3:1 that the excess loss from a 1.3:1 VSWR at 160
is completely trivial and negligible! It may not be completely
intellectually satisfying to have -j11 of reactance at the load, but it
should match easily and the antenna should work very well!  Enjoy!

Sounds like that Array solutions static bleed is not as high in impedance as
we might wish! A large resistance might give you more satisfactory results!

GL!  Enjoy!

73,
Charlie, K4OTV





-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Tom W8JI
Sent: Friday, February 21, 2014 8:02 PM
To: Carl Braun; '160'
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

Since then I've moved the variable capacitor inside the panel and mounted it

to a ¾ think Plexiglas sheet mounted to the back plane with nylon bolts and

washers.  There is a 1 air gap between the Plexiglas and the backplane.  I
now have seen the 42+j0 ohms change to 45 - j11 ohms...that's the lowest
reactance I can tune the capacitor for. Not really sure if its +j11 ohms or
- j11 ohms but I assume if the reading was + j11 I could continue to tune

it out with the capacitor but I cant.

Does the capacitor not play well with a steel enclosure?

Any enclosure will change things, especially a metallic enclosure. Just
readjust the cap.

The other strange situation I'm experiencing is when I connect my Array
Solutions static bleed choke to the feed thru insulator at the outside of
the panel to ground the resonant frequency jumps

Re: Topband: Shunt feeding the Skyneedle - new developments

[Carl Braun]

Charlie

The cap is no where near maxed out.  I'm using approx 150pf of a 1050pf 
variable cap.  

Carl

-Original Message-
From: Charlie Cunningham [mailto:charlie-cunning...@nc.rr.com] 
Sent: Friday, February 21, 2014 6:37 PM
To: Carl Braun; 'Tom W8JI'; '160'
Subject: RE: Topband: Shunt feeding the Skyneedle - new developments

Well, you can do all that, Carl

But if your series variable capacitor is not maxed out (fully meshed) if
you can increase the capacitance enough  to get to j0, you would be at 45
+j0 and on a 1.1:1  VSWR circle. No point int trying to do better than
that!!
 Otherwise, just increase the series capacitance to bring that -j11  as
close to j0 as possible and take that! You'd be so near perfect that there
would be no real point in going further!

Your time and efforts might be better spent working on  your radial field!

73,
Charlie, K4OTV


-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl
Braun
Sent: Friday, February 21, 2014 8:46 PM
To: Charlie Cunningham; 'Tom W8JI'; '160'
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

Thanks to all who replied

Tom W8JI, your comments on the metallic panel and the static bleed choke
make sense.  I was so pleased with the FLAT SWR reading with the variable
cap outside the panel but I guess I can live with the slight SWR.  (Thanks
Charlie K4OTV).  I have a Nye Viking monster tuner but I hate to use it as
my Henry amp seems to load strangely when I have it inline so I think I'll
just live without it.  

Can I add some coax (coiled) to bring the X down on the -j11 reading? I did
this with the old Telrex and brought the X right down and out of the pic.
I'm sure Ill need much more than I would on 14MHz but I think I'd like to
try anyway.

I'm still going to drop the tower down and add two more gamma wires to
create a cage and I still have the option of pulling the gamma wire(s) away
from the tower another 8-10 inches to add a few more ohms to the equation.  

I'm having fun with the experiment.

Right now I'm hearing the beginnings of the SSB contest with N7GP, WD5COV,
W6YI with the big signals so far.  XE is the only DX I've heard.

Lots of stateside calling stateside

Carl AG6X

-Original Message-
From: Charlie Cunningham [mailto:charlie-cunning...@nc.rr.com] 
Sent: Friday, February 21, 2014 5:21 PM
To: 'Tom W8JI'; Carl Braun; '160'
Subject: RE: Topband: Shunt feeding the Skyneedle - new developments

Well, Carl

I plotted your 45-j11 load on a Smith Chart (normalized to 50 ohms) and it's
very near the origin on a 1.3:1 VSWR circle. Since you have a relatively
short feedline of LMR-400, You should be able to just tune it out at the
transmitter end of the line, and the LMR-400 line will be operating at such
a very low SWR (around 1.3:1 that the excess loss from a 1.3:1 VSWR at 160
is completely trivial and negligible! It may not be completely
intellectually satisfying to have -j11 of reactance at the load, but it
should match easily and the antenna should work very well!  Enjoy!

Sounds like that Array solutions static bleed is not as high in impedance as
we might wish! A large resistance might give you more satisfactory results!

GL!  Enjoy!

73,
Charlie, K4OTV





-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Tom W8JI
Sent: Friday, February 21, 2014 8:02 PM
To: Carl Braun; '160'
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

Since then I've moved the variable capacitor inside the panel and mounted it

to a ¾ think Plexiglas sheet mounted to the back plane with nylon bolts and

washers.  There is a 1 air gap between the Plexiglas and the backplane.  I 
now have seen the 42+j0 ohms change to 45 - j11 ohms...that's the lowest 
reactance I can tune the capacitor for. Not really sure if its +j11 ohms 
or - j11 ohms but I assume if the reading was + j11 I could continue to tune

it out with the capacitor but I cant.

Does the capacitor not play well with a steel enclosure?

Any enclosure will change things, especially a metallic enclosure. Just 
readjust the cap.

The other strange situation I'm experiencing is when I connect my Array 
Solutions static bleed choke to the feed thru insulator at the outside of 
the panel to ground the resonant frequency jumps to 2.014 MHz at 25 +j0 
ohms...remove it entirely and I'm back to my 45 - j11 ohms.

The choke is completely unnecessary with a shunt feed tower. It won't help a

thing, so leave it out.

73 Tom 

_
Topband Reflector Archives - http://www.contesting.com/_topband

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Re: Topband: Shunt feeding the Skyneedle - new developments

[Charlie Cunningham]

Well, Carl, you might pick up a littie less shunt C with the vacuum
variable, and if it will provide more capacitance, it will probably allow
you to get to j0. I guess if you don't have some other need for the high
voltage capability of the vacuum variable, It should surely do the job!

If you are at -j11, that means you have tken out enough inductance from the
gamma line that you now need a larger capacitor to resonate it.
Have fun!

73,
Charlie, K4OTV

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl
Braun
Sent: Friday, February 21, 2014 10:31 PM
To: ZR
Cc: Charlie Cunningham; 160
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

Thanks guys

The j11 ohms is the best I can get period. I was able to get j0 when the cap
was outside of the steel enclosure with a better bandwidth. Maybe I should
throw my $400 enclosure and find a fibergla$$ enclosure. But as others have
indicated I should probably just live with it. 

Do you think a smaller (physically) vacuum cap would have less interaction
with the steel enclosure.  The one I have is only 3 round and 6 long. The
air variable I'm using is 13 long and 7 round at mesh

Carl AG6X

Sent from my iPhone

 On Feb 21, 2014, at 7:11 PM, ZR z...@jeremy.mv.com wrote:
 
 The only benefit of getting it better would be a bit more 2:1 VSWR
bandwidth to keep the amp happy but even then there is sometimes a gotcha
when tuning an antenna.
 
 Carl
 KM1H
 
 
 
 Subject: Re: Topband: Shunt feeding the Skyneedle - new developments
 
 
 Well, you can do all that, Carl
 
 But if your series variable capacitor is not maxed out (fully meshed) if
 you can increase the capacitance enough  to get to j0, you would be at 45
 +j0 and on a 1.1:1  VSWR circle. No point int trying to do better than
 that!!
 Otherwise, just increase the series capacitance to bring that -j11  as
 close to j0 as possible and take that! You'd be so near perfect that there
 would be no real point in going further!
 
 Your time and efforts might be better spent working on  your radial field!
 
 73,
 Charlie, K4OTV
 
 
 -Original Message-
 From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl
 Braun
 Sent: Friday, February 21, 2014 8:46 PM
 To: Charlie Cunningham; 'Tom W8JI'; '160'
 Subject: Re: Topband: Shunt feeding the Skyneedle - new developments
 
 Thanks to all who replied
 
 Tom W8JI, your comments on the metallic panel and the static bleed choke
 make sense.  I was so pleased with the FLAT SWR reading with the variable
 cap outside the panel but I guess I can live with the slight SWR.  (Thanks
 Charlie K4OTV).  I have a Nye Viking monster tuner but I hate to use it as
 my Henry amp seems to load strangely when I have it inline so I think I'll
 just live without it.
 
 Can I add some coax (coiled) to bring the X down on the -j11 reading? I
did
 this with the old Telrex and brought the X right down and out of the pic.
 I'm sure Ill need much more than I would on 14MHz but I think I'd like to
 try anyway.
 
 I'm still going to drop the tower down and add two more gamma wires to
 create a cage and I still have the option of pulling the gamma wire(s)
away
 from the tower another 8-10 inches to add a few more ohms to the equation.
 
 I'm having fun with the experiment.
 
 Right now I'm hearing the beginnings of the SSB contest with N7GP, WD5COV,
 W6YI with the big signals so far.  XE is the only DX I've heard.
 
 Lots of stateside calling stateside
 
 Carl AG6X
 
 -Original Message-
 From: Charlie Cunningham [mailto:charlie-cunning...@nc.rr.com]
 Sent: Friday, February 21, 2014 5:21 PM
 To: 'Tom W8JI'; Carl Braun; '160'
 Subject: RE: Topband: Shunt feeding the Skyneedle - new developments
 
 Well, Carl
 
 I plotted your 45-j11 load on a Smith Chart (normalized to 50 ohms) and
it's
 very near the origin on a 1.3:1 VSWR circle. Since you have a relatively
 short feedline of LMR-400, You should be able to just tune it out at the
 transmitter end of the line, and the LMR-400 line will be operating at
such
 a very low SWR (around 1.3:1 that the excess loss from a 1.3:1 VSWR at 160
 is completely trivial and negligible! It may not be completely
 intellectually satisfying to have -j11 of reactance at the load, but it
 should match easily and the antenna should work very well!  Enjoy!
 
 Sounds like that Array solutions static bleed is not as high in impedance
as
 we might wish! A large resistance might give you more satisfactory
results!
 
 GL!  Enjoy!
 
 73,
 Charlie, K4OTV
 
 
 
 
 
 -Original Message-
 From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Tom
W8JI
 Sent: Friday, February 21, 2014 8:02 PM
 To: Carl Braun; '160'
 Subject: Re: Topband: Shunt feeding the Skyneedle - new developments
 
 Since then I've moved the variable capacitor inside the panel and mounted
it
 
 to a ¾ think Plexiglas sheet mounted to the back plane with nylon bolts
and
 
 washers.  There is a 1 air gap between

Re: Topband: Shunt feeding the Skyneedle - new developments

[Charlie Cunningham]

Well, that would surely suggest that you should be able to reach j0, by
increasing the series capacitance, Carl, unless there's a shunt-C term that
has entered the picture after mouning that big variable capacitor in the
metallic enclosure. But, again, why bother!

73,
Charlie, K4OTV

-Original Message-
From: Carl Braun [mailto:carl.br...@lairdtech.com] 
Sent: Friday, February 21, 2014 10:39 PM
To: Charlie Cunningham; 'Tom W8JI'; '160'
Subject: RE: Topband: Shunt feeding the Skyneedle - new developments

Charlie

The cap is no where near maxed out.  I'm using approx 150pf of a 1050pf
variable cap.  

Carl

-Original Message-
From: Charlie Cunningham [mailto:charlie-cunning...@nc.rr.com]
Sent: Friday, February 21, 2014 6:37 PM
To: Carl Braun; 'Tom W8JI'; '160'
Subject: RE: Topband: Shunt feeding the Skyneedle - new developments

Well, you can do all that, Carl

But if your series variable capacitor is not maxed out (fully meshed) if you
can increase the capacitance enough  to get to j0, you would be at 45
+j0 and on a 1.1:1  VSWR circle. No point int trying to do better than
that!!
 Otherwise, just increase the series capacitance to bring that -j11  as
close to j0 as possible and take that! You'd be so near perfect that there
would be no real point in going further!

Your time and efforts might be better spent working on  your radial field!

73,
Charlie, K4OTV


-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl
Braun
Sent: Friday, February 21, 2014 8:46 PM
To: Charlie Cunningham; 'Tom W8JI'; '160'
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

Thanks to all who replied

Tom W8JI, your comments on the metallic panel and the static bleed choke
make sense.  I was so pleased with the FLAT SWR reading with the variable
cap outside the panel but I guess I can live with the slight SWR.  (Thanks
Charlie K4OTV).  I have a Nye Viking monster tuner but I hate to use it as
my Henry amp seems to load strangely when I have it inline so I think I'll
just live without it.  

Can I add some coax (coiled) to bring the X down on the -j11 reading? I did
this with the old Telrex and brought the X right down and out of the pic.
I'm sure Ill need much more than I would on 14MHz but I think I'd like to
try anyway.

I'm still going to drop the tower down and add two more gamma wires to
create a cage and I still have the option of pulling the gamma wire(s) away
from the tower another 8-10 inches to add a few more ohms to the equation.  

I'm having fun with the experiment.

Right now I'm hearing the beginnings of the SSB contest with N7GP, WD5COV,
W6YI with the big signals so far.  XE is the only DX I've heard.

Lots of stateside calling stateside

Carl AG6X

-Original Message-
From: Charlie Cunningham [mailto:charlie-cunning...@nc.rr.com]
Sent: Friday, February 21, 2014 5:21 PM
To: 'Tom W8JI'; Carl Braun; '160'
Subject: RE: Topband: Shunt feeding the Skyneedle - new developments

Well, Carl

I plotted your 45-j11 load on a Smith Chart (normalized to 50 ohms) and it's
very near the origin on a 1.3:1 VSWR circle. Since you have a relatively
short feedline of LMR-400, You should be able to just tune it out at the
transmitter end of the line, and the LMR-400 line will be operating at such
a very low SWR (around 1.3:1 that the excess loss from a 1.3:1 VSWR at 160
is completely trivial and negligible! It may not be completely
intellectually satisfying to have -j11 of reactance at the load, but it
should match easily and the antenna should work very well!  Enjoy!

Sounds like that Array solutions static bleed is not as high in impedance as
we might wish! A large resistance might give you more satisfactory results!

GL!  Enjoy!

73,
Charlie, K4OTV





-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Tom W8JI
Sent: Friday, February 21, 2014 8:02 PM
To: Carl Braun; '160'
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

Since then I've moved the variable capacitor inside the panel and mounted it

to a ¾ think Plexiglas sheet mounted to the back plane with nylon bolts and

washers.  There is a 1 air gap between the Plexiglas and the backplane.  I
now have seen the 42+j0 ohms change to 45 - j11 ohms...that's the lowest
reactance I can tune the capacitor for. Not really sure if its +j11 ohms or
- j11 ohms but I assume if the reading was + j11 I could continue to tune

it out with the capacitor but I cant.

Does the capacitor not play well with a steel enclosure?

Any enclosure will change things, especially a metallic enclosure. Just
readjust the cap.

The other strange situation I'm experiencing is when I connect my Array
Solutions static bleed choke to the feed thru insulator at the outside of
the panel to ground the resonant frequency jumps to 2.014 MHz at 25 +j0
ohms...remove it entirely and I'm back to my 45 - j11 ohms.

The choke is completely unnecessary with a shunt feed tower

Re: Topband: Shunt feeding the Skyneedle - new developments

[Carl Braun]

I'm working on the radial field weekly.  

Here is a theoretical question that results from my particular QTH.  The 
Skyneedle is situated near a secondary blacktop driveway that is in the back of 
my property.  I have to run radials over the blacktop to the rest of the 
property and, in order to keep things kind of neat, I'm using multi-conductor 
rotor cable as radials that travel over the blacktop.  I have both 6 conductor 
and 3 conductor control cable that I'm using.  I strip back the jacket at the 
radial ring...fan out the wires 3 apart and attach them to the 1 1/2 copper 
pipe I'm using as a radial ring around the base of the 'Needle'.  Then the 
radial wires converge back into the cable jacket then travel across the 10' 
blacktop driveway and then they are removed from the cable jacket where they 
fan out into the dirt and are buried.  Most of these radial wires are 60' to 
100' once they leave the jacket.

Any problem with what I'm doing here?  I understand that it would be better if 
they fanned out directly from the base but I can have 50+ wires traveling over 
the blacktop.

I was even considering getting an asphalt blade and cutting some channels into 
the blacktop...burying the jacketed cable into the asphalt and then sealing 
then in so I'm not running over them or tripping over them when playing Frisbee 
with the hound.

My Guatemalan yard worker has been burying radial wires for the last month and 
thinks that I'm LOCO but he likes getting paid at the end of the day.

As we speak I have a total of 34 radials with the shortest being 30' with the 
longest at 100'.  Most of them are 60-70'.  Four of them are tied into my 40m 
phased array radial field comprised of 90-100 radials under each antenna 
ranging from 40' to 80'.  I can change the height of these verticals from 33' 
for 40m to 66' for 80m.  1/2 wl spacing on 40 and 1/4 wl spacing on 80.

Carl AG6X

-Original Message-
From: Charlie Cunningham [mailto:charlie-cunning...@nc.rr.com] 
Sent: Friday, February 21, 2014 7:36 PM
To: 'ZR'; Carl Braun; '160'
Subject: RE: Topband: Shunt feeding the Skyneedle - new developments

Well, if I recall correctly, Carl, Carl said his  feedline was about 70' of
LMR-400, so even at 2 2:1 or 2.5:1 VSWR, the excess losses in 70' of LMR-400
at 1.8 MHz are almost 0, so if he can match it OK at the transmitter end of
the line- no real point in making heroic efforts to achieve a perfect
match!  He'd gain more by working on his radial field, and he really should
do that before doing any more tuning because improving the radials WILL
affect the antenna impedance.

73,
Charlie, K4OTV

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of ZR
Sent: Friday, February 21, 2014 10:11 PM
To: Charlie Cunningham; 'Carl Braun'; '160'
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

The only benefit of getting it better would be a bit more 2:1 VSWR bandwidth
to keep the amp happy but even then there is sometimes a gotcha when tuning
an antenna.

Carl
KM1H



Subject: Re: Topband: Shunt feeding the Skyneedle - new developments


Well, you can do all that, Carl

But if your series variable capacitor is not maxed out (fully meshed) if you
can increase the capacitance enough  to get to j0, you would be at 45
+j0 and on a 1.1:1  VSWR circle. No point int trying to do better than
that!!
 Otherwise, just increase the series capacitance to bring that -j11  as
close to j0 as possible and take that! You'd be so near perfect that there
would be no real point in going further!

Your time and efforts might be better spent working on  your radial field!

73,
Charlie, K4OTV


-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl
Braun
Sent: Friday, February 21, 2014 8:46 PM
To: Charlie Cunningham; 'Tom W8JI'; '160'
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

Thanks to all who replied

Tom W8JI, your comments on the metallic panel and the static bleed choke
make sense.  I was so pleased with the FLAT SWR reading with the variable
cap outside the panel but I guess I can live with the slight SWR.  (Thanks
Charlie K4OTV).  I have a Nye Viking monster tuner but I hate to use it as
my Henry amp seems to load strangely when I have it inline so I think I'll
just live without it.

Can I add some coax (coiled) to bring the X down on the -j11 reading? I did
this with the old Telrex and brought the X right down and out of the pic.
I'm sure Ill need much more than I would on 14MHz but I think I'd like to
try anyway.

I'm still going to drop the tower down and add two more gamma wires to
create a cage and I still have the option of pulling the gamma wire(s) away
from the tower another 8-10 inches to add a few more ohms to the equation.

I'm having fun with the experiment.

Right now I'm hearing the beginnings of the SSB contest with N7GP, WD5COV,
W6YI with the big signals so far.  XE is the only DX I've heard

Re: Topband: Shunt feeding the Skyneedle - new developments

[Charlie Cunningham]

Hi, Carl

Well, I think that what you are doing with your radials should be OK. I
guess I'd rather get them under the asphalt if  I could where they wouldn't
get torn up or b a trip hazard.

BTW I I was playing with your match on the Smith Chart and if you'll add
about 1 uHy inductance in series with the connector (SO-239?) where  you
feedline leaves the enclosure, that will take you to 45 +j0, but I'd be
concerned about incurring more losses in the inductor than any tiny mismatch
loss from the -j11 term. I probably wouldn't do it.

73,
Charlie, K4OTV


-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl
Braun
Sent: Friday, February 21, 2014 10:56 PM
To: Charlie Cunningham; 'ZR'; '160'
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

I'm working on the radial field weekly.  

Here is a theoretical question that results from my particular QTH.  The
Skyneedle is situated near a secondary blacktop driveway that is in the back
of my property.  I have to run radials over the blacktop to the rest of the
property and, in order to keep things kind of neat, I'm using
multi-conductor rotor cable as radials that travel over the blacktop.  I
have both 6 conductor and 3 conductor control cable that I'm using.  I strip
back the jacket at the radial ring...fan out the wires 3 apart and attach
them to the 1 1/2 copper pipe I'm using as a radial ring around the base of
the 'Needle'.  Then the radial wires converge back into the cable jacket
then travel across the 10' blacktop driveway and then they are removed from
the cable jacket where they fan out into the dirt and are buried.  Most of
these radial wires are 60' to 100' once they leave the jacket.

Any problem with what I'm doing here?  I understand that it would be better
if they fanned out directly from the base but I can have 50+ wires traveling
over the blacktop.

I was even considering getting an asphalt blade and cutting some channels
into the blacktop...burying the jacketed cable into the asphalt and then
sealing then in so I'm not running over them or tripping over them when
playing Frisbee with the hound.

My Guatemalan yard worker has been burying radial wires for the last month
and thinks that I'm LOCO but he likes getting paid at the end of the day.

As we speak I have a total of 34 radials with the shortest being 30' with
the longest at 100'.  Most of them are 60-70'.  Four of them are tied into
my 40m phased array radial field comprised of 90-100 radials under each
antenna ranging from 40' to 80'.  I can change the height of these verticals
from 33' for 40m to 66' for 80m.  1/2 wl spacing on 40 and 1/4 wl spacing on
80.

Carl AG6X

-Original Message-
From: Charlie Cunningham [mailto:charlie-cunning...@nc.rr.com]
Sent: Friday, February 21, 2014 7:36 PM
To: 'ZR'; Carl Braun; '160'
Subject: RE: Topband: Shunt feeding the Skyneedle - new developments

Well, if I recall correctly, Carl, Carl said his  feedline was about 70' of
LMR-400, so even at 2 2:1 or 2.5:1 VSWR, the excess losses in 70' of LMR-400
at 1.8 MHz are almost 0, so if he can match it OK at the transmitter end of
the line- no real point in making heroic efforts to achieve a perfect
match!  He'd gain more by working on his radial field, and he really should
do that before doing any more tuning because improving the radials WILL
affect the antenna impedance.

73,
Charlie, K4OTV

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of ZR
Sent: Friday, February 21, 2014 10:11 PM
To: Charlie Cunningham; 'Carl Braun'; '160'
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

The only benefit of getting it better would be a bit more 2:1 VSWR bandwidth
to keep the amp happy but even then there is sometimes a gotcha when tuning
an antenna.

Carl
KM1H



Subject: Re: Topband: Shunt feeding the Skyneedle - new developments


Well, you can do all that, Carl

But if your series variable capacitor is not maxed out (fully meshed) if you
can increase the capacitance enough  to get to j0, you would be at 45
+j0 and on a 1.1:1  VSWR circle. No point int trying to do better than
that!!
 Otherwise, just increase the series capacitance to bring that -j11  as
close to j0 as possible and take that! You'd be so near perfect that there
would be no real point in going further!

Your time and efforts might be better spent working on  your radial field!

73,
Charlie, K4OTV


-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl
Braun
Sent: Friday, February 21, 2014 8:46 PM
To: Charlie Cunningham; 'Tom W8JI'; '160'
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

Thanks to all who replied

Tom W8JI, your comments on the metallic panel and the static bleed choke
make sense.  I was so pleased with the FLAT SWR reading with the variable
cap outside the panel but I guess I can live with the slight SWR.  (Thanks
Charlie K4OTV).  I have

Re: Topband: Shunt feeding the Skyneedle

[Tom W8JI]

You can temporarily use an inductor in series with the cap to extend the 
range. It will not be a good idea for transmitting, but OK for tuning.


- Original Message - 
From: Carl Braun carl.br...@lairdtech.com

To: Tom W8JI w...@w8ji.com
Cc: 160 topband@contesting.com
Sent: Tuesday, February 04, 2014 10:27 PM
Subject: Re: Topband: Shunt feeding the Skyneedle



Thanks for the input Tom

The only variable cap I have is the EF Johnson which is 60-160pf. I have 
some ham radio stuff at my parents house not the least is a Jennings 
1000pf vac variable rated at 5KV or 7.5kv. I was hoping to use that with a 
12v motor for QSYing up the band for contesting. I'll have to ask mom to 
send it to CA in a pkg with some cookies.


When the gamma arm was at 90' I was able to add 160pf to get a resonance 
point around 1825 but the resistance was still high at 58-60 and X was 
20++. Maybe the big vacuum cap  would bring that R and X down to where it 
needs to be.


ON4UNs figure 9-85 on page 9-71 of his third edition shows that a tower 
that is electrical 110 to 130 degrees should have a tap height around 20 
meters and a matching cap of 400pf. That being said it may be a good idea 
to get the vac variable into service. I would assume I would want to raise 
the gamma arm back up to 90' as it resonated closer to 1825 than the 
latest iteration which shows a Fr near

1.977


Sent from my iPhone


On Feb 4, 2014, at 6:40 PM, Tom W8JI w...@w8ji.com wrote:

Here's what changed though...when I had the gamma arm at 90' with the 14 
gauge gamma wire 24 away from the tower I was able to insert my Johnson 
60-160pf variable cap in series with the gamma wire to get approx 58-60 
ohms at X=20.  The cap was 2/3 meshed at this point.  


That's the right way. You have to cancel the reatcance of the drop arm to 
get a good reading. Maybe you need a larger capacitor to hit the bottom 
of the band? Resistance normally goes up in a case like yours as 
frequency is drecreased.


NOW that I've lowered the gamma arm to the 67' level...I insert my 
variable cap and the antenna resonates at 1.970 MHz with R=36 ohms and 
X=0. For some odd reason the MFJ SWR reading shows 1.0:1 with this 36 ohm 
reading and, inside the shack, the Ft1000D shows 1.0:1 swr from 1.988 to 
1.950 and a 1.5:1 range of 2.007 to 1.930


What does more capacitance do?

It now appears that the antenna is a bit short but why am I seeing 
these crazy high resistance readings with no variable cap in line?


You should see them. The MFJ detector is a 50 ohm bridge. It will 
overflow and give all kinds of goofy readings when impedance is far away 
from 50 ohms.


How can I lower the resonant freq without moving the gamma arm up? 
Increase the spacing of the gamma wire from the tower? Add more 
radials?


I would have left it at the top and shorted the wire to the tower at 
different places until I found the sweet spot. But you have to dip the 
reactance out to really know what you have.



I was going to build a three conductor wire cage with the wires spaced 
10 apart or so once I had an idea where the antenna resonates.  Would a 
fatter gamma trio drop the resonant freq or just change the capacitance 
value of the antenna?


A fatter shunt wire will lower reactance and resistance. You will need 
more C, and the tuned resistance will be a bit lower.

_
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Topband: Shunt feeding the Skyneedle

[Carl Braun]

Topbanders

If you followed my post on 'In search of resonance' you'll see that I was 
struggling with feeding a 160m inverted L up close to my 90' Skyneedle.  Tom 
W8JI suggested that I cut back the L to 129' but the same phenomenon was 
seen...that being the VERTICAL section of the inverted L was being completely 
suppressed by the Skyneedle.  At 129' long the antenna resonated nicely on 8.2 
MHz or so...indicating the vertical section was still suppressed and the top 
29' was resonating.  With this in mind I decided to run a shunt wire from the 
top to see where the antenna resonates.  Here's what I found...

The Skyneedle is 90' tall and has a 13' mast sticking out the top that mounts a 
Telrex 20M546 yagi on a 15m boom.

The aluminum gamma arm was attached at the 90' level at 24 away from the tower 
and held in place by PVC standoffs.  See attached photo if the reflector lets 
me post an attachment.

The MFJ read 380 ohms at 1825 and the X is way off the scale.  I inserted an EF 
Johnson 10-160pf air variable capacitor at the base...in series...and was able 
to tune the antenna to 60 ohms and the X=22.  If I played with the cap there 
was a real sharp drop in reactance showing X=12.  The air variable was about ¾ 
meshed.

Here are the other resonant points...

15.8 MHz X=0 R=37 with pos and neg reactance on either side of X=0.  This freq 
showed the sharpest dip of any of the three.

Next was 10.6 MHz X=0 R=23 with pos and neg reactance on either side of X=0.

The last real dip I saw was at 5.3 Mhz with X=0 R=10

No dips below these frequencies but as I stated earlier I tuned the MFJ 259 to 
1825 and then played with the variable cap where I saw the big drop in 
impedance. (58-60 ohms at X=12 to 22.

Here are my questions for the gurus...

Do I attempt to match the antenna using a gamma match by tapping the Skyneedle 
at the 67' level to see how it reacts with regards to R and X?  (Note - I 
cannot vary my gamma arm height as this is a tubular tower and there are few 
places to bolt on the gamma arm...90', 67', 46' and 25' with the latter being 
the crows nest platform).


Or


Can I leave the gamma arm at 90' and rely on an Omega match to tune the antenna?



Carl

_
Topband Reflector Archives - http://www.contesting.com/_topband

Re: Topband: Shunt feeding the Skyneedle

[Carl Braun]

Tom and group

The SWR is 2.4:1 at 1822

I have an old Heathkit tuner that has a pair of air variables that I may 
temporarily yank to experiment with gamma vs. omega matching.  I've got a wing 
wang capacitance meter that would tell me the values once I get something to 
resonate.

The 160pf Johnson variable is 3/4 meshed so I don't see additional C being 
needed in series.  I think I will have to add a parallel C to get it down to 50 
ohms and x=0.  If I can get the tower to 50/x=0 then I'll substitute a vac 
variable in for the Johnson.  The Johnson SHOULD work as a parallel cap as it's 
good for 7KV according to the Johnson literature.  See pic.

Also, I've been basing a lot of my values (tap height and gamma spacing) on 
ON4UNs charts.  But I found some English amateur who did a study on 
gamma/Omega/Beta matching and found that ON4UNs calculations are up to 2X out 
of whack.  I also found an old article on shunt feeding towers from Ham Radio 
magazine that gave tap height, gamma spacing and C curves. His calculations 
were off quite a bit as compared to ON4UNs.  I attributed this to computer 
modeling vs. none back in the day and would tend to think the modeling results 
are more accurate.  See attached article.  I see a good 20-40 degrees 
difference between the old school article and ON4UNs calculations.

I don't do any modeling though I'd like to try EZNEC or? one of these days to 
see what my various antennas really look like.

So, i'm assuming you're suggesting that I drop the gamma arm down to the 67' 
level and see what the impedance looks like?  If so, I'm guessing the series C 
required to tune would increase in value?

Please advise

Thanks

Carl AG6X


-Original Message-
From: Tom W8JI [mailto:w...@w8ji.com] 
Sent: Monday, February 03, 2014 8:58 AM
To: Carl Braun; '160'
Subject: Re: Shunt feeding the Skyneedle

the vertical section was still suppressed and the top 29' was resonating. 
With this in mind I decided to run a shunt wire from the top to see where 
the antenna resonates.  Here's what I found..

I was afraid the tower was messing up the L. This is what happens when they 
are are nearly resonant.

You can't measure tower resonance with a drop wire. The drop wire is a stub 
or shorted transmission line in parallel with the common mode impedance 
presented by the drop wire and tower combination. It is just a mess of stuff 
going on.

 
The MFJ read 380 ohms at 1825 and the X is way off the scale.  I inserted an 
EF Johnson 10-160pf air variable capacitor at the base.in series.and was 
able to tune the antenna to 60 ohms and the X=22.  If I played with the cap 
there was a real sharp drop in reactance showing X=12.  The air variable was 
about ¾ meshed.



Reducing the lenth (tap point height) of the drop wire is a better way to 
get impedance right. Or, better still, use a multiple wire drop to make the 
drop diameter look larger. That will reduce Q, require more C, and should 
reduce impedance.

You are so close at 60 ohms I would not worry. Adjust the cap for lowest 
SWR. What is the SWR??



_
Topband Reflector Archives - http://www.contesting.com/_topband

Re: Topband: Shunt feeding the Skyneedle

[Carl Braun]

ON4UNs graph in his book states that my 27m tower with 13' mast and 5 ele 20m 
monobander (@ 28m high) is good for about 115 degrees. Other old school 
references place it at 140 degrees. 

Per my past posts I have a gamma arm at 90' and 25-28 inches from the tower. I 
have 380 to 400 ohms at the bottom of the gamma wire to gnd. If I insert my EFJ 
160pf air variable I can get the antenna to tune to 60 ohms and X=20 or so. 

This morning I was copying Asian stations on 160 and the tuned into the BC 
band. Using my 40m vertical array as a reference I switched back and forth 
between my shunt fed tower and the array. At 600AM the signal strength on the 
40m antennas were stronger. At 1200AM the array and the shunted tower were 
equal at 1700AM ESPN radio was a good 30 to 40db stronger on the shunted tower. 
Then the sensitivity decreased as I approached 1800 but the tower was still 
20db stronger than the 40m antenna when listening to the FT5 pileup. 

More experimentation with gamma arm placement today

Carl AG6X

Sent from my iPhone

 On Feb 4, 2014, at 8:13 AM, ZR z...@jeremy.mv.com wrote:
 
 Any idea how much top loading that 5 el 46' boom monster contributes?
 
 At a prior QTH in the 80's I had a 90' 25G toploaded with a 10-15-20M stack 
 of PV-4 monobanders and about 18' of mast. The 20M boom was 40' and the tower 
 resonated at 1620KHz  if I remember. Sure worked great once I figured out 
 that 60 radials werent so hot over sand and added a mesh extending 50' from 
 the base.
 
 The gamma rod was the shield of 3/4 CATV coax about 2' from the tower and 
 the best tap point was around 60' if I remember.
 
 Carl
 KM1H
 
 
 - Original Message - From: Carl Braun carl.br...@lairdtech.com
 To: '160' topband@contesting.com
 Cc: 'Tom W8JI' w...@w8ji.com
 Sent: Monday, February 03, 2014 11:17 AM
 Subject: Topband: Shunt feeding the Skyneedle
 
 
 
 Topbanders
 
 If you followed my post on 'In search of resonance' you'll see that I was 
 struggling with feeding a 160m inverted L up close to my 90' Skyneedle.  Tom 
 W8JI suggested that I cut back the L to 129' but the same phenomenon was 
 seen...that being the VERTICAL section of the inverted L was being completely 
 suppressed by the Skyneedle.  At 129' long the antenna resonated nicely on 
 8.2 MHz or so...indicating the vertical section was still suppressed and the 
 top 29' was resonating.  With this in mind I decided to run a shunt wire from 
 the top to see where the antenna resonates.  Here's what I found...
 
 The Skyneedle is 90' tall and has a 13' mast sticking out the top that mounts 
 a Telrex 20M546 yagi on a 15m boom.
 
 The aluminum gamma arm was attached at the 90' level at 24 away from the 
 tower and held in place by PVC standoffs.  See attached photo if the 
 reflector lets me post an attachment.
 
 The MFJ read 380 ohms at 1825 and the X is way off the scale.  I inserted an 
 EF Johnson 10-160pf air variable capacitor at the base...in series...and was 
 able to tune the antenna to 60 ohms and the X=22.  If I played with the cap 
 there was a real sharp drop in reactance showing X=12.  The air variable was 
 about ¾ meshed.
 
 Here are the other resonant points...
 
 15.8 MHz X=0 R=37 with pos and neg reactance on either side of X=0.  This 
 freq showed the sharpest dip of any of the three.
 
 Next was 10.6 MHz X=0 R=23 with pos and neg reactance on either side of X=0.
 
 The last real dip I saw was at 5.3 Mhz with X=0 R=10
 
 No dips below these frequencies but as I stated earlier I tuned the MFJ 259 
 to 1825 and then played with the variable cap where I saw the big drop in 
 impedance. (58-60 ohms at X=12 to 22.
 
 Here are my questions for the gurus...
 
 Do I attempt to match the antenna using a gamma match by tapping the 
 Skyneedle at the 67' level to see how it reacts with regards to R and X? 
 (Note - I cannot vary my gamma arm height as this is a tubular tower and 
 there are few places to bolt on the gamma arm...90', 67', 46' and 25' with 
 the latter being the crows nest platform).
 
 
 Or
 
 
 Can I leave the gamma arm at 90' and rely on an Omega match to tune the 
 antenna?
 
 
 
 Carl
 
 _
 Topband Reflector Archives - http://www.contesting.com/_topband
 
 
 -
 No virus found in this message.
 Checked by AVG - www.avg.com
 Version: 2014.0.4259 / Virus Database: 3684/7058 - Release Date: 02/03/14
 
 
_
Topband Reflector Archives - http://www.contesting.com/_topband

Re: Topband: Shunt feeding the Skyneedle

[Carl Braun]

Topbanders

Well, after experimenting with shortening the gamma wire from the bottom I saw 
NO changes on the MFJnone.  So, option two was to lower the whole tower 
down and remove the gamma arm from the 90' level and remount it at the 67' 
level.  That done I cranked the tower back up and looked at the R at the bottom 
of the gamma wire.  I saw 380 to 400 Ohms...the same reading that I saw when 
the gamma arm was at 90'!!!  Frustrating.

Here's what changed though...when I had the gamma arm at 90' with the 14 gauge 
gamma wire 24 away from the tower I was able to insert my Johnson 60-160pf 
variable cap in series with the gamma wire to get approx 58-60 ohms at X=20.  
The cap was 2/3 meshed at this point.  

NOW that I've lowered the gamma arm to the 67' level...I insert my variable cap 
and the antenna resonates at 1.970 MHz with R=36 ohms and X=0.  For some odd 
reason the MFJ SWR reading shows 1.0:1 with this 36 ohm reading and, inside the 
shack, the Ft1000D shows 1.0:1 swr from 1.988 to 1.950 and a 1.5:1 range of 
2.007 to 1.930.

It now appears that the antenna is a bit short but why am I seeing these crazy 
high resistance readings with no variable cap in line?

How can I lower the resonant freq without moving the gamma arm up?  Increase 
the spacing of the gamma wire from the tower? Add more radials?

I was going to build a three conductor wire cage with the wires spaced 10 
apart or so once I had an idea where the antenna resonates.  Would a fatter 
gamma trio drop the resonant freq or just change the capacitance value of the 
antenna?

Lots of questions but I feel I'm making progress as the FLAT SWR high in the 
band indicates the antenna wants to work well but I need to lower the resonant 
frequency.

Comments please

Thanks

Carl AG6X




-Original Message-
From: ZR [mailto:z...@jeremy.mv.com] 
Sent: Tuesday, February 04, 2014 8:13 AM
To: Carl Braun; '160'
Cc: 'Tom W8JI'
Subject: Re: Topband: Shunt feeding the Skyneedle

Any idea how much top loading that 5 el 46' boom monster contributes?

At a prior QTH in the 80's I had a 90' 25G toploaded with a 10-15-20M stack 
of PV-4 monobanders and about 18' of mast. The 20M boom was 40' and the 
tower resonated at 1620KHz  if I remember. Sure worked great once I figured 
out that 60 radials werent so hot over sand and added a mesh extending 50' 
from the base.

The gamma rod was the shield of 3/4 CATV coax about 2' from the tower and 
the best tap point was around 60' if I remember.

Carl
KM1H


- Original Message - 
From: Carl Braun carl.br...@lairdtech.com
To: '160' topband@contesting.com
Cc: 'Tom W8JI' w...@w8ji.com
Sent: Monday, February 03, 2014 11:17 AM
Subject: Topband: Shunt feeding the Skyneedle



Topbanders

If you followed my post on 'In search of resonance' you'll see that I was 
struggling with feeding a 160m inverted L up close to my 90' Skyneedle.  Tom 
W8JI suggested that I cut back the L to 129' but the same phenomenon was 
seen...that being the VERTICAL section of the inverted L was being 
completely suppressed by the Skyneedle.  At 129' long the antenna resonated 
nicely on 8.2 MHz or so...indicating the vertical section was still 
suppressed and the top 29' was resonating.  With this in mind I decided to 
run a shunt wire from the top to see where the antenna resonates.  Here's 
what I found...

The Skyneedle is 90' tall and has a 13' mast sticking out the top that 
mounts a Telrex 20M546 yagi on a 15m boom.

The aluminum gamma arm was attached at the 90' level at 24 away from the 
tower and held in place by PVC standoffs.  See attached photo if the 
reflector lets me post an attachment.

The MFJ read 380 ohms at 1825 and the X is way off the scale.  I inserted an 
EF Johnson 10-160pf air variable capacitor at the base...in series...and was 
able to tune the antenna to 60 ohms and the X=22.  If I played with the cap 
there was a real sharp drop in reactance showing X=12.  The air variable was 
about ¾ meshed.

Here are the other resonant points...

15.8 MHz X=0 R=37 with pos and neg reactance on either side of X=0.  This 
freq showed the sharpest dip of any of the three.

Next was 10.6 MHz X=0 R=23 with pos and neg reactance on either side of X=0.

The last real dip I saw was at 5.3 Mhz with X=0 R=10

No dips below these frequencies but as I stated earlier I tuned the MFJ 259 
to 1825 and then played with the variable cap where I saw the big drop in 
impedance. (58-60 ohms at X=12 to 22.

Here are my questions for the gurus...

Do I attempt to match the antenna using a gamma match by tapping the 
Skyneedle at the 67' level to see how it reacts with regards to R and X? 
(Note - I cannot vary my gamma arm height as this is a tubular tower and 
there are few places to bolt on the gamma arm...90', 67', 46' and 25' with 
the latter being the crows nest platform).


Or


Can I leave the gamma arm at 90' and rely on an Omega match to tune the 
antenna?



Carl

_
Topband Reflector Archives - http

Re: Topband: Shunt feeding the Skyneedle

[ZR]

Any idea how much top loading that 5 el 46' boom monster contributes?

At a prior QTH in the 80's I had a 90' 25G toploaded with a 10-15-20M stack 
of PV-4 monobanders and about 18' of mast. The 20M boom was 40' and the 
tower resonated at 1620KHz  if I remember. Sure worked great once I figured 
out that 60 radials werent so hot over sand and added a mesh extending 50' 
from the base.


The gamma rod was the shield of 3/4 CATV coax about 2' from the tower and 
the best tap point was around 60' if I remember.


Carl
KM1H


- Original Message - 
From: Carl Braun carl.br...@lairdtech.com

To: '160' topband@contesting.com
Cc: 'Tom W8JI' w...@w8ji.com
Sent: Monday, February 03, 2014 11:17 AM
Subject: Topband: Shunt feeding the Skyneedle



Topbanders

If you followed my post on 'In search of resonance' you'll see that I was 
struggling with feeding a 160m inverted L up close to my 90' Skyneedle.  Tom 
W8JI suggested that I cut back the L to 129' but the same phenomenon was 
seen...that being the VERTICAL section of the inverted L was being 
completely suppressed by the Skyneedle.  At 129' long the antenna resonated 
nicely on 8.2 MHz or so...indicating the vertical section was still 
suppressed and the top 29' was resonating.  With this in mind I decided to 
run a shunt wire from the top to see where the antenna resonates.  Here's 
what I found...


The Skyneedle is 90' tall and has a 13' mast sticking out the top that 
mounts a Telrex 20M546 yagi on a 15m boom.


The aluminum gamma arm was attached at the 90' level at 24 away from the 
tower and held in place by PVC standoffs.  See attached photo if the 
reflector lets me post an attachment.


The MFJ read 380 ohms at 1825 and the X is way off the scale.  I inserted an 
EF Johnson 10-160pf air variable capacitor at the base...in series...and was 
able to tune the antenna to 60 ohms and the X=22.  If I played with the cap 
there was a real sharp drop in reactance showing X=12.  The air variable was 
about ¾ meshed.


Here are the other resonant points...

15.8 MHz X=0 R=37 with pos and neg reactance on either side of X=0.  This 
freq showed the sharpest dip of any of the three.


Next was 10.6 MHz X=0 R=23 with pos and neg reactance on either side of X=0.

The last real dip I saw was at 5.3 Mhz with X=0 R=10

No dips below these frequencies but as I stated earlier I tuned the MFJ 259 
to 1825 and then played with the variable cap where I saw the big drop in 
impedance. (58-60 ohms at X=12 to 22.


Here are my questions for the gurus...

Do I attempt to match the antenna using a gamma match by tapping the 
Skyneedle at the 67' level to see how it reacts with regards to R and X? 
(Note - I cannot vary my gamma arm height as this is a tubular tower and 
there are few places to bolt on the gamma arm...90', 67', 46' and 25' with 
the latter being the crows nest platform).



Or


Can I leave the gamma arm at 90' and rely on an Omega match to tune the 
antenna?




Carl

_
Topband Reflector Archives - http://www.contesting.com/_topband


-
No virus found in this message.
Checked by AVG - www.avg.com
Version: 2014.0.4259 / Virus Database: 3684/7058 - Release Date: 02/03/14


_
Topband Reflector Archives - http://www.contesting.com/_topband

Re: Topband: Shunt feeding the Skyneedle

[Carl Braun]

Thanks for the input Tom

The only variable cap I have is the EF Johnson which is 60-160pf. I have some 
ham radio stuff at my parents house not the least is a Jennings 1000pf vac 
variable rated at 5KV or 7.5kv. I was hoping to use that with a 12v motor for 
QSYing up the band for contesting. I'll have to ask mom to send it to CA in a 
pkg with some cookies. 

When the gamma arm was at 90' I was able to add 160pf to get a resonance point 
around 1825 but the resistance was still high at 58-60 and X was 20++. Maybe 
the big vacuum cap  would bring that R and X down to where it needs to be. 

ON4UNs figure 9-85 on page 9-71 of his third edition shows that a tower that is 
electrical 110 to 130 degrees should have a tap height around 20 meters and a 
matching cap of 400pf. That being said it may be a good idea to get the vac 
variable into service. I would assume I would want to raise the gamma arm back 
up to 90' as it resonated closer to 1825 than the latest iteration which shows 
a Fr near
1.977 
 
 
Sent from my iPhone

 On Feb 4, 2014, at 6:40 PM, Tom W8JI w...@w8ji.com wrote:
 
 Here's what changed though...when I had the gamma arm at 90' with the 14 
 gauge gamma wire 24 away from the tower I was able to insert my Johnson 
 60-160pf variable cap in series with the gamma wire to get approx 58-60 ohms 
 at X=20.  The cap was 2/3 meshed at this point.  
 
 That's the right way. You have to cancel the reatcance of the drop arm to get 
 a good reading. Maybe you need a larger capacitor to hit the bottom of the 
 band? Resistance normally goes up in a case like yours as frequency is 
 drecreased.
 
 NOW that I've lowered the gamma arm to the 67' level...I insert my 
 variable cap and the antenna resonates at 1.970 MHz with R=36 ohms and X=0. 
 For some odd reason the MFJ SWR reading shows 1.0:1 with this 36 ohm reading 
 and, inside the shack, the Ft1000D shows 1.0:1 swr from 1.988 to 1.950 and a 
 1.5:1 range of 2.007 to 1.930
 
 What does more capacitance do?
 
 It now appears that the antenna is a bit short but why am I seeing these 
 crazy high resistance readings with no variable cap in line?
 
 You should see them. The MFJ detector is a 50 ohm bridge. It will overflow 
 and give all kinds of goofy readings when impedance is far away from 50 ohms.
 
 How can I lower the resonant freq without moving the gamma arm up? Increase 
 the spacing of the gamma wire from the tower? Add more radials?
 
 I would have left it at the top and shorted the wire to the tower at 
 different places until I found the sweet spot. But you have to dip the 
 reactance out to really know what you have.
 
 
 I was going to build a three conductor wire cage with the wires spaced 10 
 apart or so once I had an idea where the antenna resonates.  Would a fatter 
 gamma trio drop the resonant freq or just change the capacitance value of the 
 antenna?
 
 A fatter shunt wire will lower reactance and resistance. You will need more 
 C, and the tuned resistance will be a bit lower. 
_
Topband Reflector Archives - http://www.contesting.com/_topband

Re: Topband: Shunt feeding the Skyneedle

[Tom W8JI]

the vertical section was still suppressed and the top 29' was resonating. 
With this in mind I decided to run a shunt wire from the top to see where 
the antenna resonates.  Here's what I found..


I was afraid the tower was messing up the L. This is what happens when they 
are are nearly resonant.


You can't measure tower resonance with a drop wire. The drop wire is a stub 
or shorted transmission line in parallel with the common mode impedance 
presented by the drop wire and tower combination. It is just a mess of stuff 
going on.



The MFJ read 380 ohms at 1825 and the X is way off the scale.  I inserted an 
EF Johnson 10-160pf air variable capacitor at the base.in series.and was 
able to tune the antenna to 60 ohms and the X=22.  If I played with the cap 
there was a real sharp drop in reactance showing X=12.  The air variable was 
about ¾ meshed.




Reducing the lenth (tap point height) of the drop wire is a better way to 
get impedance right. Or, better still, use a multiple wire drop to make the 
drop diameter look larger. That will reduce Q, require more C, and should 
reduce impedance.


You are so close at 60 ohms I would not worry. Adjust the cap for lowest 
SWR. What is the SWR??




_
Topband Reflector Archives - http://www.contesting.com/_topband

Re: Topband: Shunt feeding the Skyneedle

[Tom W8JI]

So, i'm assuming you're suggesting that I drop the gamma arm down to the 67' 
level and see what the impedance looks like?  If so, I'm guessing the series 
C required to tune would increase in value?




There will be some tap point where the shunt capacitor is not required.

Eliminating the shunt cap will increase bandwidth, reduce voltages, and 
improve efficiency.


I'm not sure where the point is, but if I were doing it, I would just leave 
the tap point alone and move a shorting wire to the tower from the shunt 
wire up and down along the shunt wire and look for 50 ohms J0 when reactance 
is nulled.



_
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