Re: Topband: How good is good enough

[Wes]

Good point.  I have a permanently connected 20K 10W wire wound resistor on my 
inverted-L feedpoint.


Wes  N7WS

 On 11/12/2022 5:21 PM, Lee STRAHAN wrote:

And don't forget to discharge the element to ground before connecting to your 
measuring device. Static is NOT your friend in this case.
Lee  K7TJR




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

Re: Topband: How good is good enough

[m.r.c.]

DXpediton style

take 3-4 feet of bare solid # 10 # 12 copper wire and make a loop around the 
base of the antenna support- make it larger if necessary, wrap and solder the 
ends of the loop


Wrap a couple turns from each radial around the loop wire.  Solder.  The joints 
are far enough apart to make soldering reasonably easy even with MANY radials.


If you must use a dis similar metal, use the same technique and split bolt wire 
clamps, feed two at a time through each split bolt


Run as heavy a wire as you think necessary from the ground ring to the feedline 
shield, transformer return, whatever goes to ground.


Robin
WA6CDR
VP6DX, etc


- Original Message - 
From: "Jim Brown" 

To: 
Sent: Saturday, November 12, 2022 10:13
Subject: Re: Topband: How good is good enough



On 11/12/2022 10:02 AM, CUTTER DAVID via Topband wrote:
I'd be interested to know how you make the joints, then add joints to joints, 
then...doesn't it get a bit lumpy?  Do you solder or crimp or nuts and bolts, 
joints in three at a time...?


I've done it two ways. There's a DX Eng radial plate at the base of my Tee 
vertical connecting a very large number of on-ground radials. For a couple of 
verticals sloping off my 120 ft tower, fed at their base and using the tower 
as a passive reflector, I use copper split-bolt connectors to connect four 
elevated radials for each sloper. I also use split-bolts to connect on-ground 
radials for the tower (it needs a good radial system because it's a passive 
reflector).


73, Jim K9YC
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Re: Topband: How good is good enough

[Lee STRAHAN]

And don't forget to discharge the element to ground before connecting to your 
measuring device. Static is NOT your friend in this case.
Lee  K7TJR

-Original Message-
From: Topband  On Behalf Of Rob 
Atkinson
Sent: Saturday, November 12, 2022 3:50 PM
To: topband@contesting.com
Subject: Re: Topband: How good is good enough

>Just cut 20 more 70' radials.  Time to go play in the yard.

If that were all I could add, I'd switch them to 40 35' radials.

The R component of my inverted L on around 1840 is 11 ohms.  X is around 20.  
That's with 101 radials.  I look for a R of at least 15 ohms where X is minimal 
on an analyzer sweep.  At that point the ground system is getting good.  The 
vertical part of the L should be
at least 50 feet.Just ground the analyzer and put the vertical
element right into it.

73
Rob
K5UJ
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Re: Topband: How good is good enough

[Rob Atkinson]

>Just cut 20 more 70' radials.  Time to go play in the yard.

If that were all I could add, I'd switch them to 40 35' radials.

The R component of my inverted L on around 1840 is 11 ohms.  X is
around 20.  That's with 101 radials.  I look for a R of at least 15
ohms where X is minimal on an analyzer sweep.  At that point the
ground system is getting good.  The vertical part of the L should be
at least 50 feet.Just ground the analyzer and put the vertical
element right into it.

73
Rob
K5UJ
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Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: How good is good enough

[Jim Brown]

On 11/7/2022 1:27 PM, Pete Smith N4ZR wrote:
Is it worth laying down more radials, or am I approaching diminishing 
returns?


It depends a lot on the nature of your soil, and how much a dB or two is 
worth to you. These slides for a talk I've done at Pacificon, Visalia, 
and for several ham clubs is mostly about 160M radial systems. Nothing 
in it is original to me, but rather summarizing a lot of wisdom from 
others.


http://k9yc.com/160MPacificon.pdf

73, Jim K9YC
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Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: How good is good enough

[Jim Brown]

On 11/12/2022 10:02 AM, CUTTER DAVID via Topband wrote:

I'd be interested to know how you make the joints, then add joints to joints, 
then...doesn't it get a bit lumpy?  Do you solder or crimp or nuts and bolts, 
joints in three at a time...?


I've done it two ways. There's a DX Eng radial plate at the base of my 
Tee vertical connecting a very large number of on-ground radials. For a 
couple of verticals sloping off my 120 ft tower, fed at their base and 
using the tower as a passive reflector, I use copper split-bolt 
connectors to connect four elevated radials for each sloper. I also use 
split-bolts to connect on-ground radials for the tower (it needs a good 
radial system because it's a passive reflector).


73, Jim K9YC
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Re: Topband: How good is good enough

[CUTTER DAVID via Topband]

I'd be interested to know how you make the joints, then add joints to joints, 
then...doesn't it get a bit lumpy?  Do you solder or crimp or nuts and bolts, 
joints in three at a time...?

David G3UNA


> On 12/11/2022 16:41 Grant Saviers  wrote:
> 
>  
> The 34 ohms is the sum of Rr (antenna radiation Z over perfect ground) 
> and Rg (ground R loss).  Rr depends on the dimensions of the L plus a 
> bit of wire loss.  My guess is Rr is about 10 ohms less than 34 ohms, 
> some easy modeling will determine it.
> 
> Then it is a question of what antenna efficiency you want vs cost and 
> time for more radials.  If 10 ohms is Rg, then about 1/3 of the TX power 
> is warming the worms.
> 
> Grant KZ1W
> 
> On 11/12/2022 07:31, ws6x@gmail.com wrote:
> > In my experience here in "ROCK"ingham County, I didn't reach the point of 
> > diminishing returns until around 32 radials of varying lengths (Most were 
> > either 50 or 100' long.). Much would depend on length, configuration, 
> > terrain and ground conductivity.
> > Jim - WS6X
> > 
> > -Original Message-
> > From: Topband  On Behalf 
> > Of Pete Smith N4ZR
> > Sent: Monday, November 7, 2022 4:27 PM
> > To: topband reflector 
> > Subject: Topband: How good is good enough
> > 
> > Now that the lawn mowing is done for the season, I resuscitated my 160M 
> > inverted L.  With 13 on the ground radials, each roughly 70 feet long, 
> > measured R of 34 ohms seems OK to me.  Is it worth laying down more 
> > radials, or am I approaching diminishing returns?
> > --
> > 73, Pete N4ZR
> > 
> > 
> > _
> > Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
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Re: Topband: How good is good enough

[Pete Smith N4ZR]

Just cut 20 more 70' radials.  Time to go play in the yard.

73, Pete N4ZR
Check out the new Reverse Beacon Network
web server at<https://reversebeacon.net>.
For spots, please use your favorite
"retail" DX cluster.

On 11/12/2022 11:41 AM, Grant Saviers wrote:
The 34 ohms is the sum of Rr (antenna radiation Z over perfect ground) 
and Rg (ground R loss).  Rr depends on the dimensions of the L plus a 
bit of wire loss.  My guess is Rr is about 10 ohms less than 34 ohms, 
some easy modeling will determine it.


Then it is a question of what antenna efficiency you want vs cost and 
time for more radials.  If 10 ohms is Rg, then about 1/3 of the TX 
power is warming the worms.


Grant KZ1W

On 11/12/2022 07:31, ws6x@gmail.com wrote:
In my experience here in "ROCK"ingham County, I didn't reach the 
point of diminishing returns until around 32 radials of varying 
lengths (Most were either 50 or 100' long.). Much would depend on 
length, configuration, terrain and ground conductivity.

Jim - WS6X

-Original Message-
From: Topband  On 
Behalf Of Pete Smith N4ZR

Sent: Monday, November 7, 2022 4:27 PM
To: topband reflector 
Subject: Topband: How good is good enough

Now that the lawn mowing is done for the season, I resuscitated my 
160M inverted L.  With 13 on the ground radials, each roughly 70 feet 
long, measured R of 34 ohms seems OK to me.  Is it worth laying down 
more radials, or am I approaching diminishing returns?

--
73, Pete N4ZR


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Re: Topband: How good is good enough

[Grant Saviers]

The 34 ohms is the sum of Rr (antenna radiation Z over perfect ground) 
and Rg (ground R loss).  Rr depends on the dimensions of the L plus a 
bit of wire loss.  My guess is Rr is about 10 ohms less than 34 ohms, 
some easy modeling will determine it.


Then it is a question of what antenna efficiency you want vs cost and 
time for more radials.  If 10 ohms is Rg, then about 1/3 of the TX power 
is warming the worms.


Grant KZ1W

On 11/12/2022 07:31, ws6x@gmail.com wrote:

In my experience here in "ROCK"ingham County, I didn't reach the point of 
diminishing returns until around 32 radials of varying lengths (Most were either 50 or 
100' long.). Much would depend on length, configuration, terrain and ground conductivity.
Jim - WS6X

-Original Message-
From: Topband  On Behalf Of 
Pete Smith N4ZR
Sent: Monday, November 7, 2022 4:27 PM
To: topband reflector 
Subject: Topband: How good is good enough

Now that the lawn mowing is done for the season, I resuscitated my 160M 
inverted L.  With 13 on the ground radials, each roughly 70 feet long, measured 
R of 34 ohms seems OK to me.  Is it worth laying down more radials, or am I 
approaching diminishing returns?
--
73, Pete N4ZR


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Re: Topband: How good is good enough

[Frank W3LPL]

Hi Pete,

Buy all means install more radials.
At 70 foot radial length diminishing returns is at about 30 radials

73
Frank
W3LPL

- Original Message -
From: "Pete N4ZR N4ZR" 
To: "topband" 
Sent: Monday, November 7, 2022 9:27:09 PM
Subject: Topband: How good is good enough

Now that the lawn mowing is done for the season, I resuscitated my 160M 
inverted L.  With 13 on the ground radials, each roughly 70 feet long, 
measured R of 34 ohms seems OK to me.  Is it worth laying down more 
radials, or am I approaching diminishing returns?

-- 
73, Pete N4ZR
Check out the new Reverse Beacon Network
web server at<https://reversebeacon.net>.
For spots, please use your favorite
"retail" DX cluster.
_
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Re: Topband: How good is good enough

[ws6x.ars]

In my experience here in "ROCK"ingham County, I didn't reach the point of 
diminishing returns until around 32 radials of varying lengths (Most were 
either 50 or 100' long.). Much would depend on length, configuration, terrain 
and ground conductivity.
Jim - WS6X  

-Original Message-
From: Topband  On Behalf Of 
Pete Smith N4ZR
Sent: Monday, November 7, 2022 4:27 PM
To: topband reflector 
Subject: Topband: How good is good enough

Now that the lawn mowing is done for the season, I resuscitated my 160M 
inverted L.  With 13 on the ground radials, each roughly 70 feet long, measured 
R of 34 ohms seems OK to me.  Is it worth laying down more radials, or am I 
approaching diminishing returns?
--
73, Pete N4ZR


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

Topband: How good is good enough

[Pete Smith N4ZR]

Now that the lawn mowing is done for the season, I resuscitated my 160M 
inverted L.  With 13 on the ground radials, each roughly 70 feet long, 
measured R of 34 ohms seems OK to me.  Is it worth laying down more 
radials, or am I approaching diminishing returns?


--
73, Pete N4ZR
Check out the new Reverse Beacon Network
web server at.
For spots, please use your favorite
"retail" DX cluster.
_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: How Good is Good Enough?

[Pete Smith N4ZR]

This is exactly why I got to looking at BOGs - I lack the space in a 
Northeasterly direction (Northwest too, for that matter).  Mine is 220 
feet, as suggested by some experiments with the resonant frequency of a 
dipole laid on the ground to derive a velocity factor - a technique 
suggested by K2AV.

My thinking on putting the preamp at the antenna end was that I would 
improve the SNR and potentially the directivity by amplifying the 
desired signal before sending it down the coax where common mode signal 
pickup, to some degree, seemed inevitable.  But if the preamp is 
amplifying those signals as well, then I clearly need to rethink.

73, Pete N4ZR
The World Contest Station Database, updated daily at www.conteststations.com
The Reverse Beacon Network at http://reversebeacon.net, blog at 
reversebeacon.blogspot.com,
spots at telnet.reversebeacon.net, port 7000 and
arcluster.reversebeacon.net, port 7000


On 3/11/2012 9:52 PM, ZR wrote:
 Very possible on your farm Mike, time to experiment I'd say.

 Carl
 KM1H


 - Original Message -
 From: Mike Watersmikew...@gmail.com
 To: topbandtopband@contesting.com
 Sent: Sunday, March 11, 2012 9:19 PM
 Subject: Re: Topband: How Good is Good Enough?


 Thanks, Carl!

 Seems to me that laying on the ground, the VF would be considerably lower,
 and so we could shorten them.

 73, Mike
 www.w0btu.com

 On Sun, Mar 11, 2012 at 7:58 PM, ZRz...@jeremy.mv.com  wrote:

 Ive said several times that my 500' BOG's dont need a preamp. The signal
 level may be 5-6dB lower

 ___
 UR RST IS ... ... ..9 QSB QSB - hw? BK


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 No virus found in this message.
 Checked by AVG - www.avg.com
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 UR RST IS ... ... ..9 QSB QSB - hw? BK

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Re: Topband: How Good is Good Enough?

[Dan Kovatch]

I'm in Carl's camp. Both my Bogs are shorter at about 350 feet but one was 
once over 500 and worked fine (had to shorten due to 'development of real 
estate'. I terminate at 270 ohms and wind xfrms for the same impedance. No 
preamp needed and they are very quiet so signals just pop out of the noise 
floor.

Dan W8CAR

-Original Message- 
From: ZR
Sent: Sunday, March 11, 2012 8:58 PM
To: Mike Waters ; topband
Subject: Re: Topband: How Good is Good Enough?

Ive said several times that my 500' BOG's dont need a preamp. The signal
level may be 5-6dB lower than the elevated ones in the same direction but
thats more likely due to signal angle.

One or two on here keep claiming 500' wont work and I say it all depends
upon the ground.mine is about as poor as you can get.

For best performance you need to know your RF ground resistance and wind the
transformer accordingly. I used 250 Ohms for the ground.

Carl
KM1H


- Original Message - 
From: Mike Waters mikew...@gmail.com
To: topband topband@contesting.com
Sent: Sunday, March 11, 2012 6:12 PM
Subject: Re: Topband: How Good is Good Enough?


 How does the signal level from a BOG compare to the signal level from an
 elevated Beverage? I'm sure the output from a BOG is less. But how much
 less? Enough to require a remote preamp? I've always wondered.

 I --and many others-- have found a remote preamp on an *elevated* Beverage
 to be totally unnecessary, even with the lossy matching transformers that
 I
 used in the past. The only DC I ever run down my ~600' of  RG-6 feeding a
 Beverage is to reverse directions.

 73, Mike
 www.w0btu.com

 On Sun, Mar 11, 2012 at 8:50 AM, Pete Smith N4ZR
 n...@contesting.comwrote:

 I have about 350 feet of quad-shield RG-6 ... it has only one BOG on it

 ___
 UR RST IS ... ... ..9 QSB QSB - hw? BK


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Re: Topband: How Good is Good Enough?

[Petr Ourednik]

Mike,

I am confirming Carl's experiences. Just in my case the BOG is 600' long
and terminated at 330 ohms. When I tried to use my W7IUV preamp giving
20dB
it was too much and noisy. So finaly I am using this preamp with W2PM
rotary
loop and BOG is used alone w/o preamp and works very well on my
property.
(50 ohms feed line system is used)

73 - Petr, OK1RP




On Mon, 12 Mar 2012 07:29:50 -0400, Dan Kovatch
w8...@buckeye-express.com said:
 I'm in Carl's camp. Both my Bogs are shorter at about 350 feet but one
 was 
 once over 500 and worked fine (had to shorten due to 'development of real 
 estate'. I terminate at 270 ohms and wind xfrms for the same impedance.
 No 
 preamp needed and they are very quiet so signals just pop out of the
 noise 
 floor.
 
 Dan W8CAR
 
 -Original Message- 
 From: ZR
 Sent: Sunday, March 11, 2012 8:58 PM
 To: Mike Waters ; topband
 Subject: Re: Topband: How Good is Good Enough?
 
 Ive said several times that my 500' BOG's dont need a preamp. The signal
 level may be 5-6dB lower than the elevated ones in the same direction but
 thats more likely due to signal angle.
 
 One or two on here keep claiming 500' wont work and I say it all depends
 upon the ground.mine is about as poor as you can get.
 
 For best performance you need to know your RF ground resistance and wind
 the
 transformer accordingly. I used 250 Ohms for the ground.
 
 Carl
 KM1H
 
 
 - Original Message - 
 From: Mike Waters mikew...@gmail.com
 To: topband topband@contesting.com
 Sent: Sunday, March 11, 2012 6:12 PM
 Subject: Re: Topband: How Good is Good Enough?
 
 
  How does the signal level from a BOG compare to the signal level from an
  elevated Beverage? I'm sure the output from a BOG is less. But how much
  less? Enough to require a remote preamp? I've always wondered.
 
  I --and many others-- have found a remote preamp on an *elevated* Beverage
  to be totally unnecessary, even with the lossy matching transformers that
  I
  used in the past. The only DC I ever run down my ~600' of  RG-6 feeding a
  Beverage is to reverse directions.
 
  73, Mike
  www.w0btu.com
 
  On Sun, Mar 11, 2012 at 8:50 AM, Pete Smith N4ZR
  n...@contesting.comwrote:
 
  I have about 350 feet of quad-shield RG-6 ... it has only one BOG on it
 
  ___
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  Version: 10.0.1424 / Virus Database: 2113/4865 - Release Date: 03/11/12
 
 
 ___
 UR RST IS ... ... ..9 QSB QSB - hw? BK 
 
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Re: Topband: How Good is Good Enough?

[Tracey Gardner]

I'd be interested to  know what critter/rodent damage these BOGs get?
My experience, in the UK, of leaving the last 60m of my Beverage lying on 
the ground for a few days, is that the insulation got chewed through in 
seven places.

I would be interested in trying a BOG but I have a feeling that it wouldn't 
last long here.

73s Tracey G5VU 

___
UR RST IS ... ... ..9 QSB QSB - hw? BK

Re: Topband: How Good is Good Enough?

[ZR]

I went with the 2 BOG's stricty because of noise crud from yuppie neighbors 
in line with the SE and SW elevated 2 wire reversibles. When they shut off 
their toys and go to bed the elevated ones are better.

The SW one stops 50' from their house which is too big for the property 
anyway.

If you need a preamp on any Beverage you have a problem IMO. Its too long, 
poorly terminated or there is a lot of feedline loss.

Im running 750' of 1/2 CATV hardline to the relay boxes and well decoupled 
quad shield RG-6 to the antennas. Most are short runs but one is about 200' 
that is lightly stapled to trees in parallel with but 15-20' away from the 
antenna which is the 750' E/W and one of the quietest since it points into 
deep woods both ways.

The very first step in evaluating a system is to directly terminate the 
feedline far end in a 50 or 75 Ohm resistor. I use the standard CATV screw 
on F connector 1/4 W type. There should be dead silence from the BCB on up; 
I test to 20M.

Getting rid of common mode is easy but expensive. It requires lots of 31 mix 
FT-240 toroids, ground rods and attention to connector assembly/sealing. 
Transformers should be BN73-202 binocular core only with particular care to 
match the real impedances and isolate primary from secondary for minimal 
capacitive coupling. Balun core windings and transformers wound on toroids 
have poor isolation.
The advertised premade boxes are a pure waste of money if you want the best 
results. You need to know your own ground resistance and not just buy 
something generic simply because someone who writes a web page says so.

I dont know if Id trust trying to use a resonant dipole on the ground to 
determine the VF of a non resonant wire. In any case keep the VF at about .6 
or higher when determining the maximum length of the BOG, Slinky, or any 
other Beverge form.

Carl
KM1H


- Original Message - 
From: Pete Smith N4ZR n...@contesting.com
To: topband@contesting.com
Sent: Monday, March 12, 2012 7:29 AM
Subject: Re: Topband: How Good is Good Enough?


 This is exactly why I got to looking at BOGs - I lack the space in a
 Northeasterly direction (Northwest too, for that matter).  Mine is 220
 feet, as suggested by some experiments with the resonant frequency of a
 dipole laid on the ground to derive a velocity factor - a technique
 suggested by K2AV.

 My thinking on putting the preamp at the antenna end was that I would
 improve the SNR and potentially the directivity by amplifying the
 desired signal before sending it down the coax where common mode signal
 pickup, to some degree, seemed inevitable.  But if the preamp is
 amplifying those signals as well, then I clearly need to rethink.

 73, Pete N4ZR
 The World Contest Station Database, updated daily at 
 www.conteststations.com
 The Reverse Beacon Network at http://reversebeacon.net, blog at 
 reversebeacon.blogspot.com,
 spots at telnet.reversebeacon.net, port 7000 and
 arcluster.reversebeacon.net, port 7000


 On 3/11/2012 9:52 PM, ZR wrote:
 Very possible on your farm Mike, time to experiment I'd say.

 Carl
 KM1H


 - Original Message -
 From: Mike Watersmikew...@gmail.com
 To: topbandtopband@contesting.com
 Sent: Sunday, March 11, 2012 9:19 PM
 Subject: Re: Topband: How Good is Good Enough?


 Thanks, Carl!

 Seems to me that laying on the ground, the VF would be considerably 
 lower,
 and so we could shorten them.

 73, Mike
 www.w0btu.com

 On Sun, Mar 11, 2012 at 7:58 PM, ZRz...@jeremy.mv.com  wrote:

 Ive said several times that my 500' BOG's dont need a preamp. The 
 signal
 level may be 5-6dB lower

 ___
 UR RST IS ... ... ..9 QSB QSB - hw? BK


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 Checked by AVG - www.avg.com
 Version: 10.0.1424 / Virus Database: 2113/4865 - Release Date: 03/11/12

 ___
 UR RST IS ... ... ..9 QSB QSB - hw? BK

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___
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Re: Topband: How Good is Good Enough?

[ZR]

Two winters ago I had insulated #10 stranded chewed completely thru in a few 
places and all concentrated in a 100' area. Spliced and soldered and it 
hasnt happened since. Lots of deer and other critters around here so anyone 
could have been the culprit.
That BOG is made of odd lengths of scrap #10 to 16 insulated and lays on the 
typical woodland ground cover, pine needles and leaves. I shake it free 
every season so it doesnt wind up getting buried.

Carl
KM1H



- Original Message - 
From: Tracey Gardner tracey.gard...@talktalk.net
To: topband@contesting.com
Sent: Monday, March 12, 2012 9:11 AM
Subject: Re: Topband: How Good is Good Enough?



 I'd be interested to  know what critter/rodent damage these BOGs get?
 My experience, in the UK, of leaving the last 60m of my Beverage lying on
 the ground for a few days, is that the insulation got chewed through in
 seven places.

 I would be interested in trying a BOG but I have a feeling that it 
 wouldn't
 last long here.

 73s Tracey G5VU

 ___
 UR RST IS ... ... ..9 QSB QSB - hw? BK


 -
 No virus found in this message.
 Checked by AVG - www.avg.com
 Version: 10.0.1424 / Virus Database: 2113/4866 - Release Date: 03/12/12
 

___
UR RST IS ... ... ..9 QSB QSB - hw? BK

Re: Topband: How Good is Good Enough?

[N1BUG]

 If you need a preamp on any Beverage you have a problem IMO. Its too long,
 poorly terminated or there is a lot of feedline loss.

Or you've been forced into some other bad situation.

I have a local noise problem that is beyond my control. 
Unfortunately I can't afford the DXE noise canceller so I got an 
MFJ. With my ~600 foot Beverages as main antenna and a very short 
vertical as the aux antenna it will completely null the noise (on 
most Beverages). Unfortunately with its high noise floor I lose 
several dB S/N unless I use a preamp ahead of it.

My Beverages have lower signal output than most in some directions, 
since they are reversible using WD-1A wire (lossy as a transmission 
line).

Not everyone can construct an ideal station, but even with all these 
problems it is far better than not having Beverages at all.

The bottom line is using a preamp buys me several dB S/N I cannot 
get any other way (only when using the noise canceller).

Paul
___
UR RST IS ... ... ..9 QSB QSB - hw? BK

Re: Topband: How Good is Good Enough?

[ZR]

I dont find WD-1A or WF-16/U to be lossy at all when properly terminated at 
both ends. Thats what is used here for the 5 reversibles and a reversible 
BOG will be tried soon.

Carl
KM1H


- Original Message - 
From: N1BUG p...@n1bug.com
To: Topband topband@contesting.com
Sent: Monday, March 12, 2012 11:22 AM
Subject: Re: Topband: How Good is Good Enough?


 If you need a preamp on any Beverage you have a problem IMO. Its too 
 long,
 poorly terminated or there is a lot of feedline loss.

 Or you've been forced into some other bad situation.

 I have a local noise problem that is beyond my control.
 Unfortunately I can't afford the DXE noise canceller so I got an
 MFJ. With my ~600 foot Beverages as main antenna and a very short
 vertical as the aux antenna it will completely null the noise (on
 most Beverages). Unfortunately with its high noise floor I lose
 several dB S/N unless I use a preamp ahead of it.

 My Beverages have lower signal output than most in some directions,
 since they are reversible using WD-1A wire (lossy as a transmission
 line).

 Not everyone can construct an ideal station, but even with all these
 problems it is far better than not having Beverages at all.

 The bottom line is using a preamp buys me several dB S/N I cannot
 get any other way (only when using the noise canceller).

 Paul
 ___
 UR RST IS ... ... ..9 QSB QSB - hw? BK


 -
 No virus found in this message.
 Checked by AVG - www.avg.com
 Version: 10.0.1424 / Virus Database: 2113/4866 - Release Date: 03/12/12
 

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UR RST IS ... ... ..9 QSB QSB - hw? BK

Re: Topband: How Good is Good Enough?

[Guy Olinger K2AV]

 I dont know if Id trust trying to use a resonant dipole on the ground to
 determine the VF of a non resonant wire. In any case keep the VF at about
 .6
 or higher when determining the maximum length of the BOG, Slinky, or any
 other Beverge form.

 Carl
 KM1H


It was clear there was a lot of guessing and assumptions in the world of
BOG.  So we decided to investigate.

We MEASURED a lot of wire on ground VF a couple of years ago in and around
Raleigh.  Not speculated, or guessed.  MEASURED.  Fellers went out here and
there and spread out 151' DOGS, and reported resonance, plus X and R
readings for resonance and +/- 50 kHz.  The 151' was chosen to have a
simple (46m) metric equivalent and a resonance up where the MFJ's could see
it and roughly in the 160 meter band or above.

They were measuring anywhere between .45 and .8 VF. Sometimes, nearly that
variation in the same back yard just by reorienting the wire. In an
individual case you could get a lot of variation by NOT getting the BOG
down to the dirt.

In plugging that kind of variation into BOG models, that was such a drastic
effect on pattern and performance, that if you didn't begin with a VF
measurement in your exacted intended spot for the bog, you were just
throwing away front to back, or in some cases, reversing the pattern.

Finally settled on what ever length for the BOG was gotten by 1) getting
the wire right down on the dirt as you were going to leave and use it, and
2) pruning the DOG to 1140 kHz, and then reconnecting the wire in place to
use as a BOG.  There was also a formula for computing the length from the
151' DOG resonance, so people could use the MFJ meters (they don't read
down that far in the BC band).  The problem with that was that the 151 feet
did not cover the entire BOG length, and you were ASSUMING that the
remaining seventy or whatever feet was over the same kind of stuff as the
151.

If the VF happens to be one of the 0.45 jobs and you use 500 feet, you can
actually get a pattern reversal.  That's a pretty huge variable to leave in
the unknown.

I spent some time digging up BOG tales.  They were all over the place as to
whether they worked or not.  There was also a notable occurrence of
assuming that regular beverage dimensions worked for BOGs, and that long
BOGs would always work better than short BOGs.  There was also a clear
majority of reporting failure and abandoning the concept.

The length you get with the 1140 kHz DOG trick was the *ONLY* length I was
ever able to get to work in a BOG model that had a satisfactory pattern.
 Never able to get 500 feet to model anything with the possible max front
to back.  I am left having to assume that folks using those are simply
using the BOG's ability to reject nearby noise and hear the skywave, which
is there regardless of the length unless the pattern has reversed.  That
could be very useful in a given situation.  But that property also applies
to shortie BOGs as well.

If a northeast BOG is done right, from our NC part of the country, an S9
station from Arkansas or Texas SHOULD be knocked way down, indicating
significant front to back, and also killing a lot of QRN that comes from
that direction.

I have also found the BOG's local rejection quality to be severely
compromised by close elevated conductors and particularly by resonant
overhead conductors, fence wires, above ground power wires, ladderline
feeds to other antennas.  BTDT.  Talking about 20 dB difference in
rejection of back side power buzzes, by removing the overhead.  I was able
to get one of those situations to model out and the fix tracked the model.

73, Guy.
___
UR RST IS ... ... ..9 QSB QSB - hw? BK

Re: Topband: How Good is Good Enough?

[Garry Shapiro]

My experience with canid (coyote and wolf) urines suggests that if 
canids are not the local predator of interest--coyotes in England?--it 
may not work.

Garry, NI6T

On 3/12/2012 6:15 AM, Pete Smith N4ZR wrote:
 Two words - coyote urine.  Seriously  the local Southern States
 sells a critter repellent based on dried coyote urine.

 In our case, the biggest critter problem with my BOG so far has been
 deer - tangle-footed beasts!

 73, Pete N4ZR
 The World Contest Station Database, updated daily at www.conteststations.com
 The Reverse Beacon Network at http://reversebeacon.net, blog at 
 reversebeacon.blogspot.com,
 spots at telnet.reversebeacon.net, port 7000 and
 arcluster.reversebeacon.net, port 7000


 On 3/12/2012 9:11 AM, Tracey Gardner wrote:
 I'd be interested to  know what critter/rodent damage these BOGs get?
 My experience, in the UK, of leaving the last 60m of my Beverage lying on
 the ground for a few days, is that the insulation got chewed through in
 seven places.

 I would be interested in trying a BOG but I have a feeling that it wouldn't
 last long here.

 73s Tracey G5VU

 ___
 UR RST IS ... ... ..9 QSB QSB - hw? BK

 ___
 UR RST IS ... ... ..9 QSB QSB - hw? BK

___
UR RST IS ... ... ..9 QSB QSB - hw? BK

Re: Topband: How Good is Good Enough?

[ZR]

Its very easy to match when using the BN73-202 if you use half turn steps 
when needed and use an antenna bridge to confirm since ferrite Al values 
have a wide tolerance.

And with a low impedance line such as WD-1A there IS a difference in antenna 
mode and transmission line mode values. Plus you have to use the correct 
impedance value for the CT transformers.

Carl
KM1H


- Original Message - 
From: Andrey Fedorishchev ra6...@gmail.com
To: ZR z...@jeremy.mv.com
Cc: Topband topband@contesting.com; N1BUG p...@n1bug.com
Sent: Monday, March 12, 2012 12:55 PM
Subject: Re: Topband: How Good is Good Enough?


 the KEY WORD is: ... when properly terminated at both ends  ...

 not so easy with FireRite 73 binoculars

 and the line impedance IS different from different manufacturer ...




 2012/3/12 ZR z...@jeremy.mv.com

 I dont find WD-1A or WF-16/U to be lossy at all when properly terminated 
 at
 both ends. Thats what is used here for the 5 reversibles and a reversible
 BOG will be tried soon.

 Carl
 KM1H


 - Original Message -
 From: N1BUG p...@n1bug.com
 To: Topband topband@contesting.com
 Sent: Monday, March 12, 2012 11:22 AM
 Subject: Re: Topband: How Good is Good Enough?


  If you need a preamp on any Beverage you have a problem IMO. Its too
  long,
  poorly terminated or there is a lot of feedline loss.
 
  Or you've been forced into some other bad situation.
 
  I have a local noise problem that is beyond my control.
  Unfortunately I can't afford the DXE noise canceller so I got an
  MFJ. With my ~600 foot Beverages as main antenna and a very short
  vertical as the aux antenna it will completely null the noise (on
  most Beverages). Unfortunately with its high noise floor I lose
  several dB S/N unless I use a preamp ahead of it.
 
  My Beverages have lower signal output than most in some directions,
  since they are reversible using WD-1A wire (lossy as a transmission
  line).
 
  Not everyone can construct an ideal station, but even with all these
  problems it is far better than not having Beverages at all.
 
  The bottom line is using a preamp buys me several dB S/N I cannot
  get any other way (only when using the noise canceller).
 
  Paul
  ___
  UR RST IS ... ... ..9 QSB QSB - hw? BK
 
 
  -
  No virus found in this message.
  Checked by AVG - www.avg.com
  Version: 10.0.1424 / Virus Database: 2113/4866 - Release Date: 03/12/12
 

 ___
 UR RST IS ... ... ..9 QSB QSB - hw? BK




 -- 
 Andrey Fedorishchev,
 RA6LBS


 www.RA6LBS.ru
 ___
 UR RST IS ... ... ..9 QSB QSB - hw? BK


 -
 No virus found in this message.
 Checked by AVG - www.avg.com
 Version: 10.0.1424 / Virus Database: 2113/4866 - Release Date: 03/12/12
 

___
UR RST IS ... ... ..9 QSB QSB - hw? BK

Re: Topband: How Good is Good Enough?

[ZR]

There is a major difference between a resonant antenna and a one wire 
transmission line whose sole purpose in life is to be unbalanced in respect 
to ground.

Trying to compare them doesnt work well and neither does modelling these 
types of grounds unless you work for the government and have access to 
software that has been especially developed for such things. It is clear 
that there are still a lot of assumptions being made with questionable 
conclusions. This is often followed by statements that it is to be taken as 
gospel by everyone. Internet sites are full of that stuff since these 
assumptions ignore the huge variability of Mother Earth.

A resonant antenna on or very close to the ground is strongly affected by 
different conductivity conditions beneath it even if just in small areas. A 
BOG is not affected since it doesnt require or even want resonance to work 
and a portion of ground that is only a fraction of a wavelength is 
meaningless at 160M.

A BOG 's impedance can be anywhere from 200 to well under 50 Ohms depending 
upon the RF ground conductivity. A 269B, a mutitap matching transformer, and 
variable carbon pot for a termination can be used and having a helper is a 
good addition.

Dont be surprised if the transformer turns out to be a 1:1 or even 2:1 with 
the feedline being the higher number if you have well above average ground.

A BOG will have a naturally high F/B since the losses smooth out the VSWR 
ripple making a perfect transformer and termination match a bit less 
critical.  A BOG is also more sensitive to common mode feedline currents and 
requires those extra steps to eliminate it.

Since an elevated 2 wave length Beverage still has a high VF even over 
average ground it holds that a 1 wave BOG hasnt reached its reversal point 
yet. At a prior QTH here in town I found a 1500' Beverage 10' high to be 
excellent and at 2100' it was useless. Ive done a lot of walking over the 
30+ years Ive been using Beverages.

Finding the maximum useable length should be done after a rain storm as that 
will be the point of lowest VF. Or simply start at 500' or so and chop off 
50' at a time if it has already flipped. Conversely keep adding if you want 
to get the benefit of length. Use a 4' ground rod and a couple of 30' 
radials at the far end to establish a half a**ed ground since that part isnt 
critical yet and simply move it as needed.

Carl
KM1H




- Original Message - 
From: Guy Olinger K2AV
To: ZR
Cc: Pete Smith N4ZR ; topband@contesting.com
Sent: Monday, March 12, 2012 1:02 PM
Subject: Re: Topband: How Good is Good Enough?


I dont know if Id trust trying to use a resonant dipole on the ground to
determine the VF of a non resonant wire. In any case keep the VF at about .6
or higher when determining the maximum length of the BOG, Slinky, or any
other Beverge form.


Carl
KM1H



It was clear there was a lot of guessing and assumptions in the world of 
BOG.  So we decided to investigate.


We MEASURED a lot of wire on ground VF a couple of years ago in and around 
Raleigh.  Not speculated, or guessed.  MEASURED.  Fellers went out here and 
there and spread out 151' DOGS, and reported resonance, plus X and R 
readings for resonance and +/- 50 kHz.  The 151' was chosen to have a simple 
(46m) metric equivalent and a resonance up where the MFJ's could see it and 
roughly in the 160 meter band or above.


They were measuring anywhere between .45 and .8 VF. Sometimes, nearly that 
variation in the same back yard just by reorienting the wire. In an 
individual case you could get a lot of variation by NOT getting the BOG down 
to the dirt.


In plugging that kind of variation into BOG models, that was such a drastic 
effect on pattern and performance, that if you didn't begin with a VF 
measurement in your exacted intended spot for the bog, you were just 
throwing away front to back, or in some cases, reversing the pattern.


Finally settled on what ever length for the BOG was gotten by 1) getting the 
wire right down on the dirt as you were going to leave and use it, and 2) 
pruning the DOG to 1140 kHz, and then reconnecting the wire in place to use 
as a BOG.  There was also a formula for computing the length from the 151' 
DOG resonance, so people could use the MFJ meters (they don't read down that 
far in the BC band).  The problem with that was that the 151 feet did not 
cover the entire BOG length, and you were ASSUMING that the remaining 
seventy or whatever feet was over the same kind of stuff as the 151.


If the VF happens to be one of the 0.45 jobs and you use 500 feet, you can 
actually get a pattern reversal.  That's a pretty huge variable to leave in 
the unknown.


I spent some time digging up BOG tales.  They were all over the place as to 
whether they worked or not.  There was also a notable occurrence of assuming 
that regular beverage dimensions worked for BOGs, and that long BOGs would 
always work better than short BOGs.  There was also a clear majority

Topband: How Good is Good Enough?

[Pete Smith N4ZR]

I have about 350 feet of quad-shield RG-6 going out to a receiving 
antenna hub which has a 20-db ARR preamp on the end of the line, 
followed by an 8-way relay switch.  The feedline is lying on the ground, 
or more correctly on the stubble of a mowed hayfield.  At the moment, it 
has only one BOG on it, but I plan to add other BOGs and a K9AY loop for 
some comparative tests.  The feedline has a center tapped common mode 
choke about 15 feet from the hub, a la ON4UN and K9YC references - 14 
turns of RG-6 on each of 2 #31 toroids.

My question is this.  If I disconnect the one BOG, and listen to the 
feedline and preamp, how quiet should it be?  How would I go about 
testing its quietness?  If it is not quiet enough in this configuration, 
what would my next step be?  Another common mode choke at the shack 
entrance?

-- 
73, Pete N4ZR
The World Contest Station Database, updated daily at www.conteststations.com
The Reverse Beacon Network at http://reversebeacon.net, blog at 
reversebeacon.blogspot.com,
spots at telnet.reversebeacon.net, port 7000 and
arcluster.reversebeacon.net, port 7000

___
UR RST IS ... ... ..9 QSB QSB - hw? BK

Re: Topband: How Good is Good Enough?

[Mike Waters]

How does the signal level from a BOG compare to the signal level from an
elevated Beverage? I'm sure the output from a BOG is less. But how much
less? Enough to require a remote preamp? I've always wondered.

I --and many others-- have found a remote preamp on an *elevated* Beverage
to be totally unnecessary, even with the lossy matching transformers that I
used in the past. The only DC I ever run down my ~600' of  RG-6 feeding a
Beverage is to reverse directions.

73, Mike
www.w0btu.com

On Sun, Mar 11, 2012 at 8:50 AM, Pete Smith N4ZR n...@contesting.comwrote:

 I have about 350 feet of quad-shield RG-6 ... it has only one BOG on it

___
UR RST IS ... ... ..9 QSB QSB - hw? BK

Re: Topband: How Good is Good Enough?

[ZR]

Ive said several times that my 500' BOG's dont need a preamp. The signal 
level may be 5-6dB lower than the elevated ones in the same direction but 
thats more likely due to signal angle.

One or two on here keep claiming 500' wont work and I say it all depends 
upon the ground.mine is about as poor as you can get.

For best performance you need to know your RF ground resistance and wind the 
transformer accordingly. I used 250 Ohms for the ground.

Carl
KM1H


- Original Message - 
From: Mike Waters mikew...@gmail.com
To: topband topband@contesting.com
Sent: Sunday, March 11, 2012 6:12 PM
Subject: Re: Topband: How Good is Good Enough?


 How does the signal level from a BOG compare to the signal level from an
 elevated Beverage? I'm sure the output from a BOG is less. But how much
 less? Enough to require a remote preamp? I've always wondered.

 I --and many others-- have found a remote preamp on an *elevated* Beverage
 to be totally unnecessary, even with the lossy matching transformers that 
 I
 used in the past. The only DC I ever run down my ~600' of  RG-6 feeding a
 Beverage is to reverse directions.

 73, Mike
 www.w0btu.com

 On Sun, Mar 11, 2012 at 8:50 AM, Pete Smith N4ZR 
 n...@contesting.comwrote:

 I have about 350 feet of quad-shield RG-6 ... it has only one BOG on it

 ___
 UR RST IS ... ... ..9 QSB QSB - hw? BK


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UR RST IS ... ... ..9 QSB QSB - hw? BK

Re: Topband: How Good is Good Enough?

[ZR]

Very possible on your farm Mike, time to experiment I'd say.

Carl
KM1H


- Original Message - 
From: Mike Waters mikew...@gmail.com
To: topband topband@contesting.com
Sent: Sunday, March 11, 2012 9:19 PM
Subject: Re: Topband: How Good is Good Enough?


 Thanks, Carl!

 Seems to me that laying on the ground, the VF would be considerably lower,
 and so we could shorten them.

 73, Mike
 www.w0btu.com

 On Sun, Mar 11, 2012 at 7:58 PM, ZR z...@jeremy.mv.com wrote:

 Ive said several times that my 500' BOG's dont need a preamp. The signal
 level may be 5-6dB lower

 ___
 UR RST IS ... ... ..9 QSB QSB - hw? BK


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 No virus found in this message.
 Checked by AVG - www.avg.com
 Version: 10.0.1424 / Virus Database: 2113/4865 - Release Date: 03/11/12
 

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UR RST IS ... ... ..9 QSB QSB - hw? BK