Re: [Elecraft] ANTENNA QUESTION

[rich hurd WC3T]

As Wayne N6KR mentioned yesterday,

"I’ll be speaking at Pacificon's antenna symposium tomorrow (Friday, Oct.
20th). My presentation, from 3:30 to 4:30 PM, is on antennas for
ultra-portable HF operation. This talk was a late addition, a previous
speaker having dropped out.

If you’re interested in attending the symposium, check the website (
pacificon.org). Tickets must be purchase in advance.

As part of my talk I’ll be discussing a new portable antenna, the Elecraft
AX1, designed specifically for the KX2 and KX3. We’ll also be showing the
prototype at our booth.

We’re not taking orders for the AX1 yet, so please don’t call Elecraft Hq
about it :)  That said, I’ll be happy to send out an early draft of the FAQ
on request. Please email me directly.

73,
Wayne
N6KR"

---
72,
Rich Hurd / WC3T / DMR: 3142737
PA Army MARS, Northampton County RACES, EPA-ARRL Public Information Officer
for Scouting
Latitude: 40.761621 Longitude: -75.288988  (40°45.68' N 75°17.33' W) Grid:
*FN20is*


On Fri, Oct 20, 2017 at 3:51 PM, Gerry Miller  wrote:

>  WHAT IS THE AX1 THAT I HAVE READ COMMENTS ABOUT.  ARE THERE FURTHER
> DESCRIPTIONS OR PHOTO'S RE THIS ANTENNA?GERRY MILLER, aa...@juno.com
> 
> 1 Simple Trick Removes Eye Bags & Lip Lines In Seconds
> Fit Mom Daily
> http://thirdpartyoffers.juno.com/TGL3141/59ea54012a29154013571st03vuc
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[Elecraft] ANTENNA QUESTION

[Gerry Miller]

 WHAT IS THE AX1 THAT I HAVE READ COMMENTS ABOUT.  ARE THERE FURTHER 
DESCRIPTIONS OR PHOTO'S RE THIS ANTENNA?GERRY MILLER, aa...@juno.com

1 Simple Trick Removes Eye Bags & Lip Lines In Seconds
Fit Mom Daily
http://thirdpartyoffers.juno.com/TGL3141/59ea54012a29154013571st03vuc
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Re: [Elecraft] Antenna Question

[David Aslin G3WGN]

Danny,
Glad you like them.
Maybe I need to start a ‘no barrel connectors’ group ;-)
73, David G3WGN  M6O

From: danny.higg...@keme.co.uk [mailto:danny.higg...@keme.co.uk]
Sent: 13 October 2016 09:52
To: CUTTER DAVID <d.cut...@ntlworld.com>; David Aslin G3WGN 
<da...@aslinvc.com>; elecraft <elecraft@mailman.qth.net>
Subject: RE: [Elecraft] Antenna Question

Hi David.

Thanks for the information. I ordered some compression PL259s and SO239s 
yesterday direct from Barenco, and they arrived this morning, at a fraction of 
the cost I last paid from a retail Ham supplier. They look quite chunky with 
protective caps on the end, which I would not expect from a cheap manufacturer. 
 I can at last get rid of the SO239 barrels that have given me intermittent 
problems on my long co-ax cables.

Regards,

Danny, G3XVR

From: CUTTER DAVID<mailto:d.cut...@ntlworld.com>
Sent: 12 October 2016 09:17
To: Dave G3WGN M6O<mailto:da...@aslinvc.com>; 
elecraft<mailto:elecraft@mailman.qth.net>
Subject: Re: [Elecraft] Antenna Question

I bought a batch of Barenco 259s amongst others and I am mightily impressed,
very chunky, very smooth and not expensive.

David, G3UNA

>
> On 11 October 2016 at 22:50 Dave G3WGN M6O 
> <da...@aslinvc.com<mailto:da...@aslinvc.com>> wrote:
>
>
> Not oddball in EU, nor expensive. Good quality ones are available from
> Kabel-Kusch in Germany and Barenco in UK:
>
>
> http://www.barenco.co.uk/uhf-line-socket-so239-jacks-rg213-clamp-top-hat-compression-body-solder-pin-165425.
> China RF do some good ones via Fleabay too.
> We use these extensively in our 6Gs DXpeditions, together with compression
> type PL259s. A side benefit is that it's easy to terminate the coax feed
> from multiple station in female connectors (forming a 'patch panel' in
> effect) so there is zero risk of cross-coupling 2 stations.
> My own station has mostly been converted to compression types; but there
> are
> Amphenols in there too. Motivation to change? Ease of waterproofing the
> compression types.
> Just my 2 pence/2c,
> 73, David G3WGN M6O WJ6O
>
>
>
> Josh Fiden wrote
> > Cable mount female UHF is an oddball and expensive. To avoid barrels, I
> > use type N female cable mount which are common.
> >
> > 73,
> > Josh W6XU
> >
> > On 10/11/2016 3:52 AM, Nr4c wrote:
> >> Why use barrels? Doesn't Amphenol or Pastornack make a female UHF
> >> connector to put on cable end. For this specific use, a custom built
> >> cable seems appropriate.
> >
> > __
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Re: [Elecraft] Antenna Question

[danny.higgins]

Hi David.

Thanks for the information. I ordered some compression PL259s and SO239s 
yesterday direct from Barenco, and they arrived this morning, at a fraction of 
the cost I last paid from a retail Ham supplier. They look quite chunky with 
protective caps on the end, which I would not expect from a cheap manufacturer. 
 I can at last get rid of the SO239 barrels that have given me intermittent 
problems on my long co-ax cables.

Regards,

Danny, G3XVR

From: CUTTER DAVID
Sent: 12 October 2016 09:17
To: Dave G3WGN M6O; elecraft
Subject: Re: [Elecraft] Antenna Question

I bought a batch of Barenco 259s amongst others and I am mightily impressed,
very chunky, very smooth and not expensive.

David, G3UNA

> 
> On 11 October 2016 at 22:50 Dave G3WGN M6O <da...@aslinvc.com> wrote:
> 
> 
> Not oddball in EU, nor expensive. Good quality ones are available from
> Kabel-Kusch in Germany and Barenco in UK:
> 
>
> http://www.barenco.co.uk/uhf-line-socket-so239-jacks-rg213-clamp-top-hat-compression-body-solder-pin-165425.
> China RF do some good ones via Fleabay too.
> We use these extensively in our 6Gs DXpeditions, together with compression
> type PL259s. A side benefit is that it's easy to terminate the coax feed
> from multiple station in female connectors (forming a 'patch panel' in
> effect) so there is zero risk of cross-coupling 2 stations.
> My own station has mostly been converted to compression types; but there
> are
> Amphenols in there too. Motivation to change? Ease of waterproofing the
> compression types.
> Just my 2 pence/2c,
> 73, David G3WGN M6O WJ6O
> 
> 
> 
> Josh Fiden wrote
> > Cable mount female UHF is an oddball and expensive. To avoid barrels, I
> > use type N female cable mount which are common.
> >
> > 73,
> > Josh W6XU
> >
> > On 10/11/2016 3:52 AM, Nr4c wrote:
> >> Why use barrels? Doesn't Amphenol or Pastornack make a female UHF
> >> connector to put on cable end. For this specific use, a custom built
> >> cable seems appropriate.
> >
> > __
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Re: [Elecraft] Antenna Question

[Richard Fjeld]

(I am trying to get caught up on my email. Forgive me if this has been closed.)

This caught my eye, and I agree.  I have found when buying PL-259's that are 
made in a 'metric' country, there can be slight problems converting to the 
dimensions used in North America.

I have chased SWR troubles almost in circles only to find the tip of an 
imported PL-259 was making intermittent contact with the SO-239 socket.  A 
simple fix was to apply a bit of solder to the tip and then file it down until 
I could feel a gentle friction as I plugged it into the socket.

Another important item in a PL-259 is a good tinned surface for soldering.  I 
like the so called 'silver plated' plugs when I can find them.  I don't know if 
they are truly silver plated, but they do take solder beautifully.

Dick, n0ce


On 10/11/2016 11:36 AM, Jim Brown wrote:
On Tue,10/11/2016 6:29 AM, Charlie T, K3ICH wrote:
I'm curious as to exactly why a "junk" connector supposedly has so much more 
loss than a "good" connector?

Junk connectors have several issues. One of the issues is control of dimensions 
-- the diameter of the tip must be "right" to make a solid and reliable 
connection to the mating connector. I've seen junk barrels, tees, and elbows 
that had a tiny spring between the ends of the connector.

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Re: [Elecraft] Antenna Question

[CUTTER DAVID]

I bought a batch of Barenco 259s amongst others and I am mightily impressed,
very chunky, very smooth and not expensive.

David, G3UNA

> 
> On 11 October 2016 at 22:50 Dave G3WGN M6O  wrote:
> 
> 
> Not oddball in EU, nor expensive. Good quality ones are available from
> Kabel-Kusch in Germany and Barenco in UK:
> 
>
> http://www.barenco.co.uk/uhf-line-socket-so239-jacks-rg213-clamp-top-hat-compression-body-solder-pin-165425.
> China RF do some good ones via Fleabay too.
> We use these extensively in our 6Gs DXpeditions, together with compression
> type PL259s. A side benefit is that it's easy to terminate the coax feed
> from multiple station in female connectors (forming a 'patch panel' in
> effect) so there is zero risk of cross-coupling 2 stations.
> My own station has mostly been converted to compression types; but there
> are
> Amphenols in there too. Motivation to change? Ease of waterproofing the
> compression types.
> Just my 2 pence/2c,
> 73, David G3WGN M6O WJ6O
> 
> 
> 
> Josh Fiden wrote
> > Cable mount female UHF is an oddball and expensive. To avoid barrels, I
> > use type N female cable mount which are common.
> >
> > 73,
> > Josh W6XU
> >
> > On 10/11/2016 3:52 AM, Nr4c wrote:
> >> Why use barrels? Doesn't Amphenol or Pastornack make a female UHF
> >> connector to put on cable end. For this specific use, a custom built
> >> cable seems appropriate.
> >
> > __
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> 
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> 
> 
> 
> 
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Re: [Elecraft] Antenna Question

[Dave G3WGN M6O]

Not oddball in EU, nor expensive.  Good quality ones are available from
Kabel-Kusch in Germany and Barenco in UK:
http://www.barenco.co.uk/uhf-line-socket-so239-jacks-rg213-clamp-top-hat-compression-body-solder-pin-165425.
 
China RF do some good ones via Fleabay too.
We use these extensively in our 6Gs DXpeditions, together with compression
type PL259s.  A side benefit is that it's easy to terminate the coax feed
from multiple station in female connectors (forming a 'patch panel' in
effect) so there is zero risk of cross-coupling 2 stations.  
My own station has mostly been converted to compression types; but there are
Amphenols in there too.  Motivation to change? Ease of waterproofing the
compression types.
Just my 2 pence/2c,
73, David G3WGN M6O WJ6O



Josh Fiden wrote
> Cable mount female UHF is an oddball and expensive. To avoid barrels, I 
> use type N female cable mount which are common.
> 
> 73,
> Josh W6XU
> 
> On 10/11/2016 3:52 AM, Nr4c wrote:
>> Why use barrels?  Doesn't Amphenol or Pastornack make a female UHF
>> connector to put on cable end.  For this specific use, a custom  built
>> cable seems appropriate.
> 
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Re: [Elecraft] Antenna Question

[Mark Tosiello]

Here's what I use for the run up the mast to my HexBeam. The center
conductor is stranded copper, and the jacket is thermoplastic elastomer.
MUCH more flexible than standard LMR-400...thus, the name LMR-400 UltraFlex:

https://www.dxengineering.com/parts/tmv-lmr-400ultra

I have a run going up the mast support forming a loop at the HexBeam. About
25 feet of a run of 250 feet of standard LMR-400. Barrel connectors cause
negligible signal loss. Connection is protected by internal "Stuff"
application, and externally by Coax-Seal.

Mark KD8EDC

On Mon, Oct 10, 2016 at 9:37 PM, John Parker  wrote:

> There is a stranded center conductor version of the LM400, do not remember
> what the designation is. I plan to use some for the same reason, going
> around a rotor to a HexBeam.
> 73, John WB4UHCK3 #2165
>
> On Monday, October 10, 2016 6:16 PM, "hsherr...@reagan.com" <
> hsherr...@reagan.com> wrote:
>
>
>  OK all. I'm installing a 6m rotating beam and feeding it with LMR400.
> Would you connect the LMR to the antenna and allow it to move with the
> rotation, or run a short length of something much more flexible between the
> antenna and LMR? I have my concerns that the solid heavy inner conductor of
> the LMR won't take much movement.
>
> Harlan
> K4HES
>
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Re: [Elecraft] Antenna Question

[Josh Fiden]

Cable mount female UHF is an oddball and expensive. To avoid barrels, I 
use type N female cable mount which are common.


73,
Josh W6XU

On 10/11/2016 3:52 AM, Nr4c wrote:

Why use barrels?  Doesn't Amphenol or Pastornack make a female UHF connector to 
put on cable end.  For this specific use, a custom  built cable seems 
appropriate.


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Re: [Elecraft] Antenna Question

[Jim Brown]

On Tue,10/11/2016 6:29 AM, Charlie T, K3ICH wrote:

I'm curious as to exactly why a "junk" connector supposedly has so much more loss than a 
"good" connector?


Junk connectors have several issues. One of the issues is control of 
dimensions -- the diameter of the tip must be "right" to make a solid 
and reliable connection to the mating connector. I've seen junk barrels, 
tees, and elbows that had a tiny spring between the ends of the connector.


When I got back on the air in 2003, I stocked my "junk box" with a lot 
of these cheap connector adapters at ham flea markets, and over the next 
3-5 years, they caused outright failures and intermittent problems that 
were difficult to track down. At one point, I had added elbow connectors 
in my shack to make cable routing cleaner. An hour into a contest 
running legal limit, I saw SWR going sky high on an antenna, found the 
elbow very hot to the touch. Removing it solved the problem. The tiny 
spring had overheated. I've had these junk connectors fall apart 
mechanically. I've had the dielectric in junk PL-259s melt when I 
soldered the center conductor. And so on.


W3LPL advises to use Amphenol connectors exclusively, and to use only 
83-1SP for PL-259s. I strongly agree with him. I know nothing about 
what's available in EU -- my comments apply to North America.



73, Jim K9YC


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Re: [Elecraft] Antenna Question

[riese-k3djc]

a much better good connector that prople think

Bob K3DJC


On Tue, 11 Oct 2016 09:29:19 -0400 "Charlie T, K3ICH" 
writes:
> I'm curious as to exactly why a "junk" connector supposedly has so 
> much more
> loss than a "good" connector?
>
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Re: [Elecraft] Antenna Question

[Charlie T, K3ICH]

I'm curious as to exactly why a "junk" connector supposedly has so much more
loss than a "good" connector?

They're probably both (nickel, silver ???) plated brass with a dielectric
insulator usually Teflon,  phenolic or ??

Is it the plating, the insulator, the fit of the threads, the
solder-ability, or what, that makes the lossy?

I can understand it if the dimensions are way off or they don't thread on
properly, but that should be obvious in the installation process.

Not trying to start a fight or insult anyone.


73, Charlie k3ICH

 




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Re: [Elecraft] Antenna Question

[Vic Rosenthal 4X6GP]

SOME 'junk' PL259s are fine. If there are problems with the threads you 
will know right away. I have had some that are plated with something 
that won't take solder, or which have plastic insulation that melts when 
you solder the center pin. But again, you will know this right away.


SO239s and barrels may have contact tension problems that take awhile to 
manifest themselves. And elbows and Ts can have internal issues (like 
the famous elbows with little springs to join the two parts). For these, 
only Amphenol or mil-spec will do.


Having said all this, just before I moved here, I ordered a bunch of 
Amphenol connectors, including the PL259s.


73,
Vic, 4X6GP
Rehovot, Israel
Formerly K2VCO
http://www.qsl.net/k2vco/

On 11 Oct 2016 11:38, Jim Brown wrote:

On Mon,10/10/2016 4:49 PM, Josh Fiden wrote:

If you're concerned about the additional loss of a barrel connector at
50MHz, you should be using feedline with lower loss than LMR400 up the
tower.


The loss in GOOD quality UHF connectors and barrels at 50 MHz is
negligible. There are urban legends (false, as usual) claiming that
every connector loses a dB. The grain of truth is that JUNK connectors
may introduce significant loss, but GOOD connectors and barrels do NOT.
"Good" means Amphenol 83-1SP for the PL-259s, and Amphenol or surplus
MIL-spec for the barrels.

Several years ago, I made up more than a dozen 100 ft cables using a
cable of somewhat better construction than LMR400 (Commscope 3227) for a
DX trip. The connectors were Amphenol 83-1SP that I soldered myself. To
test those cables, I spliced them together using Amphenol barrels and
measured the loss of about 1300 ft of cable up to 500 MHz using HP
generator and spectrum analyzer. The measured loss was LESS than the
manufacturer's spec. There were 27 83-1SPs and 13 barrels in line.

JUNK connectors are the shiny,unbranded stuff you see at ham flea
markets, and sold online and in ham magazines.

73, Jim K9YC

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Re: [Elecraft] Antenna Question

[Nr4c]

Why use barrels?  Doesn't Amphenol or Pastornack make a female UHF connector to 
put on cable end.  For this specific use, a custom  built cable seems 
appropriate. 

Sent from my iPhone
...nr4c. bill


> On Oct 11, 2016, at 4:38 AM, Jim Brown  wrote:
> 
>> On Mon,10/10/2016 4:49 PM, Josh Fiden wrote:
>> If you're concerned about the additional loss of a barrel connector at 
>> 50MHz, you should be using feedline with lower loss than LMR400 up the tower.
> 
> The loss in GOOD quality UHF connectors and barrels at 50 MHz is negligible. 
> There are urban legends (false, as usual) claiming that every connector loses 
> a dB. The grain of truth is that JUNK connectors may introduce significant 
> loss, but GOOD connectors and barrels do NOT. "Good" means Amphenol 83-1SP 
> for the PL-259s, and Amphenol or surplus MIL-spec for the barrels.
> 
> Several years ago, I made up more than a dozen 100 ft cables using a cable of 
> somewhat better construction than LMR400 (Commscope 3227) for a DX trip. The 
> connectors were Amphenol 83-1SP that I soldered myself. To test those cables, 
> I spliced them together using Amphenol barrels and measured the loss of about 
> 1300 ft of cable up to 500 MHz using HP generator and spectrum analyzer. The 
> measured loss was LESS than the manufacturer's spec. There were 27 83-1SPs 
> and 13 barrels in line.
> 
> JUNK connectors are the shiny,unbranded stuff you see at ham flea markets, 
> and sold online and in ham magazines.
> 
> 73, Jim K9YC
> 
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Re: [Elecraft] Antenna Question

[Jim Brown]

On Mon,10/10/2016 4:49 PM, Josh Fiden wrote:
If you're concerned about the additional loss of a barrel connector at 
50MHz, you should be using feedline with lower loss than LMR400 up the 
tower.


The loss in GOOD quality UHF connectors and barrels at 50 MHz is 
negligible. There are urban legends (false, as usual) claiming that 
every connector loses a dB. The grain of truth is that JUNK connectors 
may introduce significant loss, but GOOD connectors and barrels do NOT. 
"Good" means Amphenol 83-1SP for the PL-259s, and Amphenol or surplus 
MIL-spec for the barrels.


Several years ago, I made up more than a dozen 100 ft cables using a 
cable of somewhat better construction than LMR400 (Commscope 3227) for a 
DX trip. The connectors were Amphenol 83-1SP that I soldered myself. To 
test those cables, I spliced them together using Amphenol barrels and 
measured the loss of about 1300 ft of cable up to 500 MHz using HP 
generator and spectrum analyzer. The measured loss was LESS than the 
manufacturer's spec. There were 27 83-1SPs and 13 barrels in line.


JUNK connectors are the shiny,unbranded stuff you see at ham flea 
markets, and sold online and in ham magazines.


73, Jim K9YC

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Re: [Elecraft] Antenna Question

[Vic Rosenthal]

One way to do it with a single piece of stiff coax is to place a standoff about 
a foot long above and below the rotor. Then form the coax into a spiral of 
several turns between the standoffs. Rotation will just tighten or loosen the 
spiral and not stress the coax at all. The standoffs also take the weight of 
the coax.

Vic 4X6GP

> On 11 Oct 2016, at 01:14, hsherr...@reagan.com wrote:
> 
> OK all. I'm installing a 6m rotating beam and feeding it with LMR400. Would 
> you connect the LMR to the antenna and allow it to move with the rotation, or 
> run a short length of something much more flexible between the antenna and 
> LMR? I have my concerns that the solid heavy inner conductor of the LMR won't 
> take much movement.
> 
> Harlan
> K4HES
> 
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Re: [Elecraft] Antenna Question

[Edward R Cole]

I do the same as Josh:
http://www.kl7uw.com/6m_Dec-2013_1.jpg

Multiple turns of LMR-400.  That connects to 7/8-Heliax coming up the 
tower leg.


73, Ed - KL7UW

From: Josh Fiden <j...@voodoolab.com>
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] Antenna Question
Message-ID: <b9aa5441-6cb3-78d7-a24f-4645beba9...@voodoolab.com>
Content-Type: text/plain; charset=windows-1252; format=flowed

LMR400 is really stiff. When I used it as a rotor loop, I made a couple
of hoops around rather than directly flexing the cable around the tower.
Not sure if that makes sense. In any case, doing it again I would
definitely use a more flexible jumper for the rotor loop running to the
antenna. In the shack I'm making jumpers from RG-214 which is very
flexible and would work great as a rotor loop as well.

73,
Josh W6XU



73, Ed - KL7UW
http://www.kl7uw.com
"Kits made by KL7UW"
Dubus Mag business:
dubus...@gmail.com

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Re: [Elecraft] Antenna Question

[Mark E. Musick]

I use LMR400-FLEX for my rotor loops and have had no problems. It has been
up since 1999 or 2000. LMR400-FLEX is the designator for the stranded center
conductor version. I also have used Davis FLEX LMR400 equivalent and if I
remember correctly Davis-FLEX that is what is stamped on the feedline. The
difference between LMR400 solid center conductor and LMR400 FLEX stranded
center conductor has a loss of about .1 or .2db more at 50 MHz. Again if my
memory is correct.

Mark, WB9CIF

-Original Message-
From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of John
Parker
Sent: Tuesday, October 11, 2016 1:38 AM
To: hsherr...@reagan.com; Elecraft Reflector <elecraft@mailman.qth.net>
Subject: Re: [Elecraft] Antenna Question

There is a stranded center conductor version of the LM400, do not remember
what the designation is. I plan to use some for the same reason, going
around a rotor to a HexBeam.
73, John WB4UHCK3 #2165 

On Monday, October 10, 2016 6:16 PM, "hsherr...@reagan.com"
<hsherr...@reagan.com> wrote:
 

 OK all. I'm installing a 6m rotating beam and feeding it with LMR400. Would
you connect the LMR to the antenna and allow it to move with the rotation,
or run a short length of something much more flexible between the antenna
and LMR? I have my concerns that the solid heavy inner conductor of the LMR
won't take much movement.

Harlan
K4HES

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Re: [Elecraft] Antenna Question

[Clay Autery]

On 10/10/2016 8:37 PM, Josh Fiden wrote:

> On 10/10/2016 5:39 PM, Clay Autery wrote:
>> All things being equal... IF you are using LMR-400 as the main feedline,
>> there is NO REASON to use a different diameter at the rotator...
> The point was using a lower loss cable for the long run up the tower,
> such as hardline, then flexible cable for the rotor/drip loop and
> short distance to the antenna feedpoint. At VHF, this is typical.

Right...  I'd use the best/lowest loss feedline I could afford/source,
too...  and then use a smaller jumper...  I was simply responding to the
OP who said he was using LMR 400 and saying that LMR-400 CAN and IS
frequently used as that "jumper" for the rotator loop...  or something
similarly sized in the .4-.5 inch range
>> Fail to see why an antenna failure or swap would require soldering "up
>> the tower"...
> Failure is not necessarily the antenna. It could be the solid center
> conductor fracture after being flexed too many times :)

THAT would be the result of improper design/installation
>
> If you swap antennas and it's a single run of cable, you have to
> manipulate the antenna on the tower to access the feedpoint. Then, for
> example, if you put up a longer boom yagi, the feedpoint will most
> likely be further away from the tower and your existing feedline won't
> reach.

Point taken  I'm not a big part swapper/upgrader...  I build things
the best I can so I don't have to upgrade, so I didn't think of that... 
This situation would likely not occur for me, as I said above...  I
would likely NEVER use LMR-400 for a feedline run up a tower.  I'd use
the biggest/best feedline I could source/afford.

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MONTAC Enterprises
(318) 518-1389

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Re: [Elecraft] Antenna Question

[Bob]

OOPS...  Original left here in HTML not plain text.   Don't know why. Elecraft 
in address book is listed as plain text only


Sorry,

Bob

K2TK



 Forwarded Message 
Subject:Re: [Elecraft] Antenna Question
Date:   Mon, 10 Oct 2016 21:21:14 -0400
From:   Bob <k...@ptd.net>
To: Josh Fiden <j...@voodoolab.com>, Elecraft Reflector 
<elecraft@mailman.qth.net>



For sure a consideration.There never is a perfect solution all is a 
compromise.   For me I wanted a single run because I see any extra  connectors 
as a potential failure points.  My Tower is crank up/tilt-over so not even as 
much of a repair or change issue.


Nobody has mentioned it here but Times makes a LMR400 Ultraflex.  A possible 
solution.  The slightly increased loss on 50MC maybe about equal to the extra 
connector loss.Another cable I have been happy with is this:


http://www.davisrf.com/buryflex.php

A ham owned company that has been very responsive to requests.   Of my 7 feeds 6 
use it and no issues and a few pieces are getting close to 8 years old.


73,

Bob

K2TK ex KN2TKR (1956) & K2TKR


<http://www.davisrf.com/buryflex.php>

On 10/10/2016 7:49 PM, Josh Fiden wrote:

With an unbroken feedline, a failure or antenna swap can require soldering 
connectors up the tower. Not fun. If you're concerned about the additional 
loss of a barrel connector at 50MHz, you should be using feedline with lower 
loss than LMR400 up the tower. Wrap the barrel connection with good quality 3m 
vinyl tape and paint over with Scotchkote to keep water out.


YMMV!

73,
Josh W6XU

On 10/10/2016 3:44 PM, Clay Autery wrote:

I believe the use of a single
unbroken feedline from the antenna to the shack (when possible) trumps
the inconvenience of properly engineering an install that does NOT put
unnecessary repetitive bending moments on the line.





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Re: [Elecraft] Antenna Question

[Josh Fiden]

Completely agree. If access isn't a problem and the additional loss of 
more flexible cable is tolerable, that's a great solution. I haven't 
used Davis Bury-FLEX but heard very positive reports about it.


73,
Josh W6XU

On 10/10/2016 6:21 PM, Bob wrote:


For sure a consideration.There never is a perfect solution all is 
a compromise.   For me I wanted a single run because I see any extra  
connectors as a potential failure points.  My Tower is crank 
up/tilt-over so not even as much of a repair or change issue.


Nobody has mentioned it here but Times makes a LMR400 Ultraflex.  A 
possible solution.  Another cable I have been happy with is this:


http://www.davisrf.com/buryflex.php



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Re: [Elecraft] Antenna Question

[Josh Fiden]

On 10/10/2016 5:39 PM, Clay Autery wrote:

All things being equal... IF you are using LMR-400 as the main feedline,
there is NO REASON to use a different diameter at the rotator...
The point was using a lower loss cable for the long run up the tower, 
such as hardline, then flexible cable for the rotor/drip loop and short 
distance to the antenna feedpoint. At VHF, this is typical.

Fail to see why an antenna failure or swap would require soldering "up
the tower"...
Failure is not necessarily the antenna. It could be the solid center 
conductor fracture after being flexed too many times :)


If you swap antennas and it's a single run of cable, you have to 
manipulate the antenna on the tower to access the feedpoint. Then, for 
example, if you put up a longer boom yagi, the feedpoint will most 
likely be further away from the tower and your existing feedline won't 
reach.


73,
Josh W6XU
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Re: [Elecraft] Antenna Question

[John Parker]

There is a stranded center conductor version of the LM400, do not remember what 
the designation is. I plan to use some for the same reason, going around a 
rotor to a HexBeam.
73, John WB4UHCK3 #2165 

On Monday, October 10, 2016 6:16 PM, "hsherr...@reagan.com" 
 wrote:
 

 OK all. I'm installing a 6m rotating beam and feeding it with LMR400. Would 
you connect the LMR to the antenna and allow it to move with the rotation, or 
run a short length of something much more flexible between the antenna and LMR? 
I have my concerns that the solid heavy inner conductor of the LMR won't take 
much movement.

Harlan
K4HES

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Re: [Elecraft] Antenna Question

[Bob]

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Re: [Elecraft] Antenna Question

[Clay Autery]

All things being equal... IF you are using LMR-400 as the main feedline,
there is NO REASON to use a different diameter at the rotator...

I was simply responding to what the OP said were the conditions... NOT
the "ideal"...

Bottom line... IF you engineer and install things properly, the fewer
breaks in the feedline, the better...

Fail to see why an antenna failure or swap would require soldering "up
the tower"... unless for some reason you change feedline to antenna
connector type  not likely...  or you compromised a connector
termination or failed to weather protect properly  In either case,
your odds of doing one of those things increase with every additional
connector you add to the line.

BTW, using the -DB suffix (if available) for any Times cable will
radically reduce the chances of moisture ingress on the feedline...

__
Clay Autery, KY5G
MONTAC Enterprises
(318) 518-1389

On 10/10/2016 6:49 PM, Josh Fiden wrote:
> With an unbroken feedline, a failure or antenna swap can require
> soldering connectors up the tower. Not fun. If you're concerned about
> the additional loss of a barrel connector at 50MHz, you should be
> using feedline with lower loss than LMR400 up the tower. Wrap the
> barrel connection with good quality 3m vinyl tape and paint over with
> Scotchkote to keep water out.
>
> YMMV!
>
> 73,
> Josh W6XU
>
> On 10/10/2016 3:44 PM, Clay Autery wrote:
>> I believe the use of a single
>> unbroken feedline from the antenna to the shack (when possible) trumps
>> the inconvenience of properly engineering an install that does NOT put
>> unnecessary repetitive bending moments on the line.
>
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Re: [Elecraft] Antenna Question

[Fred Jensen]

As is military practice as well.  If you really want to get picky, the 
400 should come up to the connector [sealed of course] and supported on 
the tower, and then the jumper forms the drip loop to prevent water 
running down the coax from running over ... and eventually into ... the 
connector.


I don't think I'd run 400 all the way to a rotating antenna.

73,

Fred K6DGW
Sparks NV USA
Washoe County DM09dn


On 10/10/2016 4:34 PM, Phil Kane wrote:

On 10/10/2016 3:14 PM, hsherr...@reagan.com wrote:


Would you connect the LMR to the antenna and allow it to move with the 
rotation, or run a short length of something much more flexible between the 
antenna and LMR?


Commercial practice is to use a flexible jumper and "drip loop" between
the feedline and the antenna, even if the antenna is fixed solid to the
tower/mast.  This relieves the stress on the antenna connector.

73 de K2ASP - Phil Kane
Elecraft K2/100   s/n 5402


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Re: [Elecraft] Antenna Question

[Josh Fiden]

With an unbroken feedline, a failure or antenna swap can require 
soldering connectors up the tower. Not fun. If you're concerned about 
the additional loss of a barrel connector at 50MHz, you should be using 
feedline with lower loss than LMR400 up the tower. Wrap the barrel 
connection with good quality 3m vinyl tape and paint over with 
Scotchkote to keep water out.


YMMV!

73,
Josh W6XU

On 10/10/2016 3:44 PM, Clay Autery wrote:

I believe the use of a single
unbroken feedline from the antenna to the shack (when possible) trumps
the inconvenience of properly engineering an install that does NOT put
unnecessary repetitive bending moments on the line.


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Re: [Elecraft] Antenna Question

[Phil Kane]

On 10/10/2016 3:14 PM, hsherr...@reagan.com wrote:

> Would you connect the LMR to the antenna and allow it to move with the 
> rotation, or run a short length of something much more flexible between the 
> antenna and LMR?

Commercial practice is to use a flexible jumper and "drip loop" between
the feedline and the antenna, even if the antenna is fixed solid to the
tower/mast.  This relieves the stress on the antenna connector.

73 de K2ASP - Phil Kane
Elecraft K2/100   s/n 5402

>From a Clearing in the Silicon Forest
Beaverton (Washington County) Oregon
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Re: [Elecraft] Antenna Question

[Clay Autery]

You'll get lots of suggestions, but I believe the use of a single
unbroken feedline from the antenna to the shack (when possible) trumps
the inconvenience of properly engineering an install that does NOT put
unnecessary repetitive bending moments on the line.

Do the research  There's all kinds of info on how to create/route a
feedline for rotator use...

Most of the people I know with tall towers and big antennae use LMR-400
(or similar size) AS the "smaller jumper".

No reason NOT to use LMR-400 from the antenna to the station...

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MONTAC Enterprises
(318) 518-1389

On 10/10/2016 5:14 PM, hsherr...@reagan.com wrote:
> OK all. I'm installing a 6m rotating beam and feeding it with LMR400. Would 
> you connect the LMR to the antenna and allow it to move with the rotation, or 
> run a short length of something much more flexible between the antenna and 
> LMR? I have my concerns that the solid heavy inner conductor of the LMR won't 
> take much movement.
>
> Harlan
> K4HES
>
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Re: [Elecraft] Antenna Question

[Josh Fiden]

LMR400 is really stiff. When I used it as a rotor loop, I made a couple 
of hoops around rather than directly flexing the cable around the tower. 
Not sure if that makes sense. In any case, doing it again I would 
definitely use a more flexible jumper for the rotor loop running to the 
antenna. In the shack I'm making jumpers from RG-214 which is very 
flexible and would work great as a rotor loop as well.


73,
Josh W6XU

On 10/10/2016 3:14 PM, hsherr...@reagan.com wrote:

OK all. I'm installing a 6m rotating beam and feeding it with LMR400. Would you 
connect the LMR to the antenna and allow it to move with the rotation, or run a 
short length of something much more flexible between the antenna and LMR? I 
have my concerns that the solid heavy inner conductor of the LMR won't take 
much movement.

Harlan
K4HES


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Re: [Elecraft] Antenna Question

[Mel Farrer via Elecraft]

I don't know the suggested turning radius of LMR400.  In my system I use about 
6 foot jumper of RG213 to do the section around the rotating section.  I use a 
KLM 8 el and the total length is longer.

Mel, K6KBE


  From: John Stengrevics <jstengrev...@comcast.net>
 To: hsherr...@reagan.com 
Cc: Elecraft Reflector <elecraft@mailman.qth.net>
 Sent: Monday, October 10, 2016 3:17 PM
 Subject: Re: [Elecraft] Antenna Question
   
I run LMR400 to my 6 & 2 meter antennas with no problems.  Just leave enough 
slack around the rotor and you’ll be fine.

John
WA1EAZ

> On Oct 10, 2016, at 6:14 PM, hsherr...@reagan.com wrote:
> 
> OK all. I'm installing a 6m rotating beam and feeding it with LMR400. Would 
> you connect the LMR to the antenna and allow it to move with the rotation, or 
> run a short length of something much more flexible between the antenna and 
> LMR? I have my concerns that the solid heavy inner conductor of the LMR won't 
> take much movement.
> 
> Harlan
> K4HES
> 
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Re: [Elecraft] Antenna Question

[John Stengrevics]

I run LMR400 to my 6 & 2 meter antennas with no problems.  Just leave enough 
slack around the rotor and you’ll be fine.

John
WA1EAZ

> On Oct 10, 2016, at 6:14 PM, hsherr...@reagan.com wrote:
> 
> OK all. I'm installing a 6m rotating beam and feeding it with LMR400. Would 
> you connect the LMR to the antenna and allow it to move with the rotation, or 
> run a short length of something much more flexible between the antenna and 
> LMR? I have my concerns that the solid heavy inner conductor of the LMR won't 
> take much movement.
> 
> Harlan
> K4HES
> 
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[Elecraft] Antenna Question

[hsherriff]

OK all. I'm installing a 6m rotating beam and feeding it with LMR400. Would you 
connect the LMR to the antenna and allow it to move with the rotation, or run a 
short length of something much more flexible between the antenna and LMR? I 
have my concerns that the solid heavy inner conductor of the LMR won't take 
much movement.

Harlan
K4HES

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[Elecraft] Antenna question

[david beckwith]

Just moved and my K3 needs a new antenna. My only option is to run a wire 
antenna over my roof--I have about 110-120 feet to play with and I can get one 
end up off the ground 25 feet and the center and other end about 35 feet. Any 
ideas?  Or references to an antenna group that can help?  Thanks Bunches and 73
Dave K6CGE
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Re: [Elecraft] Antenna question

[James Bennett]

A doublet. Center fed with either 600 ohm or 450 ohm ladder line, a 4:1 balun 
close to your shack and as short a length of coax from the balun to your K3 as 
possible. Using a tuner (either the K3 internal or an external), you will be 
able to work 80 through 10 meters, and possibly six meters. This sort of 
antenna works GREAT.


 On Oct 17, 2014, at 1:45 PM, david beckwith david.beckw...@att.net wrote:
 
 Just moved and my K3 needs a new antenna. My only option is to run a wire 
 antenna over my roof--I have about 110-120 feet to play with and I can get 
 one end up off the ground 25 feet and the center and other end about 35 feet. 
 Any ideas?  Or references to an antenna group that can help?  Thanks Bunches 
 and 73
 Dave K6CGE
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Re: [Elecraft] Antenna question

[george fritkin via Elecraft]

Alpha Delta LB-PLUS.  they are  tough and work great
 
George, W6GF 


On Friday, October 17, 2014 1:45 PM, david beckwith david.beckw...@att.net 
wrote:
  


Just moved and my K3 needs a new antenna. My only option is to run a wire 
antenna over my roof--I have about 110-120 feet to play with and I can get one 
end up off the ground 25 feet and the center and other end about 35 feet. Any 
ideas?  Or references to an antenna group that can help?  Thanks Bunches and 73
Dave K6CGE
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Re: [Elecraft] Antenna question

[Larry Gerhardstein]

Dave,
I have a K3 (#7360) with ATU and 347 ft. long wire 30 ft height. It 
tunes up ok but performance is questionable.  This same antenna performs 
better with my external MFJ tuner.

Larry W7IN

On 10/17/2014 20:45, david beckwith wrote:

Just moved and my K3 needs a new antenna. My only option is to run a wire 
antenna over my roof--I have about 110-120 feet to play with and I can get one 
end up off the ground 25 feet and the center and other end about 35 feet. Any 
ideas?  Or references to an antenna group that can help?  Thanks Bunches and 73
Dave K6CGE
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Re: [Elecraft] Antenna question

[Don Wilhelm]

Dave,

Make it a balanced dipole antenna (equal lengths on either side of the 
feedpoint) for best efforts in keeping RF off the feedline.  The actual 
length does not matter a lot, but it should be greater than 80% of the 
half wavelength for the lowest band of interest.


Use open wire line or 450 ohm ladder line to feed it down to the point 
where it enters the shack - hopefully you can run the feedline 
perpendicular from the radiator for at least 1/4 wavelength on the 
lowest frequency of interest for lowest radiator to feedline pickup.  
Put a good 1:1 current mod choke at that point.  See page 29 of K9YC's 
RFI tutorial http://www.audiosystemsgroup.com/RFI-Ham.pdf
for instructions on how to construct a very effective current mode choke 
- note: a good balun *is* a current mode choke, but many fail to perform 
as well as the ones tested by K9YC.


You will need a tuner, and any Elecraft tuner should do the job nicely.  
If it does not, then you may have to make some adjustments in the length 
of the parallel feedline to see if you can achieve success on all bands 
of interest.


You may want to take a look at the Antenna and Transmission Line article 
on my website www.w3fpr.com for a bit on non-math theory on antennas.


73,
Don W3FPR

On 10/17/2014 4:45 PM, david beckwith wrote:

Just moved and my K3 needs a new antenna. My only option is to run a wire 
antenna over my roof--I have about 110-120 feet to play with and I can get one 
end up off the ground 25 feet and the center and other end about 35 feet. Any 
ideas?  Or references to an antenna group that can help?  Thanks Bunches and 73
Dave K6CGE



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Re: [Elecraft] Antenna question

[Fred Jensen]

Don pretty much described my low band antenna.  Full Disclosure: I live 
on 5 acres and have a 70' tower.  That said, it is a Sloping V [I'd call 
it an inverted V except is isn't resonant on any band], about 210' on a 
side from the top of the tower.  450 ohm window line to the bottom of 
the tower, DXE 4:1 balun, and coax into the house.  I have chokes on the 
coax at the balun and at the weatherhead entrance, but I've never had 
any problems with RFITS [RF In The Shack] with or without the chokes.


It works well on 80-40-30, requires a tuner of course [KAT500].  Works 
on 160 but warms the clouds and worms, I use an Inv-L for top band.  It 
also works on all the bands up from 30 but the pattern gets fairly 
complex and squirts my RF in a lot of non-productive directions because 
it's so big.


My experience is that an 88 ft doublet, center-fed, works really well on 
40 and up in frequency, often used by those activating summits in 
Summits On The Air.  Shorter doublets are also effective, and not being 
resonant doesn't really matter [in some cases, it helps].  Neither does 
what you do with the ends.  Most of the radiation comes from the center, 
high current sections.


450 ohm window line is sensitive to moisture ... if you set up your 
tuner for dry conditions and it's now raining, things will need retuning.


Keep in mind the wisdom of Tom, N6BT, Anything conductive will radiate 
if you get power into it.


73,

Fred K6DGW
- Northern California Contest Club
- CU in the 2015 Cal QSO Party 3-4 Oct 2015
- www.cqp.org

On 10/17/2014 3:54 PM, Don Wilhelm wrote:


Make it a balanced dipole antenna (equal lengths on either side of the
feedpoint) for best efforts in keeping RF off the feedline.  The actual
length does not matter a lot, but it should be greater than 80% of the
half wavelength for the lowest band of interest.

Use open wire line or 450 ohm ladder line to feed it down to the point
where it enters the shack - hopefully you can run the feedline
perpendicular from the radiator for at least 1/4 wavelength on the
lowest frequency of interest for lowest radiator to feedline pickup. Put
a good 1:1 current mod choke at that point.  See page 29 of K9YC's RFI
tutorial http://www.audiosystemsgroup.com/RFI-Ham.pdf
for instructions on how to construct a very effective current mode choke
- note: a good balun *is* a current mode choke, but many fail to perform
as well as the ones tested by K9YC.

You will need a tuner, and any Elecraft tuner should do the job nicely.
If it does not, then you may have to make some adjustments in the length
of the parallel feedline to see if you can achieve success on all bands
of interest.

You may want to take a look at the Antenna and Transmission Line article
on my website www.w3fpr.com for a bit on non-math theory on antennas.



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Re: [Elecraft] Antenna question

[James Bennett]

Fred is right about the 450-ohm stuff getting funky in wet weather. Cause my 
tuners to do the clicky-click dance whenever it rains here, although we've been 
pretty dry the past few years. Because of this, I plan on replacing my 450-ohm 
line with 600-ohm ladder line in a couple weeks.  I had the 600-ohm stuff on 
that doublet initially but a change in roofing materials made me change. Long 
story.  Anyway, as you probably know, antennas work much better when built or 
adjusted when the weather is horrible!!!

Jim / W6JHB


 On Oct 17, 2014, at 4:57 PM, Fred Jensen k6...@foothill.net wrote:
 
 Don pretty much described my low band antenna.  Full Disclosure: I live on 5 
 acres and have a 70' tower.  That said, it is a Sloping V [I'd call it an 
 inverted V except is isn't resonant on any band], about 210' on a side from 
 the top of the tower.  450 ohm window line to the bottom of the tower, DXE 
 4:1 balun, and coax into the house.  I have chokes on the coax at the balun 
 and at the weatherhead entrance, but I've never had any problems with RFITS 
 [RF In The Shack] with or without the chokes.
 
 It works well on 80-40-30, requires a tuner of course [KAT500].  Works on 160 
 but warms the clouds and worms, I use an Inv-L for top band.  It also works 
 on all the bands up from 30 but the pattern gets fairly complex and squirts 
 my RF in a lot of non-productive directions because it's so big.
 
 My experience is that an 88 ft doublet, center-fed, works really well on 40 
 and up in frequency, often used by those activating summits in Summits On The 
 Air.  Shorter doublets are also effective, and not being resonant doesn't 
 really matter [in some cases, it helps].  Neither does what you do with the 
 ends.  Most of the radiation comes from the center, high current sections.
 
 450 ohm window line is sensitive to moisture ... if you set up your tuner for 
 dry conditions and it's now raining, things will need retuning.
 
 Keep in mind the wisdom of Tom, N6BT, Anything conductive will radiate if 
 you get power into it.
 
 73,
 
 Fred K6DGW
 - Northern California Contest Club
 - CU in the 2015 Cal QSO Party 3-4 Oct 2015
 - www.cqp.org
 
 On 10/17/2014 3:54 PM, Don Wilhelm wrote:
 
 Make it a balanced dipole antenna (equal lengths on either side of the
 feedpoint) for best efforts in keeping RF off the feedline.  The actual
 length does not matter a lot, but it should be greater than 80% of the
 half wavelength for the lowest band of interest.
 
 Use open wire line or 450 ohm ladder line to feed it down to the point
 where it enters the shack - hopefully you can run the feedline
 perpendicular from the radiator for at least 1/4 wavelength on the
 lowest frequency of interest for lowest radiator to feedline pickup. Put
 a good 1:1 current mod choke at that point.  See page 29 of K9YC's RFI
 tutorial http://www.audiosystemsgroup.com/RFI-Ham.pdf
 for instructions on how to construct a very effective current mode choke
 - note: a good balun *is* a current mode choke, but many fail to perform
 as well as the ones tested by K9YC.
 
 You will need a tuner, and any Elecraft tuner should do the job nicely.
 If it does not, then you may have to make some adjustments in the length
 of the parallel feedline to see if you can achieve success on all bands
 of interest.
 
 You may want to take a look at the Antenna and Transmission Line article
 on my website www.w3fpr.com for a bit on non-math theory on antennas.
 
 
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Re: [Elecraft] Antenna question

[Walter Underwood]

In a dry climate, ladder line is fine, but good coax has low losses, too, and 
is less fussy about being run next to the gutters.

It is rare for a dipole to be perfectly balanced (thanks to near field objects 
like houses), so a high-quality current balun at the antenna can really help 
reject common mode noise. I recommend Balun Designs. Mine dropped the noise by 
6dB.

Also consider the “loop skywire”. A loop often fits into the same space as a 
dipole and lots of people like them.

For pre-built dipoles, I’m happy with my Hy Power Antenna: 
http://www.hypowerantenna.com/

wunder
K6WRU
CM87wj
http://observer.wunderwood.org/

On Oct 17, 2014, at 6:35 PM, James Bennett w6...@me.com wrote:

 Fred is right about the 450-ohm stuff getting funky in wet weather. Cause my 
 tuners to do the clicky-click dance whenever it rains here, although we've 
 been pretty dry the past few years. Because of this, I plan on replacing my 
 450-ohm line with 600-ohm ladder line in a couple weeks.  I had the 600-ohm 
 stuff on that doublet initially but a change in roofing materials made me 
 change. Long story.  Anyway, as you probably know, antennas work much better 
 when built or adjusted when the weather is horrible!!!
 
 Jim / W6JHB
 
 
 On Oct 17, 2014, at 4:57 PM, Fred Jensen k6...@foothill.net wrote:
 
 Don pretty much described my low band antenna.  Full Disclosure: I live on 5 
 acres and have a 70' tower.  That said, it is a Sloping V [I'd call it an 
 inverted V except is isn't resonant on any band], about 210' on a side from 
 the top of the tower.  450 ohm window line to the bottom of the tower, DXE 
 4:1 balun, and coax into the house.  I have chokes on the coax at the balun 
 and at the weatherhead entrance, but I've never had any problems with RFITS 
 [RF In The Shack] with or without the chokes.
 
 It works well on 80-40-30, requires a tuner of course [KAT500].  Works on 
 160 but warms the clouds and worms, I use an Inv-L for top band.  It also 
 works on all the bands up from 30 but the pattern gets fairly complex and 
 squirts my RF in a lot of non-productive directions because it's so big.
 
 My experience is that an 88 ft doublet, center-fed, works really well on 40 
 and up in frequency, often used by those activating summits in Summits On 
 The Air.  Shorter doublets are also effective, and not being resonant 
 doesn't really matter [in some cases, it helps].  Neither does what you do 
 with the ends.  Most of the radiation comes from the center, high current 
 sections.
 
 450 ohm window line is sensitive to moisture ... if you set up your tuner 
 for dry conditions and it's now raining, things will need retuning.
 
 Keep in mind the wisdom of Tom, N6BT, Anything conductive will radiate if 
 you get power into it.
 
 73,
 
 Fred K6DGW
 - Northern California Contest Club
 - CU in the 2015 Cal QSO Party 3-4 Oct 2015
 - www.cqp.org
 
 On 10/17/2014 3:54 PM, Don Wilhelm wrote:
 
 Make it a balanced dipole antenna (equal lengths on either side of the
 feedpoint) for best efforts in keeping RF off the feedline.  The actual
 length does not matter a lot, but it should be greater than 80% of the
 half wavelength for the lowest band of interest.
 
 Use open wire line or 450 ohm ladder line to feed it down to the point
 where it enters the shack - hopefully you can run the feedline
 perpendicular from the radiator for at least 1/4 wavelength on the
 lowest frequency of interest for lowest radiator to feedline pickup. Put
 a good 1:1 current mod choke at that point.  See page 29 of K9YC's RFI
 tutorial http://www.audiosystemsgroup.com/RFI-Ham.pdf
 for instructions on how to construct a very effective current mode choke
 - note: a good balun *is* a current mode choke, but many fail to perform
 as well as the ones tested by K9YC.
 
 You will need a tuner, and any Elecraft tuner should do the job nicely.
 If it does not, then you may have to make some adjustments in the length
 of the parallel feedline to see if you can achieve success on all bands
 of interest.
 
 You may want to take a look at the Antenna and Transmission Line article
 on my website www.w3fpr.com for a bit on non-math theory on antennas.
 
 
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Re: [Elecraft] Antenna question

[Wes (N7WS)]

Quoting myself:
Besides, I think that low angle is often overrated. 


Here's some supporting evidence: (for ARRL members)

http://www.nxtbook.com/nxtbooks/arrl/qst_201203/index.php#/42

Wes  N7WS
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Re: [Elecraft] Antenna question

[WILLIS COOKE]

It depends on which side of Chicago you are talking.  NW of Chicago there is a 
big lode of iron which makes verticals work very well with few radials as they 
do here on the Gulf Coast for DX.  A 43 ft vertical is 5/8 wave on 20 meters 
which will give it about 3 db gain over a 1/4 wave vertical with equal 
counterpoise.  Both will do better than a horizontal dipole at average heights 
and are easier to erect than a dipole at 50 to 100 feet.  Low dipoles will 
usually do better at distances less than 1000 miles and well counterpoised 
verticals at distances more than 2000 miles.  Conductive grounds will allow you 
to get away with fewer radials, but if you live in the desert the counterpoise 
will be difficult.  It depends is a phrase that rings true with antennas more 
than other things.  Read the ARRL Antenna Handbook from cover to cover then 
read it again.  Repeat at 1 or 2 year intervals and buy a new copy every few 
years.  Understanding antennas is
 difficult for Physicists and Electrical Engineers (I am both) and even more 
difficult for others, so plan on putting in the study, modeling time, 
construction time and enjoy.  It is arguably the most difficult and enjoyable 
part of ham radio. 
 
Willis 'Cookie' Cooke, TDXS DX Chairman
K5EWJ  Trustee N5BPS, USS Cavalla, USS Stewart



 From: Rich reh...@ix.netcom.com
To: elecraft@mailman.qth.net 
Sent: Thursday, February 13, 2014 9:07 AM
Subject: Re: [Elecraft] Antenna question
 

Does that middle of the country include Chicago?

Rich
NU6T

On 2/13/2014 5:33 AM, James Rodenkirch wrote:


 And QST recently published a piece showing that a better use of a 43 ft 
 vertical might be as the center support for horizontal dipoles for 80 and 40, 
 a concept with which I strongly agree. (smiley face annotation removed)
 As stated by a frtend of mine, after eading the above little ditty and 
 replying, initially, Snort, my friends goes on to addobviously, the 
 author of that uninformed statement hasn't had to work stations on 80 and 40 
 from the middle of the country when signal arrival angles start changing 
 dramatically and rapidly. (smiley face annotation re-inserted)
 72/u3, Jim Rodenkirch K9JWV



 Date: Tue, 11 Feb 2014 23:09:23 -0800
 From: j...@audiosystemsgroup.com
 To: elecraft@mailman.qth.net
 Subject: Re: [Elecraft] Antenna question

 On 2/11/2014 3:36 PM, George Thornton wrote:
 I have a small lot.  I currently am using a 3 element Yagi that barely fits 
 on the property.  I was thinking about getting a vertical as a second HF 
 antenna.
 As it happens, over the past year or so I've been engaged in a serious
 modeling study that compares the performance of vertical and horizontal
 antennas at mounting heights that are practical for hams in your
 situation. So the real question is, what will that vertical add to your
 station beside a second antenna for SO2R?

 If I were in your situation, I would add an antenna only to cover bands
 that the tri-bander does not. Even the best vertical is unlikely to
 outperform the tribander unless you happen to be blessed with REALLY
 good ground conductivity, and even then only by a dB or so at low
 elevation angles. Second, if I were to add a vertical, it would be one
 that is configured as a center-fed dipole, and I would add it ONLY if I
 could elevate it at least 20 ft.

 Yes, I know this wasn't the question you asked, but it needs to be asked
 and answered. :)  Also, by all means pay attention to K6DGW's comments,
 with which I completely concur.

 There's a link to a presentation I did last fall of the vertical height
 issue, and also one about the recently popular 43 ft vertical.
 http://k9yc.com/publish.htm

 I'm still working on the comparison of verticals to horizontal antennas
 -- I've done all the modeling and know the results, but haven't
 organized it to show yet. AD5X has also done some excellent work on the
 43 ft vertical idea. And QST recently published a piece showing that a
 better use of a 43 ft vertical might be as the center support for
 horizontal dipoles for 80 and 40, a concept with which I strongly agree. :)

 73, Jim K9YC


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Re: [Elecraft] Antenna question

[James Rodenkirch]

And QST recently published a piece showing that a better use of a 43 ft 
vertical might be as the center support for horizontal dipoles for 80 and 40, a 
concept with which I strongly agree. (smiley face annotation removed)
As stated by a frtend of mine, after eading the above little ditty and 
replying, initially, Snort, my friends goes on to addobviously, the 
author of that uninformed statement hasn't had to work stations on 80 and 40 
from the middle of the country when signal arrival angles start changing 
dramatically and rapidly. (smiley face annotation re-inserted)
72/u3, Jim Rodenkirch K9JWV



 Date: Tue, 11 Feb 2014 23:09:23 -0800
 From: j...@audiosystemsgroup.com
 To: elecraft@mailman.qth.net
 Subject: Re: [Elecraft] Antenna question
 
 On 2/11/2014 3:36 PM, George Thornton wrote:
  I have a small lot.  I currently am using a 3 element Yagi that barely fits 
  on the property.  I was thinking about getting a vertical as a second HF 
  antenna.
 
 As it happens, over the past year or so I've been engaged in a serious 
 modeling study that compares the performance of vertical and horizontal 
 antennas at mounting heights that are practical for hams in your 
 situation. So the real question is, what will that vertical add to your 
 station beside a second antenna for SO2R?
 
 If I were in your situation, I would add an antenna only to cover bands 
 that the tri-bander does not. Even the best vertical is unlikely to 
 outperform the tribander unless you happen to be blessed with REALLY 
 good ground conductivity, and even then only by a dB or so at low 
 elevation angles. Second, if I were to add a vertical, it would be one 
 that is configured as a center-fed dipole, and I would add it ONLY if I 
 could elevate it at least 20 ft.
 
 Yes, I know this wasn't the question you asked, but it needs to be asked 
 and answered. :)  Also, by all means pay attention to K6DGW's comments, 
 with which I completely concur.
 
 There's a link to a presentation I did last fall of the vertical height 
 issue, and also one about the recently popular 43 ft vertical.
 http://k9yc.com/publish.htm
 
 I'm still working on the comparison of verticals to horizontal antennas 
 -- I've done all the modeling and know the results, but haven't 
 organized it to show yet. AD5X has also done some excellent work on the 
 43 ft vertical idea. And QST recently published a piece showing that a 
 better use of a 43 ft vertical might be as the center support for 
 horizontal dipoles for 80 and 40, a concept with which I strongly agree. :)
 
 73, Jim K9YC
 
 
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Re: [Elecraft] Antenna question

[Rich]

Does that middle of the country include Chicago?

Rich
NU6T

On 2/13/2014 5:33 AM, James Rodenkirch wrote:



And QST recently published a piece showing that a better use of a 43 ft vertical 
might be as the center support for horizontal dipoles for 80 and 40, a concept with which 
I strongly agree. (smiley face annotation removed)
As stated by a frtend of mine, after eading the above little ditty and replying, initially, 
Snort, my friends goes on to addobviously, the author of that uninformed 
statement hasn't had to work stations on 80 and 40 from the middle of the country when signal 
arrival angles start changing dramatically and rapidly. (smiley face annotation re-inserted)
72/u3, Jim Rodenkirch K9JWV




Date: Tue, 11 Feb 2014 23:09:23 -0800
From: j...@audiosystemsgroup.com
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] Antenna question

On 2/11/2014 3:36 PM, George Thornton wrote:

I have a small lot.  I currently am using a 3 element Yagi that barely fits on 
the property.  I was thinking about getting a vertical as a second HF antenna.

As it happens, over the past year or so I've been engaged in a serious
modeling study that compares the performance of vertical and horizontal
antennas at mounting heights that are practical for hams in your
situation. So the real question is, what will that vertical add to your
station beside a second antenna for SO2R?

If I were in your situation, I would add an antenna only to cover bands
that the tri-bander does not. Even the best vertical is unlikely to
outperform the tribander unless you happen to be blessed with REALLY
good ground conductivity, and even then only by a dB or so at low
elevation angles. Second, if I were to add a vertical, it would be one
that is configured as a center-fed dipole, and I would add it ONLY if I
could elevate it at least 20 ft.

Yes, I know this wasn't the question you asked, but it needs to be asked
and answered. :)  Also, by all means pay attention to K6DGW's comments,
with which I completely concur.

There's a link to a presentation I did last fall of the vertical height
issue, and also one about the recently popular 43 ft vertical.
http://k9yc.com/publish.htm

I'm still working on the comparison of verticals to horizontal antennas
-- I've done all the modeling and know the results, but haven't
organized it to show yet. AD5X has also done some excellent work on the
43 ft vertical idea. And QST recently published a piece showing that a
better use of a 43 ft vertical might be as the center support for
horizontal dipoles for 80 and 40, a concept with which I strongly agree. :)

73, Jim K9YC


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Re: [Elecraft] Antenna question

[Wes (N7WS)]

Well, I was speaking of my situation.

I'm in the Sonoran Desert of southern AZ with ground that varies from granite to 
sand to caliche within a few feet distance.


Although many (most?) hams consider vertical antennas to be low-angle 
radiators, they often fail to consider the efficiency of that low-angle 
radiator.  My modeling shows that even a low lambda dipole with its high-angle 
radiation often has more signal radiated at the vertical's optimum (low) angle 
than the vertical does.  Plotting the two antennas and overlaying the plots will 
easily show this.


Now I'm not going to argue with the guys with heroic vertical phased array 
installations and the like, but for the typical guy contemplating a modest 
vertical installation v. a straightforward dipole or inverted-vee I would (and 
did) choose the dipole. Besides, I think that low angle is often overrated.


Although I'm normally loath to state anecdotal evidence,  my paralleled wires 40 
and 80-meter inverted-vee with apex at 40 ft and ends at 20 feet models as a 
NVIS antenna, but I have 148 DXCC countries (including antipodal FT5ZM) worked 
on 80-meters and I don't much care for 80-meters so seldom operate there.


Wes  N7WS

On 2/12/2014 4:17 PM, Jim Brown wrote:

On 2/12/2014 7:29 AM, Wes (N7WS) wrote:
Also known as, The worst horizontal antenna is better than the best vertical 
antenna theory.  It's always worked out for me.  Now if I lived on the beach...


Hi Wes,

Based on my model studies, I wouldn't go that far -- it depends on how high 
either of the antennas are, as well as the quality of the ground. If your 
criteria is low angle radiation and you have better than average soil, a 
vertical dipole that's 20 ft or more above ground will beat a low dipole. Here 
in the mountains, our soil is stinko, so the only band where a vertical beats 
a horizontal dipole is 160M.


73, Jim K9YC


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Re: [Elecraft] Antenna question

[Jim Brown]

On 2/13/2014 1:04 PM, Wes (N7WS) wrote:

Well, I was speaking of my situation.

I'm in the Sonoran Desert of southern AZ with ground that varies from 
granite to sand to caliche within a few feet distance. 


My modeling studies, as well as my results with soil that's nearly as 
bad, are in complete agreement with your analysis.


73, Jim K9YC


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Re: [Elecraft] Antenna question

[Don Wilhelm]

Wes and all,

From my practical experience, your modeling analysis is correct.
I have a vertical for 80 and 40 with elevated radials (full size except 
for the loading of the 40 meter trap) - in A/B tests compared with my 80 
and 40 meter dipoles with the center at 45 feet and ends at 20 feet or 
greater, I have found that copy on *all* stations is better using the 
dipoles than with the vertical.


The only reason the vertical stays up is because it also functions as a 
160 meter inverted L which is my only 160 meter antenna at the present time.


73,
Don W3FPR

On 2/13/2014 4:04 PM, Wes (N7WS) wrote:

Well, I was speaking of my situation.

I'm in the Sonoran Desert of southern AZ with ground that varies from 
granite to sand to caliche within a few feet distance.


Although many (most?) hams consider vertical antennas to be 
low-angle radiators, they often fail to consider the efficiency of 
that low-angle radiator.  My modeling shows that even a low lambda 
dipole with its high-angle radiation often has more signal radiated 
at the vertical's optimum (low) angle than the vertical does.  
Plotting the two antennas and overlaying the plots will easily show this.


Now I'm not going to argue with the guys with heroic vertical phased 
array installations and the like, but for the typical guy 
contemplating a modest vertical installation v. a straightforward 
dipole or inverted-vee I would (and did) choose the dipole. Besides, 
I think that low angle is often overrated.


Although I'm normally loath to state anecdotal evidence,  my 
paralleled wires 40 and 80-meter inverted-vee with apex at 40 ft and 
ends at 20 feet models as a NVIS antenna, but I have 148 DXCC 
countries (including antipodal FT5ZM) worked on 80-meters and I don't 
much care for 80-meters so seldom operate there.




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Re: [Elecraft] Antenna question

[Dale Putnam]

My modeling experience pretty much says the same... for higher angle 
arrivals... the dipoles under 1/2 or more, will be better... especially when 
placed within one hop of the ocean. (East or West.)..  HOWEVER... taking 
one hop off... (that's the same almost) as gaining 2 - 3 S unites... is 
better.. and taking one hop off with a dipole... at less thanoptimum height is 
nigh on impossible. With an optimum vertical.. or LOW angle antenna...it IS 
possible.  This is all derived with modeling.. AND   Since I don't believe 
computers have ever actually DONE IT... I kinda like to prove it empirically.  
And I have... the last time was with FT5ZM... with a very LOW angle antenna... 
they were attained on4 bands the dipole didn't work.  The dipole at near 
optimum height was 3 S units lower in rx... on a calibratedS meter THAT 
particular day and it was 1 - 3 S units less for over a week that I 
listened... HOWEVER.. there werea few times.. especially when the band was ful
 l of QSB..shifting and changing... that the dipole did hear better... and 
significantly... for short periods of time.   I, being one, and only me... 
prefer to hear for a much longer period of time... more reliably... rather than 
count on a few short bursts of signal, ... every cycle of the band (about 2 
times a day )  I can't count on being at the radio at the optimum time... 
but I can count on being at the radio when I want to!
Have a great day, 
 
 
--...   ...--
Dale - WC7S in Wy
 
 

  
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Re: [Elecraft] Antenna question

[Stephen Selberg]

I'm not by any means an antenna expert. All I can say is with ft5zm, they
were much stronger on the vertical than my dipole on 20 meters. Some how
some way, I was able to work them on 40 cw with the hustler vertical.

The conclusion I've come to is there's times where my dipole works better
for DX and there's times the vertical works better. Guess that's why I
still have them both up. But that's what makes Amateur Radio so fun, seeing
what works and what doesn't, and how one might be great one day, but not so
good the next. I love radio...

Enjoy experimenting...

73 Steve KS6PD

Sent from my iPhone. Forgive the typos.


On Thursday, February 13, 2014, Dale Putnam daleput...@hotmail.com wrote:

 My modeling experience pretty much says the same... for higher angle
 arrivals... the dipoles under 1/2 or more, will be better... especially
 when placed within one hop of the ocean. (East or West.)..  HOWEVER...
 taking one hop off... (that's the same almost) as gaining 2 - 3 S unites...
 is better.. and taking one hop off with a dipole... at less thanoptimum
 height is nigh on impossible. With an optimum vertical.. or LOW angle
 antenna...it IS possible.  This is all derived with modeling.. AND
 Since I don't believe computers have ever actually DONE IT... I kinda like
 to prove it empirically.  And I have... the last time was with FT5ZM...
 with a very LOW angle antenna... they were attained on4 bands the
 dipole didn't work.  The dipole at near optimum height was 3 S units lower
 in rx... on a calibratedS meter THAT particular day and it was 1 -
 3 S units less for over a week that I listened... HOWEVER.. there werea few
 times.. especially when the band was ful
  l of QSB..shifting and changing... that the dipole did hear better... and
 significantly... for short periods of time.   I, being one, and only me...
 prefer to hear for a much longer period of time... more reliably... rather
 than count on a few short bursts of signal, ... every cycle of the band
 (about 2 times a day )  I can't count on being at the radio at the
 optimum time... but I can count on being at the radio when I want to!
 Have a great day,


 --...   ...--
 Dale - WC7S in Wy




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Re: [Elecraft] Antenna question

[Edward R Cole]

George,

You do not say what power you are transmitting and it would be 
helpful to know the separation between the antennas. Will the 
vertical be as high as the yagi?  Need to know what frequency is used.


OK, in lieu of this data I will make some assumptions and show you 
the math to calculate the power received.

F = 3.5-MHz
Po = 100w = 50 dBm
separation = 60 feet = 18.3m
cross-pol loss = 20 dB (it will not be quite this much at this close 
separation)

L = 32.4 + 20 Log F + 20 Log d, where F= MHz and d= km
L = the space loss between antenna, in dB
L = 32.4 +20 Log (3.5) + 20 Log (18.3/1000)
L = 32.4 + 10.9 - 5
L = 38 dB
Ltot = L + Lcross-pol = 58 dB
Po - Ltot = -8 dBm

That is a very strong signal but will not hurt the 
receiver.  Typically anything under 0 dBm is safe.  I run 1500w and 
have a preamp attached to the TR coax relay and have had no problems 
blowing up the very sensitive transistor in the preamp if the relay 
isolation is equal to the power in dBm.


Now cross-pol loss is probably not 20 dB but more like 15 dB and your 
antennas are in near-field so these formula are not quite 
accurate.  Ideally you would measure the power on the receiving 
antenna with a milliwatt power meter but I suppose you do not have 
one.  Also I did not include antenna gains in this, but in close 
proximity they are probably not accurate.


I have tested my tower mounted preamp by sending a test signal to an 
antenna about 130-foot away and using the space loss formula pretty 
accurately predicted received signal level.  This let me test the 
preamp sensitivity without removing it from the tower.


If you have a scope look at the received RF signal and measure the 
peak voltage.

P = E^2*R or
E = sq-rt (P/50)
P = 0 dBm = 0.001w
sq-rt(0.001/50) = .004v

73, Ed - KL7UW
PS: If you run more than 100w then either short the receiver antenna 
line or use a coax relay to disconnect it when transmitting.



Date: Tue, 11 Feb 2014 23:36:09 +
From: George Thornton gthorn...@thorntonmostullaw.com
To: 'elecraft @ mailman . qth . net' elecraft@mailman.qth.net
Subject: Re: [Elecraft] Antenna question
Message-ID:
040f2ec01a53458babf11914164d5...@server.thorntonmostullaw.com
Content-Type: text/plain; charset=us-ascii

This might be a stupid question, but here goes.

I have a small lot.  I currently am using a 3 element Yagi that 
barely fits on the property.  I was thinking about getting a vertical 
as a second HF antenna.  If I put it up it is going to have to be 
pretty close to the Yagi.


I have a dual receive K3.  If I have both receivers going, one on 
each channel, and I broadcast on one of these antennas, am I in any 
danger of overloading and frying the other receiver?



73, Ed - KL7UW
http://www.kl7uw.com
Kits made by KL7UW
Dubus Mag business:
dubus...@gmail.com

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Re: [Elecraft] Antenna question

[Ralf Wilhelm]

Hi George,

The 130 feet corresponds to lambda/2 on 80 and you can use the far field 
approximation (that Ed is using) there...

At short distances (less than a quarter or a sixth of the wavelength), however, 
1/r^2 and 1/r^3 (near field) components of E and H fields are still present 
(or dominant) and the far field approximation should not be used. You also have 
to be careful with the cross-polarization argument, since the electrical near 
field has all three vector components almost anywhere in space and the coupling 
can be much higher (depending on how well symmetry is preserved in the 
yagi+vertical system). 

Better use a NEC based program (e.g. EZNEC or the free 4nec2), if you have on 
access to a milliwatt-meter/scope and have to calculate...

By the way, P should read 
P= E*I = E^2/R 
=  E=sqrt(P*R)=223mV 
for a 0dBm (S9+67dB) signal (?)


Greetings 

Ralf, DL6OAP


 

Am 12.02.2014 um 10:31 schrieb Edward R Cole kl...@acsalaska.net:

 George,
 
 You do not say what power you are transmitting and it would be helpful to 
 know the separation between the antennas. Will the vertical be as high as the 
 yagi?  Need to know what frequency is used.
 
 OK, in lieu of this data I will make some assumptions and show you the math 
 to calculate the power received.
 F = 3.5-MHz
 Po = 100w = 50 dBm
 separation = 60 feet = 18.3m
 cross-pol loss = 20 dB (it will not be quite this much at this close 
 separation)
 L = 32.4 + 20 Log F + 20 Log d, where F= MHz and d= km
 L = the space loss between antenna, in dB
 L = 32.4 +20 Log (3.5) + 20 Log (18.3/1000)
 L = 32.4 + 10.9 - 5
 L = 38 dB
 Ltot = L + Lcross-pol = 58 dB
 Po - Ltot = -8 dBm
 
 That is a very strong signal but will not hurt the receiver.  Typically 
 anything under 0 dBm is safe.  I run 1500w and have a preamp attached to the 
 TR coax relay and have had no problems blowing up the very sensitive 
 transistor in the preamp if the relay isolation is equal to the power in dBm.
 
 Now cross-pol loss is probably not 20 dB but more like 15 dB and your 
 antennas are in near-field so these formula are not quite accurate.  Ideally 
 you would measure the power on the receiving antenna with a milliwatt power 
 meter but I suppose you do not have one.  Also I did not include antenna 
 gains in this, but in close proximity they are probably not accurate.
 
 I have tested my tower mounted preamp by sending a test signal to an antenna 
 about 130-foot away and using the space loss formula pretty accurately 
 predicted received signal level.  This let me test the preamp sensitivity 
 without removing it from the tower.
 
 If you have a scope look at the received RF signal and measure the peak 
 voltage.
 P = E^2*R or
 E = sq-rt (P/50)
 P = 0 dBm = 0.001w
 sq-rt(0.001/50) = .004v
 
 73, Ed - KL7UW
 PS: If you run more than 100w then either short the receiver antenna line or 
 use a coax relay to disconnect it when transmitting.
 
 
 Date: Tue, 11 Feb 2014 23:36:09 +
 From: George Thornton gthorn...@thorntonmostullaw.com
 To: 'elecraft @ mailman . qth . net' elecraft@mailman.qth.net
 Subject: Re: [Elecraft] Antenna question
 Message-ID:
040f2ec01a53458babf11914164d5...@server.thorntonmostullaw.com
 Content-Type: text/plain; charset=us-ascii
 
 This might be a stupid question, but here goes.
 
 I have a small lot.  I currently am using a 3 element Yagi that barely fits 
 on the property.  I was thinking about getting a vertical as a second HF 
 antenna.  If I put it up it is going to have to be pretty close to the Yagi.
 
 I have a dual receive K3.  If I have both receivers going, one on each 
 channel, and I broadcast on one of these antennas, am I in any danger of 
 overloading and frying the other receiver?
 
 
 73, Ed - KL7UW
 http://www.kl7uw.com
Kits made by KL7UW
 Dubus Mag business:
dubus...@gmail.com
 
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Re: [Elecraft] Antenna question

[George Danner]

Good advice:
I use wire antennas for 40m  80m with a HexBeam for the higher bands  a 
5BTV vertical. My sub-receiver is connected to a 50' vertical wire. The 
vertical wire is about 20' (horizontally) from the wire antennas and about 
30' from the 5BTV and HexBeam
When I installed the KPA500 I did the same test starting at 10 watts on 80m 
through 10m. I found that there was enough isolation on all antennas to 
leave the sub-receiver connected. I use the sub-receiver for diversity and 
would miss that feature.
George

--
From: WILLIS COOKE wrco...@yahoo.com
Sent: Tuesday, February 11, 2014 10:21 PM
To: George Thornton gthorn...@thorntonmostullaw.com; 'elecraft @ 
mailman . qth . net' elecraft@mailman.qth.net
Subject: Re: [Elecraft] Antenna question

Since the K3 will do the QRP thing down to 100 mw, think about installing 
the vertical above the beam on the mast and gradually try more and more 
power out of the K3 until you start getting some overloading.  At least you 
can find your answer without frying anything and some folks find QRP lots of 
fun.  Maybe you will too!

Willis 'Cookie' Cooke, TDXS DX Chairman
K5EWJ  Trustee N5BPS, USS Cavalla, USS Stewart



 From: George Thornton gthorn...@thorntonmostullaw.com
To: 'elecraft @ mailman . qth . net' elecraft@mailman.qth.net
Sent: Tuesday, February 11, 2014 5:36 PM
Subject: Re: [Elecraft] Antenna question


This might be a stupid question, but here goes.

I have a small lot.  I currently am using a 3 element Yagi that barely fits 
on the property.  I was thinking about getting a vertical as a second HF 
antenna.  If I put it up it is going to have to be pretty close to the Yagi.

I have a dual receive K3.  If I have both receivers going, one on each 
channel, and I broadcast on one of these antennas, am I in any danger of 
overloading and frying the other receiver?


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Re: [Elecraft] Antenna question

[George Danner]

Good advice:
I use wire antennas for 40m  80m with a HexBeam for the higher bands  a 
5BTV vertical. My sub-receiver is connected to a 50' vertical wire. The 
vertical wire is about 20' (horizontally) from the wire antennas and about 
30' from the 5BTV and HexBeam
When I installed the KPA500 I did the same test starting at 10 watts on 80m 
through 10m. I found that there was enough isolation on all antennas to 
leave the sub-receiver connected. I use the sub-receiver for diversity and 
would miss that feature.
George

--
From: WILLIS COOKE wrco...@yahoo.com
Sent: Tuesday, February 11, 2014 10:21 PM
To: George Thornton gthorn...@thorntonmostullaw.com; 'elecraft @ 
mailman . qth . net' elecraft@mailman.qth.net
Subject: Re: [Elecraft] Antenna question

Since the K3 will do the QRP thing down to 100 mw, think about installing 
the vertical above the beam on the mast and gradually try more and more 
power out of the K3 until you start getting some overloading.  At least you 
can find your answer without frying anything and some folks find QRP lots of 
fun.  Maybe you will too!

Willis 'Cookie' Cooke, TDXS DX Chairman
K5EWJ  Trustee N5BPS, USS Cavalla, USS Stewart



 From: George Thornton gthorn...@thorntonmostullaw.com
To: 'elecraft @ mailman . qth . net' elecraft@mailman.qth.net
Sent: Tuesday, February 11, 2014 5:36 PM
Subject: Re: [Elecraft] Antenna question


This might be a stupid question, but here goes.

I have a small lot.  I currently am using a 3 element Yagi that barely fits 
on the property.  I was thinking about getting a vertical as a second HF 
antenna.  If I put it up it is going to have to be pretty close to the Yagi.

I have a dual receive K3.  If I have both receivers going, one on each 
channel, and I broadcast on one of these antennas, am I in any danger of 
overloading and frying the other receiver?


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Re: [Elecraft] Antenna question

[Wes (N7WS)]

Also known as, The worst horizontal antenna is better than the best vertical 
antenna theory.  It's always worked out for me.  Now if I lived on the beach.


Wes  N7WS

On 2/12/2014 12:09 AM, Jim Brown wrote:

[snip]
I'm still working on the comparison of verticals to horizontal antennas -- 
I've done all the modeling and know the results, but haven't organized it to 
show yet. AD5X has also done some excellent work on the 43 ft vertical idea. 
And QST recently published a piece showing that a better use of a 43 ft 
vertical might be as the center support for horizontal dipoles for 80 and 40, 
a concept with which I strongly agree. :)


73, Jim K9YC



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Re: [Elecraft] Antenna question

[Ralf Wilhelm]

Hi Ed,

Actually, my S9+67 dB for 0dBm turned out to be wrong - I lost one 6 dB in my 
book keeping, so 0dBm is S9+73 dB - or S9 equals -73 dBm (which is the number I 
had in mind).

No doubt about the space loss formula and the far field  - free space loss is 
no dissipative loss like for example loss in the ground but just a geometry 
factor. Basically the free space formula calculates the aperture area of 
your rx antenna divided by the area of a sphere centered on the tx antenna and 
with radius r (r being the distance). But this is the free space loss only if 
E and H fields decay as 1/r because that means that power density decays as 
1/r^2 and integration over the sphere yields the total emitted power (which is 
the idea behind the formula) and by definition 1/r decay is the far field. If 
the 1/r^2 and 1/r^3 components of the fields have not already decayed, the 
space loss formula gives wrong results (which is why the german FCC 
equivalent wants us to either perform a near field calculation or  a 
measurement if we run more than 10 Watts ERP to be sure that we don't exceed 
the near field limits).

Regarding the polarization decoupling you mentioned: one can see by a little 
gedankenexperiment (as we say in physics even in english) that all electrical 
field vector components exist in the near field of the transmitting antenna: a 
part of the near field of a (electrically short) dipole follows the charge 
distribution on the dipole immediately (almost no retardation) and looks 
pretty much the same as the field between a positive and a negative charge (a 
static dipole) - or a short magnet - there are some field lines leaving the 
positve charge perpendicular to the antenna axis and then bending towards the 
other charge. If you view this from the side, you can see that even a perfectly 
horizontally polarized antenna has a vertical near field component, but for a 
short dipole, this decays as 1/r^3 (I think so) and is not present in the far 
field any more but might be dominant in the near field - so, with the vertical 
in the near field, the polarization decoupling can be d
 rastically reduced. Only if the yagi plus vertical system is symmetric - the 
(balanced) yagi pointing exactly towards the vertical or exactly  in the 
opposite direction - this near field component will vanish (for symmetry 
reasons) and the polarization decoupling works, but for the other directions of 
the yagi it won't...

So, regardless if you simulate or measure, don't forget to turn the yagi 
antenna into several directions - may be the coupling is stronger when one end 
of the driven element is close to the vertical...


Greetings

Ralf, DL6OAP





Am 12.02.2014 um 21:46 schrieb Edward R Cole kl...@acsalaska.net:

 Ralf,
 
 Thanks for catching my mistake in the ohm's law formula.
 P = E^2/R
 
 Regarding using the far-field loss formula it is probably prudent to try 
 measuring power on the receiving antenna when transmitting on the other 
 antenna (the yagi).  At the very least check with a SWR meter in the lowest 
 power range and see if you detect anything.  If the meter deflects or 
 twitches power is probably way too high and you need some kind of 
 protection device.  There are some simple milliwatt power meter designs in 
 some ham Handbooks (look for field strength meters); simplest is a IN34 and 
 1ma meter.  If you blow up the 1N34 you have your answer!  Better that you 
 use a couple 20-dB coax attenuators before the meter at first.  I no power is 
 seen then remove one and test again.
 
 You can rely on using 0 dBm as maximum survivable input to the receiver, but 
 the receiver still will be driven into compression and not usable while 
 transmitting.
 
 My example of 130-feet was at 144-MHz so not a fair comparison with HF freq. 
 which have much longer wavelength.
 
 The space loss formula is useful for making measurements at far-field (google 
 it)
 
 73, Ed - KL7UW
 
 
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Re: [Elecraft] Antenna question

[Bill Turner]

I see a number of people are trying to calculate whether any damage 
would be done by the situation originally posted.


Frankly, I think this is a dangerous approach. There are too many 
variables in a particular situation to risk  depending on calculations 
when expensive equipment is endangered.


If  you must go ahead with your situation, I strongly suggest, as others 
have done, that you measure the interaction rather than try to calculate 
it.


73, Bill W6WRT

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Re: [Elecraft] Antenna question

[Charlie T, K3ICH]

Wire a small grain-of-wheat incandescent light bulb to the unused antenna 
feed and fire up the transmitter.  If the bulb lights brightly, you need 
some protection.  Admittedly, this is a crude test, but it can point to a 
problem and takes into account all those variables in the calculations.  Try 
all bands and start at low power, otherwise, you may blow the bulb before 
any relative results can be gleaned.


73, Charlie k3ICH


- Original Message - 
From: Bill Turner dezrat1...@wildblue.net

To: elecraft@mailman.qth.net
Sent: Wednesday, February 12, 2014 5:45 PM
Subject: Re: [Elecraft] Antenna question


I see a number of people are trying to calculate whether any damage would 
be done by the situation originally posted.


Frankly, I think this is a dangerous approach. There are too many 
variables in a particular situation to risk  depending on calculations 
when expensive equipment is endangered.


If  you must go ahead with your situation, I strongly suggest, as others 
have done, that you measure the interaction rather than try to calculate 
it.


73, Bill W6WRT

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Re: [Elecraft] Antenna question

[Jim Brown]

On 2/12/2014 7:29 AM, Wes (N7WS) wrote:
Also known as, The worst horizontal antenna is better than the best 
vertical antenna theory.  It's always worked out for me.  Now if I 
lived on the beach...


Hi Wes,

Based on my model studies, I wouldn't go that far -- it depends on how 
high either of the antennas are, as well as the quality of the ground. 
If your criteria is low angle radiation and you have better than average 
soil, a vertical dipole that's 20 ft or more above ground will beat a 
low dipole. Here in the mountains, our soil is stinko, so the only band 
where a vertical beats a horizontal dipole is 160M.


73, Jim K9YC
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Re: [Elecraft] Antenna question

[Jack]

When we had our place in Silver Springs, NV, our 40-meter 4-square, with 
an excellent radial system, was killer. I cannot imagine anything short 
of a full-size 2, possibly 3, element yagi up at least 70 feet even 
coming close. I would think it would take the 3-element yagi to even 
approach the F/B ratio of the 4-square.


On the beach works *real* well. Any antenna we tried at Ballenita, 
Ecuador, worked great. The QTH was roughly 10-meters inland from 
high-tide! :)


Jack, W6NF/VE4SNA/HC2UA
Shelley, K7MKL/HC2UB

On 2/12/2014 3:17 PM, Jim Brown wrote:

On 2/12/2014 7:29 AM, Wes (N7WS) wrote:
Also known as, The worst horizontal antenna is better than the best 
vertical antenna theory.  It's always worked out for me.  Now if I 
lived on the beach...


Hi Wes,

Based on my model studies, I wouldn't go that far -- it depends on how 
high either of the antennas are, as well as the quality of the ground. 
If your criteria is low angle radiation and you have better than 
average soil, a vertical dipole that's 20 ft or more above ground will 
beat a low dipole. Here in the mountains, our soil is stinko, so the 
only band where a vertical beats a horizontal dipole is 160M.


73, Jim K9YC
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Re: [Elecraft] Antenna question

[Phil Wheeler]

Bill,

You don't trust the traditional Smoke Test? :-)

73, Phil w7ox

On 2/12/14, 2:45 PM, Bill Turner wrote:
I see a number of people are trying to calculate 
whether any damage would be done by the 
situation originally posted.


Frankly, I think this is a dangerous approach. 
There are too many variables in a particular 
situation to risk  depending on calculations 
when expensive equipment is endangered.


If  you must go ahead with your situation, I 
strongly suggest, as others have done, that you 
measure the interaction rather than try to 
calculate it.


73, Bill W6WRT


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Re: [Elecraft] Antenna question

[John]

I love my 40 mtr 4 SQ  it's in the woods of FAR NW WI. Poor soil, good ground 
system (36 each vertical) and very exact construction. Antennas are surrounded 
by much taller aspen. I moved from a location where I had a big 2 element at 
125'. It feels very similar and at 72, I'm done climbing big towers.  Sure is 
easier to maintain/fix/adjust. For those considering, it's verybroadbanded and 
even has directivity on 30!  Worked FT5ZM on CW and rtty on 30 using the 40 mtr 
4 SQ. 
It stinks for ss on 40, but great band opener for DX (further away the better). 
John, N0IJ
Sent from my iPhone

 On Feb 12, 2014, at 5:34 PM, Jack vhfp...@gmail.com wrote:
 
 When we had our place in Silver Springs, NV, our 40-meter 4-square, with an 
 excellent radial system, was killer. I cannot imagine anything short of a 
 full-size 2, possibly 3, element yagi up at least 70 feet even coming close. 
 I would think it would take the 3-element yagi to even approach the F/B ratio 
 of the 4-square.
 
 On the beach works *real* well. Any antenna we tried at Ballenita, Ecuador, 
 worked great. The QTH was roughly 10-meters inland from high-tide! :)
 
 Jack, W6NF/VE4SNA/HC2UA
 Shelley, K7MKL/HC2UB
 
 On 2/12/2014 3:17 PM, Jim Brown wrote:
 On 2/12/2014 7:29 AM, Wes (N7WS) wrote:
 Also known as, The worst horizontal antenna is better than the best 
 vertical antenna theory.  It's always worked out for me.  Now if I lived 
 on the beach...
 
 Hi Wes,
 
 Based on my model studies, I wouldn't go that far -- it depends on how high 
 either of the antennas are, as well as the quality of the ground. If your 
 criteria is low angle radiation and you have better than average soil, a 
 vertical dipole that's 20 ft or more above ground will beat a low dipole. 
 Here in the mountains, our soil is stinko, so the only band where a vertical 
 beats a horizontal dipole is 160M.
 
 73, Jim K9YC
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Re: [Elecraft] Antenna question

[EricJ]

Surprised me too. It ALWAYS produces results.

Eric
KE6US

On 2/12/2014 3:46 PM, Phil Wheeler wrote:

Bill,

You don't trust the traditional Smoke Test? :-)

73, Phil w7ox

On 2/12/14, 2:45 PM, Bill Turner wrote:
I see a number of people are trying to calculate whether any damage 
would be done by the situation originally posted.


Frankly, I think this is a dangerous approach. There are too many 
variables in a particular situation to risk  depending on 
calculations when expensive equipment is endangered.


If  you must go ahead with your situation, I strongly suggest, as 
others have done, that you measure the interaction rather than try to 
calculate it.


73, Bill W6WRT


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Re: [Elecraft] Antenna question

[Bill Turner]

ORIGINAL MESSAGE:  (may be snipped)

On 2/12/2014 3:46 PM, Phil Wheeler wrote:

Bill,

You don't trust the traditional Smoke Test? :-)

73, Phil w7ox 


REPLY:

Of course I trust it. I use it whenever I need smoke.  :-)

73, Bill W6WRT

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Re: [Elecraft] Antenna question

[George Thornton]

This might be a stupid question, but here goes.

I have a small lot.  I currently am using a 3 element Yagi that barely fits on 
the property.  I was thinking about getting a vertical as a second HF antenna.  
If I put it up it is going to have to be pretty close to the Yagi.

I have a dual receive K3.  If I have both receivers going, one on each channel, 
and I broadcast on one of these antennas, am I in any danger of overloading and 
frying the other receiver?


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Re: [Elecraft] Antenna question

[Barry LaZar]

George,
That is a very good question. However, it is hard to quess. But, 
one thing going in your favor is that one antenna is horizontal and the 
other is vertical. This will minimize the amount of coupling between the 
two. If you can get some horizontal separation between the two, it just 
might be physically safe. If you get really good decoupling, it could be 
on the order of 30 db. that means that a 100 Watts will look like 100 mw 
to your receiver.


I actually do a variant of what you are asking here. I have a 
Carolina Windom and an 18' base tuned vertical. I know there must be 
some interaction, but so far nothing has smoked. I know better than to 
try this without really looking at it, but I didn't think and did it 
anyway. My antennas are about 15-20 apart horizontally and 15 feet 
vertically. Maybe I had better have a look at it myself. But, my guess 
is you'll be OK as long as you don't need to receive at the same time 
you are transmitting. You will overdrive your receiver and not hear 
anything during transmissions, but the 100 mw or less into the receiver 
should be physically safe. That part of the answer should be answered by 
Elecraft as to the maximum energy the receiver can tolerate.


73,
Barry
K3NDM



On 2/11/2014 6:36 PM, George Thornton wrote:

This might be a stupid question, but here goes.

I have a small lot.  I currently am using a 3 element Yagi that barely fits on 
the property.  I was thinking about getting a vertical as a second HF antenna.  
If I put it up it is going to have to be pretty close to the Yagi.

I have a dual receive K3.  If I have both receivers going, one on each channel, 
and I broadcast on one of these antennas, am I in any danger of overloading and 
frying the other receiver?


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Re: [Elecraft] Antenna question

[Richard Solomon]

I have a Pennant receiving antenna about 100' from my 160 Meter Antenna.
I put a scope on the Pennant coax and keyed the rig. At about 1 KW out, I
saw about 6 volts pk-pk.

I bought a Receiver protection device.

73, Dick, W1KSZ


On 2/11/2014 4:36 PM, George Thornton wrote:

This might be a stupid question, but here goes.

I have a small lot.  I currently am using a 3 element Yagi that barely fits on 
the property.  I was thinking about getting a vertical as a second HF antenna.  
If I put it up it is going to have to be pretty close to the Yagi.

I have a dual receive K3.  If I have both receivers going, one on each channel, 
and I broadcast on one of these antennas, am I in any danger of overloading and 
frying the other receiver?


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Re: [Elecraft] Antenna question

[Bill Turner]

ORIGINAL MESSAGE:  (may be snipped)

On 2/11/2014 3:36 PM, George Thornton wrote:

I have a dual receive K3.  If I have both receivers going, one on each channel, 
and I broadcast on one of these antennas, am I in any danger of overloading and 
frying the other receiver?


REPLY:

The field around an antenna is very strong compared to the input of a 
receiver which is expecting a fraction of a microwatt. Not something to 
be messed with.


If you must do this I would recommend installing a relay to short out 
the non-transmitting antenna, and you should sequence it so it closes a 
few milliseconds before beginning TX and opens a few milliseconds after 
ceasing TX. Even better than simple shorting, use an SPDT relay so that 
when the relay activated, the antenna is disconnected and the receiver 
input is shorted to ground, separate from the antenna. This provides 
even more isolation between the two.




73, Bill W6WRT

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Re: [Elecraft] Antenna question

[Monovasia]

I would do it at all! Especially at power

Sent from my iPhone

 On Feb 11, 2014, at 7:16 PM, Bill Turner dezrat1...@wildblue.net wrote:
 
 ORIGINAL MESSAGE:  (may be snipped)
 
 On 2/11/2014 3:36 PM, George Thornton wrote:
 I have a dual receive K3.  If I have both receivers going, one on each 
 channel, and I broadcast on one of these antennas, am I in any danger of 
 overloading and frying the other receiver?
 
 REPLY:
 
 The field around an antenna is very strong compared to the input of a 
 receiver which is expecting a fraction of a microwatt. Not something to be 
 messed with.
 
 If you must do this I would recommend installing a relay to short out the 
 non-transmitting antenna, and you should sequence it so it closes a few 
 milliseconds before beginning TX and opens a few milliseconds after ceasing 
 TX. Even better than simple shorting, use an SPDT relay so that when the 
 relay activated, the antenna is disconnected and the receiver input is 
 shorted to ground, separate from the antenna. This provides even more 
 isolation between the two.
 
 
 
 73, Bill W6WRT
 
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Re: [Elecraft] Antenna question

[Phil Debbie Salas]

Check out the front-end protector in the “Articles” section of my website at 
www.ad5x.com.

Phil – AD5X
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Re: [Elecraft] Antenna question

[Fred Jensen]

On 2/11/2014 3:36 PM, George Thornton wrote:

This might be a stupid question, but here goes.


Only unasked questions are stupid.


I have a small lot.  I currently am using a 3 element Yagi that
barely fits on the property.  I was thinking about getting a vertical
as a second HF antenna.  If I put it up it is going to have to be
pretty close to the Yagi.


You will likely find that a vertical anything will be 1-2 S-units 
noisier than your horizontal yagi [or any other horizontal antenna, in 
general], *unless* you have essentially *no* man-made noise.  You said 
small lot which suggests an urban or suburban environment.  I have a 
tri-bander, a large sloping Vee for 160-30, and a GAP Titan vertical on 
the pipe that carries my coax up to the roof and to the other antennas. 
 I can almost always count on the GAP being a couple of S-units noiser 
than the other two on any of the bands they work on.


I have a dual receive K3.  If I have both receivers going, one on
each channel, and I broadcast on one of these antennas, am I in any
danger of overloading and frying the other receiver?


Antennas all have a near-field and a far-field and the definition of 
near and far depends on the operating frequency, among some other 
things.  The lower the frequency [longer wavelength], the farther far 
is from the antenna.  If a second antenna is located within the 
near-field of the first, they will become a coupled system ... the 
second antenna will behave as if it was an element or elements of the 
first antenna.  In this case, some fairly large amounts of RF power can 
show up at the end of the second antennas coax.  Obviously, it depends a 
huge amount on the power you intend to run.  5W may safe.


If the second antenna is clearly in the far-field of the first, the 
coupled power is much much lower.  The signal will be huge in the second 
receiver, but not likely to be damaging to components.


I'm on the crew that activates Alpine County in the Calif QSO Party [no 
permanent hams there].  First year we tried M/2, we had CW and SSB in 
one cabin.  Considering that the aggregate ham experience of the crew 
was well over 200 years, I can't explain why we did this. :-)


The 80 and 75 inverted Vee's were undoubtedly in each other's 
near-fields, not sure about the 40's, but we had bandpass filters for 
each rig.  I was on 80 CW in the middle of the night, the phone op 
decided to try 75 ... he switched the filters, I called CQ, and I fried 
the diodes in the front end of his K3.  We now have the two stations at 
opposite ends of the campground [maybe 500 meters?], and we have no 
problems.


So George, I'd be very careful.  The cross-polarization would be in your 
favor but if you're on 20 or below and close means less than a 
wavelength at best, it could mean problems.


Hope this helps

73,

Fred K6DGW
- Northern California Contest Club
- CU in the 2014 Cal QSO Party 4-5 Oct 2014
- www.cqp.org

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Re: [Elecraft] Antenna question

[Monovasia]

NOT

Sent from my iPhone

 On Feb 11, 2014, at 7:20 PM, Monovasia pontia...@monovasia.com wrote:
 
 I would do it at all! Especially at power
 
 Sent from my iPhone
 
 On Feb 11, 2014, at 7:16 PM, Bill Turner dezrat1...@wildblue.net wrote:
 
 ORIGINAL MESSAGE:  (may be snipped)
 
 On 2/11/2014 3:36 PM, George Thornton wrote:
 I have a dual receive K3.  If I have both receivers going, one on each 
 channel, and I broadcast on one of these antennas, am I in any danger of 
 overloading and frying the other receiver?
 
 REPLY:
 
 The field around an antenna is very strong compared to the input of a 
 receiver which is expecting a fraction of a microwatt. Not something to be 
 messed with.
 
 If you must do this I would recommend installing a relay to short out the 
 non-transmitting antenna, and you should sequence it so it closes a few 
 milliseconds before beginning TX and opens a few milliseconds after ceasing 
 TX. Even better than simple shorting, use an SPDT relay so that when the 
 relay activated, the antenna is disconnected and the receiver input is 
 shorted to ground, separate from the antenna. This provides even more 
 isolation between the two.
 
 
 
 73, Bill W6WRT
 
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Re: [Elecraft] Antenna question

[Mike K2MK]

Hi George,

I'm not 100% sure but I don't think your SUB RX has to be ON to be damaged.
I believe that just connecting an antenna to the AUX RF input will allow RF
into the SUB RX. 

There is an internal protective device on the input to the SUB RX called a
carrier operated relay (COR). You can see it in the manual in some of the
block diagrams. When you get your vertical you can try transmitting with the
yagi at low power and gradually increase your power. If you hear a clicking
sound you are tripping the COR. That's your positive indication that you
should either decrease power or add external protection. 

There are devices available to put in your SUB RX antenna line for overload
protection but you can also use the KEY OUT signal to energize a relay to
disconnect your SUB RX antenna. There is also a lower current KEY OUT signal
on pin 10 of the accessory connector. You can use that to trip a low current
device that in turn activates a relay.

73,
Mike K2MK



George A. Thornton-2 wrote
 This might be a stupid question, but here goes.
 
 I have a small lot.  I currently am using a 3 element Yagi that barely
 fits on the property.  I was thinking about getting a vertical as a second
 HF antenna.  If I put it up it is going to have to be pretty close to the
 Yagi.
 
 I have a dual receive K3.  If I have both receivers going, one on each
 channel, and I broadcast on one of these antennas, am I in any danger of
 overloading and frying the other receiver?





--
View this message in context: 
http://elecraft.365791.n2.nabble.com/Re-Antenna-question-tp7584071p7584085.html
Sent from the Elecraft mailing list archive at Nabble.com.
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Re: [Elecraft] Antenna question

[WILLIS COOKE]

Since the K3 will do the QRP thing down to 100 mw, think about installing the 
vertical above the beam on the mast and gradually try more and more power out 
of the K3 until you start getting some overloading.  At least you can find your 
answer without frying anything and some folks find QRP lots of fun.  Maybe you 
will too!
 
Willis 'Cookie' Cooke, TDXS DX Chairman
K5EWJ  Trustee N5BPS, USS Cavalla, USS Stewart



 From: George Thornton gthorn...@thorntonmostullaw.com
To: 'elecraft @ mailman . qth . net' elecraft@mailman.qth.net 
Sent: Tuesday, February 11, 2014 5:36 PM
Subject: Re: [Elecraft] Antenna question
 

This might be a stupid question, but here goes.

I have a small lot.  I currently am using a 3 element Yagi that barely fits on 
the property.  I was thinking about getting a vertical as a second HF antenna.  
If I put it up it is going to have to be pretty close to the Yagi.

I have a dual receive K3.  If I have both receivers going, one on each channel, 
and I broadcast on one of these antennas, am I in any danger of overloading and 
frying the other receiver?


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Re: [Elecraft] Antenna question

[Jim Brown]

On 2/11/2014 3:36 PM, George Thornton wrote:

I have a small lot.  I currently am using a 3 element Yagi that barely fits on 
the property.  I was thinking about getting a vertical as a second HF antenna.


As it happens, over the past year or so I've been engaged in a serious 
modeling study that compares the performance of vertical and horizontal 
antennas at mounting heights that are practical for hams in your 
situation. So the real question is, what will that vertical add to your 
station beside a second antenna for SO2R?


If I were in your situation, I would add an antenna only to cover bands 
that the tri-bander does not. Even the best vertical is unlikely to 
outperform the tribander unless you happen to be blessed with REALLY 
good ground conductivity, and even then only by a dB or so at low 
elevation angles. Second, if I were to add a vertical, it would be one 
that is configured as a center-fed dipole, and I would add it ONLY if I 
could elevate it at least 20 ft.


Yes, I know this wasn't the question you asked, but it needs to be asked 
and answered. :)  Also, by all means pay attention to K6DGW's comments, 
with which I completely concur.


There's a link to a presentation I did last fall of the vertical height 
issue, and also one about the recently popular 43 ft vertical.

http://k9yc.com/publish.htm

I'm still working on the comparison of verticals to horizontal antennas 
-- I've done all the modeling and know the results, but haven't 
organized it to show yet. AD5X has also done some excellent work on the 
43 ft vertical idea. And QST recently published a piece showing that a 
better use of a 43 ft vertical might be as the center support for 
horizontal dipoles for 80 and 40, a concept with which I strongly agree. :)


73, Jim K9YC


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Re: [Elecraft] Antenna Question

[Geoffrey Mackenzie-Kennedy]

Neil,

Were you able to see if the shortened fan dipole used by the county ERC has
the feeder connected to all three elements, as would be the case with a
typical fan dipole?

If the feeder is connected *only* to the mid-point of the longest element,
and the two shorter elements are unbroken lengths of wire running parallel
to the longest wire, then this antenna would belong to the family of
multiband antennas known as Coupled Resonators.  It would be tricky though
to use linear loading with these antennas.

73,

Geoff
LX2AO


On Monday, June 18, 2012 at 5:26 AM, Niel Skousen wrote:

 I'm pretty sure I've seen this antenna on the net, but don't recall the 
 name nor have I been able to find a link to a description / design data.

 The county ERC has a 'shortened fan dipole' with three parallel elements, 
 spaced about 18-24 apart on each side.   the longest element folds back 
 around the mid-  length element toward the shortest element.   The 
 antenna end insulator / guy rope is attached to the long element, where it 
 folds back.   There appears (from the
 ground) to be a 6~8 insulator / gap between the end of the shortest 
 element, and the longest element where its been folded back.  no traps, 
 loading coils, or loading
 resistors that I can see.

 I'm assuming three or four band coverage (80, 40, 20, and 15 ??) with a 
 75m dipole, a 40m dipole (with 15m as a freebie), and a 20 m dipole.   but 
 would be
 interested in more technical details if anyone can decipher my text 
 description above…



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Re: [Elecraft] Antenna Question

[Don Wilhelm]

Neil,

When you see an antenna element folded back on itself like that, think 
linear loading (look it up in the ARRL Handbook or similar).  There is 
no magic, but it is one way of shortening an antenna.  It is not as 
efficient as a full length antenna, but is more efficient than using 
loading coils.  Everything is relative.
If you have the space to put up full size half wave dipole antennas, 
that is the way to go.  If you need shortened antennas for the lower 
bands, linear loading is one way to achieve resonance with shortened length.

73,
Don W3FPR

On 6/17/2012 11:26 PM, Niel Skousen wrote:
 I'm pretty sure I've seen this antenna on the net, but don't recall the name 
 nor have I been able to find a link to a description / design data.

 The county ERC has a 'shortened fan dipole' with three parallel elements, 
 spaced about 18-24 apart on each side.   the longest element folds back 
 around the mid-length element toward the shortest element.   The antenna end 
 insulator / guy rope is attached to the long element, where it folds back.   
 There appears (from the ground) to be a 6~8 insulator / gap between the end 
 of the shortest element, and the longest element where its been folded back.  
 no traps, loading coils, or loading resistors that I can see.

 I'm assuming three or four band coverage (80, 40, 20, and 15 ??) with a 75m 
 dipole, a 40m dipole (with 15m as a freebie), and a 20 m dipole.   but would 
 be interested in more technical details if anyone can decipher my text 
 description above…

 Thanks
 Niel


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Re: [Elecraft] Antenna Question

[WILLIS COOKE]

A note on folded back antennae.  I have a 3 element SteppIR with the 30/40 kit. 
 The antenna is mounted at about 67 feet above the ground.  I have compared the 
folded antenna at 67 feet to a full sized inverted V at 40 feet and find 
it noticeably stronger.  Even though it is only a dipole which is a little more 
than half length it is noticeably bi-directive with deep nulls off the element 
ends.  It is quite effective as a DX antenna and I believe the SteppIR claim 
that it is only one or two dB down from a full sized rotatable dipole.  Of 
course, its improved performance over the inverted V is mostly because of the 
elevation difference, but I would not hesitate to fold the ends of a dipole if 
restricted by lot size or other physical restraints. 
 
Willis 'Cookie' Cooke 
K5EWJ  Trustee N5BPS, USS Cavalla, USS Stewart


- Original Message -
From: Don Wilhelm w3...@embarqmail.com
To: Niel Skousen nskou...@talisman-intl.com
Cc: Elecraft Reflector elecraft@mailman.qth.net; qr...@mailman.qth.net
Sent: Monday, June 18, 2012 6:18 AM
Subject: Re: [Elecraft] Antenna Question

Neil,

When you see an antenna element folded back on itself like that, think 
linear loading (look it up in the ARRL Handbook or similar).  There is 
no magic, but it is one way of shortening an antenna.  It is not as 
efficient as a full length antenna, but is more efficient than using 
loading coils.  Everything is relative.
If you have the space to put up full size half wave dipole antennas, 
that is the way to go.  If you need shortened antennas for the lower 
bands, linear loading is one way to achieve resonance with shortened length.

73,
Don W3FPR

On 6/17/2012 11:26 PM, Niel Skousen wrote:
 I'm pretty sure I've seen this antenna on the net, but don't recall the name 
 nor have I been able to find a link to a description / design data.

 The county ERC has a 'shortened fan dipole' with three parallel elements, 
 spaced about 18-24 apart on each side.   the longest element folds back 
 around the mid-length element toward the shortest element.   The antenna end 
 insulator / guy rope is attached to the long element, where it folds back.   
 There appears (from the ground) to be a 6~8 insulator / gap between the end 
 of the shortest element, and the longest element where its been folded back.  
 no traps, loading coils, or loading resistors that I can see.

 I'm assuming three or four band coverage (80, 40, 20, and 15 ??) with a 75m 
 dipole, a 40m dipole (with 15m as a freebie), and a 20 m dipole.   but would 
 be interested in more technical details if anyone can decipher my text 
 description above…

 Thanks
 Niel


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Re: [Elecraft] Antenna Question

[Vic K2VCO]

I agree that folding the low-current parts of an antenna is a good way to make 
it smaller.

But there are several things at work in the comparison between the Steppir 
element and the 
V. Of course the height is one of them. But if you model an inverted V (90 
degree angle 
between wires) and a dipole at the same height you will see that the dipole has 
significantly more gain. Many inverted V's are constructed with even smaller 
angles, which 
are worse. The V pattern also has smaller nulls on the ends.

Finally, the Steppir undoubtedly has some kind of balun, and its feedline runs 
perpendicular to the antenna for 1/2 wavelength. All of these things improve 
the nulls. 
They also reduce noise pickup on the feedline.

On 6/18/2012 5:26 AM, WILLIS COOKE wrote:
 A note on folded back antennae.  I have a 3 element SteppIR with the 30/40 
 kit.  The
 antenna is mounted at about 67 feet above the ground.  I have compared the 
 folded
 antenna at 67 feet to a full sized inverted V at 40 feet and find it 
 noticeably
 stronger.  Even though it is only a dipole which is a little more than half 
 length it
 is noticeably bi-directive with deep nulls off the element ends.  It is quite 
 effective
 as a DX antenna and I believe the SteppIR claim that it is only one or two dB 
 down from
 a full sized rotatable dipole.  Of course, its improved performance over the 
 inverted V
 is mostly because of the elevation difference, but I would not hesitate to 
 fold the
 ends of a dipole if restricted by lot size or other physical restraints.

 Willis 'Cookie' Cooke K5EWJ  Trustee N5BPS, USS Cavalla, USS Stewart


 - Original Message - From: Don Wilhelmw3...@embarqmail.com To: Niel
 Skousennskou...@talisman-intl.com Cc: Elecraft 
 Reflectorelecraft@mailman.qth.net;
 qr...@mailman.qth.net Sent: Monday, June 18, 2012 6:18 AM Subject: Re: 
 [Elecraft]
 Antenna Question

 Neil,

 When you see an antenna element folded back on itself like that, think 
 linear loading
 (look it up in the ARRL Handbook or similar).  There is no magic, but it is 
 one way
 of shortening an antenna.  It is not as efficient as a full length antenna, 
 but is more
 efficient than using loading coils.  Everything is relative. If you have the 
 space to
 put up full size half wave dipole antennas, that is the way to go.  If you 
 need
 shortened antennas for the lower bands, linear loading is one way to achieve 
 resonance
 with shortened length.

 73, Don W3FPR

 On 6/17/2012 11:26 PM, Niel Skousen wrote:
 I'm pretty sure I've seen this antenna on the net, but don't recall the name 
 nor have
 I been able to find a link to a description / design data.

 The county ERC has a 'shortened fan dipole' with three parallel elements, 
 spaced
 about 18-24 apart on each side.   the longest element folds back around the
 mid-length element toward the shortest element.   The antenna end insulator 
 / guy
 rope is attached to the long element, where it folds back.   There appears 
 (from the
 ground) to be a 6~8 insulator / gap between the end of the shortest 
 element, and the
 longest element where its been folded back.  no traps, loading coils, or 
 loading
 resistors that I can see.

 I'm assuming three or four band coverage (80, 40, 20, and 15 ??) with a 75m 
 dipole, a
 40m dipole (with 15m as a freebie), and a 20 m dipole.   but would be 
 interested in
 more technical details if anyone can decipher my text description above…

 Thanks Niel

-- 
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco/
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Re: [Elecraft] Antenna Question

[Willis]

Indeed!  The purpose of the inverted V was for local NVIS coverage and was 
mentioned anecdotally to illustrate that folded back elements can be very 
effective if needed.  They reduce the mechanical problems of erecting and 
turning a rotating dipole with minimal degradation.  I can see a significant 
advantage where a shorter antenna is needed.  We are fortunate to have a wide 
range of designs for our wide range of antenna problems.

Sent from my iPhone

On Jun 18, 2012, at 10:27, Vic K2VCO k2vco@gmail.com wrote:

 I agree that folding the low-current parts of an antenna is a good way to 
 make it smaller.
 
 But there are several things at work in the comparison between the Steppir 
 element and the 
 V. Of course the height is one of them. But if you model an inverted V (90 
 degree angle 
 between wires) and a dipole at the same height you will see that the dipole 
 has 
 significantly more gain. Many inverted V's are constructed with even smaller 
 angles, which 
 are worse. The V pattern also has smaller nulls on the ends.
 
 Finally, the Steppir undoubtedly has some kind of balun, and its feedline 
 runs 
 perpendicular to the antenna for 1/2 wavelength. All of these things improve 
 the nulls. 
 They also reduce noise pickup on the feedline.
 
 On 6/18/2012 5:26 AM, WILLIS COOKE wrote:
 A note on folded back antennae.  I have a 3 element SteppIR with the 30/40 
 kit.  The
 antenna is mounted at about 67 feet above the ground.  I have compared the 
 folded
 antenna at 67 feet to a full sized inverted V at 40 feet and find it 
 noticeably
 stronger.  Even though it is only a dipole which is a little more than half 
 length it
 is noticeably bi-directive with deep nulls off the element ends.  It is 
 quite effective
 as a DX antenna and I believe the SteppIR claim that it is only one or two 
 dB down from
 a full sized rotatable dipole.  Of course, its improved performance over the 
 inverted V
 is mostly because of the elevation difference, but I would not hesitate to 
 fold the
 ends of a dipole if restricted by lot size or other physical restraints.
 
 Willis 'Cookie' Cooke K5EWJ  Trustee N5BPS, USS Cavalla, USS Stewart
 
 
 - Original Message - From: Don Wilhelmw3...@embarqmail.com To: Niel
 Skousennskou...@talisman-intl.com Cc: Elecraft 
 Reflectorelecraft@mailman.qth.net;
 qr...@mailman.qth.net Sent: Monday, June 18, 2012 6:18 AM Subject: Re: 
 [Elecraft]
 Antenna Question
 
 Neil,
 
 When you see an antenna element folded back on itself like that, think 
 linear loading
 (look it up in the ARRL Handbook or similar).  There is no magic, but it 
 is one way
 of shortening an antenna.  It is not as efficient as a full length antenna, 
 but is more
 efficient than using loading coils.  Everything is relative. If you have the 
 space to
 put up full size half wave dipole antennas, that is the way to go.  If you 
 need
 shortened antennas for the lower bands, linear loading is one way to achieve 
 resonance
 with shortened length.
 
 73, Don W3FPR
 
 On 6/17/2012 11:26 PM, Niel Skousen wrote:
 I'm pretty sure I've seen this antenna on the net, but don't recall the 
 name nor have
 I been able to find a link to a description / design data.
 
 The county ERC has a 'shortened fan dipole' with three parallel elements, 
 spaced
 about 18-24 apart on each side.   the longest element folds back around the
 mid-length element toward the shortest element.   The antenna end insulator 
 / guy
 rope is attached to the long element, where it folds back.   There appears 
 (from the
 ground) to be a 6~8 insulator / gap between the end of the shortest 
 element, and the
 longest element where its been folded back.  no traps, loading coils, or 
 loading
 resistors that I can see.
 
 I'm assuming three or four band coverage (80, 40, 20, and 15 ??) with a 75m 
 dipole, a
 40m dipole (with 15m as a freebie), and a 20 m dipole.   but would be 
 interested in
 more technical details if anyone can decipher my text description above…
 
 Thanks Niel
 
 -- 
 Vic, K2VCO
 Fresno CA
 http://www.qsl.net/k2vco/
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[Elecraft] Antenna Question

[Niel Skousen]

I'm pretty sure I've seen this antenna on the net, but don't recall the name 
nor have I been able to find a link to a description / design data.

The county ERC has a 'shortened fan dipole' with three parallel elements, 
spaced about 18-24 apart on each side.   the longest element folds back around 
the mid-length element toward the shortest element.   The antenna end insulator 
/ guy rope is attached to the long element, where it folds back.   There 
appears (from the ground) to be a 6~8 insulator / gap between the end of the 
shortest element, and the longest element where its been folded back.  no 
traps, loading coils, or loading resistors that I can see.

I'm assuming three or four band coverage (80, 40, 20, and 15 ??) with a 75m 
dipole, a 40m dipole (with 15m as a freebie), and a 20 m dipole.   but would be 
interested in more technical details if anyone can decipher my text description 
above…

Thanks
Niel


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Re: [Elecraft] Antenna Question

[Ron D'Eau Claire]

I don't recognize that one, Niel, but keep in mind that many antennas used
by the Military and Emergency Comm centers are *very* inefficient. The
requirement is usually for broader bandwidths and simple designs over gain
or efficiency. 

For example, the famous BW broadband broadband folded dipole
(http://www.bwantennas.com/ama/fdipole.ama.htm ) has been criticized by
countless hams for throwing away at least half (3 dB) of the applied RF, but
high efficiency was never its goal. That antenna provides a decent match
across a wide frequency range, usually covering several Ham bands, in
exchange for putting twice as much RF into it as you'd need for the same
signal on a narrow-bandwidth conventional antenna. 

Neither emergency services or the military have any need or interest in
working DX or busting a pileup. They are interested in simple, easy-to-use
antennas for ranges from a few dozen to a couple hundred miles, maximum.  

73, Ron AC7AC

-Original Message-
From: elecraft-boun...@mailman.qth.net
[mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Niel Skousen
Sent: Sunday, June 17, 2012 8:26 PM
To: Elecraft Reflector; qr...@mailman.qth.net
Subject: [Elecraft] Antenna Question

I'm pretty sure I've seen this antenna on the net, but don't recall the name
nor have I been able to find a link to a description / design data.

The county ERC has a 'shortened fan dipole' with three parallel elements,
spaced about 18-24 apart on each side.   the longest element folds back
around the mid-length element toward the shortest element.   The antenna end
insulator / guy rope is attached to the long element, where it folds back.
There appears (from the ground) to be a 6~8 insulator / gap between the end
of the shortest element, and the longest element where its been folded back.
no traps, loading coils, or loading resistors that I can see.

I'm assuming three or four band coverage (80, 40, 20, and 15 ??) with a 75m
dipole, a 40m dipole (with 15m as a freebie), and a 20 m dipole.   but would
be interested in more technical details if anyone can decipher my text
description above.

Thanks
Niel


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Re: [Elecraft] Antenna Question for KX1

[Dave]

Paul

You might like to check out this antenna idea on the Adventure Radio 
Society web site:


http://www.arsqrp.com/ars/pages/back_issues/2006_text/0506_text/N7XJa.html

Looks good to me, and it's been used on 40/30/20 with a KX1.

73 Dave, G4AON
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RE: [Elecraft] Antenna Question for KX1

[Chuck]

Is the coax ok?

Add or remove length from antenna. Guessing interaction
between coax  antenna. This should demonstrate that pretty
quick. 

What is the impedance range of auto tuner?


Don Wilhelm [EMAIL PROTECTED] wrote:
__
Paul,

A balun may or may not help. and in any case, a balun or
no balun is not the 
answer to your situation - the 20 ft of coax is acting
like an impedance 
transformer, and without a thorough analysis of your antenna
and feedline 
system, it is difficult to say what would help.  Perhaps some
experimentation is in order - add a 4:1 balun and see what
happens, simlarly 
try a 1:1 balun, try changing the length of the parallel
feedline, and try 
changing the length of the coax.  All these things will
influence the 
results, as will changing the length of the antenna wires.
 If you do not 
have adequate instrumentation to analyze the system, then
a bit of old 
fashioned 'cut and try' may be the way to properly answer
your questions - 
in any case, keep notes of what happens so you will know
which way to go 
when making future changes.  When you find something that
works, rejoice and 
let us know, perhaps some of us can give you some info
relating to why it 
works.

73,
Don W3FPR

 -Original Message-

 I have been playing with my KX1 in the back yard the
last week or so and 
 found that about 26ft of wire in the hot side of the bnc
 connector and about
 the same to the cold side gets me a good match with the
built in ATU on 
 40,30,20m

 Now if I use the same wires but add 20ft of coax between the
 radio and these
 wires I find it very hard to get a match on any band,
do I need to use a 
 balun at the end of the coax?

 Any thoughts

 Paul

 M0BMN



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Re: [Elecraft] Antenna Question for KX1

[Trevor Day]

In message [EMAIL PROTECTED], Paul Webb 
[EMAIL PROTECTED] writes

Hi All



I have been playing with my KX1 in the back yard the last week or so and
found that about 26ft of wire in the hot side of the bnc connector and about
the same to the cold side gets me a good match with the built in ATU on
40,30,20m

Now if I use the same wires but add 20ft of coax between the radio and these
wires I find it very hard to get a match on any band, do I need to use a
balun at the end of the coax?

Any thoughts

Paul


Hi Paul,
I believe you are on a hiding to nothing attempting to reproduce the 
results via a length of coax cable.  Remember those initial results were 
obtained with the ATU connected directly to the antenna.  Everything 
after the ATU is effectively the antenna and is likely to radiate, 
including the coax. Adding a balun will do absolutely nothing except to 
change the electrical antenna length (where the antenna in this case is 
the coax and the original wires), your coax will still radiate and you 
are likely to get poor results.


With this sort of antenna the ATU must *always* be at the antenna end of 
the feeder, whether that be directly after the ATU in the KX1 as in your 
initial trials, or at the antenna end of the 20 foot of coax as you 
attempted later.  The only exception to this is when the antenna 
presents an electrical quarter wave or odd multiple thereof.  In those 
cases, no ATU is necessary.


Trev G3ZYY

--
Trevor Day
UKSMG #217
www.uksmg.org

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Re: [Elecraft] Antenna Question for KX1

[Dave]

Paul

The loss in poorly matched coax can be very high, you might consider 
using a length of 300 Ohm ribbon cable instead. You will need a balun at 
the KX1 end of the ribbon. With my K1 across 40/30/20/15 I find a 66 
foot top (33' each side) with 32 foot of ribbon tunes with the KAT1 in 
my K1. I understand the tuning range of the KX1 ATU is even less than 
that fitted to a K1, so you might have to play around with the length of 
ribbon to get a satisfactory match. The advantage is you can get the 
dipole part of the antenna a reasonable height with a fishing pole or 
similar support.


73 Dave, G4AON
K1 # 1154
K2 # 1892
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RE: [Elecraft] Antenna Question for KX1

[Don Wilhelm]

Paul,

A balun may or may not help. and in any case, a balun or no balun is not the
answer to your situation - the 20 ft of coax is acting like an impedance
transformer, and without a thorough analysis of your antenna and feedline
system, it is difficult to say what would help.  Perhaps some
experimentation is in order - add a 4:1 balun and see what happens, simlarly
try a 1:1 balun, try changing the length of the parallel feedline, and try
changing the length of the coax.  All these things will influence the
results, as will changing the length of the antenna wires.  If you do not
have adequate instrumentation to analyze the system, then a bit of old
fashioned 'cut and try' may be the way to properly answer your questions -
in any case, keep notes of what happens so you will know which way to go
when making future changes.  When you find something that works, rejoice and
let us know, perhaps some of us can give you some info relating to why it
works.

73,
Don W3FPR

 -Original Message-

 I have been playing with my KX1 in the back yard the last week or so and
 found that about 26ft of wire in the hot side of the bnc
 connector and about
 the same to the cold side gets me a good match with the built in ATU on
 40,30,20m

 Now if I use the same wires but add 20ft of coax between the
 radio and these
 wires I find it very hard to get a match on any band, do I need to use a
 balun at the end of the coax?

 Any thoughts

 Paul

 M0BMN



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Re: [Elecraft] Antenna Question for KX1

[Alexandra Carter]

Try taking a big fat toroid from somewhere and looping your coax 
through that about 15 times at the antenna end and see how that works 
for you. Alternately, put a bunch of clip-on beads on the coax at the 
antenna end and try that. Alternately, try lengthening the antenna on 
the 'hot' side as the coax braid may be acting as the ground side. Not 
saying I know, just saying, Try. 73 de Alex NS6Y.


On Apr 30, 2006, at 5:49 PM, Don Wilhelm wrote:


Paul,

A balun may or may not help. and in any case, a balun or no balun is 
not the
answer to your situation - the 20 ft of coax is acting like an 
impedance
transformer, and without a thorough analysis of your antenna and 
feedline

system, it is difficult to say what would help.  Perhaps some
experimentation is in order - add a 4:1 balun and see what happens, 
simlarly
try a 1:1 balun, try changing the length of the parallel feedline, and 
try

changing the length of the coax.  All these things will influence the
results, as will changing the length of the antenna wires.  If you do 
not

have adequate instrumentation to analyze the system, then a bit of old
fashioned 'cut and try' may be the way to properly answer your 
questions -
in any case, keep notes of what happens so you will know which way to 
go
when making future changes.  When you find something that works, 
rejoice and
let us know, perhaps some of us can give you some info relating to why 
it

works.

73,
Don W3FPR


-Original Message-

I have been playing with my KX1 in the back yard the last week or so 
and

found that about 26ft of wire in the hot side of the bnc
connector and about
the same to the cold side gets me a good match with the built in ATU 
on

40,30,20m

Now if I use the same wires but add 20ft of coax between the
radio and these
wires I find it very hard to get a match on any band, do I need to 
use a

balun at the end of the coax?

Any thoughts

Paul

M0BMN




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[Elecraft] Antenna Question for KX1

[Paul Webb]

Hi All

 

I have been playing with my KX1 in the back yard the last week or so and
found that about 26ft of wire in the hot side of the bnc connector and about
the same to the cold side gets me a good match with the built in ATU on
40,30,20m

Now if I use the same wires but add 20ft of coax between the radio and these
wires I find it very hard to get a match on any band, do I need to use a
balun at the end of the coax? 

Any thoughts

Paul

M0BMN

 

 


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Re: [Elecraft] Antenna Question for KX1

[Ed - K9EW]

Hi Paul,

Without modeling your antenna, I don't know what the feedpoint impedances
are, but it's a good thing that you can match them with the KX-1.  The 20
foot length of coax is transforming the impedance to something outside the
range of your KX-1, and a balun wouldn't help unless (perhaps) it was also
an impedance transformer.

Hope this answers your question.

73,
ed - k9ew
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Re: [Elecraft] Antenna question

[Charles Greene]

Tom,

While you can run the ladder line right to the shack and connect directly 
to the K2, a balun mounted outside and a coax run to the rig works well and 
you avoid having to run the ladder line inside which sometimes can be 
problematic.  There are several low cost 4:1 baluns on the market including 
the Elecraft one, or you can use a BA-58 or BA-8 kit of ferrite beads over 
the coax from Palomar.   As my late friend George used to say, a 1:1 balun 
works as well in this application as a 4:1.  You need to avoid a length of 
feed line such that the sum of the length of the feed line times its 
velocity factor plus 1/2 the length of the dipole is 1/2 wave length.  Then 
keep the length of coax times its velocity factor unequal to a 1/2 wave 
length too.  Best to keep the coax run short.  That is to avoid a current 
node either at the position of the balun or at the K2.


73,  Chas, W1CG

At 09:57 PM 8/20/2005, Tom McCulloch wrote:

Hi all,
 I'm considering putting up a 40 meter dipole fed with a 450 ladder line. 
I have a K2 which I run at about 5 to watts (I do not have the 100 watt 
amp).  The K2 also has the internal ATU.


 I have always used 50 ohm coax up until now.  Is there anything I should 
know about using the K2 with 450 ohm feedline?  (Will I need a balun, or 
can I just feed the ladderline directly to the K2's ATU and that will 
take care of the match.


Thanks for your help.

Tom, WB2QDG

K2 1103
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[Elecraft] Antenna Question

[James R. Duffey]

Tom - You should use a 1:1 balun to feed the balanced line with the K2
tuner. You can easily make one by wrapping a dozen or so turns of RG-58
through a type 43 or 61 core FT140 or larger. Diz, at

http://partsandkits.com/index.asp

is a good source of these toroids.

Alternately, you can slip a half dozen type 73 ferrite beads over RG-58. The
beads are available from Mouser as part number 2643540002. COvering hte
whole assembly wiht heatchrink tubing keeps things from moving around.

I would avoid using a 4:1 balun. On those bands where the antenna impedance
is low the balun will make it lower and harder to match and will result in
more loss in the tuner.

If you have trouble tuning the antenna, you can add an additional section of
feeder to help the match. Others have popinted this out sa well.

If you feed the antenna with balanced feeder you don't need to make the
dipole resonant, yoiu can make it any convenient length. Some lengths have
advantages over than others, but if you make it shorter than about 0.4
wavelengths, SWR on even a balanced feeder will be high and losses will be
large for long runs. - Dr. Megacycle KK6MC/5

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RE: [Elecraft] Antenna question - Balun

[Mike W]

On 21 Aug 2005 at 8:40, Robert Tellefsen wrote:

 Two things will make matching easier.  Get two
 baluns, 1:1 and 4:1.  Put them on the two
 antenna ports of the ATU

Looking at the two versions of the BL1 for 1:1 and 4:1
Can you not use a 2pco ( dpdt ) switch or relay to change between the two ?.

Commons to the two inner windings ( see BL1.pdf ).
 Short them for interconnect on the NO connections for 4:1
 Parallel them on the NC connections for 1:1.

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RE: [Elecraft] Antenna question - Balun

[Robert Tellefsen]

Yes, it can be done, Mike.
Remember that the 4:1 balun will be happiest seeing
an impedance around 200-300 ohms, though.  The
4:1 ratio really only holds when the impedances are
correct.  Once you throw in a mixed load that is
well away from this value, plus an unknown amount of
reactance, the ratio changes and losses can mount.
Not a serious concern at QRP power levels, but at 100w
it could cook a balun that is seriusly mismatched.

The best way to use baluns is to adjust your balanced
feedline length on a given band to give very little
reactance, regardless of the resistive part of the load
impedance.  The ATU will have an easier time matching
a resistive load than one with combined reactance and
resistance.  The baluns will work best when the loads
are resistive, even if the wrong value.  When you mix in
reactance, the balun will have unpredictable ratios and
losses.

Good luck and 73
Bob N6WG
The Little Station with Attitude

-Original Message-
From: Mike W [mailto:[EMAIL PROTECTED]
Sent: Sunday, August 21, 2005 4:03 PM
To: Robert Tellefsen; elecraft@mailman.qth.net
Subject: RE: [Elecraft] Antenna question - Balun




On 21 Aug 2005 at 8:40, Robert Tellefsen wrote:

 Two things will make matching easier.  Get two
 baluns, 1:1 and 4:1.  Put them on the two
 antenna ports of the ATU

Looking at the two versions of the BL1 for 1:1 and 4:1
Can you not use a 2pco ( dpdt ) switch or relay to change between the two ?.

Commons to the two inner windings ( see BL1.pdf ).
 Short them for interconnect on the NO connections for 4:1
 Parallel them on the NC connections for 1:1.

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[Elecraft] Antenna question

[Tom McCulloch]

Hi all,
 I'm considering putting up a 40 meter dipole fed with a 450 ladder line. 
I have a K2 which I run at about 5 to watts (I do not have the 100 watt 
amp).  The K2 also has the internal ATU.


 I have always used 50 ohm coax up until now.  Is there anything I should 
know about using the K2 with 450 ohm feedline?  (Will I need a balun, or can 
I just feed the ladderline directly to the K2's ATU and that will take care 
of the match.


Thanks for your help.

Tom, WB2QDG

K2 1103 


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Re: [Elecraft] Antenna question

[Rick Dettinger]

Hi Tom - I don't think you mentioned what bands you intend to use  the
antenna for.  If just 40M, then you may do as well with coax and not need
the tuner.  If you use it for an all band doublet, the tuner may have
difficulty on some bands depending on the impedence and the lenght of the
feedline.  Without the balun,  you may have radiation from the feedline,
which may not be a problem or it may cause problems in the shack with RF
getting into equipment or noise on receive if the source is near the rig.  I
use a doublet but I increased the lenght to 88 ft and the k2 handles it well
on most bands.  I plan to increase the lenght to 100 ft to get better
efficiency on 80 meters.  I use a 1 to 1 balun.  A 4 to 1 balun may work
better on some frequencies but would likely give less efficiency on 80
meters due to low radiation resistance.  Finally, changing the lenght of the
feed line can improve the match on some bands with a possible worse match on
others.  Multiband antennas are always a compromise and experimenting may be
required.Rick - K7MW
Original Message -
From: Tom McCulloch [EMAIL PROTECTED]
To: elecraft@mailman.qth.net
Sent: Saturday, August 20, 2005 6:57 PM
Subject: [Elecraft] Antenna question


 Hi all,
   I'm considering putting up a 40 meter dipole fed with a 450 ladder line.
 I have a K2 which I run at about 5 to watts (I do not have the 100 watt
 amp).  The K2 also has the internal ATU.

   I have always used 50 ohm coax up until now.  Is there anything I should
 know about using the K2 with 450 ohm feedline?  (Will I need a balun, or
can
 I just feed the ladderline directly to the K2's ATU and that will take
care
 of the match.

 Thanks for your help.

 Tom, WB2QDG

 K2 1103

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