A/B antenna switch for ladder line fed antennas

[Kevin Rock]

I have a fancy switch for A/B antenna testing for coaxially fed antennas
but do not know what folks use for antenna switches with antennas fed by
ladder lines.  I want to compare a 160 meter full wave loop fed with
homebrew ladder line to a G5RV fed by 450 window line.  Any suggestions?  
I knife switch of some sort like we used in grade school science labs in
the '60s?  Or is there something more modern?
    Kevin.  KD5ONS  


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[Ron D'Eau Claire-2]

Kevin, KD5ONS wrote:
I have a fancy switch for A/B antenna testing for coaxially fed antennas
but do not know what folks use for antenna switches with antennas fed by
ladder lines.  I want to compare a 160 meter full wave loop fed with
homebrew ladder line to a G5RV fed by 450 window line.  Any suggestions?  

-----------------------------------------------------------

One of the problems you run into A/B testing is that you can't wait for a
re-tune. Any delay more than a fraction of a second is too long under most
conditions unless you're working on a very long wavelength (160/80 meters)
and testing ground wave signals.

So the smart thing to do is to put a proper matching network at the end of
each ladder line, then switch the 50-ohm coaxial links to the rig.

If you're not sure of your matching networks, reverse them after collecting
data and make sure you get the same results.

Ron AC7AC


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[NR5A]

Here is what I use and it works great ! ! !
http://www.io.com/~n5fc/ant_sw.htm

Jerry - NR5A
----- Original Message -----
From: "Kevin Rock" <[hidden email]>
To: "Elecraft" <[hidden email]>; <[hidden email]>
Sent: Monday, July 18, 2005 6:02 PM
Subject: [Elecraft] A/B antenna switch for ladder line fed antennas

> I have a fancy switch for A/B antenna testing for coaxially fed antennas
> but do not know what folks use for antenna switches with antennas fed by
> ladder lines.  I want to compare a 160 meter full wave loop fed with
> homebrew ladder line to a G5RV fed by 450 window line.  Any suggestions?
> I knife switch of some sort like we used in grade school science labs in
> the '60s?  Or is there something more modern?
>     Kevin.  KD5ONS
>
>
> --
> No virus found in this outgoing message.
> Checked by AVG Anti-Virus.
> Version: 7.0.323 / Virus Database: 267.9.1/51 - Release Date: 7/18/2005
>
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>

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[Geoffrey Mackenzie-Kennedy-2]

Yes there is Kevin, it is called a relay, and it goes 'clack' in the night!
In the distant past I used relays to switch an open wire feeder between legs
of  V beams at HF running 1 kW,  using the 'open' type of relay used for
power switching, rated at 15 amps, inside a weatherproof container. Just
don't 'hot switch'. One other precaution, don't compare antennas too often
at 3am, you will wake the neighbours - or in your case the Mountain Lions.

73, Geoff
GM4ESD


----- Original Message -----
From: "Kevin Rock" <[hidden email]>
To: "Elecraft" <[hidden email]>; <[hidden email]>
Sent: Tuesday, July 19, 2005 1:02 AM
Subject: [Elecraft] A/B antenna switch for ladder line fed antennas


>I have a fancy switch for A/B antenna testing for coaxially fed antennas
>but do not know what folks use for antenna switches with antennas fed by
>ladder lines.  I want to compare a 160 meter full wave loop fed with
>homebrew ladder line to a G5RV fed by 450 window line.  Any suggestions?  I
>knife switch of some sort like we used in grade school science labs in the
>'60s?  Or is there something more modern?
>    Kevin.  KD5ONS

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[Don Wilhelm-3]

Kevin,

If you have a KAT2 or a KAT100, that switch is built in.  Connect each
feedline to a 1:1 current balun and a short piece of coax to the tuner -
Pre-tune each antenna before your comparison, and the ANT 1/2 button will
switch them for you.

73,
Don W3FPR

> -----Original Message-----
>
> I have a fancy switch for A/B antenna testing for coaxially fed antennas
> but do not know what folks use for antenna switches with antennas fed by
> ladder lines.  I want to compare a 160 meter full wave loop fed with
> homebrew ladder line to a G5RV fed by 450 window line.  Any suggestions?
> I knife switch of some sort like we used in grade school science labs in
> the '60s?  Or is there something more modern?
>     Kevin.  KD5ONS
>

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Checked by AVG Anti-Virus.
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[Kevin Rock]

Thank you for the fine suggestions and nice photos.

John, W2AGN, you and my father would have enjoyed each other's hand built
cases.  He crafted one for each of his hobbies.  He was trained as a
cabinet maker by my great grandfather.

It looks like I will take bits from each idea and use a relay to do some
of the work.  As usual I'll kluge a few ideas together until I get what I
want.  Since I use a chart to tune each antenna I don't worry about
matching rapidly.  While I am running my nets I have been known to jump
 from my ladder line fed G5RV to a coaxially fed G5RV and back again while
calling by retuning on the fly from my charts for the various antennas.  
My auto tuner is a bit old fashioned: I use my eyes, my head, and my hand
;)  Keeps me thinking while I am copying code and trying to dig out a
faint one.

I am unsure where I can find a knife switch but I do like the idea of the
barrier strips.  I use them to keep our phone lines working and up out of
the reach of the ravenous gnawing critters who've broken our Internet
connection more than once.  Those mountain lions come in handy for
clearing a swath out of the critter gene pool ;)

I wish I still had my stock of telephone stepping relays.  I had a few
dozen new in box I could have used to craft some nifty antenna switches.  
However a few relays in a binary tree could be used to open quite a number
of possibilities.  The trees are only getting taller so I could have any
number of open line and ladder line fed test antennas.  A good switching
system is all that stands in my way.

Onward to destiny!  Or: "Ad astra per aspera!"
    Kevin.  KD5ONS




On Mon, 18 Jul 2005 17:02:53 -0700, Kevin Rock <[hidden email]>
wrote:

> I have a fancy switch for A/B antenna testing for coaxially fed antennas
> but do not know what folks use for antenna switches with antennas fed by
> ladder lines.  I want to compare a 160 meter full wave loop fed with
> homebrew ladder line to a G5RV fed by 450 window line.  Any
> suggestions?  I knife switch of some sort like we used in grade school
> science labs in the '60s?  Or is there something more modern?
>     Kevin.  KD5ONS




--
No virus found in this outgoing message.
Checked by AVG Anti-Virus.
Version: 7.0.323 / Virus Database: 267.9.1/51 - Release Date: 7/18/2005

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[Jack Brindle]

On Jul 18, 2005, at 6:35 PM, Kevin Rock wrote:

> I am unsure where I can find a knife switch but I do like the idea  
> of the barrier strips.

It's not a great one, but Radio Shack #275-1537 costs $2.99 and will  
do the trick.


- Jack Brindle, W6FB
------------------------------------------------------------------------
---------------------


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[David Toepfer]

I have thought of pairing up a 4-position Alpha-Delta coax switch back-to-back,
but time and expense have prevented it.  I have also thought through a few
schematics to do it remotely to my attic with relays.  But here's a simple
homebrew one (<http://www.io.com/~n5fc/ant_sw.htm>) I found at N5ESE's site
(<http://www.io.com/~n5fc/>).  There's some good info here.

David, K3TUE

--- Kevin Rock <[hidden email]> wrote:

> I have a fancy switch for A/B antenna testing for coaxially fed antennas
> but do not know what folks use for antenna switches with antennas fed by
> ladder lines.  I want to compare a 160 meter full wave loop fed with
> homebrew ladder line to a G5RV fed by 450 window line.  Any suggestions?  
> I knife switch of some sort like we used in grade school science labs in
> the '60s?  Or is there something more modern?
>     Kevin.  KD5ONS  
>
>
> --
> No virus found in this outgoing message.
> Checked by AVG Anti-Virus.
> Version: 7.0.323 / Virus Database: 267.9.1/51 - Release Date: 7/18/2005
>
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
> You must be a subscriber to post to the list.
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>
> Help: http://mailman.qth.net/subscribers.htm
> Elecraft web page: http://www.elecraft.com
>

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[n6wg]

Kevin
I use DPDT relays here to switch my 450 ohm feedlines.
Works very well.
73, Bob N6WG

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]]On Behalf Of Kevin Rock
Sent: Monday, July 18, 2005 5:03 PM
To: Elecraft; [hidden email]
Subject: [Elecraft] A/B antenna switch for ladder line fed antennas


I have a fancy switch for A/B antenna testing for coaxially fed antennas
but do not know what folks use for antenna switches with antennas fed by
ladder lines.  I want to compare a 160 meter full wave loop fed with
homebrew ladder line to a G5RV fed by 450 window line.  Any suggestions?  
I knife switch of some sort like we used in grade school science labs in
the '60s?  Or is there something more modern?
    Kevin.  KD5ONS  


--
No virus found in this outgoing message.
Checked by AVG Anti-Virus.
Version: 7.0.323 / Virus Database: 267.9.1/51 - Release Date: 7/18/2005

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