OT ... Coax DC isolator

[John Saxon]

Off topic here:

I am experimenting with two different antennas and would like to switch between them with a relay.  I am considering getting an isolator that permits placing the DC control voltage on the rf coax.  Any thoughts on this?  I have never done this before and would appreciate any advice/suggestions.

OH...I am using my K3/10...so maybe not ENTIRELY off topic :-)

--
John 
K5ENQ
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[Cookie]

It is not very hard to do this John.  Just feed the RF in and out with a couple of RF capacitors and feed the DC in and out through 1 or 2 MH chokes  I think MFJ has them for sale and I know they have them in tje MFJ 927 AMP.
 
Willis 'Cookie' Cooke, TDXS DX Chairman
K5EWJ & Trustee N5BPS, USS Cavalla, USS Stewart


________________________________
 From: John Saxon <[hidden email]>
To: "[hidden email]" <[hidden email]>
Sent: Tuesday, February 11, 2014 12:34 PM
Subject: [Elecraft] OT ... Coax DC isolator
 

Off topic here:

I am experimenting with two different antennas and would like to switch between them with a relay.  I am considering getting an isolator that permits placing the DC control voltage on the rf coax.  Any thoughts on this?  I have never done this before and would appreciate any advice/suggestions.

OH...I am using my K3/10...so maybe not ENTIRELY off topic :-)

--
John 
K5ENQ
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[Barry K3NDM]

John,
     Does isolators are called bias-Ts. They are a common way to do what
you want. You should be able to buy one without great difficulty. Just
make sure that the one you buy is for the frequency range you plan to
use it in. MFJ makes one for HF if that is where you plan to operate.

73,
Barry
K3NDM


On 2/11/2014 1:34 PM, John Saxon wrote:

> Off topic here:
>
> I am experimenting with two different antennas and would like to switch between them with a relay.  I am considering getting an isolator that permits placing the DC control voltage on the rf coax.  Any thoughts on this?  I have never done this before and would appreciate any advice/suggestions.
>
> OH...I am using my K3/10...so maybe not ENTIRELY off topic :-)
>
> --
> John
> K5ENQ
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>

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[Svend Spanget]

Here is an interesting article:
http://www.ad5x.com/images/Articles/BiasT3amp.pdf
Svend, OZ7UV

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[mcduffie]

On Tue, 11 Feb 2014 10:34:20 -0800 (PST), John Saxon wrote:

> I am experimenting with two different antennas and would like to switch bet=
> ween them with a relay. =A0I am considering getting an isolator that permit=
> s placing the DC control voltage on the rf coax. =A0Any thoughts on this? =
> =A0I have never done this before and would appreciate any advice/suggestion=
> s.

Well, I'm NOT using a K3 :o), but I use the MFJ 2-position remote switch and
have no issues with it so far.  It's nice to not have to install another run of
coax to the remote antenna location yet.  I intend to eventually, but it got me
by for now.  It's a 300 foot run and the switch works as advertised.  It comes
without a power source (they sell separately), but does have the DC inserter box
that the antenna 1-2 switch is mounted in.  It is unhandy to have it on the
shelf, because the coax hooks to it also.  But because they are merely switching
power on and off to the remote relay, you can leave it turned on, and switch the
power going to it via a desk mounted switch to accomplish the same thing.  Any
existing 12V supply will work.

Gary
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[gm3sek]

And here's another:

<http://www.ifwtech.co.uk/g3sek/in-prac/best-of.htm#0904>

Click on <April 2009> to download the complete magazine article.



73 from Ian GM3SEK

>-----Original Message-----
>From: [hidden email] [mailto:elecraft-
>[hidden email]] On Behalf Of Svend Spanget
>Sent: 11 February 2014 20:18
>To: elecraft @ mailman . qth . net
>Subject: Re: [Elecraft] OT ... Coax DC isolator
>
>Here is an interesting article:
>http://www.ad5x.com/images/Articles/BiasT3amp.pdf
>Svend, OZ7UV
>
>______________________________________________________________

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