[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 __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] OT ... Coax DC isolator
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 johnbsa...@yahoo.com To: elecraft@mailman.qth.net elecraft@mailman.qth.net 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 __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] OT ... Coax DC isolator
The thing that puts DC on coax is called a bias tee, so search for that. --wunder (K6WRU) On Feb 11, 2014, at 11:00 AM, WILLIS COOKE wrco...@yahoo.com wrote: 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 johnbsa...@yahoo.com To: elecraft@mailman.qth.net elecraft@mailman.qth.net 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 __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] OT ... Coax DC isolator
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:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] OT ... Coax DC isolator
Here is an interesting article: http://www.ad5x.com/images/Articles/BiasT3amp.pdf Svend, OZ7UV __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] OT ... Coax DC isolator
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 __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] OT ... Coax DC isolator
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: elecraft-boun...@mailman.qth.net [mailto:elecraft- boun...@mailman.qth.net] 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 __ __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
[Elecraft] OT ... Coax DC Isolator
Many, many thanks for the fine comments and suggestions. I am going with the MFJ-4712 which is the bias tee and the relay and switch...complete and ready-to-go. Thanks again 73, John K5ENQ __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] OT ... Coax DC Isolator
Are there possible precautions to take when running DC through a remote antenna (coax) switch that may go to ground when the power is off? Dick - KA5KKT __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
