Coaxial Transfer Switches
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Just did some shopping on the Internet and found transfer switches by Teledyne starting at about $275. Did not find any Birds, used or otherwise, and the Transcos I found were in the $800 range. I confess this was a very quick search.
Interesting that many if not most of them require 28 VDC. Anyone know why? Is that a marine application? These seem too heavy for aviation. The subject is of interest because I have two MFJ SPDT switches, neither of which I particularly like. One of them works fine if the switch knob is toggled back and forth a few times. And that’s the one that’s been indoors all its life. Anyone found something DPDT, store-bought and acceptable, in a moderate price range? Ted, KN1CBR ------------------------------ Message: 22 Date: Mon, 2 Jan 2017 17:17:46 +0000 From: Richard Fjeld <[hidden email]> To: "[hidden email]" <[hidden email]> Subject: Re: [Elecraft] {OT} - Variation on use of a coaxial switch (stan levandowski) Message-ID: <[hidden email]> Content-Type: text/plain; charset="Windows-1252" This sounds the same, and I made it to protect the front end of each radio by switching the radio not being tested to my dummy load in case one of the radios should transmit. I intended my switch for receive comparisons. I am surprised the commercial switches can handle a kilowatt and provide adequate isolation. I wouldn't want to use that kind of power with the switch I made. I didn't know about the switches you mention. I thought there should be a need for them, so I called MFJ. I like to protect my equipment. I know guys who don't think this way. Maybe MFJ didn't sell any and discontinued them. At the time, I thought they described them rather vaguely, missing the whole purpose. Maybe I haven't found them on their website now. Dick, n0ce On 1/2/2017 7:06 AM, Charlie T, K3ICH wrote: > Several companies (Bird, Transco) make what you describe. It is a four > terminal coax relay called a "Transfer Switch" that for example, connects > any two antennas to any two radios, but never at the same time. In other > words, radio A connects to antenna 1, and at the same time, radio B connects > to antenna 2. Activating the switch ( either mechanical or electrically > activated) changes the condition for A to 2 and B to 1. Most are good for a > kilowatt well up into the UHF ranges. For HF, I made one using a heavy > DPDT relay. > > 73 Charlie k3ICH > > ------------------------------ Message: 23 Date: Mon, 2 Jan 2017 12:32:49 -0500 From: Don Wilhelm <[hidden email]> To: [hidden email] Cc: [hidden email] Subject: Re: [Elecraft] KXPA100 with PX3 Message-ID: <[hidden email]> Content-Type: text/plain; charset=utf-8; format=flowed Ray, Have you tried running the TX Gain Calibration on the KX3? It may be that the KX3 wattmeter is not well calibrated. If you do the TX Gain Calibration manually, it must be done on each band. The KX3 Utility automates the process. 73, Don W3FPR On 1/2/2017 11:55 AM, [hidden email] wrote: > Don and others, > > The good news is that you were right: the RJ-45 connectors in the > control cable were not making good contact. I fixed that and PA ON > operation of the KXPA100 is now working. > > The bad news, however, is that in Basic operation with PA OFF, the > KX3/KXPA100 puts out full power, but the most I can get out of it with > PA ON is 50-60 watts. The attenuator is set for OUT/AUTO and there is > no more than 1 or 2 watts reflected power. > > ------------------------------ Message: 24 Date: Mon, 2 Jan 2017 12:42:49 -0500 From: [hidden email] To: [hidden email] Cc: [hidden email] Subject: Re: [Elecraft] KXPA100 with PX3 Message-ID: <[hidden email]> Content-Type: text/plain; charset=utf-8 Hi Don, I tried that but an external wattmeter confirmed the KXPA100 forward and reflected power readings. Something in the KX3 is holding down the power output when PA is ON, but not when PA is off. 73 Ray W2RS -----Original Message----- From: Don Wilhelm <[hidden email]> To: rsoifer1 <[hidden email]> Cc: elecraft <[hidden email]> Sent: Mon, Jan 2, 2017 10:33 am Subject: Re: [Elecraft] KXPA100 with PX3 Ray, Have you tried running the TX Gain Calibration on the KX3? It may be that the KX3 wattmeter is not well calibrated. If you do the TX Gain Calibration manually, it must be done on each band. The KX3 Utility automates the process. 73, Don W3FPR On 1/2/2017 11:55 AM, [hidden email] wrote: > Don and others, > > The good news is that you were right: the RJ-45 connectors in the > control cable were not making good contact. I fixed that and PA ON > operation of the KXPA100 is now working. > > The bad news, however, is that in Basic operation with PA OFF, the > KX3/KXPA100 puts out full power, but the most I can get out of it with > PA ON is 50-60 watts. The attenuator is set for OUT/AUTO and there is > no more than 1 or 2 watts reflected power. > > ------------------------------ Message: 25 Date: Mon, 2 Jan 2017 10:45:00 -0700 (MST) From: Bob N3MNT <[hidden email]> To: [hidden email] Subject: Re: [Elecraft] KXPA100 with PX3 Message-ID: <[hidden email]> Content-Type: text/plain; charset=us-ascii What band are you seeing this reduced power out on. It will most likely be different for each band. -- View this message in context: http://elecraft.365791.n2.nabble.com/KXPA100-with-PX3-tp7625187p7625370.html Sent from the Elecraft mailing list archive at Nabble.com. ------------------------------ Subject: Digest Footer _______________________________________________ Elecraft mailing list Post to: [hidden email] http://mailman.qth.net/mailman/listinfo/elecraft You must be a subscriber to post. Elecraft web page: http://www.elecraft.com ------------------------------ End of Elecraft Digest, Vol 153, Issue 4 **************************************** ______________________________________________________________ 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 Message delivered to [hidden email] |
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On Mon,1/2/2017 12:51 PM, Dauer, Edward wrote:
> Anyone found something DPDT, store-bought and acceptable, in a moderate price range? I think I posted yesterday that the Alpha Delta switches seem properly done, and should provide good isolation. They make a 2x1 and a 4x1. You would need two of them. I own several that I've used up to 440 MHz. I've not measured them, but I've also not noticed any issues. 73, Jim K9YC ______________________________________________________________ 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 Message delivered to [hidden email] |
Re: Coaxial Transfer Switches
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In reply to this post by Edward A. Dauer
I just bought a DPDT toggle switch to replace a winch control with push
buttons. The guy at the counter said his catalog specs showed 50 A at 12 volts. That seems hard to believe, but it seems rugged and I needed it now. I bought it at NAPA auto parts. It was about $12 incl sales tax. One thing that may have driven the price up is that I needed a momentary with center off. They had enough to chose from that he had to look it up in his parts book. Dick, n0ce On 1/2/2017 2:51 PM, Dauer, Edward wrote: > Just did some shopping on the Internet and found transfer switches by Teledyne starting at about $275. Did not find any Birds, used or otherwise, and the Transcos I found were in the $800 range. I confess this was a very quick search. > > Interesting that many if not most of them require 28 VDC. Anyone know why? Is that a marine application? These seem too heavy for aviation. > > The subject is of interest because I have two MFJ SPDT switches, neither of which I particularly like. One of them works fine if the switch knob is toggled back and forth a few times. And that’s the one that’s been indoors all its life. Anyone found something DPDT, store-bought and acceptable, in a moderate price range? > > Ted, KN1CBR > > ______________________________________________________________ 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 Message delivered to [hidden email] |
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In reply to this post by Edward A. Dauer
I’m using a variety of MFJ switches, some have not had their position changed for some months. I suggest you take the back of and use some switch cleaner on the contacts.
73 de David, M0XDF -- When I am working on a problem I never think about beauty. I only think about how to solve the problem. But when I have finished, if the solution is not beautiful, I know it is wrong. -R. Buckminster Fuller, engineer, designer, and architect (1895-1983) > On 2 Jan 2017, at 20:51, Dauer, Edward <[hidden email]> wrote: > > Just did some shopping on the Internet and found transfer switches by Teledyne starting at about $275. Did not find any Birds, used or otherwise, and the Transcos I found were in the $800 range. I confess this was a very quick search. > > Interesting that many if not most of them require 28 VDC. Anyone know why? Is that a marine application? These seem too heavy for aviation. > > The subject is of interest because I have two MFJ SPDT switches, neither of which I particularly like. One of them works fine if the switch knob is toggled back and forth a few times. And that’s the one that’s been indoors all its life. Anyone found something DPDT, store-bought and acceptable, in a moderate price range? > ______________________________________________________________ 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 Message delivered to [hidden email] |
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