Topband: RX antenna switch

[Brian Moran]

Here's one that works for TX & Rx. http://www.qsl.net/k5lxp/projects/CoaxSwitch/CoaxSwitch.html With lockout, etc. A homebrew version of the '6 pack' kind of box from array solutions. I have the Array Solutions one, and it works great.


I have built a small one for RX only that uses SMD relays, however it does NOT prevent the same antenna from used simultaneously. I wanted a small footprint, so used RJ45's to handle the switching signals to the switching boxes. It's great with a K3 to put different antennas in different ears with diversity mode, and makes it easier to pick out geographically distinct stations in the sound field. If you want the PCB layout, I can email it to you; the RX switchbox is in daily use.


If you're really going to build one of these, you should also see what VP6DI did (Eric Scace K3NA has an article you can google for) as far as equalizing signals when multiple radios listened to the same antenna, minimizing leakage of signals BACK INTO the antennas from a transmitting radio (it happens, even with the best of radios); he also went as far as breaking out 160m listening from 80m listening, and segregating 80m phone from 80m cw portions of the band.

If it were the 'ideal' thing, there'd be a box with a matrix of switches (A x B), gain blocks that could be put in/out of the circuit, BPFs that could be put in and out, 'muting' of any RX output that is connected to a transmitter that is transmitting, RX overload protection, and some general purpose inputs to select the 'configuration'. Probably a PIC to run it, with a nice GUI app to configure it.   


- Brian N9ADG





________________________________
 From: Dave G4GED <radiodave.g4ged at tiscali.co.uk>
To: "Dave Anderson, K4SV" <davek4sv at yahoo.com>; TopBand Reflector <topband at contesting.com> 
Sent: Friday, December 30, 2011 7:15 AM
Subject: Re: Topband: RX antenna switch
 
----- Original Message ----- 
Got a note from Gary K9AY, he says no time to make the RAS8x2 switches, real
work is too busy. So I suspect until Gary can make more they are not
available.
Dave Anderson, K4SV
----------------------------------------------------------

That's a pity, I was just about to order one!

I haven't a clue of the methods of interlock switching the RAS8x2 uses but
as it looks like we're going to have to make our own and my need to keep to
simple click-clunk technology. I believe that using relays with a spare 
contact in such a cicuit that disables any other relay once operated, would 
do the job?

Before I set about reinventing the wheel, does anyone have the knowledge or
a basic circuit diagram for this sort of relay interlocking please?
Tnx Dave

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UR RST IS ... ... ..9 QSB QSB - hw? BK