Here in the USA during the ARRL VHF/UHF/Microwave contests typical operating procedure is to make a contact on 2m and then quickly work the same station on all of his available bands up through the microwaves. I love operating these contests from SOTA summits…what could be better!
I have the three SG-Labs portable transverters and I need a fast, lightweight, low “wear and tear” way to switch between the transverters. The transverters are driven by 2m and in one case 70cm…so the switch has to handle at least 70cm. Power isn’t really an issue as the drive on the transverters is adjustable and can be quite low. What I am doing now, switching coax lines, is time consuming and I worry about the wear and tear on the rig’s connector. Ideally I could switch so quickly I could check the bands regularly for activity that I might get a chance to be a part of.
I can’t seem to find a lightweight manual QRP 2m/70cm antenna switch which I could use to feed the three different transverters. Surely someone somewhere must make such an animal? Any Ideas? An ideal solution is one I can buy and not have to make as time is quite short for me lately.
If anyone has a better idea on how to feed the transverters—perhaps there is some sort of patch cable with push together connectors out there—I would love to hear it.
I made up a Single Pole 6Throw switch by using a suitable multi-throw switch mounted in a small diecast box, with several BNC sockets on it. One BNC for input, with 6 for outputs, with the box labelled appropriately. I used RG316 coax from each socket solder spill (& ground connection) to the appropriate connection point on the switch, with the ground of the coax unterminated at the switch and dressed clear of the connection. It worked fine with an FT-817 and 2 m. I never checked the VSWR / Return Loss on 70 cm, but the switch arrangement worked fine for 2 m.
Personally I would use something like a Tohtsu CX-120A or CX-120P Miniature Coaxial Relay wired up to suit. The DC switching for it could also be arranged to apply power to the relevant transverter if required.
For two transverters, could you run VHF from the rear antenna and UHF from the front?
Not sure if the 817 would provide enough isolation for this.
I have only run 2 transverters + 2m from summits for which I use separate radios on each band.
I really like the idea of switching power as well–but as for the relay current drain is there some way around that? Its not all that much power but if I run the relay in the powered up mode for the majority of the contest that could add up…
The relay remains powered up when you use the “b” connector I imagine? And then power off to go to A? Its not just hit it with power momentarily to switch, correct?
The CX-120P is SPDT as per standard for a coaxial relay. I used to use an old Londex relay for the purpose of switching the FT-817 to separate linears and it worked quite well. I used a rotary switch and the power was also applied to the appropriate linear. I had the Londex “off” for 2m which was the main band. I have seen latching relays on eBay, but they have usually been multi-way. That’s not much use.