What Antenna Switch?

KenAlexander

I see there is now the capability to control an external antenna switch! I had a look at the help file. Lots of things for programmers, but not a word about hardware, which seems odd. What switch do I use? I assume it is controlled by USB from my computer.

Is there a manual somewhere that has this information?

Thanks and 73,

Ken VE3HLS

KenAlexander

Supplementary question: How many antennas can I switch with this extension and associated hardware?

73,

Ken VE3HLS

jks

I've updated the operating guide to have a pointer to the latest antenna switch README file (on Github) which lists all the supported switches since the integration of the switch code into the Kiwi server: http://kiwisdr.com/quickstart/index.html#id-3rd-party-ext

barneyuk

Ken, I have built my own switch units that are controlled from Beagle GPIO using the Antenna switch extension by Kari, OH1KK.

I used a relatively inexpensive 8 channel relay board that uses opto couplers between the relays and the GPIO pins on the beagle. The opto couplers only draw a current of 5ma from the GPIO pins when triggering the relays. The relay board itself runs off 5 VDC.

The board I used was the "AEDIKO 8 Channel Relay Module DC 5V Relay Switch with Optocoupler Isolation High/Low Level Trigger". Available from various sources, I got mine from Amazon UK https://www.amazon.co.uk/AEDIKO-Channel-Optocoupler-Isolation-Trigger/dp/B0B99X4CJN

Construction was simply a diecast box with the board inside and sockets for the antennas and the control lines.

I have built 3 of these, all work without a hitch, two in use on my Kiwis.

G8JNJ

Some previous notes here about using the GPIO port.

https://forum.kiwisdr.com/index.php?p=/discussion/comment/7539

Regards,

Martin

barneyuk

Most if not all worries in that original thread are taken care of by virtue of the opto isolators on the board I am using. Certainly wouldn't use one without them.

Oh some of the info on that old thread is out of date, example, antennas 8,9 and 10 are now accessible via the webui.

G8JNJ

Using opto isolators is sensible, but there is a lot of switching noise on the GPIO lines, that can produce unwanted RF noise.

So It's still a good idea to add RC filter networks at the point of exit from the KiWi case.

Regards,

Martin

KenAlexander

Thanks for all of the ideas and suggestions, guys!

I had the manual dexterity to do that kind of electronic work about 20 years ago, but not anymore. Plus, the thought of opening up my Kiwi and soldering things to it terrifies me.

I'll continue with my antenna projects and use the one that I think works best overall. If someone wants me to try another antenna they can e-mail me.

Thanks again,

Ken VE3HLS