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Wednesday, 26 August 2015

A Starter for 10 GHz

Well,

Due to being rather poorly and  ending up having my thyroid removed, I've not done much in the way of radio.

However, for some time now I have been interested in learning more about the microwave bands and the amateur allocations we have in that part of the spectrum.

I attended a Microwave Roundtable event at Finningley ARS quite a while ago and met some very clever chaps who messed about at these frequencies. As a consequence I have been trying to create a "starter for 10GHz" in the background for a while.

The heart of the system is a transverter from Kuhne Electronics - this is a basic 144MHz to 10GHz transverter. To utilise this device you need a few ancillary bits to create a system, but mainly an antennamabob and a TX RX relay.

Here is the main transverter box with the other bits and bobs completed:



You can see the TX/RX relay - this is a latching RF relay which is fired from 12V using the circuit on the veroboard you can see. There is a BNC socket for an external 10MHZ signal; conviniently just like the one I made here: GPS OCXO, there's an SO239 for the IF (which is 144MHz) plus a line from the IF radio for PTT. A couple of LEDs and that bit is complete.

I managed to find two different antennamabobs for 10GHz, there's this one:


and this one:


I also bought myself an old satellite dish of eBay for £10:


So with a little bit of metal bashing and a speaker tripod, I have ended up with this:



I have simply mounted the smaller of the two 10GHz horn antennas in the same place that the LNB was when I got the dish.

Now, how on earth do I test this???

I will be using my FT-817 as the 144MHz driver and receiver, but I have no test gear for these frequencies so generating a signal to test the RX was going to be tough.

In steps Kevin, G3AAF. He has done some very clever things with a common bluetooth module using software and has come up with an RF source which can be used as a kind of home beacon/test RF source. It's called BTThing:



I've added the box and an PCB antenna from Sam, G4DDK:




So this set to 2592 MHz will give me a harmonic in the 10 GHz band at 10,368 MHz; and lo and indeed behold I can hear this signal on my setup.

I haven't yet tried the horn and dish combination but will set up a test area somewhere in the house tomorrow and give it a whirl.

I've had a kind offer of some elmering in these matters from Peter, G3PHO so I should be able to test this out fully when he has some time.

Here's our Elmo dog for a change:


Local conditions.

1 comment:

  1. Hi,
    Nice to see you after a gap.
    Wish you, a speedy and stable recovery,
    regards
    sarma from India

    ReplyDelete