More Testing - Starter for 10GHz

Well,

You may recall a while ago I started a microwave project called "A Starter for 10GHz" and I did some basic testing of the RX here. Today I have been to visit Peter, G3PHO and his amazing emporium of test gear; together we have tested the TX side of the project successfully.

I've done a few other things since I came back from visiting Peter - the first being to devise a way to get my DC to 1.5GHz spectrum analyser to display 10GHz signals following some excellent inspiration from Peter.

Here's a picture of a eBay purchased LNB:

This device is very high specification and uses a PLL local oscillator, here's the spec (in German) from the box:

So basically it's designed to receive 10.7 GHz to 12.75GHz with a local oscillator of 9.75GHz. If you inject a tone to the DC supply you switch to the 10.6 GHz local oscillator also available, but we don't want that for our purpose.

Now, I've made a very simple Bias-T to send some DC up the coax feed to the LNB:

and used this to connect the LNB to the input of my Spectrum Analyser:

 

Very much inspired by the ARRL $25 10GHz Signal Generator I purchased a couple of the HB 100 units from eBay for a few $s. I have added a voltage regulator plus a couple of caps:

This is switched on and running on the bench as is BTThing I told you about back here. BTThing is set to 2592 MHz making the 4th harmonic at 10.368 GHz.

The Spectrum Analyser screen looks like this:

The smaller peak to the right is BTThing. Doing the maths, we have:

Which is pretty damn close to the 4th harmonic calculation of 10.368 GHz.

Using a similar technique:

We can deduce that the HB100 $25 ARRL signal generator is on 10.345 GHz.

Local conditions. All good egh?

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.