Wednesday, July 13, 2016

Boys with Toys

Even at my age of 55, I still feel like a boy when it comes to my electronic (not to mention radio electronic) toys. Especially if my friends keep encouraging me by sending me links to interesting articles on the Internet. Like the document (tnx OK1DXD) where I found following picture:

Nice ... especially after finding dual mixer (two mixers with integrated LO power divider) on eBay:

The seller stated max frequency 18GHz and max IF frequency 150MHz. Well, I overstepped the IF maximum almost 10x and the mixer still worked, so I hope that RF inputs will accept 24GHz.

Now, what to test? Easy pick. I have found a nice waveguide filter on 10567.5MHz:

So, I have located couple of cables, not really suited for 10GHz but at least with SMA connectors, and connected everything together:

Where to get LO signal from? That was easy too - my favorite ELCOM synthesizer provided +13dBm on the frequency of 11GHz:

So far so good ... but will that thing work? I have turned my RIGOL analyzer on and activated the Tracking Generator - and YES, it worked:

Let's try to zoom in to check how steep the filter is:

Pretty good, actually. The passband is flat and only ~40MHz wide. Looks like good filter for general use. With this mixer, I should be able to re-tune it to 10368MHz easily.

Of course, I need to calibrate the "Y" axis. No idea how much attenuation came from the mixer itself. Some definitely was introduced from the measuring cables ... still work to do on my side. I will also try to use the same principle (different Local Oscillator and maybe different mixer) for 24GHz.

73 Herbert

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