The HX Files 016.

Hello and welcome to Xtract 16 of the HX Files.

Some brain storming.

During a tea drinking session with Tony (EI 4 DIB) one topic that came up was what to do when you want to test a receiver or a transmitter and there is nobody around to receive a signal from or indeed to send one to.

So not living on top of a mountain I would have no DX stations to lookout for, so the talk came around to a project consisting of a receiver on one band and a transmitter on another. So after more tea (and a visit to the bathroom)

 it was decided that a visit to a couple of my stock locations was called for, to see what parts I had that could be used and would not run the risk of been used for another project.

A Hunting I will go.

After a couple of hours hunting for the parts in my stock stash’s, (shed number 2 and under the bed) and a spot of stocktaking, I decided that a 1.2 GHz receiver and a 10 GHz transmitter would be the frequencies of choice.

 In photo 1 above, with the exceptions of some phono and DC power leads, you can see the parts that would be used in the project. The finished project would be used to receive a 1.2 GHz signal and then that signal would be re-transmitted on 10 GHz. The receiver’s audio and video signal would go direct from the 1.2 GHz to the audio/video inputs of the 10GHz transmitter. The project box used is one of the waterproof ABS type so that I would have piece of mind when or if it ever rained The first thing I done was to do a parts layout in the box to see what would go were, not just the TX and RX, but smaller parts like the cables use for carrying the voltage, audio and video, a DC distribution bar, fuse holders and aerial sockets.  The mounting hardware was bolted through the box and a good quality sealer used to prevent water ingress. A sub chassis was used to secure the various parts so that if I had work on the unit it could be removed easily (ish). So after some measuring and marking (photo 2 below) I cut an opening in one of the side of the box, this opening is the size of the aperture of the solfen head .I would attach the 10GHz on one end of the box and the N type socket on the opposite end of the same size.

 I attached the solfen head to the inside of the box and a small extension piece of waveguide that can be seen in photo 1, with that piece having one flange with threaded holes and the other without the thread . I screwed the unthreaded end to the solfen head and the other end of the extension with the thread would be a lot easier than using small nuts and bolts. I could also quickly attach and remove various aerials for testing and some other fittings, such as a slot aerial, a horn type aerial, even a transition from waveguide to a SMA or N type and most importantly, some attenuators to minimize the RF output, so I would get a better test from a weak signal as what was the point of putting out a QRO signal when QRPP was what I wanted to test the receiver’s, and also, I did not want to “nuke” myself. It would be attached to the fence at the bottom of my garden about 53ft from the shack with some attenuators fitted. If I decided to use this project out and about portable it would not be a big deal to undo it.
Photo 3 below shows the unit before the spaghetti ( the wiring) was added.
 photo 4 below,shows the aerials I would use when the unit was up and running ,the aerial on top is a 23cms slot aerial that is covered with heat shrink, on the bottom left of the picture is a slot aerial and on the right is a horn type aerial both for  10GHz.

Testing, Testing.

Tony’s back garden is 100ft long and it was used for some testing of the finished unit, using a rubber duck type aerial with an adapter for the receiving the 1.2GHz signal and the slot aerial for10 GHz. So using a 1.2 GHZ TX, and a modified LNB and an analogue satellite receiver for 10 GHz receiving, the testing was carried out and all went well,

With all the test carried out and passed, the kettle was put on and the tea drank, later on that night at home I decided to make a mod to the unit, I used 2 long leads, one end of each lead was joined to each of the rx/tx units and those leads were joined by a back to back phono plug joiners. The reason for this was that if I brought it to another ham’s shack the system would be mounted on their mast and with the joiner inside their shack the operator could remove the joiner and connect a camera and then he or she would be transmitting on 10GHz, also by connecting a TV on the other lead you would be receiving 1.2GHz. Not exactly what one would call hi-tech, but it works and it may also get another ham onto the microwave bands and that has to be a good thing.

As a result of the testing of this project I decided to make one the other way around 1.2 GHZ TX and 10 GHz RX. I will have some photos of that next time.

That’s all for this Xtract, and I hope all your signals are P5.

73’s Pat.