Tuesday, November 8, 2011

the HX Files 017

The HX files 017.
Hello and welcome to Xtract 017 of the HX Files.
In this issue.
 Photos, of a 10GHz RX and 23cms TX, operating /p on 1296GHz SSB
 and Goodies from Friedrichshafen.
 Last time in the HX Files.
 I mentioned about building the opposite
 of what was built, (23cms RX and 10GHz TX)
This time it would be 10GHz RX, and 23cms TX. You can see in photo 1 on the left  the setup, with the23cms TX on the  botom right and surprise surprise, the 10 GHz RX on the top left. The 10 GHz RX is a modified LNB, not the normal Sky type but one that is finished in wave guide. The aerials used were the same as the other unit, a slot for 23cms and a Horn type for 10GHz. The unit for the time been would be finished with N type fittings and I would use some adapters like the last time so I could use different types of aerials, I know that using any adapters would cause some power loss but I was not worried by this as I was not making a DX Beacon I was only going to use it from the bottom of my garden which is around 17mts long. The aerial for the 1.2GHz is a dummy load that can be seen in photo 2 below eft.
 I found that this aerial was good enough to do the job of reaching me.  This TX/RX would be easy (ish) to build in the small box like the last one, but unlike it this unit would not be the handy portable or demo unit as the kit would also involve an analogue satellite RX. So the signal would picked up by the RX aerial first and then via the transition to the LNB, and then down to the Sat RX and then back up to the 23cms TX, the cables used would be some coaxial cable from the LNB to the Sat RX, and from the Sat RX the audio and video would be sent up some phono leads to the 23cms TX, and a DC lead for the TX. The marking out and drilling of the box would not be too much of a struggle as the holes I needed were near to the sizes I had drill bits for and would only involve having to do a minimal amount of filing and run the risk of oval holes, I don’t have a large enough reamer for the job but the files would do as long as I took my time as the box was very easy to file and the holes could get bigger all to quick.
 Oops.
I made a chassis template from a cereal box first and then I would  transferred it on to a piece of clear Perspex and then drill out the holes and file the corners for a better fit, but on drilling the second last hole in the Perspex it cracked and snapped in two, and that was followed by words like gosh darn and blast which could be heard coming from the machine shop (the kitchen) I had no more of the Perspex so I used some hardboard instead, but this chassis would only be for testing and would not be a permanent solution as the hardboard would attract moisture and not only fall apart but short out the equipment as I did not use big spacers and if  the chassis did warp it would short out the TX board  and that would not be a good thing. When I was marking out the box I was wondering how to install the LNB, I noticed that at the F connector was at the back of the LNB and that its retaining nut was on the outside, which meant the nut could be used to hold the LNB firmly to the project box and by using the waveguide to SMA adapter and a SMA to N type that was chassis mount would hold the other end and as you may have notice in photo 3 below left, the F and N terminals are close together.
Some UHF Qso’s.
I had a few SSB contacts on 1.2GHz; yes I took some time away from ATV (WHAT!!!) I went /P with Dundalk Amateur Radio Society (EI 7 DAR ) who took part in the VHF/UHF Field day that took place on the weekend of the 2nd  and 3rd  of July. For the 1.2 GHz part of the field day, EI 7 DAR/P was manned by myself and Mark EI 9 FX, and we were using an Icom 910 (2m, 70cms and 23cms), and a 35 element Tonna. Most of the contacts on 23 cms were on the Saturday, and we only heard the same stations again on the Sunday, other members of EI 7 DAR were on 6m,4m and 2meters,  and the 2m crew scored well, they used the callsign EI 0 W/P, anyway enough of that mode.
Friedrichshafen Rally.
The rally was a good one, although the stalls were down the stuff was there, and even if you are a youngster (a pup) or a senior citizen (a grave dodger) you could have bought everything from a microphone to an aerial, and all in-between. At the rally I purchased a few goodies for 23cms and 10 GHz. The biggest was a 60 watt amp for 23cms, and a 2 watt amp to act as a driver for the 60 watt. The QRO amp uses 28 volts+/-, so a 24 volt PSU was also purchased and the one I bought had a adjustment pot fitted to the front, and under test the no load voltage was 27.8 volts and under load (a couple of 12 volt car headlight bulbs in series) dropped this to 27.5 volts and this was well within the amps parameters so I should be getting very close to full power when driven by the 2 watts. I will have to dig deep into the stock piles to look for a suitable project box. I hope to have the unit built soon and have it in the HX files in a couple of issues time if all goes to plan, and the plan is to build it primarily as a base unit, but I could use it /p. even if the main power for the transceiver is 24 volts, I would use an inverter to convert the DC power up to mains voltage, or you could purchase one of the small Lidl/Aldi generators.
That is it for this issue of Echo Ireland, see you next time and may all your reports be P5.
73’s Pat.      

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