The HX Files 019

Hello and welcome to Xtract 19 of the HX Files.

In this Xtract.

 A new 23cms transceiver for the shack.

 I would like to talk about this project that was made for use as a base transceiver; this project would be a 60 watt ATV transceiver for 23cms. The first thing to do was to get a project box that was not just big enough, but structurally  strong enough, so with safety hat on a suitable one was dug out of the stores bunker, as well as a suitable heat sink for the amps. The heat sink was originally an amp for a mobile phone system that was in the stores bunker for a couple of years, the inside was stripped out of its components, some of them for the skip, and some for the stores department, the heat sink was found to be only a couple of mm shorter than the project box and it was exactly the same height as it. The project box purchased was a used piece of scraped test equipment with most of the original parts removed before sale, after looking at the back of the box and at the heat sink that was going to be used, it was decided to use part of the original back panel (photo 1 below )as this would help with the fitting of the heat sink.

After a bit of measuring and marking, a small precision cutting device was to remove the centre of the panel, (A 100mm angle grinder). The rest of the panel was lined up with the heat sink and both marked for drilling some mounting holes. When lining up the panel up with the heat sink for drilling, care had to be taken that the holes to be drilled would be between the fins of the heat sink and there would be no need to remove any of the heat sink. Thanks to a bit of time spent placing the parts and a bit of measuring, the holes were drilled, they were close, but luckily there was just enough space to add the washers and nuts. The panel was then removed so that there was room to place the 2 amps on the heat sink, a couple of paper templates were made of the mounting holes of the amps to mark out the spots on the heat sink that were to be drilled but no matter were the templates were positioned the holes would be over a fin of the heat sink, so as the heat sink was 8mm thick the holes would be drilled to a depth of 6mm and then be taped. Thanks to Michael EI 5 GG for the master class in the use of his pillar drill and taps, and a couple of hours later the job was done. The amps were placed on the heat sink temporally and were wired up and a few tests carried out making sure they were giving out their full power, and after 1 hour on transmit the heat sink was still cool enough and more than likely it would not be transmitting for that amount of time in one go again. As the heat sink worked so well during the testing, no fans were to be used in the final design, and with that job done the back of the unit was refitted to the box. A chassis for mounting all the various parts that would be used was made from a piece of a scraped metal that once was the top of and old PC table, this had a couple of benefits as It was the type that had the perforated top, and the holes could be used for mounting the various parts, and it would also aid in air circulation. The amp requires a voltage of 24 volts at 4 amps, but the other parts like the 2 watt driver amp, the RX/TX boards, relays and various lights, would only need 12 volts to power them. I was toying with the notion of using 24 and 12 volts from external power supplies, this would not be a problem as the unit would be a base transceiver, but to go portable and having to bring a couple of power supplies was not on, so a 240v AC to 24v DC PSU was fitted into the case (photo 2 below).

 As the PSU had two separate lines out for 24volts, plan A was to use a voltage regulator I had that would drop the 24 volts to 13 volts and it would be able to handle 6 amps which was more than I needed, but I had to go with plan B as I could not find the amp. So plan B was to use a couple of smaller voltage regulators for each of the TX/RX boards to take the voltage down to the required volts, the regulators were mounted on a small heat sink that would keep them like the Fonz (cool) seen on the bottom right of photo 3 below .

The power supply used was one mentioned in a previous HX file that was purchased at a rally last year, and the fact it also had a fan installed to help with it’s cooling was not a bad thing, it has a few taped mounting holes around it’s body so using a couple of bolts of the same thread and after measuring it, a couple of holes were drilled in the side of the unit and the PSU was bolted to it.

 The PSU was placed on its side (photo 4) as doing this would leave more room in the box for the other parts. The TX/ RX boards, preamp, coaxial relay and the other parts were dry fitted in various locations until I was happy with the layout.

 Another benefit of having a perforated chassis meant I would be able to hide some of the cables, the holes could be made wider with a reamer and you could install grommets in the holes if needed so you would be left with smooth edges and not run the risk of any of the leads chaffing. The front panel was cut from a piece of an old aluminium sign, the panel would be strong as it is 3mm thick, and the it would be 312mm wide and a height of 105mm, that’s around 12”x4” in old money. The metal sign that was to be used for the front panel, was not in great condition as it had a few marks and scratches on it, so when all the drilling is finished, some sticky back plastic (well if its good enough for Blue Peter then its good enough for me) would be used, as it comes in various colours and finishes. But before all that the first thing to do was to try a couple of designs to see what want were, after the final design was chosen it was held onto the front panel with masking tape (photo 5 below                                                                                                     

The drill points marked with a punch, and after a bit of care the holes were drilled first using a 3mm drill bit and then finished off with the right size drill bits, and with the use of a file and a reamer the panel was finished, the parts were fitted on the panel and then removed to be able to apply the plastic covering. 

 As you can see in photo 6 on the left,the finished front panel with all the fittings installed. Having the back panel free of any fittings would mean that the transceiver could be placed close to the shack wall, and due to the tests carried out earlier, (it not needing any cooling fan(s), and with the carrying handles it would also mean some type of protection for the front panel. As I mentioned earlier this project would be a base unit, but if I did decide to go /P with it I would need a DC to AC converter to take the 12 volts DC to 240 volts, and as I did not want to bring a generator. That’s it for this issue of Echo Ireland, and if you would like to see other pictures of the build you can go to my blog, thehxfiles.blogspot.com.. Below is some more photos of the build.

And finally,  that may all your signals be P5. 73’s Pat.

Early layout

Final parts layout

Some tidying up left to do

The HX Files Xtract 018

Hello and welcome to xtract 018m of the HX Files.

In this issue a 20 watt transmitter with a built in receiver.

This project would be a unit that would be, not to make little of It, a spare transmitter and receiver, and instead of it being left at home, it was to be brought with the main portable transceiver (see photo I below)

Picture 1,
Photo of main rig

just in case anything happened to the main transmitter or receiver. It would be setup as a transmitter, so if needed it could be used straight away. The receiver could be switched on while the TX was on, but as they have their own aerial sockets I could monitor the TX signal without an aerial being connected to the receive socket. There was a plan A or B at the start, I had thought of plan B of making It a transceiver, and by simply adding a coaxial relay, TX/RX switch, a couple of phono sockets and patch leads it could be done, but I wanted to make this spare as a backup transmitter and to keep it as such, so I will carry on and build it as plan A and leave plan B for some time in the future.

The case for this project started life as a 100 watt 2m amplifier, and no, it was not converted to 23cms, it was however converted to junk by its previous owner. I did not ask how he let all the smoke out, but I was told that it was beyond repair, so as the whole amplifier was a large heat sink and would be very handy to have, a deal was done and it was placed into the stores, and there the amp rested for a couple of years awaiting a renaissance. (Wow that was deep, it must be Christmas).

The first thing I done was to remove the old circuit board and switches, (I forgot to take a photo), with that done the original front and rear panels were use to mark out the holes for the new panels, including a new bottom one, but before any cutting out was to be done to the panels I had to place the other parts on the heat sink to give me an idea on were to drill to attach the amp, transmitter and the receiver.





 In photo 2 on the right, you can see the front panel as a blank on the top, and on the bottom with the holes for the various switches, led’s and a couple of carrying handles that would also act as a guard to protect the front. In photo 3 below left, you can see the parts laid out out in their final position with some of the wiring done, the amp top right and the 50mw driver on the left, the receiver is on the bottom right, also seen is some connecting patch leads.

Photo 3

The amp has some pre drilled holes in its own mounting plate and that with the bonding of the amp to the larger heat sink; the amp was finally attached by marking and drilling straight through the heat sink and using some stainless steel nuts and bolts.

Photo 4 on the left shows the back panel with the amp N type socket on the left, you may notice that the two N sockets are different, one been the fitted socket on the amp and the other one a panel mount N to SMA, I was not going to remove the n type fitting from the amp and attach it to the panel via a small lead or adaptor, so not wanting to remove the N type,  a couple of small pieces of the panel was cut out so it would fit around  the sockets, and as I had not got the harder files to work on the steel , I can make a new and better rear panel.

Photo 5 on the left is a picture of the almost finished front panel; the 3 switches are for the 20 watt amp on/off, the receiver, and the DC on/off. The switches and led’s will be marked out by the labelling machine when I find it. The 6 led’s are used for the following, the DC power, amp on/off, TX on/off, RX on/off, the amp has a feature that has a DC monitor voltage that can also be used to indicate if the amp is on so I will use that one as well, and not ruling out a time in the future that the unit could be turned into a transceiver I had a spare led for displaying the relay. In photo 5 the finished front can be seen installed on the heat sink, the keen (Hungary) eye amongst you may have noticed that the led’s seem to white, but when the voltage is applied to them some of them light red and the rest green.

That is all for this Xtract of the HX Files, and indeed for 2011, I would like to thank you for the kind words when I met you at the rallies over the year, so with that, I wish you a very Happy Christmas, and a prosperous, and P45 free 2012.

May all your signals be P5.

73’s

Pat.

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 2^nd  and 3^rd  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.