Saturday, 9 March 2013

Elecraft P3 build

Today I bought a P3 kit to go with my Elecraft K3 transceiver.

Up until now I have been using a SDR-IQ and PC with Spectravue to observe signal spectrum and waterfall activity.

However, the 22inch monitor screen was becoming a bit crowded when trying to display spectrum, 'KST, JT65 and VK3UM EME planner all at the same time!

Something had to change. The something was that a decision was made to purchase a P3 and initially view spectrum on its built-in screen. Later, a P3SVGA card will be added together with another large screen monitor dedicated to the P3. The P3SVGA will also enable me to plug in a USB keyboard and operate any of the K3 data modes without needing the use of the PC.
A second advantage of the P3 is that it is better integrated with the K3 than
The SDR-IQ and Spectravue. The ability to see the frequency of both VFO A and B at a glance looks really useful.

The SDR-IQ will be repurposed to be used with my TS2000X and IF output modification at 10.695MHz. When required, it can still be connected to the switched IF output from the P3 in order to measure noise in the continuum mode. Something sadly lacking in the P3 firmware and indispensible for EME cold sky to sun noise measurements.




This picture shows the first stages of assembly of P3 serial number 2555. On the left is the back panel and on the right the front panel with the colour LCD screen and various control buttons and function selection knob.

In all it took me about 90 minutes to assemble the kit. Mostly this was checking everything was supplied, that should be, and then screwing the various ready-assembled cards into the P3 case. There were no surprises and everything fitted perfectly. This was a pleasurable experience and very therapeutic!

As my K3 was built for me ( thanks Dave) I never previously had the pleasure of following the superb Elecraft assembly instruction. I think I can see why these have been favourably likened to Heathkit at its best!

Now that the P3 has been built up it is time to check it out.......

More anon.




73 de Sam



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Thursday, 21 February 2013

Visit to Waters and Stanton

I visited W&S this morning. My trip was to purchase a KAT3 internal ATU for my K3. I couldn't wait for Dayton!
My trip coincided with the first demonstration of the new Kenwood TS990 136kHz ( the ads say 1.8MHz) to 50MHz transceiver in the UK ( it said.....) at a UK dealer.
Unfortunately I am not sure I got the correct name of the Kenwood guy who was doing the demonstration. I think it was Dave Wilkins. Apologies if I got that wrong. He did a good job, however.
My first impressions were very favourable. A nicely made radio with lots of features and buttons! Kenwood have obviously put a lot of work and thought into this new flagship radio.
For over £6k I did think it missed a couple of things I would like to have seen included. The radio is clearly aimed at the HF operator. It may not really cut it as an ideal IF radio for VHF or above. Now there is a surprise! Although it has a reasonably good transverter interface arrangement (transmit is 0dBm at the DRV socket, with receive via the Phono rx in socket), I didn't get an answer as to what its transvert band options were. Neither did I find out if it had facilities for displaying transverter IF offsets etc.
It did include an external 10MHz reference input that could also be used for reference out to synch two such radios. A nice touch that will be especially appreciated by the digital guys.
The facilities included a colour screen that can display from +/- 5 kHz to +/-500kHz in both spectrum and waterfall. However, it didn't appear to include a continuum noise measurement mode and since the radio has no IF output it cannot apparently drive e.g. an SDR-IQ receiver that can run continuum mode. If you don't know what continuum mode is used for, or how useful it is, you aren't really using your radio!
If I seriously operated HF and had the money, I would certainly consider buying one. For now my K3 offers better value. Now to go and fit the KAT3 to it and see how well it works compared to the external MFJ manual antenna matching unit I have been using.
Look for me on WSPR. When I'm in the shack or office, but busy on other things I tend to leave it on. Yesterday I was on 20m. From the WSPR reporting page I noticed that my coverage from the improvised vertical seems to be nicely omnidirectional. That is as I would expect from the vertical at the bottom of the garden, with a clear take off over more than 320 degrees.
73 for now de Sam
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Saturday, 9 February 2013

Clean up

The last two days have been given over to cleaning up the shack, which over the last year had become virtually uninhabitable!
It is amazing what you find in boxes, carefully put on one side because they are not immediately required.
One such was a perfectly good Tek current probe and mA/mV converter. It should be perfect for RF current measurements on 472kHz. Now, if only I could find a second one!
I also found my old T7F 70cm FM transceiver and two TNCs. One is a Tiny 2 and the other is a BSX2.
A lot of old PCBs were disposed of. These were mainly old computer and router boards, but included a few RF boards.
The shack floor and under the bench really looks a lot clearer now, but there is still another day or two of cleaning to be done. The test equipment bench may be clear, but a significant amount of stuff found its way onto the work bench!

73 de Sam




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Tuesday, 5 February 2013

PCB

Prompted by a visit from G7OCD yesterday I decided to sort out my PCB etching facilities.
For some months I have been unable to run my Mega triple tank etching system because the clear etch crystal solution had crystalised out, trapping the PCB holder and making it difficult to remove the tank lid to pour in near-boiling water to dissolve the crystals in the solution. I eventually had to cut the retainers from the lid, allowing me to remove it and gain access!
With access I was able to (eventually) pour in the hot water and then syphon out the spent solution. That didn't go too well as the syphon sucked up crystals and stopped working. It didn't matter what I did, I couldn't get it working again.
As I had to go to Rapid Electronics to get new crystals and other components I added a new syphon to the growing list.
These come in pairs and even the first of these also gummed up. However, the other syphon worked OK and the tank is now empty, ready for a new etching solution to be added tomorrow.
I also bought new sensitised PCB material, universal solvent and some other stuff. Now I can etch the new 4m transverter board and the two PA driver boards.

Sam





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Sunday, 27 January 2013

New 144MHz antenna

Last summer I erected a YU7EF dual band 4/6m five element yagi on my mast. A few month's ago I asked Colin, G4ERO, if he would also make me a 5m boom 144MHz YU7EF yagi.

Yesterday I took delivery of the new yagi at the monthly Codger's breakfast meeting, courtesy of G4BAO and his delivery system!

Taking advantage of the mild weather today, I assembled the yagi and put it on my mast, ready for testing.





After normalising the cable I was able to check the match direct at the yagi feedpoint, using my HP 8753C network analyser.

This showed the best match to be slightly low in frequency at 142.8MHz at 25dB, rising to 16dB ( about 1.3dB VSWR) at 144.3MHz.
I didn't have time today to play with the match, but suspect that the coax balun is slightly too long.

Next time I have the mast down I will shorten the balun by a few mm and check the match.

Listening around on 2n there wasn't much activity today, but the usual beacons were all there and about their normal strength, although a longer period of listening is required to see if their level is better or not. My 'old' Cushcraft 145B2 ten element was quite good, but it is not an optimised design, so I would expect marginally better performance on terrestrial and a fighting chance at single yagi 144MHz EME.

73 de Sam





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Wednesday, 23 January 2013

Dubus Technik 12

Received my copy of DUBUS Technik 12 today.
Full of really good stuff including a reprint of my PGA Amp.
These were also on sale at Heelweg last Saturday.

Copies should be available from the UK DUBUS representative, GM4PMK.
Google on Roger's callsign for details.

I guess they will also be available elsewhere from the numerous DUBUS country representatives.

Speaking of the PGA Amp, I now have a small number of low loss Arlon PCB versions of the PGA Amp kit. See my web page.
This will be updated in a day or so to reflect the availability of this 'other' PCB.



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Monday, 21 January 2013

Heelweg and Dwingeloo

Safely back from The Netherlands.
We ( G4BAO, G4HUP and myself) had been concerned that the dreadful snowy weather at the weekend might have meant calling off our annual visit to the Heelweg Microwave meeting ( held in Westendorp!) on the 19th January this year

As it happened it was probably a wise move to drive rather than taking a plane as in previous years. The delays experienced on some airlines just did not occur on the Stena ferry Line Harwich to Hook of Holland route and although progress was slow across The Netherlands road network on Sunday ( I was interested to see that the Dutch are no better prepared for snow than here in the UK), at least everything kept moving.

This is the first time we have taken the car, and it may not be the last. It allowed us more freedom in our schedule and the opportunity to visit the Dwingeloo dish in JO32. As this is a long way from our usual host's QTH, there has not been enough time to visit previously.

Jan, PA3FXB, had invited us to visit many times over the last few years. At last, and just after the dish was place back on the rotating plinth following refurbishment, we were able to look over the site and admire the handiwork of the original builders back in 1954/1956

This dish was used by Jan Oort of 'cloud' fame to map the galaxy HI line for the first time and is one of the sites at which the ashes of famous radio astronomer and radio amateur, Grote Reber, are intered.

The site is now well known as the location of the PI9CAM EME operation on 2m and 23,13 and 9cm

EME operation will not resume until later this year, and when it does I would like to go back again.

Next to the dish, on the Astron test range, we saw one ( or more) of the low frequency LOFER array antennas. It is shown right in the very middle of the photo and appears as a small black disc on the top of that short pole.






The Heelweg meeting was its usual excellent self with over 150 attendees, lots of test gear in use and a small number of traders doing a good trade in specialist parts for microwavers.

I would like to thank Jan, PA3FXB, for taking time to show us round the Dwingeloo dish, and to the many organisers ( too many to mention) who organise and run the Heelweg meeting.


Sam





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