GB3VHF signals

Well after having the new 13ele tonna up for a couple of weeks I recently noticed a signal around 144.430Mhz. After some quick research I discovered it to be beacon GB3VHF which outputs a JT65B signal.

I can copy the beacon on the beam S5-S6 seemingly 24hrs a day, so quite a good path between us. SNR’s of -1dB to -2dB in WSJT-X are the norm. I decided to listen with the x510n collinear vertical and to my surprise I could decode it with varying snr’s.

I ran it from around 3am on the 21/05/18 through to mid day, recorded the results and plotted them. You can easily see that the SNR improved from around 6am through to around 8:30am.

SSTV from the ISS

An SSTV image from a pass of the ISS @ 14:23z today as part of the “Expedition 55 Interkosmos” mission. I didn’t get set up in time so only managed to get the end of the last transmitted image. ISS was over north France at the time, at about 250 miles up. 145.800MHz +- some doppler. SunSDR2 Pro and the X510n vertical. 30dB over 9 signal.

The next pass at 15:50z ish was going right overhead, so I was all set up for this one. The first image (with the green noise) was received over the middle of the Atlantic (amazing 800-1000 miles away?), the second when overhead here in S.Wales and the third when passing over the east side of Poland.

The last pass of today, around 17:30z resulted in the following two images. Signal strength on the last was around S5-S7 with qsb. 

Most of the time signals were around s9+10 or so, with very little qsb. I did notice some flutter/phasing/qsb on the final image as can be seen by the noise lines over the image.

Anyway that is all for now. I will put any new images below.

73 Richie.

The (call)sign of things to come?

So, I decided to have a dabble on JT65 last night, had a listen to the bands and opted for 17m.

The frequency was quite busy but I found a spot where I could call some CQ’s. 7X3WPL came back to me, but as you can see he failed to give me a report. In fact, he ended the contact with a 73 and then started calling CQ.

So this station did not give me a signal report (look at the times), and he then went about calling CQ. I double checked back through the call/band history and could not see his call sign. Unless there was some serious QSB or some sporadic propagation openings he was not on that frequency calling cq prior to me.

So, this morning, I checked QRZ, and unsurprisingly there was a QSL waiting for my approval from 7X3WPL.

Now, as I am only a year or so on the air with this callsign, I would have liked to have had that QSO confirmed and add Algeria to my country’s worked, but no, I refuse to add something that has been so obviously made incomplete. Why bother even operating and trying to make contacts if you cant even be bothered to send a report ?  Obviously it could be, and probably is, an operating mistake but to then call CQ as well ? As it happens according to QRZ he gave me a -14 report.

Is this a sign of things to come, with more and more automation, and the 59 73 mentality ? I read about the up and runs where the last you hear from a station is R-02.

Please for the love of god, if you are operating a slow as hell mode (5-6 mins per qso) then at least send a report and see the qso through to completion. I am slowly getting fed up of wasting my time.

73

MB7UNE and balloons – KK6PNN-5

I noticed ‘in old data’ a balloon had passed over the UK on the 4th of March. KK6PNN-5 seems to have been around the earth at least once on its journey so far. Intriguing indeed !

I had received quite a number of APRS packets from the balloon through MB7UNE-10 but the one shown in the image below being the most distant.

A quick google search revealed it was released from the University of California, San Diego, on the morning of 12/02/17. A near-space balloon with an APRS pico payload on SBS balloon with H2.

Some more details…. click here !

73

3d printing – a dipole centre and a balun

So, after seeing some of the creations from a few friends, my brother and I decided to go 50/50 on a 3d printer.  I really needed a small dipole centre and balun combo, capable of 100w tops, so I decided to go about making one.

Some designs in TinkerCad, a few tweaks here, a few there, and the case was complete, together with a number of different plates enabling custom, so239 and bnc connections. The case would eventually house a 1:1 guanella current balun, using a fair-rite type 31 core.

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The case went through a number of iterations, and prints. The above design was the finalised version (hopefully, lol).  The T clip you see in the design enables the dipole centre to be attached to a painters pole or slid down a fibre mast.

I am only printing in PLA at the moment, so the balun will not stand up to 365 days a year outdoor use.

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Anyway, the printer is nearly finished cooking another, so i’ll sign off here.

73

Richie.

 

A distance on 2m

Well, I was having a tidy up in the office, and found a scrap of paper with two log entries on that I had forgotten about.  The contacts were made on the 4th June’16 during the CW National Field Day and the 6m field day, on top of GW/SW-020 (Edumund’s Tump).

I was using 100w SSB on 2m, and made contact with PN4CPN/p around 16:50utc, some 338 miles into JN29dx, with a 5/9 report both ways. Also ON6CK/p some 277 miles into JO10ps a few hours earlier, around 14:48utc, also with a 5/9 report both ways.

Interesting conditions. So much else going on that day I didn’t really have time to work any more.  I was using my original 4 ele 2m home brew beam, but this has now been reworked into a 7 ele. I will have to give it another go soon 🙂

Cheers for the contacts !  73

2m distance

BBC Micro Revival – Model B 32k

owlWell, over the years I have had loads of computers, some home brew, some commercial. They have come and gone, however, my Acorn BBC Micro – Model B 32k has always followed me around.  It was purchased second hand some 30+ years ago, after selling our beloved Acorn Electron. I can remember my mum taking me into a computer shop in Newport to look at a Sinclair Spectrum 128k with cash in hand, and telling her it would be ok to park on those lines as we were only going to be a minute. How wrong I was – parking ticket and clip around the ear later 🙂  My brother and I decided to go for a BBC Model B instead, and due to the price, second hand was the way forward. One was found, from a family in Bassaleg I seem to remember. Anyway, enough of the back story….

Or perhaps not….  For a good many years of my childhood, my brother and I used that BBC Micro, together with a friend Chris McCray we spent many a weekend, tweaking that, bodging this, downloading via prestel/teletext, listening to Music 500’s and other shenanigans. Fast forward 31 years, and my BBC Micro – Model B was in a sorry state, and would not switch on.

bbc1

After some diagnostics, I discovered the PSU was not working, a bunch of capacitors need changing, specifically C1, C2 and C9 in the PSU.

  • C1 (0.1uF (100nF) X2 class capacitor) @ 250VAC (or higher)
  • C2 (0.01uF (10nF) X2 class capacitor) @ 250VAC (or higher)
  • C9 (220uF electrolitic capacitor) @ 10V

b2

For simplicity, I picked up a kit from sprow.co.uk, just to get the PSU working again, and after 30 mins or so, the familiar double tone was heard. I will eventually change all the electrolytic caps in the PSU for peace of mind.

Everything had the looks of a 10-12 year olds bodge stamped all over it. Wires tacked in here, solder blobs there, a complete nightmare inside.

satate3 state state2

So, I pulled out everything, all the junk wires, the dodgy keyboard cable (which came from an old case that used to house the computer and had a remote keyboard), the 10k pot on cables for volume, chock blocks, it all got cleared away.

I replaced all the power cables, however some of the spades had snapped from the mother board, so I replaced those with dil header pins. The CAPS lock key on the keyboard seemed to be faulty, and after investigation the pad had been pushed off from the board. A small jumper to a piece of track fixed this.

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tidy2

The composite video out connector needed fixing, the wires had been ‘ripped’ out of the motherboard.  Things were getting better and taking shape. I gave the board a general clean up with some isopropanol and a q-tip.

After some testing I noticed that the audio seemed rather quiet and would often crackle and become inaudible. I replaced the 10k pot with a 3296 variable resistor, not the ideal solution (needs a stupid number of turns, but hey ho).  I decided to replace all the electrolytic caps on the mobo, so this was the next job, relatively easy.  Audio still unstable, I decided to replace the LM386N audio amplifier 8 pin chip and swapped out with a modern replacement, which was not the best thing to do. The old chips were 1W, this new one 0.25W, so even quieter.  I have noticed that the audio crackling has been reduced but not completely removed. Next plan is to swap this LN386N with a NJM386BD which is a 1w equivalent. I am also planning on swapping the quad op amp LM324, the chip before the LN386N.

I also picked up an MMC userport solid state disk drive, to act as a data store for the beeb, having lost the 40/80 track 5 1/4 inch drive over the years unfortunately.

Upcoming plans are to replace the remainder of the PSU caps, fix some ceramic disc caps that have been chipped by extracting roms, connect it to a vga monitor via a gfx interface board from the ttl rgb output, get the old music 500 working and a number of other simple jobs.  Chuckie egg, revs, elite and a bunch of other games were tested, and ran perfectly. Oh, I did enable colour on the composite out just to test things before the gfx board turns up.  This final picture shows her with her lid back on. Happy days 🙂

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