DV-MEGA

Just got a DV-MEGA single band 70cm Raspberry Pi hat because I wanted to have a fiddle with a hotspot for the MD380. I can get into three (sometimes four) DV repeaters from here but I do like to play with tech. This little board plugs into the Pi’s GPIO connector. I already had a spare Pi 3 from an abandoned PVR project and a PoE power unit so why not. The board will take an SMA arial directly but mine has a dummy load screwed in instead.

I’m using Andy Taylor’s Pi-Star package from http://www.pistar.uk/ – from there one can download a complete image for various boards including the Pi which, when imaged onto an SD card results in a Pi which boots up headless and presents a really nice web interface from which all configuration and monitoring can be carried out.

And it works really well. It is a doddle to set up and configure, especially given an instructional video https://www.youtube.com/watch?v=B5G4gYDdJeQ

Anyway, it also made me reconfigure the MD380 as the codeplug I had made previously was a little disorganised. I now have all four local repeaters set for all the useful talk groups in two zones each (the radio can only have 16 channels each, awkwardly), including a zone for the simplex channels which I had forgotten (!) and a separate zone for my hot spot, that one with the tx power set to low. The channel is set to colour 1, a lot of people seem to use 438MHz as the frequency (NB both tx and rx), and TG9. The slot does not matter as it’s simplex.

Connecting to a talk group is straightforward on the MD380. Menu -> Contacts -> Manual Dial and then enter the TG number e.g. 4400 for the UK wide one and press the PTT. You should hear a voice telling you that you are connected. Use 9990 for the parrot, and 4000 to disconnect. QED.

FT8

A new mode (to me) – FT8, part of the latest WSJT-X package and widely discussed of late. Having been away from radio for a few weeks I’ve been keeping up on this via a Facebook group and e-mail and itching to get back home and grab the software. I did so late last night and managed to answer one CQ after reminding myself about the mode while watching the band activity. The auto sequence was a surprise the first time I saw it working. I had a ‘proper’ go today with several successful answers to CQs. It all happens very fast!

I have also now started logging QSOs within the WSJT-X package. I had not done this previously because really I only dip in and out of this and other modes, and have plenty of time to log the few QSOs I actually make by hand. But as it’s now rather frantic I decided to have a go and it all works nicely. Of course you will by now be questioning my sanity due to the fact that previously I had no indication of DXCC or callsign worked etc., resorting to my own lookup script that checks QRZ.com to see if a callsign is new. But there was time, plus as I had fiddled with the API for QRZ.com I have a simple bit of PHP that does lookups directly.

I really must find some time to throw more wire into the loft and work different bands, as I still only have 20m and 6m to play with. Hmmm.

 

Further JT9…

Well 20m seems to keep springing into life these days, JT-wise anyway. Lots of American stations (north and south) but I have had little luck in managing many QSOs. Then last night I had a JT9 QSO all the way to Chile at 11,800km. Not bad for my bit of wet string in the loft. Mind you, looking him up on qrz.com shows a massive antenna array so he was doing all the work!

Today my first QSO was JT65 at a mere 620km. There are a lot of European stations on right now.

20m JT activity

Well last night 20m was alive with JT65 and JT9. I saw lots of stations from North America and a number from South America. I replied to a dozen or so US but no-one heard me. Oh well. I tried a couple of EU stations, again nothing. Hmmm. Then the band died off… try again tonight! Mind you, if this stuff was too easy it would not be fun.

One thing that would be useful is a clock that bleeps every minute but on the, say 45th second to remind you to look for CQs.

Feldhell – well, almost

I managed to decode some Feldhell tonight after scrabbling about for the document showing what various data modes look like. It’s a strange mode!

Unfortunately the Spanish station sending it could not receive me so no QSO, but now at least I know what to look for. It takes me back to when I was interested in telegraphy systems as a kid, some decades ago now, but I’d never seen it in any form of action – represented by computer now rather than the machinery of old. Mind you what’s to say the Spanish station does not have said machinery!

There’s a whole bunch of info over at https://www.nonstopsystems.com/radio/hellschreiber-function-operation.htm

JT9 blues

I’ve had a couple of JT9 attempts these past two days on 20m where I’ve answered a CQ and received a signal report  back, and sent mine but then received the same -nn signal report again. And again. Presumably the remote station has not been able to decode my reply. So I never get to the 73. I’m guessing the band just fades away from underneath me…

If I remember right it was the same remote station each time. I’ve had successful JT9 QSOs so I am putting these down to bad luck and I hope the other guy isn’t getting frustrated!

JT9

Well another first for me tonight, a JT9 QSO, and on my second attempts at answering a CQ. This was with a USA station apparently over a 5,600km path. But again the replies come in the Band Activity window on a different frequency. Not sure what I am doing wrong there, but this was a complete QSO ‘by the book’.

Edit: I never did follow up on this post. This is, of course perfectly normal operation, for example where someone sits on a quiet part of the segment but listens across the whole.

JT65 – mostly

I spent a couple of hours yesterday with WSJT-X trying to make some contacts by answering CQs and getting nowhere. After a lot of fiddling with settings (I spotted the ALC on the FT450D was going haywire – who’d have though it had a display!) I now have much better settings of sound system output and Tx control on the SignaLink. The Tx is now set to just below to 9 o’clock position, so almost to the third tick mark, and the sound system output is set to 29% via the Pulseaudio volume control. The power setting in WSJT-X is set to -0.9db at which level the signal still triggers the PTT relay in the SignaLink but at 100% (-0db) the ALC triggers. But no luck with answering CQs.

Actually the Pulseaudio setting threw me at first because WSJT-X uses ALSA, but the ALSAmixer shows the same 29% as set by Pulseaudio so I’m not fussing. Also, it still gives the expected power output on the PS modes and a test call on BPSK31 worked fine, so it’s all be written down.

And today I got a reply to my reply to a CQ. But it was confusing. WSJT-X has two windows, one for Band Activity and one for Rx Frequency. It’s all made very easy, you double-click on a CQ in the band Activity window and it moves your Tx and Rx frequencies to that station and pre-fills standard messages. The system can also be set to enable Tx when you click but I’ve not done this. There is time (seconds) between clicking the callsign, checking everything is ok and clicking Enable Tx.

So back to my first JT65 QSO. I clicked on a CQ as above and clicked Enable Tx and off went my reply. Remember these take a full minute each, with replies coming in a few seconds ahead of the minute mark, and everyone’s clock must be very accurate or it does not work. Well, the next message from the CQ’ing station, the reply to me showing my remotely received signal strength came on a different frequency. So it displayed in the Band Activity window and not the Rx window as I had expected. But it was a valid reply and so my next one went out – my reply including R-xx, R for received and the -xx being the strength of the station as received by me. The next message from the remote station was the same as the previous, i.e. my signal strength as received. So I halted the transmission there assuming I had got something wrong.

So not a complete QSO  but I received an eQSL card for it and so I am counting it as my first ever on JT65, and it proves my system works.

Anyway I persevered amongst other things and managed a complete JT65 QSO later in the day, but the replies still came back in the Band Activity window on a different frequency than my transmissions, and the original CQ that I answered still showing in the Rx Frequency window. Why the difference? The QSO ran fine, all messages exchanges right to the 73’s. When I can see both sides of other QSOs, or even the relevant bits they all appear at the same frequency. (note ‘frequency’ here is that displayed by WSJT-X in Hz, not the dial frequency)

…and a close one.

So far I have totted up 19 countries – finally including the UK. I managed a BPSK63 QSO with a station just a few miles away, on 20m again as this is still my only HF antenna. I’m guessing this was ground wave. Funny, I’ve been interested in, and fiddling with radio for 40+ years and yet I am only now learning about propagation, helped in a large part to the two pieces in TX Factor. See http://www.txfilms.co.uk/txfactor/ – these are really good programmes.