Thursday, November 29, 2012
Tuesday, November 20, 2012
A couple of weekends ago, I had the opportunity to take a look around the Museum of the History of Science in Oxford. There were lots of interesting exhibits but here are a few that caught my eye.
First, a blackboard. A smart scientist called Albert Einstein visited Oxford. During his lecture - he used this blackboard. I was really thrilled to see Einstein's writing.
The formula? I'm not an expert, but I believe it shows the age of the Universe. The result of which holds up pretty well.
Here's a beautiful Marconiphone receiver.
And a Marconi transmitter!
Look at this gorgeous morse key! A 'grasshopper' design. Never seen anything like it.
An excellent visit! Highly recommended if you're in the Oxford area.
Sunday, November 18, 2012
Earlier in the week I noticed that there was a new version of the WinDV software that I use in conjunction with the DVAP, version 1.5.5. I downloaded it then but it wasn't until this morning when I was doing some household chores and garden work that I had a chance to try it out. I hooked the DVAP up to REF001C and had a nice QSO with Brian, ZL1HN. During the QSO with Brian he mentioned getting a Raspberry Pi working with a DVAP which sounded an interesting project. Oh dear, I can see me getting a Pi at this rate.... I had another interesting chat with Clive 2W0CLJ who was doing good stuff with one of the DVRPTR boards and an FT7800.
Get the new version of WinDV at the dutch*star site
Friday, November 16, 2012
Running 10W at each end, both into collinears, it was an easy QSO over a path of around 140km. Not massive DX of course, but very satisfying. Following a successful exchange of signals we then turned down our power as low as it would go - around 1W in my case and were still easy able to exchange signals. Mark calculated that given the conditions at the time, around 150mW would have probably done the trick. Sadly I can't run that little power - at least not readily!
Wednesday, November 14, 2012
When I popped some dry cells in the FT790 the other day, I noticed that the springs in the battery compartment were not sufficient to keep the batteries pushed together. I emailed Yaesu but they had no spares of the battery box but did point me in the direction of some companies that could help.
However reading around last night, I saw an idea which inspired me to a possible solution. Someone on a forum had put some washers in between their batteries to keep the tension in the battery box.
I didn't have any suitable washers but this morning I headed to Homebase and had a look around. I came home armed with a couple of packs of 'Repair washers' which looked suitable. An initial effort of inserting the washers to 'pack' the batteries was unsuccessful. I then sat down with the meter to understand what was happening.
It took a few minutes but it turned out to be a corroded connection that I hadn't spotted. I cleaned that up and put the batteries and washers back. Success!
And of course, almost to the second, my iPad pinged with an email from HiFiSSB who had a battery box that they could let me have!
So, with the exception of a bit of a sloppy mode switch, the FT790 is now exactly how I want it!
Tuesday, November 13, 2012
Today doesn't seem to be a massive DX day on 28MHz. But actually it's just as interesting, although the plots are much closer.
Some of the distances of stations that I've heard this morning - between 300 and 600km would normally be in the 28MHz skip zone. In the days when I used to see how many countries I could work each year, countries like PA, ON and GW were hard going on 28MHz unless you found some backscatter.
Look at the map from this morning! The PAs, the French station just the other side of the channel, GW3LEW and yes, Julian, G4ILO! Very unusual conditions and I'm absolutely delighted to have copied Julian on his magic loft dipole.
Perhaps some Es around - certainly I was getting some big signal reports from the Ukraine this morning. It's unlikely that any of the contacts I've highlighted here are 'classic' Es but maybe some sort of weak scatter from the layer.
I've seen hints of this type of propagation in the mornings a few times now, but this is the best example I've experienced since I began my 28MHz WSPR activity this year.
Monday, November 12, 2012
The FT790R that I picked up from eBay arrived today. It's always a bit of a lottery buying old kit like that. But happily, it's essentially in good condition. It receives and transmits fine.
I've found two problems so far. The first is that the battery tray looks like it may have suffered some misfortune and I guess that the springs have failed as when I took the NiCad batteries out and put 8 C cells in, the batteries slide about without making contact. I've emailed Yaesu to see if they have a battery tray. Failing that, it may be a case of 'packing' the batteries with some metal spacers.
The second issue is that the mode switch was a bit loose. I've cleaned it up and tightened it up a bit now and it seems more reliable on USB/LSB now. When it first arrived, it was a bit intermittent on those modes.
The rig sounds great! I fired it up on SSB and listened on the FT847 and it sounds good. Same on FM - so the really important bits are sound. It has a nice feel to it. Solid, just like I remember.
Of course, for the repeaters, it has no CTCSS which has precluded too much testing on the local boxes! It does have a 1750hz tone though.
Once I sort out the battery tray, I'm looking forward to taking it out portable.
Sunday, November 11, 2012
I was busy writing the PW column this morning and doing some other work on the computer, so I didn't set the 28MHz WSPR running until around 1330z. I was running 1W as per normal.
There are some nice west coast spots today - though they didn't hear me - but good to have copied some W6/7s.
Saturday, November 10, 2012
Thanks very much for coming along to the 'My World of VHF' talk on Thursday evening. You were a more HF-orientated audience than I sometimes get, which actually made it a lot of fun! Thanks for your kind comments about the presentation and I hope there was at least something of interest to try on VHF/UHF.
I promised a couple of links:
Here is the link to the video of
As far as the SDR links - there's quite a few. Have a look at Richard, G4WFR's notes on getting one the RTL2832U and E4000 sticks going - there's lots of detail at his website
It sounds as if some of the initial batch of sticks is trying up, but the new tuner, the R820T sounds even more adaptable, with some HF coverage being possible too. Have a look at the Nooelec site Although they are based in the USA, they will ship to the UK and don't sound expensive. I believe they also send a batch file to help you set it all up.
Monday, November 05, 2012
Over the years I've been lucky enough to play with lots of rigs, many of which I have sold when the time came to move onto something 'better'. Most of the time that's good - and after all, you can't keep everything (so I believe). However, some of the time, you regret it.
The Yaesu FT790 that I had was always a favourite. I used it on FM for the local repeaters and simplex contacts on SU8 (433.200) with friends like Mark G4MEM, Graham G8XRS and Mark G6CMG. Connected up to a 21ele beam, I was thrilled when the 1W of SSB reached West Wales and on one notable occasion, the Isle of Man. I can't remember when I sold the FT790 or who had it! I think it went when I got my Trio TS780 144/432MHz base station.
But I always remember the FT790 fondly - for being a solid portable rig that was fun to have around.
And so it was that yesterday, I spotted one on eBay. Mislabelled and not getting much attention. There was only one thing to do wasn't there, really. One surprisingly low bid later and there is one on the way.
They say you should never look back - but it will be fun to see what I can do with a watt of forlorn hope! Let's hope the rig is in reasonable condition. I shall report back when it arrives.
Sunday, November 04, 2012
First thing this morning I played some 28MHz JT65A and was pleased to work ZS2I. After that I got on with a few other things so left the WSPR gear running.
There was an interruption to WSPR service this afternoon whilst Dave G4FRE and I did some interesting JT65B tests on 70MHz. Dave had got WSJT (as well as WSPR) running on his Raspberry Pi computer.
Nice to get a couple of reports, back on 28MHz WSPR from the east coast of the US, just before the band faded.