7 Jun 2012

FT817 replacement - 2 years away

The following (extract from a) post from Bryan KE6ZGP appeared on the FT817 Yahoo group in the last few days.
"Tom interviewed the Yaesu rep about their new FT-DX3000 and the FT-1D, when all was said and done he started taking questions, I went ahead and asked about a possible replacement for the FT-817. The rep then stated - due to some parts (like the LCD screen) either being no longer available or extremely hard to find, they will likely replace the FT-817 in a couple years. He wasn't sure when exactly, R&D hasn't started on anything, but the earliest we can expect to hear any solid talk is two years from now."
Now I assume this data is good and the rep from Yaesu is properly informed. If so, then any replacement to the FT817 is at least 2 years away. This gives Elecraft a clear field for a couple of years with their new KX3. The only other QRP radio on the horizon is the Ten Tec Argonaut VI which is due out towards the end of the autumn this year.



6 Jun 2012

Hendricks QRP Kits

The BitX SSB transceiver on the QRP Kits website
http://www.qrpkits.com/ have some really nice kits on their pages these days. If you are new to QRP then they offer a very nice way to join in the fun. One example is the very neat version of the famous BitX 20m SSB transceiver designed in India originally. They also have plenty of CW kits and accessory kits like ATUs, attenuators and simple pieces of test gear. I've never actually built any of these kits but they look well designed with clear building instructions.

The future of HF amateur radio

There is no doubt that HF amateur radio is changing. Fewer people ragchew these days (do you agree?) and there is considerably less activity outside of contests, mirroring a change already seen on the VHF bands. More people are using digital modes instead of phone and there is much more use of software tools to detect DX, decode and encode CW, PSK31, etc. The hobby is changing: some of the new ways of operating are very good, but along the way we are in danger of losing something of the appeal of the hobby perhaps?

Now, there is also another factor: it is very likely we will have seen the end of active sunspot cycles once the present low peak of cycle 24 declines. Many of us who experienced the peaks of 1957 through to 1980 are very unlikely to experience similar ones in our remaining lifetimes. Propagation on HF may never be as good as the second half of the 20th century for another 100 years. There are also theories that HF propagation is not as good as it was, even assuming similar solar activity, as if the ionosphere is actually changing its behaviour.

Then there is the challenge of spectrum pollution. This is already a menace for many of the lower HF bands but even bands like 10m and 6m are affected.

So, the challenge now is to look to the future, positively, and see how the future of HF will be redefined. I have no idea what the next 10 years will bring, but I suspect the use of our HF bands will be quite different by the 2020s.

Photo editing - try Gimp

Gimp screenshot example from the Gimp website
For several years I had been using an old version of Photoshop Elements to carry out basic editing of photos to add to this blog and my websites. When I "restored" my PC recently I made a decision NOT to reinstall it or MS Office, instead planning to use freely available alternatives.  For the photo editing I opted for a freeware package called Gimp, which many will know ... but I didn't. As far as I can tell so far it does everything I could before and quite a lot more all for nothing. See http://www.gimp.org/ for more information and various downloads.

5 Jun 2012

My thanks

Thank you so much for everyone's support yesterday when I was feeling quite down: nine replies on the blog and as many again directly by email is true support in the best spirit of amateur radio. The message is "don't let the idiot's beat you down", which will be my motto.

Ours is a GREAT hobby and I guess we have to accept there will be a few bad apples in the orchard.  Anyway, firmly back in gear here with a list of projects far too long to do any time soon. Several interruptions likely in the next few weeks but I'll be getting my teeth into some good ones very soon.

Very simple Spectrum Analysers

On the GQRP Yahoo group recently there was some further mention of very simple spectrum analysers with some links to very impressive, yet simple circuits. I was recently offered an old HP analyser but it was very large, very old and quite expensive: I did not want something that might soon go wrong and take up a lot of space, but I still need something simple to allow basic spectrum measurements. Nothing too accurate is needed, just an indication of harmonic levels and the like.

In essence, a spectrum analyser boils down to a receiver with a swept oscillator with its output connected to a display such as an oscilloscope. In its most simple form it could be just a crystal set in which the tuned circuit is replaced by a varicap tuned circuit with the rectified output going to a display.  The voltage applied to the varicap is a sawtooth waveform (for example derived from a 555 timer IC) which also drives the x axis of the scope: this makes the tuned circuit sweep a band of frequencies over a second or so with the receiver's rectified output connecting to the Y axis of a scope. The resulting scope trace is then a picture of the band being scanned.

Shortwave scan on the VK2ZAY mint tin spectrum analyser
An example of a simple spectrum analyser in a small mint tin is at Alan VK2ZAY's site http://www.vk2zay.net/article/256. Although Alan was doing this design for fun, the resulting circuit based around a VHF super-regen receiver in the IF is quite remarkable.  It is a seriously useful piece of test equipment. This is the YouTube video of Alan describing the circuit:


An earlier simple design is available at http://www.qsl.net/n9zia/spec/Homebrew_Spectrum_Analyzer.pdf which uses the sweep voltage to control the local oscillator of an existing receiver.

More complex designs have wide dynamic range, more linear displays and narrow IF filters to improve the resolution. "You get what you pay for", but simplicity is still capable of providing something very useful.

4 Jun 2012

A very sad day

Do you get days when everything goes wrong? Today was one of these for me.

A few weeks ago I suggested, after a long 5 day outage, that the RSGB LF-reflector migrated to a Yahoo Group. In my experience Yahoo groups are great: messages, files and photo storage and a great way to share and archive information with others of like mind. In over 15 years I have rarely had problems with any of the groups to which I belong.

After a few weeks, the group leader G3WKL decided to make the move to a Yahoo group having "taken the temperature" of the original group members. Then the "fun" began: a few people objected and started a flame war and I was centre stage of the hate, in particular from one particularly nasty and forthright individual. I could name him but will not stoop so low.

My intentions were good: I wanted to let people know that all they did with the original Blacksheep mailing list could still be done, but so much more too. Things like archiving of messages, 100GB of both file and photo storage etc.

The resulting avalanche of nasty and ill-informed posts, many of which were directed at me, has frankly sickened me. My faith in the hobby has been shattered by the bad feeling and unkindness of a few ill-informed individuals.

Amateur radio is usually a friendly and helpful community but in the last few days I have seen an altogether different and darker side of it, one which shames the community.

To be honest, I have never been nearer to throwing in the towel and taking up another hobby. This is indeed a very sad day.




3 Jun 2012

472kHz designs

GW3UEP's website has some useful new designs for 25 and 100W transmitters for the new 472-479kHz band which is expected to become available Jan 1st 2013. These designs use very standard and easily available parts and are very simple to duplicate. They would be an ideal starting point for anyone wanting to get going on the new band in 7 months time.The designs are based on earlier ones for 500kHz.
Part of GW3UEP's simple TX for 472kHz

29 May 2012

My May Objectives - achieved

This month I had two objectives:

   (a) make my 10m halo into a dual band 10m/6m version.
   (b) complete my 481THz optical speech transceiver.

Although a few days late, both objectives have been achieved with decent contacts on 10/6m and a 10.5km 2-way QSO on 481THz AM.

Several things will interrupt any objectives in the next month or so, but my next objectives are:

   (a) Improve the sensitivity of my optical transceiver RX.
   (b) Build a new transverter for the 472-479kHz band due to be released Jan 1st 2013 in the UK (we expect).

The first will allow me to use the dual-optics 481THz transceiver over longer paths. I hope to make some contacts over 20km in the next few months.

The second one (472kHz transverter) only needs to be completed before Christmas, but I'd like to get this moving soon. If possible I'd like to run the PA at around 20W - my earlier 500kHz transverter was just 5W - and to improve the RX sensitivity and selectivity. This new band will be a most interesting allocation and I expect quite a few stations to give it a try.

28 May 2012

Joining the "over 10km" optical club

This morning I got a note from Stuart G8CYW which surprised me:
"Roger,

It has occurred to me that you have joined a "select" group, who have made an optical contact over 10km here in the UK with modulated LEDs. I had a quick count up of the people I know about and I do not think there are 10 yet. (probably more I do not know about though) .....so no small achievement."
So apparently very few of the people experimenting with 481THz red LED optical communications have broken the 10km barrier for 2-way QSOs. This surprised me. At the same time I am even more encouraged to continue this fascinating area of amateur radio as there is so much more I can do. The beauty of this is that test equipment needs are basic, skills needs well within my capabilities, and the results when success comes are extremely satisfying.