30 Jun 2012

500kHz ERP

Using the coax feed to my 10m/6m halo as a vertical I've worked out the ERP currently on 500kHz OPERA. The RF power from the transverter is around 5W from an IRF510.

The 10m and 6m halo lengths correspond to a horizontal capacitance of around 35pF. Some of the feed from the shack to the bottom of the vertical section is horizontal through the loft and this has not been included (I think it may add loss though). The vertical section outside is 6m long, equivalent to a vertical capacitance of 36pF. Using standard formula this means my effective height is around 4.48m.

Radiation resistance then works out as 0.088 ohms.

Measured antenna current is 0.48A (using a current transformer and detector)

ERP = 0.48 x0.48 x 0.088 = 20mW (or lower if the losses are higher).


First 500kHz OPERA reports

Having managed to match my 6m long coax feed line (as a Marconi vertical) up to the 10/6m halo antenna on 500kHz by adding some inductance wound on a ferrite rod in the shack, I've just received my first OPERA beacon reports on the band from ON6EO at a distance of 220km and G0KTN at 210km. Reports were -30dB and -29dB S/N which is marginal.

OPERA mode on 500kHz

500kHz OPERA RX this afternoon (on left are my spots)
Having now uploaded the latest version of OPERA weak signal mode software I have been looking on 500kHz using my, as yet, untuned short vertical antenna. CPU load without waterfall is running at around 40-50% on my Dell Inspiron 630m and the PC is running in a stable way. So far copied PA0A, PA3ABK and M0FMT. If I can get the antenna resonated crudely I may try OPERA TX on 500kHz later this weekend.

10m ROS16 QSO

ROS16 10m QSO this morning: my first for some time
The last time I tried ROS and OPERA on my PC it reacted badly and crashed so I'd been reluctant to try the mode again in a hurry. However, today I loaded v7.0.9 which runs OK when the waterfall is deselected on my 6 year old Dell Inspiron 630m with 1GB RAM and a 1.73GHz Intel M processor.  As an initial test I ran 5W on 28.185MHz and managed to answer a CQ call from DK6SQ who reported me at -13dB S/N.

Denmark active on 472-479kHz band

In the last few days OZ amateurs have been granted access to the new band. Along with Monaco and Germany there are now 3 countries (to my knowledge) allowed to use this new LF band. It has been confirmed that The Netherlands will get access on Jan 1st 2013.

VLF amateur activity

There is a new VLF grabber at Darmstadt Germany that may be useful for 8.97kHz tests. It is at http://skmail.ikp.physik.tu-darmstadt.de/gvw/grabber.html. The grabber is primarliy there for VLF research into earthquake precursors.

DK7FC reports that the permit he has to use a 300m kite antenna expires soon, so he may try a further soon before that date.  Chris G3XIZ is still hoping to resume VLF tests once a new loading coil is wound. He is looking for a suitable (very long!) source of PVC covered wire.

24 Jun 2012

DYC-8x7 speech processor kit

Funk Amateur, the German magazine's online shop is selling (after a gap I believe) a neat in-line speech processor kit for the FT817 and similar Yaesu rigs called the DYC-8x7. On http://www.eham.net/reviews/detail/2546 it gets good reviews.

I'd like to order one but cannot understand how to go about it not being a German speaker. Google translate doesn't translate all the words, so I am stuck. If anyone can help I'd appreciate it, or tell me if it is available in the UK.

See http://www.box73.de/product_info.php?products_id=945 .

With a step by step translation using Google Translate I managed to register on the Funk Amateur site and place an order.

23 Jun 2012

On-line CW training at LCWO

Typical LWCO log-on page
If you are like me then your CW skills are not the world's best. Even though I am a G3 and licensed since 1967 my CW really is pretty pathetic. On an HF QSO when exchanging callsigns, reports, and serial numbers I'm usually OK, but when ragchewing with seriously good CW operators I'm embarrassed by the amount I miss. Some operators are very good and slow down, but not everyone.

However, for we CW duffers, help is at hand: http://lcwo.net/ is a rather superb on-line CW training facility that I believe could really help improve CW skills with a few minutes' effort each night. I have been to the site before and managed to improve my speed a bit but need to return there and try some more. All sorts of CW training is available at all sorts of speeds. If you want to use CW, which is an excellent mode especially for QRP, then this is worth a visit.

Ultimate QRSS/WSPR kit from Hans Summers

Hans Summers G0UPL has just announced a wonderful new kit. Amongst other modes it also supports stand-alone WSPR beaconing when used with a GPS timing reference, without a PC. This was his announcement on the GQRP Yahoo group earlier today:


This is to announce a new standalone QRSS/WSPR kit by Steve G0XAR and Hans G0UPL. The kit supports WSPR, QRSS, DFCW, FSK/CW, CW, Hell (full speed and half-speed), Slow Hell, and customisable FSK patterns. The WSPR encoding is on-chip. It supports the connection of a GPS module for frequency locking, accurate time, and location (for WSPR). Power output is measured at 185mW on the 30m version. We are selling versions for 30/40/80m and perhaps later 20m and 160m. It does not require a PC, it has an LCD and two buttons to control it.

The price is GBP 15.39 (EUR 19 or US $24 approximately) plus shipping.

You can see all the details here: http://www.hanssummers.com/qrsskitmm and order online at http://www.hanssummers.com/shop . We expect to be shipping by 27-29 June.

The kit supports the following modes:

+ QRSS mode (plain on/off keyed slow CW)
+ FSK/CW mode (frequency shift keyed slow CW)
+ DFCW mode (dual frequency CW, dit's and dah's on different frequencies)
+ WSPR mode (Weak Signal Propagation Reporter)
+ Slow-Hellschreiber (frequency shifted slow Hellschreiber)
+ Hellshreiber (full-speed standard Hellschreiber, and half-speed Hellshreiber)
+ CW (plain CW)
+ Customisable FSK patterns

Other features:

+ 24-character LCD + two-button user interface
+ User-programmable (callsign, message, speed, FSK, mode, etc.), settings stored in EEPROM
+ GPS interface, for locking the frequency in slow-speed modes
+ On-chip generation of WSPR encoded message (no PC required)
+ WSPR maidenhead locator can be generated from GPS-derived latitude/longitude
+ Selectable “frame” size, for stacked QRSS reception
+ Plain CW callsign identifier at selectable interval
+ Produces 150mW RF output, or AF output for driving an SSB transceiver
+ Higher output power by additional PA transistor and/or higher PA supply voltage

73 Hans G0UPL and Steve G0XAR

22 Jun 2012

6m WSPR and Doppler shift

Note Doppler on signals at 1742z
This evening some very strong signals have been coming in from North Africa on 6m by Es. CN8LI has been coming through on WSPR for a few hours with some people receiving him at +12dB S/N. What is interesting is the amount of Doppler on his signal at times. Also, several other signals coming through with up to 40Hz of shift over the 2 minute WSPR slot making decoding impossible. Some of this will be aircraft reflection, but some may be due to fast moving layers of ionisation in the E layer. At least with the WSPR screen such effects can be seen.

21 Jun 2012

Digital QST

Although not (yet) an ARRL member I am tempted join to get the new digital version of QST magazine. A sample of this new digital version is available from the ARRL website.

QST has been a very useful source of data going back to around 1916. I well remember thumbing through the copy in Plymouth library when attending  RAE lessons at Plymouth Tech way back in 1966.

Rigol test equipment

The Rigol Spectrum analyser at £895 plus VAT
In recent weeks I've seen several adverts on the ARRL website (I had a 30 day free trial) for test equipment made by a company called Rigol. In the UK they sell a well specified spectrum analyser for £895 plus VAT, which looks an incredible bargain for such an instrument. They also do a range of other pieces of test equipment such as scopes, waveform generators and power supplies. Although £895 is a bit out of my price range, I wonder if anyone reading this has any experience of this supplier's kit? If so, what is it like in terms of quality and reliability? If one was running a small RF design business one could set up a small, well equipped lab for a few thousand pounds with all new gear from this supplier. How do they do it?

SAQ transmission on 17.2kHz on July 1st

From the SAQ website:
Transmissions on Alexanderson Day
We plan for transmissions on Alexanderson Day Sunday 1st July. If we are allowed to use the antenna we start the machine transmitter at 8.30 UTC and a message is sent at 9.00 UTC. Second start of the transmitter at 11.30 UTC and a message is sent at 12.00 UTC. The frequency is 17.2 kHz CW.
 QSL-reports are kindly received:
 QSL reports can be given via:
- E-mail to: info@alexander.n.se
- or fax to: +46-340-674195
- or via SM bureau
- or direct by mail to: Alexander - Grimeton Veteranradios Vaenner, Radiostationen, Grimeton 72, S-432 98 Grimeton, SWEDEN
Note: SAQ is a member of the Swedish Amateur Association (SSA) and "QSL via bureau" is OK.

20 Jun 2012

ISS Flash Project

Guido PE1NNZ has sent me this interesting link about a recent experiment with the International Space Station using optical frequencies. See http://www.cqdx.ru/ham/ham_radio/iss-flash-project/ .

Back home again and the 472kHz transverter

Icefield Parkway, Alberta
After nearly a couple of astounding weeks in British Columbia and Alberta, Canada my wife and I are now back home. The scenery and wildlife were just amazing, especially the bears like the one below seen just a few metres away from us.  Although I only managed about an hour of shallow sleep on the plane back from Calgary last night I decided it was better to fight the jet-lag and get on with some chores rather than crash out and wake at 2am tomorrow.

One of the 8 black bears we encountered - this one VERY closely
Once the lawns have been trimmed and the hedge cut, I've decided to crack on with the design of a new transverter for 472-479kHz as the next project. Already there is activity from Germany and there are a number of NDB beacons to allow the receiver part to be checked. Jan 1st 2013 (the likely date of release in the UK) will arrive far too soon.

I am trying to decide on the choice of IF as I want to use an unmodified FT817. 28MHz will allow 472-479kHz to appear "in-band", but at 28MHz the start-up drift as the LO settles will still be some tens of Hertz. This hasn't proved problematic with WSPR, so guess this is my choice. At least the dial will directly read the "right" frequency e.g. 28.477kHz will correspond to 477kHz.

In view of the picture above, I am not sure what power the transverter will use bear-foot (sorry, weak joke).

18 Jun 2012

Knife Edge Refraction at VHF

Currently I am sitting in a log cabin (with a log fire) surrounded by snow capped mountain peaks wondering how 2m propagation would be from here. Sharp mountains often allow good propagation into screened valleys by refraction over the peaks sometimes with strong signals. Unfortunately I have no ham gear (apart from Echolink) to try it. Instead I am just enjoying the views. 10cm snow forecast tomorrow here, HI.

15 Jun 2012

Canadian Rockies

For the last few days I've been in the Canadian Rockies. The scenery is truly the very best I've seen (inland) anywhere on Earth. The 300km drive today from Banff to Jasper had snow capped mountains and azure blue lakes and rivers all the way. Only seen 1 HF antenna so far and that was from the Rocky Mountaineer train from Vancouver to Banff.

14 Jun 2012

Germany gets 472-479kHz

Surprisingly, news on the wires today that German amateurs have been granted early access to the new MF allocation. I wonder if OFCOM will release it early too?

9 Jun 2012

"LF Today" RSGB book on special offer

This excellent introduction to LF/MF amateur radio is available from the RSGB bookshop at just £7.99 and I can recommend it. It helped me a lot when I started and still gets referred to regularly.

CW on 136kHz

Mike G3XDV reported normal speed CW activity on 136kHz with QSOs with G3KEV and DK7FC's normal speed CW beacon. Although harder work with QRP, 136kHz is an ideal band for CW contacts. A lot of people are saddened that digital weak signal modes have rather put CW on the shelf.

VE7 Repeaters

Now 23 hours without sleep having arrived in Vancouver after a long flight from the UK. Currently in the hotel room trying to work some BC locals via Echolink connected repeaters. What I really need is SLEEP though!

7 Jun 2012

First country gets 472kHz allocation

Monaco is reported (by 3A2LF) to have allocated the 472-479kHz band to radio amateurs from May 18th as a secondary allocation with a maximum power of 1W EIRP. Others are likely to follow in the following 12 months, we hope.

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