Recording the last hours on 500kHz?

Back in the late 1940s G5UM and others recorded the last few hours of operation on the old 56MHz (5m) band on an old 78rpm disc. Sadly this disc and copies of it appear to be lost forever.

I am very much hoping that a few stations in the UK and Eire will record the last hours on the 500kHz band which is being withdrawn on Dec 31st for ever, to be replaced by 472-479kHz.  Such recordings are a valuable piece of amateur radio history which will be treasured in years to come.  It would be a pleasure to pull such recordings together for posterity, but I shall be unable to listen myself because I'll not have access to the shack at that time.

If YOU can listen between 2300-2400GMT on Dec 31st and make a few recordings of the CW activity, please send me copies and I will produce a CD or MP3 file of them all.

472kHz (quiet) RX preamp

When the grandchildren and family have all gone home next week, my first project will be to improve the RX antenna system for 472-479kHz receive. As mentioned before, I am suffering badly from SMPSU noise pick-up inside the house, so plan to install a magnetic loop and preamp somewhere towards the bottom of the garden in an attempt to minimise pick-up from my own home and from neighbours. With a loop there is also the ability to sharply tune the antenna and to null interference from the worse directions. The circuit I propose to use is a version of my 9kHz tuned preamp, which has been used to copy G, DL and OK amateur stations on 8.97kHz last year. The loop will simply be retuned to the new MF band.  Not sure whether series or parallel connection to the loop will be better as both should work depending on the FET stage configuration (common base or common source).

Proposed tuned preamp, but with values changed for 472-479kHz

Last days on 500kHz

With just a few days left before the 500kHz permits are withdrawn for ever I've been doing a last gasp bit of WSPR beaconing. It is not easy to get on as we have grandchildren sleeping in the shack, but I managed to get on for a couple of hours early this evening.

Recent 500kHz WSPR reports (10mW ERP)

Reports were received from G, PA, DL and F stations. My local noise from the central heating controller prevented me copying much on the band. Before many days I shall have to erect a separate RX antenna for 472kHz.

A Happy Christmas

A very Happy Christmas to everyone who reads this blog. Today has been spent with some of the family enjoying good food, drinks and games. More of the family comes here tomorrow and yet more later in the week. We are now sitting down watching the typical Christmas TV fare in front of the roaring fire.

Quietly in the background, my WSPR beacon has been running with best DX 2-way reports with Brazil and best reception the Nambian WSPR beacon. 

One of my presents was a book of maps of the South Devon Coastal Footpath and another the second edition of QRP Basics. In a later blog I'll review the new version.

But now it is back to mince pies and a cup of tea!

5MHz NoV

A band that I have never tried before, apart from brief periods listening, is 5MHz. So, this afternoon I applied for an NoV, which was received by return email. Not sure what kit I shall use to get on the band (or when) as nothing I have covers 5MHz TX. Perhaps another transverter design is called for.

V5/DK1CE Namibia

Whilst in the shack this morning I turned on the FT817 to hear an unidentified (for nearly 10 minutes) CW station working people and giving 599 reports in the main. I called a few times and eventually got a 599 report, still not sure who the station was. Then, finally, he gave his callsign V5/DK1CE in Namibia. All the more pleased now I know that "3 blobs" on the FT817 is just 2.5W out to the halo antenna. And another DXCC entity this year.

FT817 "power blobs" question

Having owned my FT817 (original version, not ND) for nearly 12 years I am almost too embarrassed to ask this question now.

http://upload.wikimedia.org/wikipedia/commons/5/55/Yaesu_FT-817_(1).jpg

When checking an old Bird RF power meter today I measured the power of my FT817 on and off a PSU at all power level settings. All these years I had assumed that "3 blobs" on the screen (when on a PSU) meant that I was putting out 5W. What I measured was closer to 2.5W. This did not change when the PSU was disconnected: still 2.5W. Then I pressed the button to "no blobs" and the power went up several dB, to I assume a nominal 5W. When on batteries it was "blinking 3 blobs". having re-read the FT817 (original) manual I was none the wiser: it does not mention a "no blobs" setting.

I think all these years when I had assumed my DX was being worked with 5W I was actually using just 2.5W. It looks like I should have gone to the "no blobs" setting with a PSU to get the full 5W.

So, can someone please clarify what power the FT817 should produce at all the different "blob" settings on batteries and on a 13.8V PSU?

UPDATE: I have the answer from Pete M3KXZ

Hi Roger.

On PSU:
- no blobs, output is 5W
- 3 blobs, 2.5W
- 2 blobs, 1W
- 1 blob, 0.5W

On internal batteries, the radio will default to "L///" and output 2.5W. If you
select high power, you will get 5W with "///" blinking. The other blobs are same
as for PSU.

I always run off external battery pack and the max power setting shows no blobs,
until the voltage starts to drop a bit when it automatically goes to "///"
blinking.

Well I'll be damned!  So for 12 years nearly I've been running 3dB less than I thought.

Birthday card co-incidences

Today I celebrate my 64th birthday, although it is only 5 minutes since I was 18, so be warned: time passes very quickly and speeds up as you get older!

One strange thing today was some of the birthday cards. When in Oxford a few weeks ago my XYL bought me a card for my birthday, from the OXFAM shop, with the title, "Instructions are for wimps" showing a man operating 1920s radio gear - very apt for a radio amateur. Well, blow me down, I got the same card from 3 people! If you want one to send to your friends, they have plain insides so can be used for an occasion, they come from  www.cathtatecards.com.

Now, to my mind, the operator looks a bit like Julian G4ILO. Perhaps it was his grandfather!

Surplectronics - useful source

Steve G1KQH has just pointed me to Surplectronics who supply all manner of electronics parts at VERY reasonable prices. Several of the crystals they stock are just 25p each and 50MHz clock oscillators (packaged, complete) just 99p.

Tenbox 10m AM crystal

Although I've not finished off the Tenbox 10m AM transceiver yet- too cold in the workshop and too many Christmas preparations! -  I have been looking around for some low cost crystals that would be suitable for the transmitter. Ideally, I was looking for a low cost source of HC49 crystals on 29.05MHz but have not found any. Then I spotted that the German QRP-shop has 29.000MHz crystals at a reasonable 5.5 euros. I may order a couple so I can complete a pair of QRP 10m AM transceivers. I have used QRP-shop before and they give good service.

The Tenbox may not get finished until the New Year now as we have family here for the next 10 days more or less. When there are 4 grandchildren around, amateur radio takes a back seat, especially as my operating shack is used as a bedroom for the 3 and 5 year olds.