My wife's choral concert next weekend in Cambridge

Concert Poster

My wife sings with the Cambridgeshire Choral Society (guess who does their website!) and next weekend (Sat April 27th 8pm) her choir performs in St John's College Chapel in Cambridge. Both the Vivaldi Gloria and the Faure Requiem are great pieces. If you live in the area, may I suggest you come along? Tickets are available on the door as well as in advance (see poster).  I shall be on the door acting as a steward.

Loopy on 10m - first results

This afternoon I managed to catch 10m open and got some excellent spots from 4X1RF with reports as good as -5dB S/N using 2.5W to the small magnetic loop taped to the chair in the bedroom shack. Without doing too scientific a test, the impression I get is the loop is every bit as good as the external longwire end-fed antenna in the garden.

I may move the magnetic loop up into the loft in the coming days to see how it performs there, pre-tuned to the WSPR frequency. Based on results in the bedroom, I would expect it to work well.

VHF/UHF take-off at new QTH

This evening I went up to our new, well being newly renovated, bungalow on top of our local "hill" immediately next to the Burwell windmill.

Currently the roof is being re-tiled and there was scaffolding everywhere, so I took the opportunity to climb up a ladder to the roof level to judge the VHF/UHF take-off.

Well, the good news is that even at just above the gutter level there is an excellent virtually unbroken (clear of houses) take-off from the north west all the way around to the south. With an antenna a few metres above the roof apex height, it should have a pretty good take-off in most directions.  It just begs me to get some better gear for the 2m, 70cm and possibly 23cm and 3cm bands. We'll see.

I was also checking out optical communications possibilities. At lower heights, the horizon view is obstructed, but I should be able to arrange my optical beacon for cloud-bounce and clear air forward scatter, non line-of-sight, tests with the beacon firing up at around 20 degrees up from horizontal in many directions out towards Cambridge and beyond.

Loopy results on 15m

WSPR results today with 2.5W to 80cm loop in the bedroom on 15m

Well never mind the theory - my loop WORKS well. On 15m, with the loop taped to the chair in the bedroom shack, I have already been spotted on WSPR in Japan when using just 2.5W from the FT817 at  9474km.  So, my first attempt with an indoor HF magnetic loop in the bedroom has left me very impressed.

Loop antenna in the bedroom (notice the grandchildren's toys!)

Current set-up is about 80cm diameter 6mm copper pipe inductor tuned with a small 365pF air spaced variable cap. Matched with a coupling loop 1/5 the size of the main loop made with RG58 coax. With the 365pF variable it tunes from 40m-10m, but the variable cap needs padding out as tuning is extremely sharp.

I should have tried magnetic HF loops long ago.

UPDATE 1600: Just QSYed to 14MHz with the loop in the bedroom and power reduced to 500mW and still getting plenty of WSPR reports out to 2600km or so so far.

Going loopy on 10m

Prototype 10m TX loop using 6mm copper pipe

Today I've made a small TX loop for 28MHz CW/WSPR using an odd piece of 6mm copper pipe I had around the place. As I don't want to move the frequency much and the maximum power out will be 5W (usually far less) I have used a small length of twin core mains cable, trimmed to resonance, as the capacitor to resonate the antenna. The loop is matched to 50 ohms with a small coupling loop made out of RG58 coax. Bandwidth is quite sharp suggesting the loop is working as expected.  At the time of writing (early evening)  I've only copied one signal EK6RSC at 3586km earlier in the day and am still awaiting some reports on TX. The loop is mounted on a PVC pipe taped to the back of a chair in the shack.

If successful, the idea will be to put this up in the loft at the new bungalow and use it with WISPY and a small dedicated netbook PC to run 10m WSPR.

Simple, fool proof 1296MHz transverter?

Thinking about my new QTH on top of our East Anglia "hill" (aka 20m bump) I am wondering if I should consider 1296MHz operation for the first time, if only to monitor/try the band in UKAC contests with relatively local stations. Although I have listened (briefly) on 23cm years ago with a borrowed RX converter, I've never transmitted on the band with any mode.

What I am looking for is a SIMPLE transverter for the band, either a no-tune kit or a simple ready built unit. I have no test gear for this band, which is why I've not really considered the band before. The driver would be the FT817, so any suitable band could be used for the IF.

The Down East Microwave 1296MHz transverter may be a possibility. See http://croatia-microwave.blogspot.co.uk/2010/12/w1ghz-rover-transverter-for-1296-mhz.html for a report of one built.

Incidentally I remember the 23cm antenna I used back in the 1970s with the borrowed converter: it was a 4 element yagi made with 2.5mm silver plated wire. The whole antenna sat in the palm of the hand, but worked well, even indoors mounted on a piece of bamboo cane as the mast! If I remember correctly, the design was in an early edition of VHF Communications, a magazine I subscribed to back in the 1970s.

My first QSL card for a JT9 QSO

eQSL card for JT9-1 QSO

Today I see I've received an eQSL card from Manuel EA7GDC  for one of my first JT9-1 contacts on 20m last week. I much prefer eQSL cards as these don't need to be physically stored, but can be printed out if required. In the coming days I need to check my DXCC score with eQSL cards received. Although not a DX chaser really it is fun. Most of my QSOs and eQSL cards have been for 10m QSOs and next 6m QSOs.

Sporadic-E season

We are now approaching the summer sporadic-E season in the northern hemisphere with excellent 10m, 6m and 4m (plus 2m on a few occasions) propagation across Europe, the Middle East and North Africa and sometimes far beyond.

On 6m and 10m it is possible to work out to around 2000 miles quite easily with very simple omni-directional antennas and a few watts by single or multi-hop Es.

With some luck much further is possible: a few summers back I recall the thrill of working the USA on 6m with 2.5W out from the FT817 (via a coax cable with around 3dB loss) to a V2000 vertical. ERP was just over 1W. Of course CW was used for this QSO.

Keep an eye out on these bands in the next few months as you may be surprised what can be copied. Better equipped QRO stations will be working South America, deep into Africa and Japan on 6m. Even when the sunspots don't play ball, we'll still have summertime Es. Half the fun is the surprise openings to distant places that appear and sometimes disappear within a few minutes. At other times the lower VHF bands can be wide open with S9 DX signals for hours and hours.

RSGB UK VHF/UHF Activity Contests - Tuesday nights

This year I keep forgetting to have a go in the regular UKAC contests every Tuesday evening. Activity in these is usually very good and they are great fun. Last year I went out in the field to a local high spot on both 70cm and 2m and achieved some good results with just 2.5W - remember I only found out the FT817 "3 blobs" setting was not 5W in December!  Before moving in to my new East Anglian "hilltop" QTH - well it is 20m ASL :-) - I think I'll have to do some of these contests /P from the new back garden to see how the new location will be on VHF and UHF. 

Trying to fix an HP8640B sig gen ....and failing

The disconnected shaft is just to the RHS of the YIG oscillator

In my days as a young engineer (that's a long time ago) one of the "modern" pieces of test gear on the bench was an HP8640B signal generator. I used one, on and off, throughout my RF design days in the 1970s and 1980s.. On retirement I managed to borrow one on indefinite loan from a colleague who managed to buy some of the old stock items when well past their useful lifetimes. This has worked OK for several years but a few months ago the fine tune control shaft fell off inside the box. It is not broken, it just became disconnected.  Today I attempted to fix it and expected it to be easy. I could see that it was basically 2 pieces of metal connected with a small plastic part. But can I get at it?  Can I heck!

You forget how USELESS 1960s and 1970s designs were in terms of ease of manufacture and repair. To get at the part, it looks like you have to take apart about 1 zillion screws and plastic cog wheels, and all because the designer didn't put the control about 5mm  to the left, in which case none of these complicated mechanical arrangements would have been needed!  These days, where competition, manufacturing and repair costs matter, the design would not be so unnecessarily complicated. After trying to join the 2 pieces together for nearly an hour, I gave up.  In the coming days I'll return the 8640B to its owner and I expect he'll have the manual and the patience to fix it. My eyesight is also not as good as it was and that didn't help.

The tiny Elecraft XG3 signal generator (about the size of a pack of cards) would do all I need (and a lot more) and I think will be a good investment. It also weighs about 1/100th the weight of the 8640B. I am not after a signal generator with professional calibration and noise floor performance, just a simple way of checking the performance of simple receivers.

Unless absolutely necessary KISS - keep it simple stupid. This applies as much to professional gear as to amateur gear. Don't make life harder than it need be.