20 Apr 2013

13.8V distribution board

http://www.hamradio.co.uk/sysimages/origimages/PW-100-1_pr5198_1.jpg
If you are like me, you'll have several pieces of equipment in the shack that run off 12-13.8V supplies and only one PSU that is used for everything.  This results in a very untidy arrangement.

I see that Martin Lynch sell a Mydel PW-100 4-way distribution board with fuses on each output. Although a similar unit could easily be built, this is not a bad price for a ready-made unit complete with spare connectors at around 30 pounds.

When arranging my new shack I shall have to either buy one of these or make up something similar.

A walk in the sunshine with the Ventus GPS tracker

As the weather was so beautiful this afternoon (full sun and around 13 deg C) I decided to do a country walk and track my progress using the Ventus GPS data logger bought from Martin Lynch and Sons.  The walk was 10.7km and took about 2hrs 34 minutes with a couple of relaxing breaks for a drink and a snack.  No ham radio gear was taken this time, because I forgot to charge up my VX2 handheld. Next time, HI.  Incidentally Quy was where my optical beacon reached (over the horizon) a few weeks ago. When you walk that far it seems a VERY long way away!

This is a plot of the walk taken with the low cost GPS tracker  then plotted with Google Earth.
Today's walk in the Cambridgeshire countryside

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.

19 Apr 2013

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.

18 Apr 2013

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.

16 Apr 2013

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.

12 Apr 2013

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.

10 Apr 2013

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.