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.

Low cost rotator

In my search for a low cost rotator for small and lightweight VHF/UHF yagis I see that Conrad Electronics UK sells an "external TV rotator" for £52.99, plus postage from Germany with a free 2 year warranty.

3 core cable, 70 secs 360 deg rotation, 45kg load, 300Nm bending moment, 21.6Nm torque.  See eBay item 180832166179.

Does anyone have any experience of this rotator?

What next at G3XBM?

With my recent semi-successful WSPR transmissions on 136kHz and a few outings on 500kHz I feel I'm at a crossroads now: do I go on with the LF experiments or do I have a change and do something completely different? My original aim on the LF bands was to see what could be done "simply" i.e. without large antennas and with real 5W or less QRP power from the PA. Already I have the measure of this and I doubt I'll prove much more to myself by striving further.

Next challenge? Ideas please.

VHF AM controversy

This Sunday's RSGB News contains a piece about AM operation on 145.8MHz in Scotland and alleges that some AM operators have been deliberately interfering with International Space Station communications on the same frequency. I do not know if this is true or not. If it is, then it should stop: there is no place for such behaviour in our fine hobby.

What I do know is that the RSGB has been EXTREMELY slow in publishing frequencies for VHF AM in the UK. Although people have been urging the RSGB to put an AM "centre of activity" or calling frequency in the band plans, this has still not happened, although a brief mention of 144.55MHz has been added in the footnotes a few months ago.

My recommendations are:

(1) All AM users in the UK migrate to 144.55MHz.
(2) AM operation on 145.8MHz should be phased out as soon as possible.
(3) Use of 145.8MHz for AM should be done with care to avoid any interference with ISS operations.
(4) The RSGB should publish 144.55MHz in the 2m bandplan as the agreed centre of activity for AM users.

AM is a great mode allowing simple homemade gear to make useful contacts. It would be a shame if AM users got a bad name as a result of this negative publicity.

VHF AM Yahoo group

This is a picture of G4BYE's version of my own Fredbox 2m AM transceiver design - a neat unit his is complete with proper PCB.

Many blog readers are already members of the Yahoo VHFam group. To join visit http://groups.yahoo.com/group/VHFam/ and follow the joining instructions.

At last VHF AM operation has got a mention in the latest UK VHF bandplans with the agreed "centre of AM activity" being notified in the footnotes as 144.55MHz. This spot in the European all-modes area is also used by some other users - I hear SSTV here sometimes - so it is NOT an exclusive spot, rather somewhere to look for 2m AM activity in the first instance. There's some AM activity on 145.8 still in Scotland but it would be good if users there would move to 144.55 so this became a UK-wide spot on which AM activity is likely to be found. Users can also be found on 70.26MHz on 4m.

VHF AM gear can be very simple to make and AM is an ideal mode for QRP building and experimenting. There's plenty of ex-PMR AM gear still to be found for next to nothing, ripe for use on 2m/4m AM.