UKAC - 2m SSB tonight

Just 5 QSOs this evening on 2m SSB (5W pep) with best DX 204km to G7RAU on the Isle of Wight. As my antenna would still not rotate (bolts too tight) I decided to use the halo again, which is fed with lossy RG58 coax. I am very tempted to swap the rotatable antenna for stacked big wheels with low loss feed coax. Being omni would help in these contests as if I can work over 200km with the halo and lossy cable I'd be at least one S point better on stacked big wheels and a low loss cable. I could have worked far more if I stayed on longer but after an hour my very poor voice told me to stop. There were several workable stations in IO92 square. I worked none of these this evening.

Stations worked tonight with 5W + halo on 144MHz SSB.

My 10m halo - soon time for an overhaul

After the CQWW DX contest this weekend I plan to take down my Homebase-10 halo and rebuild it. The birds have managed to tear away at  the nylon rope supporting the nested 6m halo and the wooden supports now look a bit weather beaten.

So, I plan to replace the wooden cross frame supports with PVC pipe or fibre glass rods and re-do the wire elements. These have been up in all weathers for around 4 years now, so a few pounds on a remake is justified. The antenna works so well and is so small that I cannot think of a better antenna for the 10m band short of going to a beam which would be huge by comparison and need a rotator. The neighbours are quite used to it too, which is good.

Homebase-10 28MHz wire halo antenna

Homebase-10 antenna on the back of my house.

28MHz (10m) is excellent at the moment. If you are looking for a small, simple, horizontally polarised, omni-directional antenna for 28MHz, you may want to build a copy of my Homebase-10 halo which was published in Practical Wireless a few years ago. This antenna takes hardly any space, is simple and inexpensive to make and works extremely well. All the parts apart from the wire can be obtained from your local hardware store (wood, brackets, screws etc). You should easily have change from a £10 note.

The results on WSPR today (see previous post) give some indication of how well it performs. Mine currently has a second halo nested inside the first giving me coverage on 50MHz too.

My May Objectives - achieved

This month I had two objectives:

   (a) make my 10m halo into a dual band 10m/6m version.
   (b) complete my 481THz optical speech transceiver.

Although a few days late, both objectives have been achieved with decent contacts on 10/6m and a 10.5km 2-way QSO on 481THz AM.

Several things will interrupt any objectives in the next month or so, but my next objectives are:

   (a) Improve the sensitivity of my optical transceiver RX.
   (b) Build a new transverter for the 472-479kHz band due to be released Jan 1st 2013 in the UK (we expect).

The first will allow me to use the dual-optics 481THz transceiver over longer paths. I hope to make some contacts over 20km in the next few months.

The second one (472kHz transverter) only needs to be completed before Christmas, but I'd like to get this moving soon. If possible I'd like to run the PA at around 20W - my earlier 500kHz transverter was just 5W - and to improve the RX sensitivity and selectivity. This new band will be a most interesting allocation and I expect quite a few stations to give it a try.

Dual band 10m/6m halo erected

10m and 6m nested wire halos on the mast

The Homebase-10 halo is now a Homebase-10/6 with a second dipole within the first covering the lower part of 50MHz. After just minor adjustment both bands have a near unity VSWR over the parts of the bands where there is CW/DATA/SSB activity.

Since making the changes I have exchanged 5W WSPR reports with FR1GZ  on 10m, and got -19dB S/N on 10m WSPR from CX2ABP (11127km), so that is still working as before. I have yet to work something on 6m to be able to judge the omni-directivity of the 6m halo.

Dimensions for the inner 6m dipole were simply scaled down from the values at 10m: the outer sections are 564mm long and the folded dipole inner section 873mm long (these are the dimensions each side of the feed point). A single 50 ohm RG58 coax feeds both 10m and 6m sections.

Details of the original Homebase-10 were in my Practical Wireless article a few years ago and also on my webpage at https://sites.google.com/site/g3xbmqrp/Home/homebase10 .

May Projects

All being well I have a window of a few weeks before visiting grandchildren and the like, so I have a couple of new aims:

(1) Convert the 10m halo to a dual band 10m/6m halo
This should be a fairly easy task as I already have dimensions for the 6m halo and I've air tested it in the loft. All that should be necessary is to take down the 10m halo and change the feed and support arrangements so both the 10m and 6m halos are fed from the same coax. The pair of halos well clear in the air should prove an effective QRP antenna system for my 2 favourite bands.

(2) Complete my first optical speech transceiver
Strange though this is, I have made several quite sensitive optical receivers and a couple of reasonable power QRSS3 and CW optical beacons, but I've still not got around to making a complete optical speech transceiver. Locals hereabouts use baseband audio for TX, so this is what I should do if I want to work people like Bernie G4HJW. It would be good to get a few line-of-sight short range (up to around 10-15km) 481THz QSOs in the log-book soon. Based on my optical work so far this is not a difficult task, just one I need to crack on with.

Target for both projects is within 2 weeks i.e. by May 17th. We'll see.

Homebase-6 (50MHz halo)

Homebase-6 50MHz halo prototype indoors ready for tests

This afternoon I had a go at scaling my Homebase-10 (28MHz wire halo) down to work on 50MHz. I simply scaled the dimensions by 28.3/50.1 (the ratio of the centre frequencies) and performance was almost spot on with a low VSWR in the DX part of 6m. So far I have only tried it in the shack holding the antenna in the air by hand and keying the TX to measure SWR. Next stage of tests will be to erect it in the loft space before erecting a more permanent version within the 10m halo on the top of the mast at the back of the house at a decent height. Still, a promising start. In the end I may opt for a small 6m beam like a Moxon or HB9CV though.

UPDATE 1600z : I have now erected this horizontally in my loftspace although it is more triangular than square. Match is good so I'll see how it performs locally next.

UPDATE 2100z: I am surprised that I'm unable to copy the more distant UK 6m beacons such as GB3BUX and GB3RAL which use horizontally polarised antennas. I need to monitor for longer to see if they appear by MS or tropo.

10m halo re-erected

After the winter using my pole for the 500kHz antenna, I've now replaced the 500kHz spiral topped wire with my Homebase-10 halo antenna for 28MHz that appeared in PW a few years back. Using G4IKZ 18kms away to receive my WSPR signal, I see the reports leapt up by at least 14dB, so it is certainly working well. I shall try the antenna and feeder (strapped together)  this evening to see how it performs on 500kHz. I'd expect it to be some 10dB down on the original 500kHz antenna.

Working REAL 10m DX at last!!

After calling for 15 mins I eventually worked LU1HF on 28.010MHz CW this evening by F2 or TEP. He had been calling CQ for over 15 minutes without getting a reply and then he heard my 10W to the wire halo and gave me 599. OK it was a contest exchange, so probably much weaker. I think my antenna must have quite a low angle take-off as working this station, against the rest of the world's competition, shows.This is my best 10m DX for some time at 11077kms. So who needs sunspots (the count was zero today).

A few minutes later I worked ZW5B in Brazil who got my callsign but he then lost me.

At 2138z I worked UU7J in the WPX contest.