AmateurRadio.com

This afternoon I tried 80m WSPR with the “compromise” antenna (V2000  + 2m halo with strapped feeders) with some success. On 80m I copied M0BLP and PA0WMR although there were very few stations active. I was not copied by anyone. I was going to try 160m but decided there was too little activity.

Later I used 40m and 20m with the Par end-fed.  On 40m, just one transmission resulted in 10 spots in 7 countries. The next transmission resulted in not a single report, probably because I was sitting on the frequency of a very strong station who was TXing at the time?

I later returned to 10m, and spotted EA5CYA (1376km) and LZ1OI (2145km) by Es around teatime. The Spanish station was pretty strong but the LZ was much weaker.

Son Chris and grandson Edward outside their home.

Although I shall probably go on 472kHz WSPR shortly, today has been a day largely without radio: we went on a train day return to Canterbury to see our son Chris and family. We have done this now 3 times and get about 4 hours with them. It was good.

See http://hamspots.net/3bjt/

A little while back someone introduced me to Hamspots which is a sort of  filtered spotting system for digital modes. You can chose how many bands to monitor and the modes, Very useful to see JT65 and JT9-1 activity on, say, 20, 10 and 6m.

In an attempt to establish my ERP on 472kHz, I have crunched some numbers. I think it is error free, but no doubt someone will soon tell me!

With a 1:46 step up toroid, I am measuring the DC volts rectified across a 470 ohm secondary load resistor using a small 50uA meter in series with 240k ohms (120k twice) and a series silicon diode. This circuit is straight out of the “LF Today” book available from the RSGB bookshop.

DC current = 30uA
DC voltage across 470ohm secondary load  = 0.6 + (240 x 10E3 x 30 x 10E-6)  = 7.8V
DC voltage (rms) across 470 ohm = 7.8/1.414 = 5.52Vrms
I secondary = 5.52 * 10E3/470 = 11.7mA
I primary =  46 * Is = 46 * 11.7mA = 0.54A

Rrad = 160 * pi^^2 * Heff^^2/lambda^^2 = 160 * 3.14 * 3.14 * 2 *2/(630 * 630) =0.0159 ohms

P(erp) = I^^2 * R = 0.54* 0.54 * 0.0159 W = 4.6mW

My original guesstimate of 5mW ERP is not far out!

Clearly getting the antenna much higher would help enormously as ERP is proportional to Heff^^2. All one can really be sure of is the order of magnitude. I am running low milliwatts.

Using the strapped feeder to my Par 10/20/40m as my 472kHz antenna rather than my 2m/70cm feeder, the antenna current has nearly doubled with the antenna current meter now showing 30-33uA whereas it was 18uA before. This suggests ERP has increased by around 4-5dB (ERP proportional to I^^2), but we’ll see later. The Par antenna itself is lower than the 2m/70cm antenna and runs horizontally to a tree. Average height is around 3-4m AGL. The losses may be greater.

The picture shows the 472kHz coil used (a ferrite rod would be fine but since moving it is “lost”), the 472kHz homebrew transverter (left) and the 3C90 matching coil between transverter and antenna (towards centre, LHS of coil). The small meter measures antenna current and registered 18uA last night and 30-33uA now with the Par antenna with strapped feeders.

UPDATE 1420z: G8HUH (250km) is copying in daylight a full 8dB S/N better than last night. Encouraging.

UPDATE 1448z:  M0PPP (182km) seems to be coming in stronger than last night too and in broad daylight.

UPDATE 1700z:  M0PPP  is now spotting me at 1456z, 1538z and 1620z i.e. in daylight.   He was not copying me at all last night, so I think my signal IS stronger.

Tonight is the last night my shack is being used as a bedroom. Hopefully I shall be able to operate beyond 1745z tomorrow if I want to. I am also unable to come on for the UKAC session on 2m this evening for the same reason: my shack is  a bedroom for the third night.

10m WSPR unique spots until QRT at teatime

These last few days have been exceedingly fatiguing (stroke).  Not sure if this just a bad week or whether it is extra tiring having the little ones around: although I enjoy having them it is at least twice as tiring for me: I worry about them but am too feeble to sort out things. This makes me feel SO tired.  We’ll see if I feel less tired when they go home.

A week ago I had another MRI scan to see how my brain bleed is repairing.  Today I had to go back to get the results. I was extremely relieved to hear all is repaired, my boys will not inherit the problem and all is well.

My relief was visible. This had been a real worry to my wife and I.  I dreaded further brain surgery, fearing some long-term damage might be done.   I have now been “signed off” by the neurosurgeons and should not need to see them in their clinic again.

My main problems remaining are swallow of some liquids, giddiness when walking, some stomach discomfort and profound fatigue: most days the least physical exertion totally exhausts me. I find it hard to describe just how tired I feel most of my waking day.  All these remaining issues should improve, but this could be a long time. Apparently the neurosurgeon told the DLVA in June that I am fit to drive, although their OK could take months to reach me.  A few months ago there was no way I could have driven, but now I feel ready to do so. It will be good to drive the car again.

Today has been an emotional day. I am profoundly grateful it is drawing to a close.