WSPR Beacon

[ZL2WHO]

Hi All.
Just joined a beacon yahoo group in the UK and found this.........

I'm currently trialling a multi band WSPR beacon based around an AD9852 DDS.

A PIC decodes timing information from a GPS receiver, then uses this to initiatate a WSPR transmission from stored symbols. See http://www.g4jnt.com/JTModesBcns.htm for the WSPR generating part of the beacon .

16 frequencies are pre-stored in the PIC to 32 bit resolution and selected on a pseudo-random basis for transmission. These cover frequencies in every band from 1.8 to 50MHz, and several duplicates (to make up the 16 memory locations). The duplicate entries have a slight offset so I appear on the 7 - 21MHz bands at two differnt places

The output of the DDS drives a 6 Watt Class A, 0.5 to 1000MHz broadband amplifier which goes to a completely untuned vertical antenna.
SWR is sky high and off the scale on all bands except 18Mhz wher eit is 3:1 and 3.6MHz 5:1 So radiated power will be a bit low in some cases

The sky-high VSWR still doesn't stop my signals being decoded in VK land at 16000km distance.

Andy
http://www.g4jnt.com]

The URL is here.. http://groups.yahoo.com/group/uk_beacons/message/1052

As the beacon keeper for 50.024 I want to know if there is any interest in running the wspr mode on the beacon. I know most wspr transmissions are low power, 1-5 watts so would a high power beacon be not suitable ?
If there is enough interest then im keen to look into it.

73
Mark.

[ZL2DX]

Hi Mark,
what about running a WSPR beacon on the same site?
That could be really quite interesting to see the performance comparison.

73
Chris ZL2DX

[VK2KRR]

Hi Mark,

I think it would be a great idea and good to see some local beacon operators looking at newer technology in beacons.
There are quite a few people now that have designed and operating stand alone WSPR beacons with no PC required.
I wish that more would incorporate the WSPR mode into their beacons, including 2m beacons.

Its usually accepted that people will run a little bit more power on 6m WSPR band than the usual 5W. Im not sure what your TX power is now, but I would think 20W would be fine.

You could run the beacon on the official WSPR freq of 50.293, but not continuously. It would need to be on every 6th minuet or something like that.
Or else you could leave it on your freq and run it full time or with breaks say every 6th min for example.
Or, I wonder if you could have it on your freq and run WSPR every 6th min, and in between this, run the usual CW? this could be a good compromise?

[ZL2WHO]

Hi Leigh.
The reason I mentioned the usefulness of a high power beacon running WSPR is beacuse it now has a base power of 400w and an eirp of 800. I also could not ratiate on 50.293 as this not what the licence is for.
My thought was to interrupt the standard beacon every so often and have wspr take over..

Hi Chris. ZL2DX
Yes having the beacon on the same site, or better still the same beacon was where i were coming from.

Altho I do not wspr, i do see that there many who do and I can see the advantages.

Mark.

[VK2KRR]

Hi Mark,

OK on all that. You would just have to make sure the timing is good & freq stable or else it will never decode.
I think it would be a good idea, as u mention, run CW, and at a pre-defined time period, run a WSPR transmission.

I guess the only problem could be, that most people running WSPR will be on the WSPR frequency of 50.293. Rather than your other preset freq. Thinking of this I am wondering if perhaps you would be better of incorporating JT65 as the digital transmission to implement rather than WSPR. Your freq and timing is not quite so critical then and also uses half the transmission time frame of WSPR and thus stations do not have to sit on freq for quite as long to obtain a decode.

[VK4ADC]

Mark

Another suggestion to contemplate...

Make the new beacon QSY from the normal 50.0xx area for carrier/CW/??? to 50.293 for the WSPR segment period, then back again. The beacon would then spend 3 minutes 'as normal' then the 4th minute on WSPR. It's all selectable under software control anyway and just needs the two frequency-call subroutines to be inserted into the timing loop !

If you wanted to, make the 2nd minute JT65 on 50.220 (or whatever the commonly used frequency is at present) so that it does CW/carrier on the 1st and 3rd, JT65 2nd, WSPR on the 4th minutes.

[VK5PJ]

Hi Doug and Mark,

Mark
Another suggestion to contemplate...
Make the new beacon QSY from the normal 50.0xx area for carrier/CW/??? to 50.293 for the WSPR segment period, then back again. The beacon would then spend 3 minutes 'as normal' then the 4th minute on WSPR. It's all selectable under software control anyway and just needs the two frequency-call subroutines to be inserted into the timing loop !
If you wanted to, make the 2nd minute JT65 on 50.220 (or whatever the commonly used frequency is at present) so that it does CW/carrier on the 1st and 3rd, JT65 2nd, WSPR on the 4th minutes.

I think Marks problem might be the license conditions for the beacon, if it is anything like Australia, a beacon is licensed for a single transmitter freq, which would preclude the QSY ideas.

In the case of vk5rbv on 50.315 I have considered similar ideas for a future upgrade and had thought that running it as if it was a 20 - 30% WSPR TX and then fill in the rest with traditional CW keying with some longer KEY UP times to reduce heating. Maybe that gives us the best of both worlds but the heating factor / duty cycle becomes a real issue when running a high percentage of WSPR as beacon sites are rarely temperature friendly for the average HAM beacon.

Regards,
Peter Sumner