Saturday 22 December 2012


Tonight I decided it was time to work out how to interface the HPSDR to the K1JT WSPR programme and try it on 70MHz. My Penelope board has a -20dB coupler on the output giving 0dBm which is fine for driving my DEMI L70-28 transverter (serial number 1!) to 35W maximum. The normal 0.5W output of the Penny board should be terminated in 50 ohms to protect the output stage

I use the W5WC dual RX version of POWERSDR as this allows me two 96kHz chunks of the band to be seen at the same time. Usually one is on the beacons and one is on the calling channel
First I installed my paid for copy of Virtual audio cable which will allow the audio to be connected between the 2 programmes. It was configured to support VAC1 and VAC2.
Next a copy of N8VB's VCOM programme was installed with 2 pairs of cables, COM6>COM16 and COM 7>COM17
In the HPSDR Setup, CAT control TAB the port is set to COM 16, RTS and enabled:-  

Next the VAC setup in HPSDR. VAC1 is setup as VAC2 as the input and VAC1 as the output:-

Next the WSPR programme needed setting. Audio IN is set to VAC1 and audio OUT is set to VAC2. Note these settings are the REVERSE of the HPSDR ones

Drive level to the transverter was set to produce 5W output. The 10MHz reference for the HPSDR was produced by a Thunderbolt GPS unit,  which also, with the help of KE5FX "Lady Heather" Monitoring programme was used to set the computer clock every 15 minutes. The 70/28MHz transverter Local Oscillator is not yet GPS locked; an upcoming project based on the G4HUP DFS design

The system was allowed to run whilst packing the Christmas Candy

Looking at the WSPRNET spot database it was pleasing to see the signal had been seen:-

 2012-12-22 22:16  G4FRE  70.092565  -15  0  IO82uc  5  M0NKA  IO92  95  63 
 2012-12-22 22:16  G4FRE  70.092534  -22  -1  IO82uc  5  PA0TBR  JO22pi  517  84

The PA0BTR spot was the ODX for the days spots on 4m; not bad for my Indoor Halo!

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