Wednesday, April 25, 2012

The bands are dead but can a WSPR defibrillator get results

20m WSPR results
As most of you know the conditions on HF over the last week have been dismal at the best of times. Over the weekend I found 20m to be flat and 40m was just more or less local stuff. So Monday I thought it was time to give WSPR a go again. I set the output to 1 watt and gave 40, 30 and 20m's  a go. I was surprised that 20m was alive on WSPR. It was odd that I was unable to hear any CW on 20m's but using WSPR at one watt I was heard overseas.  My fan dipole in the attic is not really setup for 30m's but with the tuner in the K3 I
30m's was local only
am able to fool the rig to see a flat match. The SWR on the other side of the K3's tuner for 30m's is about 9:1 (according to my LP100A) so with one watt from the K3 and a 9:1 match what type of power is getting up to the antenna. With the help of this calculator I can enter my feed line type, power input, frequency and SWR this will get me a rough idea of the power at the antenna. So at 1 watt with an SWR of 9:1 using 30ft of  LMR-400 on 30m's the output at the antenna is around 892mW's of  raw power!! That raw power got me local responses on WSPR.  As for 40m's with one was more or less dead.

40m's was dead


  1. Hello Mike,

    It's amazing how well the digital modes work, even under poor conditions. I've been lucky to work a few stations on 10 meters, the last few days, but I always fall back on 40 meter CW.

    It seems there's always someone there for a long chat, even at 100 miles. Hihi

  2. Nice job Mike. I was just thinking of firing up WSPR yesterday, since I haven't broken in the new-to-me laptop yet that replaced my slower PC that had lots of digital miles on it. Maybe I'll give it a go tomorrow and see if anything can be had from the Tropics.

  3. Good morning John, I have been checking out your blog and reading about the success you are having on 10m's.

  4. Hello Casey, it had been along time since I had tried WSPR and it seemed some settings had been changed on my PC. It took me some tweaking with the PC and some connections from the K3 to the PC before WSPR and my radio started to get along. Good luck with WSPR down in the "tropics".