KP4MD's blog

Our VHF WSPR Group meeting at 2012 Pacificon/ARRL National Convention was very well attended. Thanks to all who participated in our meeting.
Here is a link to our presentation slides.

All WSPR operators are welcome to read and join the 2 meter WSPR study discussion on the Google Group at Anyone may ask Glenn N6GN or myself for an invitation or log onto the site to request a subscription to the e-mail list.

The latest ARRL Propagation Broadcast mentions our 2 meter WSPR study. Check it out on

Welcome to W6SZ, W6IEE and N3IZN in Southern California!
Our group station info is posted in the table at
The spots between N6KOG and N3IZN (624 km) now hold the DX record among our group!
Thanks for activating Southern California in the California study group!


World Wide 2 meter WSPR daily spot report activity has increased 100-fold since this study commenced in June 2012.

This Excel (2000 or later) spreadsheet has added the following to GM4ISM's WSPR data download sheet: Statistical analysis of frequency, SNR and Power dBm of downloaded WSPR spot reports; Charts of frequency and SNR of spot reports vs. Date/Time UTC; and Charts of frequency and SNR of spot reports vs. hour of the day (UTC)

Steve KC6KGE, has joined N6GN, K6PZB and myself to attempt a WSPR contact on 144 MHz over the 265 mile path from northern California to the south end of the central California valley near Bakersfield. I have raised my transmitter power level to 50 watts.

Carol, KP4MD
near Sacramento, CA

I use the free open source program CamStudio to make the time lapse video clips of the WSPR window, setting the rate to one capture frame every 60,000 ms (no audio) and the playback rate at 1 frame/second. This captures ten hours in a 600 frame AVI file measuring 18 MB in size that plays back in ten minutes.

I've uploaded several videos from our 2 meter WSPR study to the YouTube playlist
Each file uploads in about 3 minutes over DSL.

Since October 2011, I've been running a Flex-1500 software defined radio in the WSPR frequency hopping mode coupled to a 40 meter full wave horizontal loop through a 4:1 Guanella balun with no other impedance matching. The standing wave ratio on the WARC bands was significantly over 3:1.

My station has been active on 6 meters since 9 June 2011. There are many uploaded 6 meter spots among European stations these days but I see almost no 6m WSPR spots in the Americas despite hearing SSB QSOs via sporadic E skip. Can those of us with the capability activate 6 meters on WSPR?


With freeware CamStudio you can make quality video clips from screen captures of your PowerSDR or other panadapter and waterfall displays. I have posted such a video that shows WSPR signals being decoded at

At times I have observed PowerSDR go into a state where all transmitted and received signals have a loud superimposed buzzsaw sound, about 20-30 Hz or so. It has been responsible for erroneous multiple simultaneous decodes of the same stations both on receive and transmit. I suspect it has to do with hardware interrupts as it seems to occur after I've used the computer for a CPU intensive task like watching a video while PowerSDR is running in the background. Stopping and restarting PowerSDR with the Start button usually seems to clear this problem.

My WSPR station resumed operation at 0700 UTC on 4 June 2011 but very few spots were received on 7 MHz due to a high (S7) noise level. The RF interference source has been identified as a Dynex DX-HDEN10 hard drive enclosure. Its power adapter produces a high level broadband RF hash when plugged into AC power that saturates the HF spectrum in the home even with the unit's power switch in the "OFF" position. Ferrites placed on the cords were useless to reduce the interference.

KP4MD WSPR station has been off the air since mid March 2011 due to hardware problems (recalled overheating HP computer due to a defective Nvidia GPU chip).

On 5 FEB 2011 I updated to WSPR2.20_r2283 to frequency hop receiving on 160 through 10 meters but had enabled transmitting only on 7 and 14 MHz where my 40 meter horizontal loop's SWR is under 1.5:1 without need for an antenna tuner.

On 6 MAR 2011 I cautiously enabled transmitting on 10, 12, and 15 meters where the SWR is less than 3:1, expecting no harm to the output transistors running a mere 5 watts. I was pleasantly surprised by spot reports comparable to others on those bands!