On properly operating a WSPR station…

Anyone who is subscribed to the QRP-L has likely been subjected to a long string of complaints against WSPR in the past week or so. This began with a generic complaint against a “consistent carrier” on 7.040. This rapidly decayed into a long series of rants against WSPR. Since I’m rather more fond of WSPR than the average QRP-L member, I chose to defend WSPR’s place in the ham radio universe.

But amidst the general complaints, there are a few points which they make which we should all take to heart. First of all, in the United States we are not allowed to operate automatic beacon transmitters below 10m. This means that you have to be in control of the station, and operate it in a manner consistent with Part 97 regulations. I’m not sure what that really means in the context of this mode, but I suspect that it means that running your beacon all night while you sleep isn’t actually legal, as fun (or useful, I would argue) as it might be to see those spots from New Zealand that occur at 4:30AM local time when you wake up and have your coffee. I believe that all hams should endeavor to operate their stations in accordance to regulations, so I think that we as WSPR operators should be at the control point of our stations when transmitting WSPR. I also think that this point of legality isn’t adequately emphasized in existing documentation, so new users of the mode may be unaware of this issue, so it would be great if we had a more prominent notice on WSJT’s site, and on wsprnet.org.

Beyond simple legality though, I’ve seen that the QRP-ers have some basis for being irritated beyond the mere legality of this operation. In the last 24 hours, I’ve logged one particular station who has operated at 100w output power, and for quite a while, was transmitting about 50% of all slots, including many back to back slots. This resulted in spots with a SNR of +5 over distances of 12000km. This isn’t a WSPR, it’s a rock concert. I think its good to keep WSPR at QRP levels or ideally QRPP levels. And let’s keep our transmit percentage down to 20% or less. As WSPR has become more popular (and it has become much more so even in the last few months, with dozens of stations on 40m and 30m) we’ll need to reduce the time we spend transmitting to mitigate collisions.

And let’s be especially careful around 40m, okay? 7.040Mhz isn’t the best choice of frequency, frankly. Lots of old time rock bound QRPers still claim it as their own, and while nobody owns a frequency, we should be courteous to all hams.

K6HX QRSS Grabber

For fun, I’ve got my new RFSPACE SDR-IQ running on my laptop using Spectrum Lab and monitoring the 30m QRSS beacon subband. I enabled its HTTP server, and now have set up a little cronscript to copy its display to my webserver once a minute. You can see an example display below (showing KC7VHS, AA5CK and WA5DJJ) or you can click on the link below, and get the live version on QRSS.info


K6HX QRSS Grabber.

I’m not sure why the frequency display on the right is wrong. Anybody have any ideas? I probably have missed something in the configuration of Spectrum Lab, but it’s rather like operating the Space Shuttle…

Autodyne receiver for WWV

While scanning QRP-L today, I found an interesting link to a project which gave some details about a little WWV receiver that can serve as a frequency standard.   I haven’t had the time to work out how it all works, but it looks reasonably straightforward:

Here’s the original schematic from Chuck Adams, K7QO:

Picture 1

Nick, WA5BDU has some variations and additional comments which are interesting:

autodynereceiver kennnick.

Bounced a signal through HO-68

This morning I got another chance at HO-68, the newest Chinese amateur satellite that was operating in FM mode. I wasn’t sure what the problem was: I had the PL tone setup right and the signals seemed strong enough. On this pass, I fought to try to find a slot to transmit, and finally at the end of the pass, confirmed that I was indeed able to get into the bird. I made the following recording of the pass, and you can hear me in the downlink twice near the end of the recording, calling (without response) to VA7VW and W7JPI. The satellite was actually configured to turn off its transponder while it was still high in the sky here (it is on for a pass over Europe, the North Pole, and then down over the states) so I think I was the last person active before it went off.

2009-12-29-HO68-FM, recording by K6HX in CM87

40th Anniversary of Apollo 11 on AO-51

Tonight the amateur satellite AO-51 made an evening pass that was almost directly overhead, and was sending a congratulatory message for Apollo 11, along with a slow scan TV image. I managed to record it, although not the greatest quality, using my little Yaesu VX-3R and my Arrow antenna. Here are links to the recording as well as the four tries at the SSTV image:

July 20th, 6:40PM recording of AO-51 over CM87

Here was the pass as predicted by my Python code (times are in UTC):

  01:39:06  +0.0° 165.4° ? 12.8°N 115.9°W - AOS 696.4
  01:40:00  +3.6° 165.4° ? 16.1°N 116.6°W -     695.9
  01:41:00  +8.3° 165.5° ? 19.7°N 117.4°W -     695.6
  01:42:00 +14.2° 165.4° ? 23.3°N 118.3°W -     695.6
  01:43:00 +22.4° 165.3° ? 27.0°N 119.1°W -     695.8
  01:44:00 +34.9° 165.0° ? 30.6°N 120.1°W -     696.2
  01:45:00 +55.9° 163.8° ? 34.2°N 121.0°W -     696.9
  01:46:00 +88.1°  99.1° ? 37.8°N 122.1°W -     697.8
  01:46:01 +88.2°  80.1° ? 37.8°N 122.1°W - MAX 697.8
  01:47:00 +57.1° 349.6° ? 41.4°N 123.2°W -     698.9
  01:48:00 +35.9° 348.3° ? 45.0°N 124.4°W -     700.3
  01:49:00 +23.3° 348.0° ? 48.5°N 125.7°W -     701.9
  01:50:00 +15.1° 348.0° ? 52.1°N 127.2°W -     703.7
  01:51:00  +9.1° 348.0° ? 55.7°N 129.0°W -     705.8
  01:52:00  +4.4° 348.1° ? 59.2°N 131.0°W -     708.0
  01:53:00  +0.4° 348.3° ? 62.7°N 133.4°W -     710.4
  01:53:06  +0.0° 348.3° ? 63.0°N 133.7°W - LOS 710.7

And here are the resulting SSTV images as decoded with Multiscan under Mac OS X:





Addendum: I played back the recording with some adjusted settings, and got this picture (somewhat better):


More WSPR/MEPT developments…

This morning I was scanning my WSPR logs and my MEPT screenshots for the night. It seemed to be pretty good. I had quite a number of spots into Australia overnight: both from VK6DI (who is nearing the end of his time in VK6 land, we hope to see you again back on the eastern side of Australia) and from a newcomer: VK2DAG. Checking back through my MEPT screenshots, I was hoping to get some nice shots from VK2ZAY, but he was pretty marginal, and there was very definitely some spreading in frequency. But I was pleased to find a few nice beacon messages from Eric, WY7USA, running at 500mw:


Addendum: A couple of hours later….


Thanks Eric!

First signals heard through the Softrock Lite II

Well, I’m not sure that the Softrock I put together is working entirely well. I’m beginning to believe that the transformer that I wound might be bad. My receiver seems a bit deaf, and also seems to have only about 20db or so of opposite side rejection (I’m getting images of signals on both sides of the center carrier frequency). I’m a bit stymied by the fact that I only have my macbook in a place where it can be used to decode the softrock, and the software for it is, well, to a first approximation, there isn’t any. I did a bit of hacking, and took a recording I made and extracted this Morse code recording, which I’ll archive here as the first that I ever got.

Morse via my Softrock

I’ll have to work on it some more in the future, but for now, I’m back to beaconing with my FT-817.

Testing New S/MT Hellschrieber Beacon ID…

I am currently running my 2w beacon with the following sequential multi-tone Hellschrieber ID on 30m:


As Colin, G6AVK pointed out, this is likely to be a lot less effective than my previous MV identifier, but if it does work, people might have a better chance of knowing who the beacon actually is. I’ll let it run for a while and see how it does. Propagation is falling off a bit for me now, but might get better later.

11 Hours of 30m Beacon Band…

Well, last night, I tweaked my recording program to produce recordings in 15 minute chunks and started it running. This morning, I had a bunch of recordings, a short run of which produced the following spectrograms (never tried this WordPress functionality before hope it works out!):

Addedum: Sigh. WordPress insisted on converting my nifty names (which told you what time they are recording) to shorter things, which didn’t preserve their relative ordering. Grump. Oh well. I think I got them sorted. By hand. How tedious.

Addendum2: Here’s W8LIW’s beacon, booming in quite strong.



Yesterday, I recorded a couple of hours of signals off of 30m, and ran them through my homegrown spectrogram code for fun. I found the following FSK CW signal (click on it to get it larger):


(The blank regions are the two minute intervals where I am sending a WSPR beacon message.)

With a bit of work, I identified the call, and exchanged email with Ted, AA5CK, who verified that it was his signal. He was operating from grid EM05eh with a power of 50mw into a vertical antenna. From my QTH in CM87ux, that works out to about 1250 miles. Very nice!

More Meter Madness

Okay, after having read WB8ICN’s postings on QRPedia, I decided to try to measure the impedence of both of my meters. I dug a 1.5M ohm resistor out of the pile, and hooked some jumper leads to it. I then did the following:

  1. Measure the resistance of the resistor, using the DVM as an ohm meter (R)
  2. Measure the voltage of a 9 volt battery, using the DVM as a volt meter. (V)
  3. Hook the resistor in series with the battery, and measure the resulting voltage. (Vm)

What we are looking for is the resistance of the meter, which we will call Rm. A little math should show that Rm = R * Vm / (V – Vm). Okay, that heavy lifting aside, let’s see what we discovered about my two meters:

For my better meter, a nice Radio Shack PC interfaceable multimeter, I got the following readings:

  1. R = 1.496M ohms
  2. V = 9.24 volts
  3. Vm = 7.94 volts

Plugging these values into the formula, we get a value for Rm of 9.18M ohms, considerably off from the 10M ohms that we used as the “nominal” value. Later, I’ll go back and work up the correction factor for the previous nights example, but for now, let’s move onto my second meter, a cheapy $20 one that I’ve used mostly to check my car battery and continuity. I recorded the following values:

  1. R = 1.480M ohms
  2. V = 9.14 volts
  3. Vm = 3.68 volts

Plugging these values in, I get about .997M ohms, or about 1Mohm! No wonder my previous readings were so crazy, with the 4.4M ohm resistance of my series resistors, this thing was dividing the peak value down considerably.

Okay, let’s go back to my dummy load experiment. First, on meter number one, we find that Rm of 9.18M ohms. If we go through my various calculations and correct for the measured values, we find that the output power should be around 4.71 watts. Doing the same for measurement number two, we’d get an output power of around 4.67 watts, both in excellent agreement!

(Note, I didn’t measure the voltage drop of the diode, I’m assuming 0.7 v. The data sheet says the maximum drop would be 1v).