Project TouCans is rock locked, meaning that it operates on a single frquency: 14057.4 kHz at teh moment. This leads to station operation that looks a bit different from most. Notice that while we do use the RBN, it's mostly as a wellness check for TouCans. For us to call a station, they have to be on frqueqncy, so we also use the tool shown in the terminal window to the left, rbn_telnet.py. We can start it with a signal range such as
python3 rbn_telnet.py -b 14057 -e 14059
The tool then connects to the RBN's telnet feed and filters for only calls between the -b and -e arguments in kHz.
Project TouCans is back up and running! The rig just stopped dead in its tracks during the NAQCC Sprint a few weeks back, and that was that. After two hours of debug and soldering yesterday, it's back.
A few things of note:
The battere was completely dead. The imuto power supplies TouCans uses hold their charge for weeks, so I'm guessing this was the number one issue. But! The battery didn't do it's usual buck supply hum into the radio, (hence me not realizing it was even close to being out of juice.)
The lack of buck supply hum might have been precipitated by the second issue I found. The audio output wire was severed within its insulation. A DC ohmmeter check indicate that there was an open circuit. I'm wondering though, if the wires were close enough together in the insulation if they weren't capactatively coupled, and therefore still producing sound and providing a bit of a filter. I replaced the wire in question, so we may never know. Here are the spots for the rig so far this morning. No backyard QSOs yet.
The recent pair of QSOs to Japan from Project TouCans from Great Basin National Park has me wondering about F2 layer ionospheric skip propagation again.
I got our F2 skips working for CZML. Here's a look at the skip path for JJ2JQF de KO6BTY. Notice the Earedson ionosonde is almost right in the middle
to pull in ionosonde data. To access different stations, you need different ursiCode values, (one per station.) These can be found at https://www.digisonde.com/ under the URSI column.
This URL worked great in the browser, but thanks to this issue, stumbled a few times in the czml plugin's calls to get_f2m.
References
Ionosonde Data
This was made possible with data collected by
Reinisch, B. W., and I. A. Galkin, Global ionospheric radio observatory (GIRO), Earth, Planets, and Space, 63, 377-381, doi:10.5047/eps.2011.03.001, 2011.
Today KO6BTY made a QSO to Japan from Great Basin National Park!!!
Not only that, but she also made her first POTA activation! She was operating from Project TouCans as KD0FNR/KO6BTY on 20 meters. Here's the QSO map, (after hitting play in the lower left corner, all the QSOs will shown for a brief moment; if you click pause you can zoom in/out and view all of them at once; continuing with 'play' will remove all QSOs and display each QSO as it happened in time during the activation):
Tuesday morning, with Project TouCans working better that it had in days, I noticed that the ends of our stranded wire antenna had begun to fray out. I grabbed a roll of washi tape from my pocket, (who doesn't take washi tape on a radio outing?), and a few minutes later, voila
The end of our antenna was no longer frayed, and nosie was down significantly! Here's a view of our activation site from the opposite angle looking out over the Great Basin of Great Basin National Park US-0032.
I made two QSOs last night from the home QTH with a lot of noise! They were to KA6JLT in Reno, NV and and WN1Z in Susanville, CA from here in San Francisco.
This time, we did not measure the power out of Project TouCans. I suspect our several decades old Radio Shack power meter has given up the ghost, or there's something wonky in one of the cheapo connectors from Amazon.
As a side note, the radio is much quieter and works better when the RF output leads are soldered directly to the banana binding posts at the top of the rig that the antenna attaches to.
Side, side note. KO6BTY and I need to keep a slightly cleaner workbench. The rig sparked and vaporized a stray shred of wire yesterday once when we powered it up.
Reading up on the Tuna Topper and funding for amateur radio projects
Since we're now blowing FETs on Project TouCans, and KO6BTY and I are giving a presentation about the rig to the San Francisco Amateur Radio Club on Friday, I've been reading up on amplifier theory. I really like this article explaining how the different classes of amplifiers work except for the horribly gendered first paragraph.
In other reading news, (it's finals week for KO6BTY and I'm getting ready for our camping trip, so mostly all I've had time to do over the last few days is read), Simon Willison pointed out that the Amateur Radio Digital Communications group has grants for advancing the usage and technology of amateur radio. Here are some examples of what's been funded.
And finally, here's a link to the article that taught me how to increase power output on the Tuna Topper by upping the bias voltage. It's an even more cool article now that I know how the calls A Tuna Topper amplifier actually works.
To wrap things up, we're hoping to get TouCans back up and running today. Here's a nighttime look at the rig from the ground. The white object is the 10 meter rig's balun.
Up until about a week and a half ago, Project TouCans and the Flying Rockmite before it had never blown a final amplifier transistor. Our good fortune with transistors was caused in large part not by any particular genius in the construction or handling of the radio, but almost entirely to radio frequency interference. When too much RF energy was reflected back into the radio on key down, the Rockmite's picokeyer would reset chirping out an only slightly irritated 73 in Morse code. Hence, we couldn't use the rig, hence we changed the antenna or repaired the rig, or turned down the bias voltage on the Tuna Topper final until we could use the rig without resetting that little keyer.
Then! Then we did something that was both cool and, (we'd later find out), somewhat daunting. We removed the last of the wires that attached Project TouCans to the Earth and our RFI just went away. Which has been great for signal quality, and as it tuns out it's occasionally been hell on the amplifier.
At present count, we're three transistors down.
After the rig dropped from about 15 feet up to the ground recently, I did a quick inspection and then, (why!!!!??? why did I do that???), decided I'd measure the rig's output power since I hadn't done that in a while. The power meter reported 3 Watts. The rig nominally outputs 5 Watts. I adjusted the bias voltage on the Tuna Topper and.. still 3 Watts. I increased the voltage two more times, and? The final transistor blew out. (Eventually taking the rechargeable battery with it.) KO6BTY and I completed our debug yesterday, reattached the power meter, (which apparently no longer works since it reported 0 Watts at all bias voltages), and fairly quickly blew out the amp transistor again as I blithely upped the bias voltage.
Turns out I can't do that anymore. our keyer RFI safeguard is gone.
Interestingly, we did discover that when the bias is set to low on the amp, there's a whistling feedback tone that appears in the audio output. When the amp is biased correctly, and before it's biased too high and takes out the transistor, (i.e. in nominal operating mode), the whistling tone goes away. Audio debug lives on to a certain extent.
We'll be dropping in transistor number four tomorrow. I'll keep you posted.