My Week in Radio

• I spent some time patching the open-source firmware for my HF radio. The original modification aimed to center and save the ATU network on the current frequency, which is effective for about 25kHz in either direction. The system saves the tuning network settings into both a cache and the database. However, it needs to update nearby saved tunings. I noticed the radio would click in new tuning networks within 1 kHz of each other. After digging into the code, I found the error in how it cached these networks.

• Unfortunately, intermod hits every Monday, so I had to jump to Allstar, even though I had tested RF earlier in the week.

Others

• WA3VEE, Ron: Discussed the Mud Mosey event.
• W8CRW, CR: Also mentioned the Mud Mosey.
• AF3Z, Jim: Had a CW sked.
• NA3CW, Chuck: Noted that the Mud Mosey operation sounded really good. Also discussed the AMPM net and propagation.
• KC3OOK, Bill: Participated in the Mud Mosey. Ron ran a net for people on their way in and out of the Mud Mosey service. Bill also served as net control for the simplex net and conducted a round table exercise to experiment with simplex.
• KC3YSM, Steve: Participated in the Mud Mosey for his first service operation.
• KC3NZT, Harvey: Listened to the roundtable.
• W1RC, Mike: Nearfest is coming up soon.
• AA3LH, Leon: Was on 10m last Tuesday, getting a 599 to Oregon, but then the signal dropped off completely. Later, he got a 599 to Los Angeles, but it also dropped off.
• KB3ZIM, Bob: Lots of mobile radio activity. Recent Chester County ARES/RACES meeting discussed revival of packet radio.
• KC3YIG, Dave: Struggling with building a vertical antenna.

Questions

• AA3LH, Leon: If flat straps are recommended for grounding, would they also be good for a counterpoise?
  • WA3VEE, Ron: Flat straps control inductance. An electrical ground is fixed, but a counterpoise is often deployed and redeployed in the field, making it hard to keep flat.
  • KC3NZT, Harvey: Probably makes no difference. He used a strap in his car because it’s cheap, and he’s used cheap wire shelves in the grass as a ground plane for a vertical, attaching to it with a strap.
  • AF3Z, Jim: Brought up the skin effect, where RF runs on the surface, not the middle. A strap may provide more surface area for RF.
  • NA3CW, Chuck: Frequency affects the depth of the skin effect. DC uses the entire conductor, 60Hz uses almost the entire conductor, but on VHF/UHF frequencies, it will stay in a copper coating on aluminum (like in LMR400).
• KC3NZT, Harvey: Are there any FCC issues with recording and replaying as a relay, especially for emergency communications (EmComm).
  • WA3VEE, Ron: ARRL started with “relaying” and that he records and plays back to demonstrate reception, so it should be fine.
  • NA3CW, Chuck: Advised to just be careful not to sound like you’re identifying as the other station.

I encountered a bug with the ATU in the X6100 running R1CBU firmware version 0.29.2.

The ATU networking information is stored in both a cache and the params.db file. When setting multiple tunings close to each other (e.g., 7073, 7074, 7075 kHz), the radio would rapidly cycle through them as the VFO was spun. This behavior cluttered the configurations and made it difficult for the ATU network to hold a stable tune near a signal.

Upon investigation, I discovered that while the cache retained all these closely spaced tunings, the params.db only saved one of them. The intention behind the new feature in R1CBU was to remove the hard boundaries between ATU configurations (which were previously every 25 or 50 kHz), allowing a single tuning network to be effective within approximately 25 kHz in either direction. The database would correctly update a nearby frequency to the middle, but the cache’s retention of every tuning caused the “thrashing” effect. Switching antennas or cycling power would reload the sparser collection of networks from the database, temporarily resolving the issue.

I filed a bug report, and submitted a pull request to fix it.

I patched the ATU code to reload the cache from the database immediately, effectively discarding the extraneous nearby networks.

Rain was predicted later in the weekend, so I headed out to Marietta Riverfront Park (US-4567) for a quick activation to beat the rain. My initial plan was to rebuild my EFHW antenna, but I cut the new wire six inches too short, and I didn’t have enough wire on the spool to start again.

I opted for my 12.5m EFRW instead. It was 7 PM, so I focused my efforts on the 40m. I successfully got about 18 contacts before I packed up for the evening.

My Week in Radio

• I have a blog of my radio notes, but I’ve fallen behind by over a month in posting.
• Tested a rybakov antenna with 4:1 balun and 25-foot wire out at a park.
• Btech UV-PRO (for APRS) has been seeing lots of beta firmware updates
• Attended a lunch with a Harrisburg 21 repeater group to learn about beacons and online tools for radio conditions
• My second 2M antenna (slim-jim) was performing badly
  • hanging next to the feed line of the higher antenna, and it was completely de-tuning it
  • pulled it up into the tree on its own line to provide space
  • still hangs lower than the other antenna to avoid interference
• contestcalendar.com has a google calendar feed, which i’ve imported to my calendar, so no more date math to figure out UTC

Others

• W8CRW, CR:
  • updated phone software, so allstar node is working.
• W3JAM, Jeff:
  • on digital to avoid connecting to anything on the roof in the storm
  • simplex net from the shack
    • always observing conditions on 2M
    • ducting
    • heard lots of distant stations, but not close
    • worked 50 miles across lancaster county
    • switched between vertical and horizontal: horizontal was better sometimes
    • new diamond antenna to install
    • swapping out everything on the shack
• NA3CW, Chuck:
  • hosting AWA pre-net
  • working on Joe’s tuner project: crimp connectors for components
• KC3OOK, Bill:
  • out in the truck to operate in the weather
  • mobile simplex net, south control
    • copied all but maybe 3 stations
• KV3JGB, Matt:
  • new parts, a choke, for the HF radio
• AF3Z, Jim:
  • visited a friend’s barn of parts for 1929 hartley oscillator
  • triton 4 didn’t turn on for CW sked: bad power supply, so switched to battery
• WA3KFT, John:
  • 100W RF to get through
  • new bracket on the tower
  • modifications for being able to tilt down the antenna.
• WA3VEE, Ron:
  • testing an IC-9700: working nicely
    • right on frequency
    • no harmonics
    • full power on every band
    • all configured
  • mud mosey for those helping, April 12, contact KC3TMT for info
• AA3LH, Leon:
  • back from weather events
  • in trailblazer, installed a new dual-band VHF/UHF radio
  • ran some 2M nets, but missed simplex net
  • 80M: rooster net and bible study net

Questions

• AF3Z, Jim:
  • AICO audio generator:
    • 2 tubes, precision resistors
    • wein bridge oscillator
    • siren like, but it varies on 15 second interval
    • what component failure causes the variation
  • WA3VEE, Ron:
    • check for a ripple from the power supply
    • sounded like a beating with the output
    • warble may vary with frequency
    • wein bridge oscillator was the first product of hewlett packard
  • WA3KFT, John:
    • check B+ voltage from the power supply and at the tube
  • NA3CW, Chuck:
    • looking at the schematic
    • uses a lightbulb to stabilize based on temperature
    • check the tubes and check that lightbulb
  • WA3VEE, Ron:
    • the lightbulb may not light, but it’ll use cold resistance of the tube
    • check continuity
    • if the power supply is giving ripple, the capacitor is bad

I setup at US-1418 for an activation. I tried to setup the 40m EFHW in a nearly vertical configuration, but my throw wasn’t high enough, so I went for a vertical 25-foot Rybakov instead. I used my 4:1 balun.

I got my activation working 10M and 15M FT8.

I’ve been learning about the BTech UV-Pro. When scannimg, it degrades the incoming APRS, even in digital mode where it checks back to the APRS channel frequently. I’ve been using stock APRSdroid over the TNC connection, but it takes a little fiddling sometimes to get it to connect.

In the new firmware, they’ve been flip-flopping features between 8.2.x and 8.3. It has bold/yellow fonts (or not), and new button actions to access groups. NOAA alerts have also come and gone to see if they affect RX performance overall.

Beacons and Online Tools to Predict Propagation

• Presented by Greg, K3EA
• RBN
• Pskreporter
• WSPRnet
• VoaCap
• Watch for openings on calling frequencies
• ARRL band maps
• Hamalert
• Hamclock
• DX clusters

A side note: SMRA hosts great presentations, so check them out some time.

I always keep a tab open to the Contest Calendar, but I discovered they have a feed for Google Calendar.

The slim jim I put up for APRS was hanging right next to the feed line of the higher quarter-wave antenna I use for local analog traffic. The feed line was de-tuning the slim jim, so reception of APRS traffic was almost non-existent. I could swap the antennas and the higher one worked much better, and the lower slim jim was greatly degraded for other FM traffic. Usually the BTech is on the lower slim jim, and the Quansheng is scanning on the higher quarter-wave.

To correct the problem, I pulled the 2 antennas up on separate ropes and separated them by a couple feet. The quarter-wave is still mounted higher than the slim jim.

My Week in Radio

• 985 breakfast
  • chatted lots of Vic and Jerry
• pota
  • 2 parks: middle creek and state game land down the road
  • set up multiple antennas: efhw + tactical delta loop
  • telescoping antenna for CB walkie talkie
• observed some degraded propagation the next day or 2 over the weekend
• need to check and tune up my slim jim again

Questions

• KC3TYX, Vic: Tried to tune into WA3KFT’s 6M net, but could only hear 1 person. What kind of antenna should he have used for local contacts like that?
  • W3MFB, Mike:
    • PVC pipe with caps and made a rigid half-wave dipole and put it on a lightweight rotor to change direction of the horizontal broadside.
    • try an omni-angle antenna (circular)
    • you may also hear better in the summer.
  • WA3KFT, John:
    • used 2 perpendicular wire dipoles thumbtacked to the ceiling in an apartment.
      • single feed point
      • omni-directional
      • feed directly with coax
      • VHF frequencies have smaller antennas
      • thicker elements give wider bandwidth (copper pipe)
  • KC3SQI, Wayne:
    • built one that looked like a hula hoop: folder 6m dipole in a loop
      • omnidirectional + wide bandwidth
      • he can lend it
  • WA3VEE, Ron:
    • double bazooka design
• WA3VEE, Ron:
  • What’s the minimum to deploy in the field for HF, VHF, UHF?
  • KC3TYX, Vic:
    • radio, hamstick, battery
  • W8CRW, CR:
    • just his truck: it has everything for UHF, VHF, HF.
  • KC3YSM, Steve:
    • looking at plans for simple wire antennas.
      • KB9VBR pota performer on a camera tripod with elevated radials
      • going to try to build that one
  • WA3KFT:
    • handful of hamsticks
  • W3MFB, Mike:
    • for emergency in car: UHF/VHF radio, CB, G90, some hamsticks
    • tune anything with a G90