Dipole

Portable Doublet

I built a doublet experiment at a park today.

• split 6.25M of speaker wire to be a 12.5M-long, center-fed, non-resonant dipole, like my portable EFRW I usually carry.
• the rest is balanced feed line
• right to the radio
• tuned 20M and barely tuned 40M on my X6100
• 2W FT8 heard in africa and europe
• next try it with a 4:1 or 9:1 balun to match better

My Weeks in Radio

• feel lucky to be in this area with lots of repeaters and traffic
• flagpole with YAGI snapped in the wind a week or 2 ago.
• strung the slim jim in the tree a little higher
• playing with nicsure firmware on the RadTel RT-880G.
• saw a great youtube video on APRS bots:
  • MPAD being very versatile for: weather, callsign lookup, location report to email
  • ISS bot that tells you the next pass
• listened to a couple sweepstakes contacts: to lazy to try to communicate that much exchange QRP SSB

Others

• WB3LNY, George:
  • Tried La Grange repeater in KY, but no one answered.
  • Keep as active as we can.
  • Use it or lose it: they’ll take it away
  • linking repeaters may help generate more traffic
• VE3HOH, Pete:
  • working on some Yaesu FT-100’s
    • predecessor to FT-857.
• KA3TKW, Tom:
  • lunch Thursday this week
    • everyone share a radio gadget
    • lots of mini demonstrations
  • ISS scrubbed the SSTV after first couple days
  • ISS ham repeater is still good though
    • high pass monday, 4:45pm
  • Russian satellites doing SSTV
    • 435.890 ARCTICSAT-1: 2 good passes Monday morning
    • 5 minute cycle, so don’t be discouraged
• KK4KKW, Steve:
  • many times can’t make contacts while traveling: 2M or 10M
  • hearing people on HF, but not making contacts
• N7JMS, John:
  • digipi doing SSTV to get ARCTICSAT-1 images
• K3DMM, Denny:
  • doing some of the sweepstakes
    • got Hawaii
  • definitely trying morning pass of arcticsat-1
  • trying for ISS pass as well
• KD3BOV, John:
  • rain gutter antenna
  • getting started with the ICOM 2730

Swap and Shop

• WB3LNY, george:
  • new bird dummy loads
• VE3HOH, Pete:
  • rohn 25 tower sections:
  • guy wire and anti-sway section for the rohn 25
  • 432MHz yagis
  • 2M yagis for weak signal
  • 950ft of philly strand on a roll
• KA3TKW, Tom:
  • shortware receivers
  • moto 25W transceivers
  • 24ft camper for sale: $1500

Matt and I activated POTA US-1743, White Clay Creek, DE. I deployed the 20m-long EFHW into a tree, which worked nicely with no SWR. Matt deployed a telescoping dipole on a mast. I worked only 40m, and Matt ran 20m. We didn’t interfere with each other at all. I forgot my 5525 power splitter to run both the laptop and radio off 12V battery, but fortunately I didn’t need it for the computer.

Reception Problems

During 985 net on Monday night, which is VHF on my UV-K5 running egzumer 0.22.0, I’d get periodic static in reception. It got bad enough to completely cut-out. I was using my simple wire dipole hanging in the tree outside.

K3IR had been frustratingly quiet as well, so I checked the antenna with the NanoVNA as it hung outside. There were no fluctuations in SWR, so it’s not connections or proximity.

I tried the Explorer QRZ-1 HT, and it sounded great on the same antenna on the same net. Is my UV-K5 broken?

To test a bit further, I ordered a new UV-K6 to compare. I also downgraded to egzumer 0.21.0 for further testing.

The next day, Tuesday morning, K3IR was sounding better, but I was getting the same periodic noises. The outside antenna doesn’t completely cut out, but shows terrible doubling/overload as if from FM station.

Inside, the magmount antenna on the 3d printer is better. Is the dipole outside too sensitive and bringing in more signal than the frontend of the UV-K5 can handle?

I have a dipole that’s 20m long (10m each side) strung through the house right to the banana plug adapter to the radio and no coax. I’ve coiled the wires together at the feed point to shorten and tune. I can run 40m with tuner turned off. I’m hitting Europe, Central America, Canada, and the midwest US.

I figure, since the wires are insulated and kept parallel to each other, the coil is serving as feed line and not part of the antenna.