985 Workbench: 2025-12-01

My Week in Radio

playing with my speaker wire doublet portable
- extended to 44ft end to end
- 10M and 40M tuned with some work
- 20M tuned easily, but killed the radio’s USB connection with every TX
- adding a current balun for next test
CQ WW CW 2025
- 20 contacts on CW
- estimated maybe 200 points
- heard Hawaii on 40M
participated in Simplex Net, and got a strong signal to west control

Others

W1RC, Mike:
- sorted stuff in the garage decide its fate
W3MFB, Mike:
- hosted the roundtable last week and this week
- heard all the controls of simplex net
- 10M HF work mobile
WA3VEE, Ron:
- visited Bar Harbor area: Elsworth and Bar Harbor repeaters
K3FF, Rene:
- installed capacitor board into Clipperton:
  - full voltage and working!
  - 700-800W out: needs some new tubes
- ATU-1000 kit
  - follow picture to assemble
KB3MNA, Chris:
- setting up home station
- studying for General
W3QP, Tim:
- activated all the summits in iowa: 2 of them
- South Dakota, Minnesota, Wisconsin
- Friday is Pottstown Club meeting: why you should be chasing SOTA
KD3BPI, Simon:
- shopping HF rigs on FB marketplace
- studying for general
NA3CW, Chuck:
- PMAM Net: 16 checkins
  - good conditions
  - lots of DX 100 heathkits sounding good
KC3OOK, Bill:
- central control for simplex net
W3KZG, Scott:
- replaced truck radio with IC-7100
- made a few HF contacts
WA3KFT, John:
- Antique Wireless 40M Net saw lots of New England
- 10M is open
KD3AIS, Tim:
- 30-inch antenna on magmount didn’t work out on truck
- playing with meshtastic: T-Beam supreme
KV3JGB, Matt:
- studying CWOps to refresh

Questions

W8CRW, CR: Made a homebrew antenna for Simplex Net. How would one figure out the max power for a homebrew antenna?
- NA3CW, Chuck:
  - “it depends”
  - size of conductor
  - contacts
  - insulation (voltage)
  - cores
  - cables
  - durability of all the components
  - a dipole and wire line with good insulators can take multiple kW
  - transformers and coils introduce weak points
- W3KZG, Scott:
  - matching circuit of a commercial antenna introduces limitations
  - in simple dipole, the feed line may be the only limit
  - run some power and see if anything is getting hot
- WA3VEE, Ron:
  - components and size of wire
  - capacitors have ratings
  - figure out the voltage on the antenna: it’s in the study manual
- WA3KFT, John:
  - on a simple dipole, the feed point is low-voltage, but the ends are very high, so that’s where you need the insulation
- W3MFB, Mike:
  - can cut insulators from PTFE scraps.
- NA3CW, Chuck:
  - at very high power, the sharp ends will form corona discharges.
    - round ends or put balls on it
    - not a problem for our power
  - a shortwave station in the Andes years ago would burn off the ends of the antennas, so they went to egg-beater ends.
- W8CRW, CR:
  - it’s actually a simple quarter-wave ground-plane
  - good to know 100W will be nothing for it
AF3Z, Jim:
- Hasn’t put specific insulator on his dipole, just tied to some paracord. Does a real insulator make a difference?
- WA3KFT, John:
  - on a 40M or 80M dipole, the end will be high voltage.
  - nylon cord is probably fine at 100W.
  - if it absorbs and holds water, it can extend and detune the antenna.
  - insulators shed water
- NA3CW, Chuck:
  - wet rope will drain energy and effect efficiency
  - 100W won’t matter much
  - some are a foot-long and heavy porcelain, etc
- WA3VEE, Ron:
  - ice on the cord with no insulator will detune the antenna
W3MFB, Mike:
- can you co-phase 20M or 40M vertical antennas? is it then directional?
- WA3VEE, Ron:
  - directional AM broadcast antennas are co-phased.
  - yes it can be done for ham frequencies
- KA3KFT, John:
  - worked at an AM station
  - 3 towers tuned and phased for a 4-leaf pattern
  - between 1/4 and 1/2 wave apart
  - varying current would allow steering of the signal
  - at the base of each tower, there was a tuning network.
  - largest node pointed toward the licensed city.
  - null pointed toward a city with a conflicting station.
- WA3VEE, Ron:
  - envision throwing rocks nearly at the same time into a pond and how the waves interact
- KD3EE, John:
  - check out Coastal Waves and Wires for recent examples of vertical yagis and vertical phased arrays.
- WA3VEE, Ron:
  - directional “protection” has been done for a long time
  - pay attention to the lengths and velocity factors of the coax
- KC3SQI, Wayne:
  - besides AM steering, check out the WVUD FM transmitter at University of Delaware.
  - had to go to phased array to protect another station when they jumped to 5kW
- W3GMS, Joe:
  - in large AM stations:
    - phaser is the equipment that changes phase for steering
    - “dog house” is the tuner the bottom of each tower
  - phasing for our-sized project is done by varying the length of coax

My Week in Radio

Others

Questions

See also