My Week in Radio
- SWR trouble with HF antenna last week was a bad connection outside the window
- Operating on RF, since I’m mobile on a hill after camera club meeting
- APRS radio went quiet, so my slim jim seems broken
Others
- WA3VEE, Ron:
- hosting upgrade classes soon
- look for article or whatever: “listening to jupiter”
- W3MFB, Mike:
- 10-10 contest over the past weekend
- good conditions
- Europe
- 10-10 contest over the past weekend
- KC3OOK, Bill:
- working on sub-panel for ham shack
- W3KZG, Scott:
- doing radio repairs while it’s cold out
- installed radios in larger rolling rack: 30U
- KA3GLI, David:
- reading the W1MFB Antenna Notebook
- building EFHW un-un
- visited RadioShack in New Holland
- KC3NZT, Harvey:
- got online confirmation for Galapagos
- AA3LH, Leon:
- Roosters Net
- working 80m and 40m, extra portion
- will work on antennas next week when warm
- AF3Z, Jim:
- FYBO (Freeze Your Buns Off) QRP contest over the weekend
Questions
- KC3OOK, Bill:
- What’s the difference between ceramic and plastic potentiometer trimmers?
- WA3KFT, John:
- ceramic may be for VHF/UHF applications
- moisture may detune a circuit being adjusted
- W3KZG, Scott:
- he has cheap plastic kit with lots of sizes. it functions fine.
- 6-8 plastic screwdrivers
- cheap is fine for light use
- NA3CW, Chuck:
- has plastic, never tried ceramic
- materials matter for trimming variable capacitors
- any material is fine for pots
- WA3VEE, Ron:
- How sensitive are some of these circuits?
- W3KZG, Scott:
- tools are non-conductive and non-inductive
- some pots can be shorted
- KN3I, John:
- GC Electronics kit should be really good; known name.
- AA3LH, Leon:
- He has a G5RV doublet for travel, and it tunes hard on 80M. If he added 10ft to each leg (51-ft legs to 61ft), would it help, and how would he need to adjust the 37-ft?
- NA3CW, Chuck:
- simulate it
- stay away from quarter wave feed lengths
- probably ok with tuner
- W3GMS, Joe:
- for the standard lengths, the impedance is around 50 ohms, so only needs the 1:1 balun.
- may need to trim the ladder line
- NA3CW, Chuck:
- G5RV is 3/2 wave for 20m, so it work well there + other bands.
- extra length will detune it for its intended use
- W3GMS, Joe:
- look into the “improved G5RV” - better tune
- adjusting probably won’t get you much
- add more open wire line and eliminate coax, and it’ll be an efficient doublet
- KB3ZIM, Bob:
- Did anyone work AM Rally? He got 30 contacts and had a blast: 10m, 40m, roundtables
- KN3I, John: just a few hours in the afternoon on 40m
- KC3NZT, Harvey:
- Testing diodes in a rectifier before a coil:
- Had to measure the current to calculate the resistance, since he couldn’t isolate anything.
- Is there a better way to test coil resistance through the diodes?
- How do diodes fail?
- WA3VEE, Ron:
- Diodes usually fail shorted
- WA3KFT, John:
- diodes change resistance with the amount of current
- isolate the diode and use DC with known resistor
- measure resistive drop across diode
- W3KZT, Scott:
- need to isolate diode from the coil to measure
- resistance in coil
- Testing diodes in a rectifier before a coil: