The Sun shone down gloriously on theā¦ yeah well ok it wasnāt quite dark yet, being being only the day after Autumn Equinox and as Daylight Savings Time was still in force, but ok, it was still the half-light of dusk as 17 folks trickled in the door at Christchurch Amateur Radio Club Clubrooms and after spending awhile kicking the tyres of whatās on the junk/recycling table, the meeting started.
First was Mark Atherton ZL3JVX with a Powerpoint presentation showing enlarged pictures of his latest project. A āPlanar Triodeā, basically a home made flat Valve heās made up as an experiment. I guess when one ācomes up withā a surplus high vacuum pump and bell jar, one finds uses for it. Mark reckons he had a full head of hair before starting the project and after many months of frustrating effort, heās already thinking up ideas for his next vacuum related project. āThe Worldās First Stupidtronā is how he described it, comprising three Triodes and incorporating Phosphor which has been salvaged from old CRT screens.
John ZL3IB was there with another one of his home made items of diagnostic test gear. A Signal
Tracer with the Probe constructed out of a felt marker pen. The outer case was cut from an offcut of rectangular downpipe (apparently John just pops into hardware stores and buys damaged lengths by the metre). He reckons itās great for working on old valve (thatās vacuum tube, for Americans) equipment.
Next up was Keith ZL4JA. (He reckons heās been licensed for 57 years, I just wanna know what moisturizer he uses, ācause to me it looks like he must have passed his ticket when he was about 4-years-old). Heād wondered if the receive capability of cheap Baofeng type radios was being compromised by excessive signals seeping in, especially from the normal FM Broadcast Band. This problem seems to be greatest on the VHF band and while using extra, external antennas fitted to Baofengs.
Using ELSIE for his prototyping and his new VNA heād done some experimenting in developing some improved filtering that could be added (externally). Personally I thought it sounded a bit hokey and
didnāt think his added filter would have very much real world effect.
The meeting paused then for a few minutes while he got set up in the radio room and then we all crowded in there, while he got a QSO happening. Well having listened in during segments, first without, and then with the new filter, I can say it was like comparing āchalk and cheeseā. The results from that homebrew filter were amazing.
The most memorable quote from the evening came from Keith when heād said earlier āI miss my days at Taitās when you could (just) do projects !ā And that was all for the night. Come on folks get out the soldering irons and shake the junkbox and see what homebrew projects can be ready for the next show-and-tell meeting.
Author Catherine ZL3CATH
