Radio Society of Greater Bixby

Earl WB5UUW from Broken Arrow, brought in this key component of an All Band Rotary Spark morse code transmitter from the WWI era, a motor driven spark gap. Together with a huge power supply (takes 2 men and a boy to lift), CW key, and aerial wires connected to the two spark posts shown, it’ll run about 10 kW and allow you to make contacts perhaps hundreds of miles distant on a good night. (You caught the part about being an All Band transmitter.)

Parker W1YG recreated a tube type Hartley Oscillator single tube transmitter as used in the 1920s and we had several pics of it at the meeting. Using a sine wave oscillator on a single frequency meant that several guys could get on the air without interfering with each other, a big improvement over wide band spark transmitters.

We also inspected an hourly chart of a 100Ah LifePo battery charging voltage. LifePos both charge and discharge in the range of 13.0 to 13.5 V which should make your 12V rig very happy. Charging is 99% complete at 13.6 V so it’s possible to use a charger meant for lead acid batteries (typically ending at 13.8 to 14V) and not have to buy a separate (and expensive) charger specific to LifePos (which usually have an internal Battery Management System that CUTS OFF if you try to charge them much over 14.4).

Rich ZQG recently bought a Palomar Engineers OCF 4010 antenna and showed the SWR chart for several bands. It wasn’t as good as claimed (usable on Every Band 40 thru 6M) probably because it’s only up 15 ft with one end drooping down to 5 ft the last 20 ft of antenna. More later. Here’s the more: Got it up 8 ft at the ends, but still only 15′ at the 4:1 balun. Tunes real good (low SWR on 40 and 15) and OK on 20 and 10, tunable or even straight through at like, 2.1 SWR or a little more. Chart says it’s supposed to be OK on the WARC bands (30, 17, and 12M) but you really need a tuner there. Six (6M) meters (SWR 2.7) is usable with a tuner.

Matt Damon starred in the movie The Martian, and was rescued partly due to a spaceship returning from Mars using a SlingShot Orbit around Earth to go back and pick him up. We discussed various orbital parameters and requirements, noting the Space Shuttle uses only 2 stages, solid boosters and the shuttle itself with an Enourmous fuel tank (as opposed to the conventional 3 stage rocket) to attain orbital velocity. See you at the next meeting 11 December. (4th Thurs canx bc Thanksgiving)