K3PGP
.Experimenter's.Corner

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Early 70's EME at K3PGP

EME Antennas - Looking North early 70's

Left: Homebrew 96 element 144 Mhz Skeleton Slot array

Center: 24 foot homebrew dish built in 1971 - 220, 432 & 1296 Mhz

Right: 6 Foot polar mounted dish - 1, 2 & 3 Ghz

This dish antenna made 432 WAC in less than 4 mounths. K2UYH was issued the 1st ever 432 Mhz WAC and K3PGP # 2 approx. 15 minutes later. Unfortunately, NO numbers appear on the certificates.

Homebrew crank up tilt over tower in background in LOWEST position.


Looking North 24 Foot Dish 1978
144 & 432 48 ele. slot on tower
Part of 96 ele. EME array on left

Looking South with the dish parked
straight up, the way it was always
stored when not in use.

LDE (Long Delayed Echo) observed with the above antenna on 432 Mhz.


Shack as it appeared 1968 to 1978

Left Photo = Operating position. The Heathkit SB-300 receiver (left side bottom) had all it's tubes removed and replaced with 40673 Dual Gate MosFets. The leads were soldered to wire the same diameter as the tube pins and simply pushed into the tube sockets! An FET (MPF-102) was used to replace the tube in the LMO and a transistor audio amp replaced the audio system. A homebrew LED digital frequency readout is visible on top of the receiver along with a tunable narrow band op-amp based audio filer used to pull the weak EME stations reflecting from the moon up out of the noise. With all the tubes gone the entire receiver system ran on 12 VDC and the original HV supply was modified to produce only 12 vdc by using the filament winding on the transformer. 30+ years later this receiver is still working. No parts (or tubes!) have needed replacement!

Right Photo = Left Rack top to bottom = 432 Mhz FM exciter, 432 1kw amp, screen & bias supplies, 300 watt 144 amp, 2 to 4 Ghz TWT (traveling wave tube amplifier), 432 SSB/CW upconverter exciter. High voltage supply in bottom of rack not visible in this photo.

Center Rack top to bottom = Large 16 segment nixie tube digital clock, 2 & 4 Ghz TD2 Exciter, 1 kw 144 amp, (used a 4CX-1000A with the screen grounded!), screen & bias supplies. 4 Kv high voltage supply is in bottom of rack not visible in this photo.

Right Rack Top to bottom = Tape recorders & misc Receivers


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