1. The VFO ( Colpits oscillator), was built in a large size chassis with big coils and running between 5-5.5 MHz. The temp. stability was excellent for that time with a total cold-warm drift of less than 500Hz.
2. Here you see the SSB exciter. The filter was of a cascade 2x half-lattice type. The x-talls were taken from FT243 WW2-junk and put on the correct QRG's (ca 450KHz) by crisping the corner(s) of the crystal-plate which moved the resonance freq. upwards without changing the Q too much.( A one way change of course ) Another method used was by means of a copper-sulphate electrolyte bath where a few um of copper was added to the (gold-plated) crystal surface. This process changed the resonance frequency downwards and was reversible. The bandwidth of the complete filter was ca. 2.5 KHz and a shape factor of 2.3 was achieved. Extra L/C filters after the lattice filters gave an excellent stopband rejection. The 450 Khz was mixed with an 8.5 Mhz L.O. to create the final i.f. of the exciter at 9 MHz. At this freq. a pair of good L/C filters was used to obtain a clean SSB signal with good spurious- and mirror freq. rejection. This 9MHz signal was than mixed with the VFO (5-5.5) for 20 or 80 mtr operation. For the other bands, additional mixers and L.O.'s were used.
3. The station could also be used for real AM. That time there were several stations that couldn't even listen to SSB ! This is the AM modulator giving ca, 10 Watt of audio with selectable audio bandwidth filtering. This unit included also the VOX and PTT system. Modulation was of g2 type in the final r.f. amplifier ( 2 x 6146 tubes ) which you see in (4).
4. This is the r.f. pre- and final amplifier using an EL83 as driver for a pair of 6146's. The output power of max 75 Watt on CW and SSB and ca. 35 Watt carrier power on AM isn't directly what we are used to today, but was quite normal during that time in Holland.
5. Well, here comes the QRO ! Six (6) tubes 807 in parallel running in single-ended, zero bias, grounded-grid, getting a max. output power of ca. 250-300 Watt on SSB. This was not so easy as the 807 is a beam-power tetrode with the beams internally connected to the cathode. This means that the socket had to be opened, the wire from the beam-plate to the cathode cut and reconnected to one of the grids. This could only be done with the U.S. made types of the 807 as the European manufacturers had the beam-plate_to_cathode connection in the glass bulb itself. The plate voltage came from a direct mains-voltage tripler (3 x 220V x SQRT2), this means that the whole chassis was floating on D.C. ( rather hazardous, isn't it ..)
6.and 7. Here are the power supplies for the VFO, exciter and final amplifier. Even the transformer in the power supply for the final r.f. amplifier (7) was home made. An old transformer was rewired by hand to get the correct voltages, which took a couple of weeks due to the H.V. sec. side of 600V. 30 years later I still have scratches on my hands from all copper wires 'gliding' through my fingers. ( I'm never going to do this again but it was a real challenge :-)
8. This Geloso RX front-end was the "real_pain_in_the_neck" ! Several modifications were necessary to cancel frontend- and mixer overloading, spurious and other nasty behaviours. ( As a poor student, I couldn't afford this stuff instead )
9. This is the RX final stage. Also here a double half-lattice filter was used at 450 KHz. It had an excellent AGC performance and a superb audio quality. ( I'm still missing that in today's Jap equipment..) This unit was built by my good friend PA0STU, today ZS6CS
10. The SWR meter L.P. filter and antenna switchbox is located here. As antennas I was using a 3 el. Mosley for 20, 15 and 10, a dipole for 80 and a vertical that could be used for 40 and 20 meters. Some other wired ( and weird :-) stuff was used for 160 meters.
Each year, we went on several field-days. Sometimes for fun only, other times to go for the first place in the CW-contest in the (rare) free areas of Rotterdam using our club station call PA0RTD. The picture above was taken in 1966 on a just_for_fun field-day ( VERON Pinksterkamp). For a change, I'm holding a microphone and not a glass of beer which was actually more common being a student in the sixties. The SSB home-brew transceiver in front of me was built by PA0SSB who is the other youngster on the picture. Jan PA0SSB was a few years later the first Ham in Europe on EME (Earth-Moon-Earth) with all home brew equipment. Also, he was probably the first in Europe that listened from his home to the Apollo crew on the way to the moon. This home made SSB transceiver, by the way, was the first one built in Holland in this compact state entirely with tubes. If I remember correct, 28 of them ! At the right hand side of the SSB transceiver you see the compact final RF amplifier with 4 pcs 807 in grounded grid. The biggest box on the picture is actually the loudspeaker :-) Jan 'SSB' was, and still is, one of those real home-brew guys that never give in !
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