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~ Under construction – I’ll add more photos soon ~
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THE STATION OPERATING BENCH AND EQUIPMENT:
♦ The shop includes two work benches. The operating work bench is L-shaped with a 10′ long side and a 3′ short side containing a sink. A second work bench, at the other end of the shop, is my “construction” workbench and is usually a mess of unfinished projects. It’s about 6′ long.
♦ The operating bench includes a homebrew 6AG7-6AG7-6L6 xmtr with about 16 watts input depending on where I set the variable B+ voltage. It is presently crystal controlled using FT-243 40 meter crystals. Ultimately, it will use the BC-221 as a vfo, which is why the xmtr has an extra 6AG7, to boost the weak output of the BC-221. I may also use a Collins T-195 PTO as a vfo which has a built-in cathode follower but also needs to have its signal boosted.
♦ A 40 & 30 meter solid state regenerative receiver with specially filtered DC from a homebrew 0-20V DC supply. It includes an RF stage and a small 2N3904 + LM386 audio amp. It uses the basic Charles Kitchen circuit. The audio output is fed into an old Autec QF-1 audio filter and the output from that is fed into a large audio amplifier & loudspeaker system. It works well on 40m and just adequately on 30m. The bandspread is insufficient on 30m – I need to fix that problem. The 40m bandspread is perfect.
♦ A Collins T-195 Permeability Tuned Oscillator was given to me, and I installed it in a home made cabinet. It is fed by a homebrew regulated power supply. I intend to use it as a VFO for various home-made transmitters, including the 6AG7-6AG7-6L6 one. It’s just fun to play with. I might convert it to Solid State some day and add a MOSFET xmtr to make it a 20 – 40 watt xmtr.
♦ Yaesu FT-840 transceiver, powered from a homebrew 13.8 volt regulated linear supply built using junk parts and a modern digital voltage meter. The slick, modern volt meter hides the fact that the insides are junkyard parts.
♦ Home-made Antenna Tuner, using the Collins 180S-1 circuit originally designed for aircraft use with a trailing wire antenna . It tunes anything I can hook it to and is good for at least a KW. The Collins circuit is a pi network (cap – variable coil – cap), except that the input cap can be switched between a series or parallel configuration. The variable coil came from the driver section of an old Navy 10KW transmitter that was being dumped into the ocean, and the tune and load caps are from an old Johnson KW Matchbox that had been badly hacked. An outboard SWR/PWR meter is used; and an outboard RF field strength meter helps out.
♦ A second Antenna Tuner is just for random wire antennas and consists of a variable inductance plus a variable capacitor in a network that can be switched to a C-L or L-C configuration. Works well with a random wire antenna or with my big horizontal loop if that’s fed through a 4:1 balun.
♦ Dummy Load is a 50 ohm, 250 watt solid state microwave load.
♦ I have two antennas: One is an inverted Vee with the apex at 50 feet and 137 foot legs, running roughly North-South. I notice that it has many lobes – even off the South end, into South America! It uses a 450 ohm twin lead feed line terminated in a home-made 4:1 air balun, wound on a piece of PVC. The output of the balun connects to a short length of 50 ohm coax that feeds the Collins clone antenna tuner. It obtains a 1:1 match on 80 – 10m. The other antenna is an approiximately 500 foot roughly shaped low elevation loop that goes through the woods behind my house – 8 to 10 feet high. It is probably a real cloud burner but it hears everything. It is fed with 450 ohm twinlead and usually connects to the Hammarlund HQ-129-X but can connect to any receiver/xmtr due to an antenna patch panel that is installed at the operating bench..
♦ A future project will provide an RF Preselector circuit, with provision for switch selectable multiple antennas, a bypass/RF amp switch and provision for routing the output to any of three receivers. The RF amp will be low gain; just enough to replace any circuit losses. The intent is selectivity, not sensitivity, as most receivers are quite sensitive on the lower HF bands.
♦ The operating bench contains a restored BC-221 that I use for various purposes and which can be used as the VFO for the 6AG7-6AG7-6L6 xmtr mentioned above. I have a second BC-221 that has been repaired but which needs calibration…it mostly sits around. There is also an LM-8 that works fine and which resides on my construction workbench.
♦ There is also a sensitive 200 ua home-made field strength meter and a Radio Shack Power/SWR meter. See “projects” – I’m rebuilding my old 1972 Heath SWR/PWR meter. I also plan to rebuild the field strength meter into a new box, with a more sensitive meter I found, and a crystal calibrator which will broadcast to any of my radios.
♦ Two “All American 5” AM radios rescued from the dump and repaired. The Westinghouse one is actually a 6 tube as it has an RF stage – quite sensitive!
♦ A dump-rescued and repaired analog solid-state Harmon-Kardon AM/FM tuner/amp & nice loudspeakers that I use for the operating bench audio amp for various pieces of equipment. It must be 40 years old…seems to have a “hot” RF end for both AM and FM When it dies I’ll build a 6L6 audio amp to replace it. I have all the parts for a nice 6L6 stereo audio amp…it’s on the project list.
♦ An older PC someone gave me, which runs Microsoft XP – it runs OK but some day I will convert it to one of the Linux Ubuntu variants as I don’t want to pay Microsoft for Windows 10, which might be too cumbersome for its small RAM-brain anyway. I need to install some CW receive/send software onto this, because while I can type fast, I can’t send CW fast…I’m a real slowpoke.