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Title: Heathkit HW-32A Post by: kb3wbb on June 17, 2011, 02:13:19 PM I picked up this Heathkit HW-32A SSB (20M) transceiver today, complete with power supply, external speaker, headphones, all cables, and original manuals. I figured it was a good starter. Is there anything special I should look for when giving it a going over?
(http://i863.photobucket.com/albums/ab191/rocketeer_2010/Radios/hw-32a-2.jpg) Larry Title: Re: Heathkit HW-32A Post by: KK4YY on June 18, 2011, 01:40:12 PM Larry,
I bought the Heathkit HW-12 75M SSB xcvr a while ago. It drove me buggy chasing problems around and around until I replaced the tube sockets. Yes, the sockets! The 9 pin tube sockets had very weak contact force. I tried the whole Deoxit route to no avail. Only replacing the sockets worked. PC board mounted sockets were not in my junkbox but I was able to modify chassis mounted ones which I had. Mine was an earlier version than yours so Heath may have used better sockets or maybe mine was just a dud in that respect. This can be an issue with ANY older tube rig and poor tube pin contact pressure can be very frustrating to troubleshoot. Contact varies with humidity, temperature, current, vibration... Nuts. Good luck with the rig and let me know if you find a way to put it on AM. Don Title: Re: Heathkit HW-32A Post by: w3jn on June 18, 2011, 02:42:27 PM They're very easy to put on AM, if you don't mind losing the receiver.
1 - remove the crystals from the crystal filter, and jumper it out. 2 - disable the ALC control, as I recall grounding the ALC line works well 3 - pull the audio tube, and feed the audio right to the cathode of the audio cathode follower. This is ~ line level input at this stage. I might have fattened up the coupling cap here, don't remember for sure. 4 - Unbalance the carrier balance for about 20-25 watts of RF output. This control tends to drift, so it's probably best to replace it with a 10-turn precision pot. Once you bypass the xtal filter the receiver will receive the whole band at once, making it pretty much worthless. The audio response is ~ 10 hz-20 KHz or more, so make sure you run some audio processing to limit the audio bandwidth. You also need to run a scope, you can make 200%+ modulation if that carrier balance drifts around. Title: Re: Heathkit HW-32A Post by: W2VW on June 18, 2011, 03:13:51 PM Pipe that receiver to a Softrock....
They're very easy to put on AM, if you don't mind losing the receiver. 1 - remove the crystals from the crystal filter, and jumper it out. 2 - disable the ALC control, as I recall grounding the ALC line works well 3 - pull the audio tube, and feed the audio right to the cathode of the audio cathode follower. This is ~ line level input at this stage. I might have fattened up the coupling cap here, don't remember for sure. 4 - Unbalance the carrier balance for about 20-25 watts of RF output. This control tends to drift, so it's probably best to replace it with a 10-turn precision pot. Once you bypass the xtal filter the receiver will receive the whole band at once, making it pretty much worthless. The audio response is ~ 10 hz-20 KHz or more, so make sure you run some audio processing to limit the audio bandwidth. You also need to run a scope, you can make 200%+ modulation if that carrier balance drifts around. Title: Re: Heathkit HW-32A Post by: WQ9E on June 18, 2011, 03:21:31 PM The Heath monobanders present interesting possibilities with their open construction/discrete component crystal filter. It would be possible to broaden the response by changing the filter crystals. You could still diode switch the filter out for transmit if you wish.
Title: Re: Heathkit HW-32A Post by: w1vtp on June 18, 2011, 06:49:27 PM Pipe that receiver to a Softrock.... They're very easy to put on AM, if you don't mind losing the receiver. 1 - remove the crystals from the crystal filter, and jumper it out. 2 - disable the ALC control, as I recall grounding the ALC line works well 3 - pull the audio tube, and feed the audio right to the cathode of the audio cathode follower. This is ~ line level input at this stage. I might have fattened up the coupling cap here, don't remember for sure. 4 - Unbalance the carrier balance for about 20-25 watts of RF output. This control tends to drift, so it's probably best to replace it with a 10-turn precision pot. Once you bypass the xtal filter the receiver will receive the whole band at once, making it pretty much worthless. The audio response is ~ 10 hz-20 KHz or more, so make sure you run some audio processing to limit the audio bandwidth. You also need to run a scope, you can make 200%+ modulation if that carrier balance drifts around. YES! Softrock will do very nicely in this application. Might see some junk off to the side but around F0, It'll be pretty and sound great |