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 Post subject: Re: Using Vintage Ham Transmitters
PostPosted: Jun Sun 23, 2019 11:02 pm 
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Collins 32V1 AM/CW is what I have. About as solid as can be, but weighing in at 105# it's no lightweight!

Scott Todd


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 Post subject: Re: Using Vintage Ham Transmitters
PostPosted: Jun Wed 26, 2019 3:02 pm 
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They are nice transmitters, about the same output power as a Valiant but much better frequency control.

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 Post subject: Re: Using Vintage Ham Transmitters
PostPosted: Jun Thu 27, 2019 12:08 am 
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Location: Charlotte NC
That is a nice looking transmitter


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 Post subject: Re: Using Vintage Ham Transmitters
PostPosted: Jul Sun 07, 2019 3:38 am 
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Location: Charlotte NC
Well I picked me up a Hallicrafters HT-32B today for $40 bucks. Will have to be restored.


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 Post subject: Re: Using Vintage Ham Transmitters
PostPosted: Jul Sun 07, 2019 2:25 pm 
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rhrailfan wrote:
Well I picked me up a Hallicrafters HT-32B today for $40 bucks. Will have to be restored.


That is a very nice transmitter and if the condition is decent that is an excellent price.

The power transformer in this series is prone to failure because the 5 volt winding for the HV rectifier shorts to the core. If it hasn't already been done, change the tube type rectifier to solid state with added dropping resistors and rewire so that the 5 volt filament winding for the HV rectifier is no longer connected. Also add inrush protection on the primary.

The HT-32B was the last of the big and heavy transmitters sold by Hallicrafters and they first intended for it to be paired with the SX-101A but then the SX-115 was introduced and that became the new recommended receiver pairing. Earlier HT-32B production had knobs to match the SX-101 series while later production had the large flute knobs that match the SX-115. The very heavy but well built HT-33B is the matching amplifier, at 120 pounds it is one of the most awkward pieces of equipment I own and one that I really don't like removing from a shelf.

Rodger WQ9E


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 Post subject: Re: Using Vintage Ham Transmitters
PostPosted: Jul Mon 08, 2019 2:41 am 
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Location: Charlotte NC
As far as condition all the knobs are missing and the power cord is trash. Inside is dusty but not in bad shape. I was told that it worked when it was placed into storage about 12 years ago.


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 Post subject: Re: Using Vintage Ham Transmitters
PostPosted: Jul Mon 08, 2019 10:05 am 
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I agree, the HT-32B is a good transmitter. I plan on pairing mine with an SX-100 I just finished working on a couple weeks ago.

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 Post subject: Re: Using Vintage Ham Transmitters
PostPosted: Jul Tue 09, 2019 2:26 am 
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I need the knobs off yours haha! I also purchased a working and great looking SX-71 with matching speaker the same day I got the HT-32B. Would the two make a good pair?


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 Post subject: Re: Using Vintage Ham Transmitters
PostPosted: Jul Tue 09, 2019 3:23 am 
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I've only done a quick check of a couple SX-71s in the last year or so, and as I remember the receiver probably wouldn't work well for SSB, but might be fairly useful on AM.

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 Post subject: Re: Using Vintage Ham Transmitters
PostPosted: Jul Tue 09, 2019 3:45 am 
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I agree with Mike's assessment of the SX-71 that it is not a great choice for substantial SSB operation. It was Hallicrafter's first double conversion receiver but it wasn't designed around SSB and it actually featured built in NBFM operation during the brief time when NBFM was expected to become popular as a way to avoid some of the problems of BCI (BroadCast Interference) but the growing popularity of television quickly made BCI a forgotten issue as TVI was a much more serious issue and made life miserable for hams and viewers and NBFM never caught on. A lot of the old timers credit TVI problems as part of the reason mobile operation became so popular in the 50s because although the rigs still caused TVI when operating in populated areas, the disgruntled TV viewer wouldn't be able to identify or attack the ham :)

Pretty much any receiver with a BFO can receive SSB but often not well or conveniently. If you plan to operate a lot of SSB with your HT-32B then a SX-96, SX-100, or SX-101 would all be excellent choices and the latest version of the SX-101 has a product detector but the earlier receivers in this family do a very decent job on SSB without the added benefit of a product detector. They are reasonably to very stable, have selectivity tailored for SSB reception, and sufficient BFO injection to do a good job on this mode.

I have both the black and white face versions of the SX-71 and although it is an interesting and quite decent receiver, it simply was not designed to be an excellent SSB receiver and MANY other later Hallicrafters receivers are a better choice. The slightly less expensive S-76 receiver of the same era introduced the 50 Khz. second IF that became the standard for later high end Hallicrafters receivers including the SX-88, SX-96, SX-100 and other later models. It is a little better for SSB than the SX-71 but a slightly later model SX-96 or 100 would be much better. The SX-111 is a cost reduced version of the SX-101 family and it is also a very good SSB receiver, the late production has a product detector. The expensive SX-88 was really the first serious Hallicrafters effort at SSB reception with the best of their 50 Khz. IF strips (special high Q IF transformers not used in later models because of expense) and a BFO amplifier to provide greater injection level on SSB. But the later and much cheaper SX-101 and SX-115 are smoother operating receivers for SSB.

Happy shopping and good luck on getting the HT-32B into shape. Find the receiver you plan to use with it because as I mentioned in an earlier post Hallicrafters used two different knob styles depending upon when it was produced and if you find and go for the somewhat expensive SX-115 receiver it would be nice to try to match the knobs.

Rodger WQ9E


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 Post subject: Re: Using Vintage Ham Transmitters
PostPosted: Jul Wed 10, 2019 2:08 am 
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Joined: May Thu 09, 2019 12:06 am
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Location: Charlotte NC
Just a while ago I fired up the SX-71 and was listening in on the 80m band and yes SSB was awefull. But I did pick up a couple guys running in AM mode which was a surprise.


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 Post subject: Re: Using Vintage Ham Transmitters
PostPosted: Jul Wed 10, 2019 2:30 am 
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rhrailfan wrote:
Just a while ago I fired up the SX-71 and was listening in on the 80m band and yes SSB was awefull. But I did pick up a couple guys running in AM mode which was a surprise.


You will find quite a bit of AM activity, 3880 and 3885 are two of the "hot" spots for 75 meter AM.

The SX-71 is usable on SSB but not great. Try to find a "long winded" group in a round table and set the SX-71 for narrow crystal selectivity in AM mode with sensitivity at maximum and carefully tune for maximum S meter reading. You won't get this perfect because the SSB signal strength is constantly varying but go "by eye" and try to hit the frequency where the average peak is highest. Leave the tuning where it is, set the response to broad crystal or normal, BFO on, AF gain well advanced and sensitivity just high enough so that the station is plainly audible. Carefully adjust the BFO for normal sounding audio and this will be the proper point for that sideband (LSB assuming you made the adjustment on 40 or 80 meters). Make note of this BFO pitch setting which will be correct whenever you want to receive LSB. Now switch to 20 meters and do the same setup procedure to find the proper BFO pitch setting for USB and make note of it.

The SX-71 BFO output isn't extremely high because it was intended primarily as a AM and CW (and NBFM) receiver so you have to run with lots of post-detection (AF gain) and minimum necessary pre-detection gain (RF gain/sensitivity control) so that the BFO to signal ratio is sufficiently high. It is reasonably stable but not as much as most later receivers designed for SSB.

Rodger WQ9E


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 Post subject: Re: Using Vintage Ham Transmitters
PostPosted: Jul Wed 10, 2019 2:57 am 
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Location: Charlotte NC
Thank you for the info. I will give it a shot tomorrow evening. I was listening on my FRG-7 when I found this AM activity then I fired up the SX-71. This was the first time in over a month of listening that I ever heard anyone running AM on 80m.


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 Post subject: Re: Using Vintage Ham Transmitters
PostPosted: Jul Wed 10, 2019 3:16 am 
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rhrailfan wrote:
Thank you for the info. I will give it a shot tomorrow evening. I was listening on my FRG-7 when I found this AM activity then I fired up the SX-71. This was the first time in over a month of listening that I ever heard anyone running AM on 80m.


You are welcome!

I am not sure what part of the country you are located in but there is probably quite a bit of AM activity near you. You will also find quite a bit on 7290 and 7295 Khz but that isn't typically as active as 75 meter AM.

My primary AM stations are a Johnson Ranger driving a Johnson Desk KW with a SX-88 receiver and a Johnson Viking 500 with a Pierson KP-81 receiver. It is an interesting mode with a good group of people most of whom are vintage gear fans and a lot of homebrew and unusual equipment shows up on AM.

Rodger WQ9E


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 Post subject: Re: Using Vintage Ham Transmitters
PostPosted: Jul Wed 10, 2019 4:02 am 
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Joined: May Thu 09, 2019 12:06 am
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Location: Charlotte NC
I am located in North Carolina


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 Post subject: Re: Using Vintage Ham Transmitters
PostPosted: Jul Wed 10, 2019 4:06 am 
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Very nice looking station Rodger!!!

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 Post subject: Re: Using Vintage Ham Transmitters
PostPosted: Jul Wed 10, 2019 5:13 am 
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I am in Charlotte. I wonder if I could tune up my Knight T60 on an MFJ 1622 and get a little piece of these AM nets.


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 Post subject: Re: Using Vintage Ham Transmitters
PostPosted: Jul Wed 10, 2019 12:56 pm 
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Thanks Mike!

Rodger WQ9E


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 Post subject: Re: Using Vintage Ham Transmitters
PostPosted: Jul Wed 10, 2019 11:47 pm 
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Location: Charlotte NC
I am located just outside Charlotte. Yes that is a nice station set up there. I need to find a metal desk like that. Googled the SX-88 and seen that that is a rare and valuable radio.


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 Post subject: Re: Using Vintage Ham Transmitters
PostPosted: Jul Thu 11, 2019 1:33 am 
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Joined: May Thu 09, 2019 12:06 am
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Location: Charlotte NC
Sitting here now with the SX-71 booming on shortwave. I tried to tune in some hams on 80m but still no luck getting it to come in clear. I did manage to snag what I think was a numbers station somewhere between 4.5 and 5Mhz that was running on sideband and I got it to come in clear. Sadly I caught the tail end of the transmission and it came to an end. This is a all original radio that has not been recapped or anything so I'm sure that after a tune up it will perform better.


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