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Manager - AB7RG
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Vintage Station Build HT-44/SX117

Created by on 2022-08-30

 

SX-117/HT-44 Station Build 

 

A couple years ago I was contacted by several SX-117 owners. They wondered if I could write a repair manual for the 117 similar to what I had written for theHT-44 and the SR series radios (REPAIR MANUALS | WD0GOF). I said I couldn’t possibly do it unless I had at least three radios for testing purposes. I was surprised when two people came forward with loaners. A week later a third one showed up at my doorstep. So, I had my three radios. Two were real dogs, the other was pristine. This worked out fine. The dogs help me wring out the test procedures. The pristine rig gave all the “what it should measure” data I needed. When the project was complete and the manual published, I returned the radios, except one. The owner (of the pristine one, K9AXN) made me a deal I could not refuse. Also, I wanted to keep one on hand in case of questions about the repair document. -- So, then I had an SX-117

 

Now, if I can find an HT-44 I could build a station. I put out the call, I was looking for a tech unit I could refurbish to make a station. WD0GMD came through with a deal I could not refuse. He said it was in good cosmetic condition but, operationally it was in sad condition. And that was great. I repair and refurbish it; I do not restore. He had no power supply. Using the HT-44 repair manual I had written several years ago. I attacked the 44 using the power supply from my SR-160 system. As a result, I made improvements to the 44 repair document and ended up with a sweet running 44.

 

So, checking the shelves I find a TO Keyer but no power supply. People who have PS-150’s that are rust buckets want tooooo much for them. Now I am thinking, the metering scheme for the HT-44 is a bit lacking. So, the power supply became the “build” part of this project. I had a PS-150 transformer, the case from an SR-160, a speaker from an S48A and bins full of parts. I also thought let’s make the station easy to set up. I would include the antenna change-over relay in the power supply. I would use the antenna relay from the SR-400, I had several. That relay is a dpdt relay which would give an extra set of contacts for adding an amp. Although the 44 has relay contacts for controlling an amp, the contacts are not as robust as the SR-400 relay contacts. Or, it could always be used to control the station “ON THE AIR” sign.

 

I would call this custom power supply the PS-44, that took a lot of thought.

 

For metering I decided on input AC current, B+ voltage, High Voltage and Plate current. The only problem with the meters was the unavailability of a 0-1000v meter to match the other meters I already had. So, I used a 0-100v meter and added a series resistor to scale it up. Other than the metering and the addition of the antenna relay, the rest of the power supply is a carbon copy of the PS-150-120 power supply. The bias adjustment is a bit awkward on the PS-150. I decided to put the adjustment on the front panel. The speaker is in the top of the case. I painted the front panel white. I heat cured the paint so I could use Visu-Com, PRESTO STIK vinyl stick-on lettering. I would have liked a little smaller lettering but, ¼ inch was the smallest I had. For the stripe, I used masking tape, cut to size with an X-acto knife. I then sprayed it with RUST-OLEUM, AMERICAN ACCENTS, ULTRA MATTE SLATE. Before the paint was totally cured, I peeled off the lettering and masking tape.

 

 

wd0gof.com

N9AMI2022-09-07
Vintage Station Build HT-44/SX117
Very nice job. I would enjoy running that setup and can appreciate the work put into the power supply. Nice to see people building. Most operators today have no idea that this was as common as there baefung ht.
VE3CUI2022-09-04
Re: Vintage Station Build HT-44/SX117
Oh, I'm not saying that there's anything especially bad, or unacceptable, with the CW signals from OT rigs --- it's just that they sound "...different", or distinct, from to-day's crop of proverbial "Banzai 2000" transceivers...

They are known to drift a tad, have unique notes, etc., that makes the majority of them stand-out --- even signals from classic Drake "Twins" that were once considered to be the "...ne plus ultra" in the amateur world (with the exception of the Collins S-line, of course!).

But the old boat anchors are otherwise just great, IMHO: they're easy to service, parts are still available, they're fun to use, & fun to just LOOK at...

And the really "good" thing about them all...? They'll still be around in working condition, LONG after to-day's crop of imports languish on some bench someplace because their manufacturers no longer support them. And I know what I speak of from experience, too, with my Yaesu FT-980 transceiver...!
Reply to a comment by : K5UJ on 2022-09-04

The reason the CW note sounds different with the old ham tube CW rigs is that they almost always used a choke input power supply with not much capacitance. That means that when the supply is loaded down, it takes a 10th of a second to settle down. Choke input supplies are find for AM and other constant loads but don't handle dynamic loads well. This means that on CW, the plate supply "rings" and you hear it as a slight AC sound on each closure of the key. Once I put a volt meter on the plate of the 807 in my Knight T-50 and saw that unloaded, the supply v. was around 700 v. but under load, that dropped to 550. Not great regulation for CW. That can be fixed, but if you like the distinctive sound, then leave it alone. Some cathode keyed rigs have clicks. That should be fixed by putting a 5 mfd cap from cathode to ground.
Reply to a comment by : VE3CUI on 2022-09-03

I just love the look, the feel --- yes, even the SMELL --- of vintage tube-filled radio gear. Once you've become accustomed to the operation & all of the nuances of a "...by-gone" radio, the thing just seems to have a unique personality all its own...! I have noticed something, however, in the ensuing years since the heyday of all those classic rigs: the CW notes that emanate from them seem to be different from the plethora of all of the "...Banzai 2000" modern-day transmitters that have taken-over the airwaves by virtue of their numbers. Now, that's not to say that the signals put-put by them are BAD, or anything --- just that they sound "...different" from all the rest. That feature was something that I simply can not recall from my early years as a Ham, some 50 years ago --- but then again, EVERYONE was using them on the air...& they really were THE standard of the time. To-day I always make it a point to try & work any & all of these pleasant "...different"-sounding stations whenever I might hear them: I just know that it will evoke warm memories from deep within me...!
K5UJ2022-09-04
Re: Vintage Station Build HT-44/SX117
The reason the CW note sounds different with the old ham tube CW rigs is that they almost always used a choke input power supply with not much capacitance. That means that when the supply is loaded down, it takes a 10th of a second to settle down. Choke input supplies are find for AM and other constant loads but don't handle dynamic loads well. This means that on CW, the plate supply "rings" and you hear it as a slight AC sound on each closure of the key. Once I put a volt meter on the plate of the 807 in my Knight T-50 and saw that unloaded, the supply v. was around 700 v. but under load, that dropped to 550. Not great regulation for CW. That can be fixed, but if you like the distinctive sound, then leave it alone.

Some cathode keyed rigs have clicks. That should be fixed by putting a 5 mfd cap from cathode to ground.
Reply to a comment by : VE3CUI on 2022-09-03

I just love the look, the feel --- yes, even the SMELL --- of vintage tube-filled radio gear. Once you've become accustomed to the operation & all of the nuances of a "...by-gone" radio, the thing just seems to have a unique personality all its own...! I have noticed something, however, in the ensuing years since the heyday of all those classic rigs: the CW notes that emanate from them seem to be different from the plethora of all of the "...Banzai 2000" modern-day transmitters that have taken-over the airwaves by virtue of their numbers. Now, that's not to say that the signals put-put by them are BAD, or anything --- just that they sound "...different" from all the rest. That feature was something that I simply can not recall from my early years as a Ham, some 50 years ago --- but then again, EVERYONE was using them on the air...& they really were THE standard of the time. To-day I always make it a point to try & work any & all of these pleasant "...different"-sounding stations whenever I might hear them: I just know that it will evoke warm memories from deep within me...!
VE3CUI2022-09-03
Vintage Station Build HT-44/SX117
I just love the look, the feel --- yes, even the SMELL --- of vintage tube-filled radio gear. Once you've become accustomed to the operation & all of the nuances of a "...by-gone" radio, the thing just seems to have a unique personality all its own...!

I have noticed something, however, in the ensuing years since the heyday of all those classic rigs: the CW notes that emanate from them seem to be different from the plethora of all of the "...Banzai 2000" modern-day transmitters that have taken-over the airwaves by virtue of their numbers. Now, that's not to say that the signals put-put by them are BAD, or anything --- just that they sound "...different" from all the rest.

That feature was something that I simply can not recall from my early years as a Ham, some 50 years ago --- but then again, EVERYONE was using them on the air...& they really were THE standard of the time. To-day I always make it a point to try & work any & all of these pleasant "...different"-sounding stations whenever I might hear them: I just know that it will evoke warm memories from deep within me...!
W4FID2022-09-02
Vintage Station Build HT-44/SX117
FANTASTIC job and a great article. I have been a "Hallicrafters man" since I was given a tired but useable SX-99 when I was a novice in 1961. Guess I still am -- I fell in love when I saw this! Still have a vintage Hallicrafters pin on a ham hat for can't remember how many years. Was with a gang at Dayton many times where 2 of them were Hallicrafters employees in their former lives. Thanks to guys like you the tradition and the good stuff lives on.
K9RJ2022-09-01
Vintage Station Build HT-44/SX117
What a beautiful job! I love it when old gear is fixed and on the air again and you did it with style!
K0RO2022-08-30
Vintage Station Build HT-44/SX117
Gorgeous!