KWS-1 (and much other) Progress

I was able to get the KWS-1 to tune up at one high frequency on each band – and I measured 300 watts out on 75M. I also used the microphone to key the transmitter in SSB mode – but besides a key down carrier, I didn’t hear the mic voice. I’ll worry about that later – it could just be the way I wired the mic – not sure – PTT is fine though – so that’s cool. I know something is still not quite right – because I couldn’t turn the PTO down to a lower frequency and get the same Grid current at the lower frequencies – which seems to suggest that the VFO or PTO got screwed up in shipping. I do still have to be bold and measure all voltages on the power supply terminal block – which requires that I defeat the kill switch. I am very confident that the finals are good – their negative bias voltage seems right – and the PA HV is 2100 – dead nuts on. The Filament voltage is also perfect. Either some other voltage could be low, or I might just start swapping some tubes – like the one in the PTO or the drivers – the 6CL6’s. Just for laughs . . . I do expect it will come down to a single wiring or component – maybe a tube, capacitor or just a connection. One thing I haven’t done is look underneath the RF Deck to see if anything is wrong. One best test will be when Tom, WY8K brings his RF Deck over – and I will immediately know if its the Power Supply or the RF Deck. I’ll look at his PTO closely, because I almost think my PTO or VFO is off somehow . . .

I feel like I am exorcising old ghosts out of my KWS-1 – and one ghost at a time. I am sure a lot of this is just me learning the “zen” and Art of Vintage Radio Maintenance, so there is that in the mix . . .

In other news – yesterday I had a big epiphany regarding the latest Data Regulations that are about to totally rock the data world. Remember the acronyms GDPR and CCPA – they will be in the news big time starting about now – and moving forward. I have prided myself on keeping up with technology in my career, and this year is no exception. I have steered my Career Truck right where it needs to be.

In the beginning of the year I had some doubts based on a gamble that I would land myself right at the “data crossroads” of Data Governance – and sure enough I did. I had built the Data Explorer Data Dictionary at Credit Karma the previous two years, and now I have used that experience to pivot into Data Governance.

Now add in my experience with Collibra while on short contract at Twitter, and that has completed my pivot. I’m becoming an expert in GDPR and CCPA from the project, product and even technical aspects, and my gamble has paid off big time.

Crazy times – but good times . . .

Hello Grid Current in Tune Mode!

Just for fun, when I got home from work – I decided to tune the KWS-1 all over the crazy place, and sure enough – I did find what looks like “resonance points” where I could get Grid Current to display from zero to full scale on the Grid setting of the meter in Tune mode – and this is the “tune for maximum smoke” approach . . . but seeing the grid current anywhere in Tune mode is a big plus . . .

I’ll spend some more time with this tomorrow when I have the time to futz with this – but its obvious I need to really understand the tuning procedure of the KWS-1. I’m right in the middle of changing work from a contract at Twitter in SF to a full time gig at LendUp in Oakland – so I have been more preoccupied than I had hoped for this week.

Another test tomorrow will be to see how much RF Power output I can get out of the rig when its tuned on some frequency. I know there is RF output – so I will get it on the air tomorrow and listen on a receiver to hear its “note”. I guess no matter what – if you can hear a signal with “key down”, that’s a start!

I’ll call Howard if I have to – but I want to record as much data as I can first.

My KWS-1 and the Strategic Air Command SSB Tests

The Strategic Air Command, Gold Dust Twins and SSB in the 1950’s – Cold War Style . . .

I purchased my KWS-1 from an antique radio shop in Sacramento called Radio Expo:
http://www.sacramentoradioexpo.com/

The owner, Doug is a real nice guy, and even taught at Stanford for a while. He came across this transmitter just under a year ago when a ham who went SK’s family sold off the ham gear. I was told that that ham used the transmitter pretty much up until his final days. I have since had Howard, W3HM restore the RF Deck – and I have restored the power supply.

I was only interested in finding and restoring a National SW-3 “Thrill Box”, but when I put out a wanted message on the NCDXC email reflector, Bruce, AH0U responded with an offer I couldn’t refuse on a Collins 75A-4 receiver. It was stunningly beautiful. I think I drooled a bit! I listen to the ARRL CW Bulletin nightly on it – it is just amazing.

The SW-3 is no slacker – I listen to KPIG AM 1510 daily on my beloved old “Thrill Box”

Now – it just so happens that Tom, WY8K is a ham who also lives in Contra Costa County, (and quite close to me as the crow flies), had approached me a few years back about helping him with his antenna system. He attended an Alameda Ham Radio Club meeting where I was giving a presentation on Heard Island, VK0EK, and he and I became fast friends. Tom owns the Gold Dust Twins – also restored by Howard, W3HM. Between Bruce and Tom – they convinced me I needed to match my 75A-4 with the KWS-1 so I would be in the very exclusive club of proud owner of the “Gold Dust Twins”.

Literally a month or two after these guys gave me that idea – one came available . . . . .

It was rough looking on the outside, but clean on the inside and it powered up at Doug’s shop! I made a bet with the devil that I could restore the Power Supply myself and save a ton of money (shipping alone) by just having the RF Deck restored by Howard, W3HM . . . what a gamble . . .

Top – gorgeous KWS-1 RF Deck restore by Howard Mills, W3HM. Bottom – “Ugly Duck’ restore of the massive and super heavy power supply by me, KY6R. Note that ugly tan-ish paint splotch – it covers military “asset tag” number, and from the 1950’s . . .

The flightpath of the SAC SSB Tests

I have done some research and found that while only 1600 or so of the KWS-1’s were ever produced, many went to the USAF Strategic Air Command or SAC and other Military concerns. When you see San Francisco in that map above, it had to be either Travis or Mather AFB outside of Sacramento. The ham that went SK basically lived as close to Mather as you can get residential wise.

That paint covers some kind of asset tag number used to auction off this gear. I have been told that only 600 of these remain. The most interesting part of all of this from a technical perspective is that Collins moved into SSB with this rig. The Air Force needed a strategic communications circuit between those points on the map above – and between outfitted some B-29 Bombers and setting up land based stations, the KWS-1 was part of a very successful SSB test.

I found this slide, (c) 2017 by W3MY where he says Travis AFB was a participant in this SAC SSB Test

So, my pursuit of “living history” continues, and is an amazingly rich adventure. My family moved to California in the late 70’s because Lockheed had been courting my father to move out west since about 1966 or so – and we almost moved to Redlands when I was in the 4th grade. It would be 12 or 13 years later that we finally made it. But it was all due to the aerospace industry – and my father was one of those guys who got into the trade after WWII. So – all of this has a very personal aspect to it.

Lockheed made quite a few of the aircraft that would have been at Mather and Travis. I worked for Lockheed for 3 years coding COBOL, so yes, there is an I direct connection to all of this.

I have RF Output and will try to tune it up and get it into my antenna switching arrangement. The Tune mode still doesn’t show Grid current, so I do expect there is something wrong. I’ll continue to try to see if I can figure it out or if I get lucky, find an elmer to stop by and set me right. In any case – I signed onto this project for the long term, knowing it would be a learning experience. I have been learning how to use my oscilloscope and have enjoyed reading the (big!) schematic and debugging the problem. When I finally get it all nailed down (and I think I am really close now), it will feel like a big triumph.

KWS-1 K101 Relay

I’m starting to think that I have a similar problem that another fellow said he had – which is that one of the relay’s had dirty contacts which left his rig not showing output. I don’t know if he had no output in Tune or Operate mode.

It might be worth opening up the bottom cover and checking out the relay and also to just make sure nothing got jarred in transit. I did clean up the big plate contactor relay in the Power Supply, and it did have a lot of dirt on it. In fact, I need to get some contact cleaner – especially since I am doing the occasional restore of old equipment.

 

KWS-1 Report

I put about 6 hours into testing the KWS-1 yesterday and another 2 today

I’ll record the important metrics here – because I can then compare these to others who have the KWS-1:

VFO INJ Test point – 600 mv Peak to Peak and 3.25 mhz with the dial tuned to 3.5 mhz

XTAL – on 40M – 4 mhz, which matches what Howard measured

6CL6 Grid – 11.6 mv and the Carrier control did change the amplitude

6CL6 Plate – 88 mv and the Carrier control did change the amplitude

6CL6 Cathode – 49.6 mv and the Carrier control did change the amplitude

Negative bias when reading off the 4X250B Grid – with one final tube pulled – 41.54 to -97.7 vdc

My readings seem in line with what Howard measured – for the most part.

The only thing that is weird is that in Tune, when I turn the Carrier control up – the oscilloscope shows the increase in amplitude of the waveform, but the Grid function of the multi-meter doesn’t show.

I do see RF out – and will practice tuning this rig up – my final test will be to tune it up to get maximum output. I can use my RF Wattmeter for this.

The KWS-1 Has Landed!

I now have RF Output!

I am very, very pleased now that I am seeing RF output on my dummy load. The tuning procedure is something I need to get used to, but it is similar to tuning a tube linear amplifier manually.

I need to analyze why I don’t see Grid Current on the built in meter and why I don’t see anything change with the carrier knob – in Tune mode. In operate I do see output on the dummy load. My oscilloscope did show that the Carrier knob was changing the Driver stage grid, plate and cathode voltages. The VFO reading on my scope was right on, as was the XTAL frequency. SO – the scope is a real keeper – it really helped me see that the rig seemed to be good – even though that Grid Meter reading issue is something I will look into.

It seems like the tune mode with carrier knob isn’t working right, but Operate is. I will make sure it isn’t just “operator error” – because that could be the case. Maybe the tuning is so sharp that you have to be really “dialed in” correctly. If I can tune it up in Operate mode, that would be OK too I guess – not sure. This is s new beast I need to tame, and I will read, re-read and talk to others regarding the tuning procedure.

But today is a milestone I’ve been looking forward to for almost 6 months. I am going to look closely at the schematic to see how the Tune and Load circuits work and what they do.

I am learning a ton – and I can say that for me – I am happiest at work, home, pretty much anywhere when I am learning something new. This grande olde radio gear that I have been playing with lately is giving me more excitement than even DXCC and chasing Honor Roll. There are many more “facets” in this part of the hobby, and it feels like a real honor to keep a 65 year old set of gear running.

Getting this rig on a 40M Bobtail or Bruce Array is my big goal and will be my “summer project” – now that it is starting to feel like summer here in Northern California.

Onward!

KWS-1 Debug: Day 1

L – R: Siglent 1202X-E, KWS-1 with MFJ-267, Fluke 117, Hickok 533A. Not shown – Heathkit IG-102 Signal Generator

Nothing better on a gorgeous Spring day – (after an especially intense work week) to have some nice coffee and then to get crackin’ on getting the Collins KWS-1 transmitter back on the air. I’ll do it – damn it!

 

The simple, but effective Heathkit IG-102 Signal Generator

I called Howard, W3HM this morning and he guided me through debugging the KWS-1 problem. But I did do my “due diligence” and make sure that these things were OK – that they “cleared QA”:

  1. No blown fuses
  2. All tubes in Power Supply are good
  3. Relays in Power Supply are good
  4. My re-capping job is 100% good – without a doubt
  5. I very quickly learned how to use my new oscilloscope

That last one meant that I had to take a Heathkit IG-102 Signal Generator out and plug it into my scope – because I had no idea what I was doing. Thank God Howard has patience with me – but boy – did I learn so fast. Also – thanks to Bruce, AH0U, who gave me the Signal Generator . . .

I checked the VFO in the KWS-1, and yes, the VFO voltage changes when I turn the Carrier control on the KWS-1.

There is a signal on the Grid, Plate and Cathode of the 6CL6 Driver Stage – which means that it seems like the Driver Stage of the RF Deck is getting what it needs. Why there is no RF Output is still a mystery, and the latest theory is that it is a keying circuit. Howard also had me pull a 4X250B final amplifier tube and check the negative bias – but using my DVM probe on the center pin in the socket – and then turning the PA Bias knob on the power supply, and sure enough – it went from -97 to -41 volts

Two friends believe that the problem is in the RF Deck – and in the keying circuit. They both think something got jarred during shipping from Howard to me.

No – I don’t have the answer yet, but I feel the huge education really is the best part of this journey. I learned a lot today and feel really great. I’ll get this bugger on the air soon – I feel I am really close!