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Collins 30L1 design questions

Discussion in 'Amateur Radio Amplifiers' started by K9AXN, Feb 16, 2018.

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  1. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    Wow! I've never seen that before.

    WIsh I had one, so I could tell people,"I'm using a 30L-1 here, with its built-in VFO and stuff. Am I on frequency okay?" and see what they say.:p
  2. N2EY

    N2EY Premium Subscriber QRZ Page

    Years ago, Ten Tec came out with their 585 transceiver - better know as the Paragon. It was contemporaneous with the Omni V and Omni VI, but had general-coverage receive.

    When I first saw the ad, I recalled one of the receivers Godley took with him to Ardrossan in 1921 - the Adams Morgan RA-10/DA-2, known as the Paragon.
  3. K9STH

    K9STH Platinum Subscriber Platinum Subscriber QRZ Page

    There are a number of things with the Collins amateur radio equipment that are not well known including the 32W-1 SSB exciter which was, basically, the upper portion of the 30L-1 transmitter / KWS-1.

    30L-1 2a.JPG

    Glen, K9STH
  4. K9AXN

    K9AXN Premium Subscriber QRZ Page


    Interesting Glen!

    Glad your family came over early to get things settled for the rest of us.

    Regards Jim
  5. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    Glen, as I think you know I have a 75A-4 and have for decades (since 1972, I was second owner) but never owned a KWS-1 and always wanted to.

    But...I'd much rather have that "original" 30L-1, which was actually a transmitter and I guess the forerunner of the KWS-1 -- because it would be fun to say, "Rig here is a 75A-4 and 30L-1."

    "Yeah, okay on the receiver and amplifier...what's the transmitter?"

    "I told you, it's a 30L-1."

    "Are you on drugs?":p

    I'll bet very few know a 30L-1 was originally a transmitter. I sure didn't.
  6. K9STH

    K9STH Platinum Subscriber Platinum Subscriber QRZ Page

    I believe, but do not know for sure, the late J. B. Jenkins, W5EU, had one of the very few "real" 30L-1 transmitters made. Although, years ago, J. B. used to occasionally do some "contract" work for me (he, along with another amateur radio operator, would assemble parts into reconditioned Motorola TSN-6000A speakers when I owned the Motorola reconditioned equipment center for the south-central United States), I never was at his house so I was never in his radio shack.

    I believe that J.B. also had at least 1-each 32W-1 exciter. He did have at least 1 of the 75A experimental receivers and a couple of early 75A-1 receivers. I know that he had 75A-1 serial number 0 (yes, there was a 0) and serial number 10. At one time, I owned 75A-1 serial number 4 but traded it off during the mid 1970s when you almost had to pay for someone's gasoline to "haul off" the older equipment! Sure wish I had it back now! I do have a 75A-1 but it is a later serial number unit.

    You could also blow someone's mind telling them that you were using a 32W-1 transmitter since there are very few of them around. Of course, most people didn't believe W5QBM when he said he was running a 30S-3 amplifier.

    Glen, K9STH
  7. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    I never heard of a 30S-3, either.

    The 30S-1 had many design deficiencies, and I owned one for many years.

    I modified the RF section in many ways, but never changed the power supply since "it worked," even with the 3B28s -- never made it solid-state or eliminated the choke or anything.

    The 4CX1000A "loafed" as long as you watched grid current, which was really the only thing to watch. The "automatic load" tuning was silly IMO and I never looked at it. That was also a bit of a misnomer as there's nothing automatic about it-- it's up to the operator to tune it.:)

    I changed the exhaust system to duct it upwards and added a 4x4" ventilated screen in the top with an air deflector so it could be pushed back against a wall, and got rid of the nutty temperature sensor, but did increase the blower capacity so it could run 1kW output power without generating much heat at all. Never had any clue why Collins didn't do that, but they may have had reasons at the time (maybe "noise?").

    The 30S-1 is "older" than the 30L-1, so it's pretty old. I replaced it with a Henry 4K Ultra (8877, GG) which runs rings around a 30S-1 in terms of just about everything including ease of tuning, IMD and output power. I don't think the 8877 existed when the 30S-1 was designed, so can't fault them for not using it.

    Charlie designed the 4K Ultra and left Henry to form his own company, ASI in Northridge, CA (3 miles from me) -- they make amazing stuff.
  8. K9STH

    K9STH Platinum Subscriber Platinum Subscriber QRZ Page

    The 30S-3 definitely had automatic tuning. Unfortunately, after the unit was tuned, the auto-tune would try to compensate for the changing load due to the SSB signal. W5QBM had to put in a switch to disable the auto-tune after the unit was "tuned up" on a particular frequency.

    Collins did have an effective auto-tune circuit that they included in the 208 and 308 series of linear amplifiers made for the military. I have told this before: One day, at the "new" corporate headquarters here in Richardson, Texas, a couple of technicians were testing a 308-U-20 amplifier. This amplifier put out a minimum of 20,000-watts over the 2 MHz to 30 MHz range. For some reason, the technicians laid out a 100-foot long piece of 12-gauge insulated wire on one of the parking lots and connected the end into the amplifier. Then, they put a key down CW signal into the amplifier driving it to the full 20,000-watts output.

    The wire started burning at the end making the wire shorter, and shorter, as it burned. So, the technicians decided to see if the automatic "shut down" circuitry would work. That is, there was a protective circuit, in the amplifier, that would disable the unit when the SWR reached a certain level. The wire got shorter, and shorter, and, as it burned, there was a burn mark put on the concrete of the parking lot. Finally, when the wire was less than 4-feet long, the protective circuit shut down the amplifier which was completely undamaged from this "experiment". That burn mark was still on the parking lot when I left the company!

    One of Art Collins business faults was that he insisted on all sorts of "features" be put in a goodly number of the products of Collins Radio Company. In fact, during production he would come up with additional "features" that he insisted be included on every unit that had not been shipped. Then, before all the units could be modified, he would come up with even more "features". The result was that products were not being shipped and, therefore, no money was coming in. To prevent this from happening, every division had an "Art project". This project was designed to keep Art occupied and away from the units in production. There never was any intention of the project producing an actual product for production, it was just to keep Art away from the items that were going to be sold.

    My division's Art project was CCCS Marine. This was way before the GPS idea was even thought of. CCCS Marine was to design, and then produce, an entire bridge (for a large yacht) that had the capability of navigating the yacht from Newport Beach, California, through the Panama Canal, and then all the way into New York harbor without a human ever having to even "touch" the helm. All the equipment was to be built by Collins Radio Company. The bridge was to be built in Richardson and the rest of the yacht was to be build in Newport Beach. However, there was a "fly in the ointment" in that Collins had no type accepted VHF FM equipment that the FCC required in the yacht. As such, Art contracted with Motorola to produce 2 "special product" Maritime-Motran units to comply with the FCC requirements. Of course, this project was never completed before Art sold out to Rockwell International.

    Each of these "Art projects" was assigned an "Engineering Project" number. One day, the division vice president instructed my secretary to close down all "EPs" on which no charges had been made within the past 12-months. So, she did. Unfortunately the "Art project" was one of these. Not only had accounting closed the projects, they had done so in a manner that did not allow the EP number to be used again. When Art heard that "his" project had been closed, he went through the roof! My secretary did not get in trouble because she had done what the VP specified. However, heads rolled in the accounting department. Since Art did not want to have to memorize a new EP number, somehow, that number did get reinstated!

    After Rockwell International took over Collins Radio, and after I had established the Motorola reconditioned equipment center for the south-central United States, one day a Collins Radio van pulled up at my loading dock (my building was about 4-miles north of the Collins plant) and 2-unopened boxes were unloaded. Inside were the 2-special products Maritime-Motran units that had been purchased for the CCCS Marine project. The new Collins Radio management had made arrangements with the Motorola Schamburg (Illinois) plant to return the units. These units had been sent to my facility so that the contents could be verified as being unused before they were then sent back to the main plant.

    Those were the days at the Collins Radio Company! I have no bad memories of Collins Radio for I was always treated very well. In fact, just before I left the company, I was given 2-pretty good raises at the same time. However, I was in a position to know the financial well being of the company and I knew that the company was in trouble. Then, one of the department managers went to work as the vice president of a microelectronics manufacturing company in the next city east of Richardson. He offered me the position as director of applications engineering with a 50% salary increase on top of the raises that I had just gotten at Collins Radio. It was a "no brainer" and I left the company. It was not that long before Art had to sell out and Rockwell International took over the company.

    I actually had another offer to leave Collins Radio. One of the assistant division directors asked me to stop by his office one day. When I entered the office, he told me to close the door. This was one of the assistant division directors with whom I had a pretty "testy" relationship especially where financial matters were concerned. He told me that he was forming a new company and that he wanted me to come to work as his comptroller! I said, "Joe, we fight like cats and dogs. So, why do you want me to come to work for you?"

    He then said, "I know it, but you keep me honest!"

    I told him that it would never work out because we would argue all the time! Besides, the other offer was already on the table.

    Glen, K9STH
  9. AG7II

    AG7II Ham Member QRZ Page

    Hi Jim,

    First of all, I am not trying to criticize the 30L1 design at all (in fact, I am enjoying the circuit topology a lot while I am restoring one.... even as simple as the meter shunt topology is quite interesting IMHO), but why only sense on one 811A's grid?

    Is there something that I am missing or just for the design simplicity?


  10. G3YRO

    G3YRO Ham Member QRZ Page

    I've never understood why Linear Amps don't sense the Grid Current, and when it gets too high, generate an ALC voltage to reduce the drive power from the Exciter.

    Surely this would be much more sensible than merely sensing the RF drive level?

    Roger G3YRO

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