Discussion in 'Amplitude Modulation' started by K5UJ, May 19, 2019.

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  1. K4KYV

    K4KYV Premium Subscriber Volunteer Moderator QRZ Page

    The "old stuff" that I look for at hamfests is more like capacitors, coils, inductors, transformers, meters, dials, wirewound and carbon composition resistors, coil clips, plate and grid cap metal spring clips, tube sockets, vintage microphones, etc., and only items I know I don't already have but could use, or specific elusive items I have been seeking for decades. The only fully-built transmitters and receivers I would even think twice about are the extremely rare or unusual, for example a high quality 1920s or 30s homebrew transmitter in excellent condition that I would actually use on the air; I don't even glance at the DX-100s, Viking IIs, or even R-390 series (unless maybe if in exceptional condition and price). Things I would have jumped onto 20 years ago, why would I bring home another, if I already have two copies? Storage space in getting to be a premium for me, and the stuff I keep an eye out for is getting sparser ever year. I would probably grab a $100 75A-4 in good shape with all the filters.

    I'm afraid you are right. Most of the vintage stuff has already been recycled through two or more previous owners, and the people who take an interest in it , if they themselves haven't gone SK, are now reaching the age where the previous owners were beginning to lighten their load. There are hardly any new enthusiasts for this kind of "stuff" coming on the scene behind us to take our place. Decades ago I only dreamt of owning a 75A-4; now I have two working 75A-4s, and two more dead ones that I'm in the process of trying to bring back to life. I could see the day in not-too-distant future when a working one in pristine condition wouldn't even fetch $100 at an event like Dayton. Nobody was interested in the rough-shape-but-restorable 75A-1 I took to Dayton last year; not even any low-ball offers.

    A young ham with a brand-new interest in building a high power AM station but with no vintage parts, equipment on hand, or extensive knowledge of hollow-state technology would likely become discouraged very quickly if he tried to gather up components and build a homebrew tube-type AM kilowatt. The stuff may be out there, but hardly anyone knows who has it or where it is (until they learn too late that a previous owner's collection was hauled to the dump), and only those who have accumulated a collection of old handbooks and magazines would even have the means of learning that technology. Instead, he would probably go the route of building up a class-E rig with solid state pulse-width modulator. Or more likely, a plug 'n play plastic radio with AM mode, into a leen-yar. A handful of power MOSFETS would be a lot cheaper and more readily available than a set of working high power transmitting tubes... and a lot lighter in weight and more compact than a high power modulation transformer with reactor. Plus, he probably has limited living and work space for putting up a ham station with antennas.

    Nevertheless, there are still a few of us around to enjoy it while we can, and it's a shame to see high quality and top-of-the-line older stuff mindlessly trashed or destroyed.
  2. N2DTS

    N2DTS Ham Member QRZ Page

    I have been giving stuff away to anyone who is building or interested.
    I can't see building anymore myself, I have 3 homebrew rigs in service and 3 more on the shelf to swap in, with different modulators, etc,
    and there is fewer people to talk to and very little interest in equipment.
    It has somewhat degenerated into general chatter or even worse, current events.

    The one part I have any interest in is a T368 mod transformer for my 4-125 rig.
    It runs 2500 volts and needs a good high voltage mod transformer.
    I figure the T368 one is oil filled and solder sealed so should not degrade inside.
    The modulator is AB1 and uses octal tubes as drivers and sounds very clean.
    It even has a magic eye tube on it to show if you hit grid current!
    Be nice to get that working for winter operation...
    Otherwise, I suppose its only replacement parts for what might crap out, but I think I have almost all of that covered.

    Still, its nice to go to a fest and see some of the old cool stuff.
  3. K4KYV

    K4KYV Premium Subscriber Volunteer Moderator QRZ Page

    That's something I miss from the early days when I was first licensed and got my first homebrew rigs on the air, back in the decade of the 1960s before incentive licensing and before the great AM vs SSB wars flared up. Most phone signals were AM; on 75m SSB was largely relegated to 3900-4000, while AM was on 3800-3900. The CW bands were packed with signals whenever the bands were open and mostly ragchew type QSOs. A large percentage of the AM rigs, at least the higher power ones, were homebrew, although there were plenty of DX-100s, Rangers, Vikings, etc, and of course, BC-610s.

    One of the topics of conversations was almost inevitably the station. They were each different. What receiver was used, what transmitter if commercially made, antenna, and how it was all hooked up. If homebrew, what tubes were used in the final and in the modulator. Sometimes after contacting a station several times and becoming acquainted with the operator and about everything had been said about comparing the stations, then the conversation might veer to general chat or specific non-radio topics. It was always interesting to learn what the other fellow was using, and sometimes from other ham's station description you got ideas on how to improve yours.

    Now, with the vast majority of ham stations plug 'n play, there's not much interesting to talk about regarding the station. I have particularly noticed that with CW where even good rag-chews are hard to find, and that's why my CW activity has dwindled in recent years. I sometimes tune across the band and listen to SSB, but usually nothing there that interests me very much. The hams on AM, particularly the ones with homebrew rigs still sometimes talk about experiences with equipment and setting up stations, but those QSOs seem fewer and further between these days.
  4. WZ5Q

    WZ5Q Ham Member QRZ Page

    ... and it never seems to fail that when you finally do find someone to engage with an in-depth technical QSO, there is always the PW station that breaks in having absolutely nothing to add to the ongoing technical conversation. All they have to offer is lengthy, meaningless chitter chatter that breaks the flow and cadence of the ongoing thoughts.

    Just using a little bit of common sense goes a long way...
    K4KYV likes this.
  5. K5UJ

    K5UJ Ham Member QRZ Page

    Same here. There's only so much I can take in without turning into Mack or that guy in S.C. Liz and Phillip went and liquidated. The one who's house looked like Fair Radio inside.
    I never got into any of this to make money so I won't be sad if I give it all away some day. I'll be happy if it all gets used. But God willing, I'll be around for a while yet and be using some of it. If I move I may have to let some things go. But ah luvs mah tubes.
    That the fellow in 7 land who sells flat rate boxes of parts? There will be one part that might be nice to have but I don't want to have to buy 40 other things to get it.
  6. K5UJ

    K5UJ Ham Member QRZ Page

    You have to round up old handbooks and magazines at hamfests. There's also a whole side beyond station building that involves tools and test gear for metal work and bench troubleshooting. Maybe when hams have had enough of plastic radio operating and are getting bored they'll discover vintage radio. I think tube gear is so removed from the plastic radio world that the new stuff has no affect on prices of old rigs and receivers. The problem is lack of demand due to fewer buyers. We can probably all think of 15 AM operators who have gone SK in the past few years.
    There are some operators with the "gift of gab" and there are some who are tongue tied and many in between. I've had QSOs where finding something interesting to talk about has been a challenge. I think that's part of the appeal of nets. Some guys are not really talkers and enjoy building and modifying most, and confine their actual use of what they have to nets. I'm usually too busy to spend a lot of time on a net but I understand why some gravitate to them. They're also a haven for piss weakers.
  7. K5UJ

    K5UJ Ham Member QRZ Page

    My impression has been that hams are either looking for parts cows, or mint condx perfect items they can just fire up and use. Anything in between that sort of looks okay but needs some work will get ignored.
    I think we're still a ways off for that. A friend told me at lunch time today that 75A-4s are still hot items in JA land. The less heavy rigs like Rangers and novice rigs, the cute stuff still has some demand.
  8. W8KHK

    W8KHK Ham Member QRZ Page

    Looking at some of the photos at Hamvention by K4NYW


    it appears that there were 75A4s with prices between 600 and 900 dollarettes. No idea whether any of them sold for those prices...

    I still prefer to use the 75A3, 75A4, and 51J4 for 75 and 40 AM, but I recently found that the RSP2 can pull out signals that were unreadable with the tube receivers. It is also nice to be able to see what is happening up and down the band.

    Except for an experimental foray into Class-E and PDM, I much prefer the tube transmitters. After over a year of collecting, I now have all the components needed to complete my series modulated 3CX3000 rig. Only iron is the plate tranny. None whatsoever in the audio path, with the possible exception of the matching transformer within the dynamic or velocity microphone.

    During the storm last week, my 75M dipole was returned to ground level. At 72, it is a bit hard for me to get it back where it was by myself. I am considering inviting some of the younger folks from the local radio club to help me get it back where it belongs. Then I could display and demonstrate some of the classic rack-mounted heavy metal, maybe stir up some interest. I have enough in the way of parts to help one or two persons build a respectable rig, no money involved. That would be a much better fate for the stash than a recycler or landfill when I can no longer enjoy the tubes myself.

    I think all of us could probably come up with novel ways of interesting some of the younger generation(s) in hollow state and AM, and most of us have excess components that could be donated to the cause. I know I would be bored stiff with a plastic SSB rig, or solid state linear. And FM/repeaters - been there, done that, no more for me.
  9. K4KYV

    K4KYV Premium Subscriber Volunteer Moderator QRZ Page

    Not to be rude, but when in a serious OTA discussion I tend to ignore pissweak breakers. But inevitably someone else in the QSO will drop everything and pick them up, instantly quenching the original intercourse.

    And, the weaker they are, the longer they talk.
  10. K4KYV

    K4KYV Premium Subscriber Volunteer Moderator QRZ Page

    Now, back to topic. How was overall attendance at the flea market this year? Some guy put these photos on line. Looks like quite a few empty spaces. I recall last year most spaces were filled. But at least some sunshine this year.

    I wonder if that "75A-4A" came from WA3PUN's estate. Scroll down about 5 rows of photos from the top. Ed had the only one I ever saw, once when I visited him, and it was not a Collins original, but a regular 75A-4 modified by one Robert W Stankus N1AAR (remember, the guy who petitioned the FCC back around 1981 to eliminate AM, and who a few years later was busted by USPS authorities for some mail-order scam selling Kenwoods, taking money but not delivering the merchandise?) The one I saw at Ed's house even had an identical looking plastic nameplate glued over the escutcheon. I'd almost bet it's the same receiver, unless Stankus did more than one.

    Last edited: May 23, 2019

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