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RF Parts Caveat Emptor

Discussion in 'Amateur Radio Amplifiers' started by AF4RK, Oct 6, 2017.

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  1. WA7PRC

    WA7PRC Ham Member QRZ Page

    That brings back memories. At a former employer, I put together a short rack w/ three 4KW/40.68MHz RF sources. The area for the PSs contained nine 30V/67A switchers. The water-cooled RF sources ran dead quiet. The air-cooled PSs were not so quiet. ;)
     
  2. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    Telecom "rectifier" units are 48V, often at 2000W or more, and pretty inexpensive surplus or NOS.

    They call them "rectifiers" (because they're used as battery chargers) but they're usually high-efficiency, well regulated switchmode power supplies and usually adjustable 36V to 54V or so.
     
  3. WA7PRC

    WA7PRC Ham Member QRZ Page

    In the Telco COs where I worked (in another life), all that was kept in the battery room. A crane was needed to lift one 2V CELL. ;)
     
  4. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    Yeah, or at least a forklift.

    I was fortunate enough to get an entire 48V Telco battery set for free back in about 1990 when AT&T was shutting down a site in Malibu. "All you have to do is come pick it up."

    Hmmm.

    I had a friend with a dump truck (not a pickup) and a lift gate and we actually got it onto the truck with a forklift to move it.

    I didn't need 48V, I only needed 14V to power my remote repeater, so we discarded all except 7 cells, and they still weighed several hundred pounds but we got it to the site (on a remote hilltop). They were already several years old but with a float charge on them (about 2A continuously) they lasted another 12 years as emergency backup for the repeater.

    Not bad for free batteries and a day's work.

    The site was without power once for 3 days and nobody even knew it, the repeater worked fine the whole time with heavy use.
     
    WA7PRC likes this.
  5. K3RU

    K3RU Ham Member QRZ Page

    In a previous and NOT MISSED life I worked for a railroad in Signal and Communications and was responsible for maintaining all-manner of HEAVY batteries of all pedigree. The most annoying were made by EXIDE I believe and were 100 pound GLASS rectangular three-cell lead-acid monsters filled with acid of course, which splashed out the vents when moved. They all-too-often failed in the WINTER, freezing and cracking the GLASS container creating a disgusting mess to be cleaned up. One location could have DOZENS of these batteries in the signal house.

    These "things" were everywhere up and down the railroad in the signal cases. It took decades but the railroad finally discovered the 20th century and replaced all those antiquated and worn-out World War II era batteries with modern equivalents which made my life much easier.

    A contractor was hired to "salvage" all the old 100 pound "monsters" and the guys which manually "humped" these things around most definitely earned their money. Battery maintenance was without a doubt the worst part of railroad signal work, digging wires and cables "in" a close second.
     
    Last edited: Nov 7, 2017
  6. W1QJ

    W1QJ Ham Member QRZ Page

    First of all DUDE, Alpha doesn't write the specs on these tubes. EIMAC DOES! So let me show you the bible. Here it is
    http://www.tubecollectors.org/eimac/archives/3cx800a7.pdf CHECK OUT PAGE 2. It clearly shows that in CW (that is key down like in loading up) 36ma (single tube) Two tone (like in SSB) 16ma (single tube) I don't care what Alpha says. You don't bend the manufactures rules to suit yourself! Now I will tell you, MY Ten Tec Titan 425 and MY AL-800H both do 1500 watts but it takes a bit more than 25ma of grid current. Of course grid current and output will vary with plate voltage. Do you routinely pull numbers out of your gool-shot?
     
    K2XT likes this.
  7. W1QJ

    W1QJ Ham Member QRZ Page

    OH, look what I found...........aren't we talking about an Alpha 86? Well look here. ///C:/Users/user/Downloads/Alpha_86_Operating_and_Technical_Manual.pdf

    CHECK OUT 4.4.2 SECTION. I don't see 25ma anyplace! Pulling numbers out of the old gool-shot.
    Looks more like the numbers I spec'ed
     
  8. K2XT

    K2XT Premium Subscriber QRZ Page

    W1QJ breaks out into the lead, rounds the far turn, down the stretch..........and IT'S W1QJ BY TEN LENGTHS !!!

    Nobody beats the King.
     
  9. K2WO

    K2WO XML Subscriber QRZ Page

    Love the King!
     

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