572B Tubes

Discussion in 'Amateur Radio Amplifiers' started by AG4RT, Nov 3, 2015.

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  1. K4PDM

    K4PDM Ham Member QRZ Page

    SWR does not affect tube life.[/QUOTE]

    If the SWR is so high that the amp cannot be tuned to resonance, the tube can end up with excessive dissipation.
    Guess I'm out of the 572B competition...retiring my Clipperton L for an AL-80B that arrives today!

    73, Paul K4PDM
     
  2. K2HAT

    K2HAT QRZ Volunteer Volunteer DX Helper QRZ Page

    Maybe not a Must Have, but I use generic 400 low loss coax to feed my 24ft vertical and my 100ft dipole., as well as my 2m-440 aprox 17ft vertical.
    All runs are over 75 ft, it is about 120 ft to the 24ft vertical.

    I bought a spool of the LL400 because of the lower loss at 440, and enjoy the added benefit of it costing less than 9913. :cool:

    I am using rg8x to my hexbeam, I have noticed more rfi in the shack, coincidence?
     
  3. W8JX

    W8JX Ham Member QRZ Page


    9913 or LMR 400 has merit on long runs on VHF/UHF but on HF the difference between it and 120 feet RG 213 is less than 1/2 a db below 30 mhz (and less at lower frequencies) and RG 213 is far more durable and much harder to damage (crush stepping on it or clamping it or kink bending it) There is is also a difference of 1 db or less even using RG8x vs 400 on 10m and below.
     
  4. K2HAT

    K2HAT QRZ Volunteer Volunteer DX Helper QRZ Page


    • I bought the Low Loss 400 because it worked well at longer lengths and was Cheaper than rg-213 even generic.
      I felt it cost effective to use, even if a little more heavy duty than I Needed on HF. You results may vary. ;)

      Kind of like, oh I am at a hamfest and found some Cetron 572b tubes for $20 each, hmm they would make decent spares for my AL-811h. :)

      Low Loss 400 Coax 500' foot Spool reel RFC400 Cinta400 LMR-400 LMR400 Shireen
      LMR400 grade cable US $231.19
      FREE Standard Shipping
      eBay item number:
      251241104272


     
  5. KA9JLM

    KA9JLM Ham Member QRZ Page

    If the SWR is so high that the amp cannot be tuned to resonance, the tube can end up with excessive dissipation.
    Guess I'm out of the 572B competition...retiring my Clipperton L for an AL-80B that arrives today!

    73, Paul K4PDM[/QUOTE]

    Does it have bad tubes ? Seems like another type tube could be put in the Cliperton L ?

    Enjoy your AL-80B.
     
    Last edited: Dec 18, 2015
  6. W8JX

    W8JX Ham Member QRZ Page

    One reason it is cheaper is because it is easily damaged so low price makes it more attractive for those on fence. Unlike 400, 213 is very rugged and much harder to damage. You want a durable cable, it will likely cost more than easily damaged 400.
     
  7. KM1H

    KM1H Ham Member QRZ Page

    Pure nonsense; LMR cables are the choice of the professional installers for excellent isolation and long term performance stability.

    Only a ham or CB klutz would damage it.
     
  8. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    There are times ya just hafta be careful.
    [​IMG]
     
  9. KA9JLM

    KA9JLM Ham Member QRZ Page

    lol.

    And before the ground rod was driven in.
     
  10. W8JX

    W8JX Ham Member QRZ Page

    Thats a joke. When I worked in flight test and money was not a factor we used 58, 142, 174, 213, 214 and 393 to name a few and NEVER used any LMR of any kind. Ruggedness of cable is a big factor in aircraft world and 400 fails here big time. It does not take a clutz to damage it as it is easy to crush or kink if not careful. The beauty of good coax is that it is tuff and hard to damage. 400 fails here. I suspect that if you hooked up a TDR to a lot of LMR runs you would see impedance bumps from damage to cable as it does not take a lot of effort to damage it. 213 on other hand is hard to damage. To suggest 400 is a rugged cable is a joke.
     

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