572B Tubes

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

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  1. G3YRO

    G3YRO Ham Member QRZ Page

    Yes, they are in the Yaesu Linears too . . .

    I suppose Yaesu carried on making the FL2100 series for quite a while after Heathkit stopped producing the SB200, so you can get one of those (plus the Z version covers 160m and the WARC bands).

    Of course, Heathkit's design was actually a clone of the Collins Linear . . . and there were lots of other almost identical copies of the circuit and layout, including the FL2000B, KW1000, FL2100, etc (I think there were others too, but can't remember)
     
  2. W8JX

    W8JX Ham Member QRZ Page

    Well theory or actual the difference down range is tuff to measure
     
  3. KM1H

    KM1H Ham Member QRZ Page

    The only accurate measuring device is the human ear which can easily tell the difference and at times many will kill for 3dB in a pileup, etc.
     
  4. W1QJ

    W1QJ Ham Member QRZ Page

    Sure that is correct in the perfect world under laboratory conditions where there is no noise floor and you measure a signal at one level against the other, but when you introduce the real world scenario where there is a noise floor to deal with, all bets are off and that half an S unit can make a big difference.
     
  5. KA9JLM

    KA9JLM Ham Member QRZ Page

    I don't need a S meter to tell if I can hear someone.
     
    KR2C likes this.
  6. VE3DXK

    VE3DXK XML Subscriber QRZ Page

    As per specs for 572B's: 572B may be operated with its axis vertical and the base down, or horizontally with pins 1 and 4 in a vertical plane.
     
  7. G3YRO

    G3YRO Ham Member QRZ Page

    Sadly a bit more power DOES make quite a difference in practice . . . and not just in pile-ups . . .

    A friend and I used to do a lot of comparisons on 160m with DX stations . . . his reports using his TL922 were considerably better than with my little FL2000B . . . until he reduced power to the same level . . . then they were usually the same!


    A 3dB signal increase by running twice the power may not sound much . . . but getting a 3dB increase in radiation from your antenna is extremely difficult !!
     
  8. W8JX

    W8JX Ham Member QRZ Page

    On VHF/UHF were you can follow a signal down to true noise floor with little or no man made noise I agree but on HF it is not the case except maybe in a lab were you are only dealing with noise floor of rig. But in real world on HF there are a lot of variables in weak signal copy with QRM, QRN and QSB to name a few and with these it takes more than 3 db to make a meaningful difference.
     
  9. KM1H

    KM1H Ham Member QRZ Page

    Maybe true for those not trained well enough but serious contest, DX, and many others in the REAL WORLD vs your real world will say different.
    Granted when a signal is S9+ and in the clear then 3dB makes little difference. You tried the same silly arguments on Eham and got laughed off so stop wasting time here.
     
  10. W8JX

    W8JX Ham Member QRZ Page


    And you gave same silly response there too. Next you will be saying LMR 400 is a must have for HF.....
     

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