[Amps] Clipperton L - GI-7B

[Joe Subich, W4TV]

On 2021-02-13 10:51 AM, Jim Thomson wrote:
> ##  meanwhile, the Elecraft K3  is a lousy  -29 db PEP  (IMD3)  at 
> 100 watts pep out.    The  ANAN 7000 / 8000 is a lousy  -30 db  pep 
> (IMD3 )   with pure  signal  disconnected.    On  most of these  SS 
> xcvrs , when power output is  reduced, the  IMD  drops like a rock.
> A  TS-850 is  -30 db  PEP  when run at  max rated  100 watts  pep
> output.....  which  drops a whole bunch  when run at  just  85 watts 
> pep out..... which then  drops  through the floor when run at  50
> watts  pep out.
All of this is a result of using output devices rated for saturated
power output at 12 Volts.  If one looks at the spec sheets for all
of the devices used in the mentioned transceivers, *IF* the spec
sheet shows parameters for IMD, it will be significantly better at
60 to 80 W PEP than at 100 W PEP.

Amateur transceiver manufacturers *MUST* get their design heads out
of where the sun don't shine and start using 24V devices for 100W
power levels and 48V devices for 200W power levels.  Driving solid
state amplifiers well past the 1 dB compression point guarantees
IMD3 worse than -30 dB and it is time to stop accepting such garbage.

73,

    ... Joe, W4TV


On 2021-02-13 10:51 AM, Jim Thomson wrote:
> ##  meanwhile, the Elecraft K3  is a lousy  -29 db PEP  (IMD3)  at  100 watts pep out.    The  ANAN 7000 / 8000 is a lousy  -30 db  pep ( IMD3 )   with pure  signal  disconnected.    On  most of these  SS  xcvrs , when power output is  reduced,
> the  IMD  drops like a rock.   A  TS-850 is  -30 db  PEP  when run at  max rated  100 watts  pep output.....  which  drops a whole bunch  when run at  just  85 watts pep out..... which then  drops  through the floor  when run at  50 watts  pep out.
> I see the same thing on my  FT-1000D  and also my  FT-1000MP-MKV.
> 
> ##  IMO,  I see nothing wrong with  referencing IMD  to pep output.     S meters  are all peak reading devices, whether  a panel meter or peak reading leds.     If  Joe ham is  say  30 db  over S9  on ssb  mode,
> but only  S9, when tuned off freq by  XX khz, then  Joe hams  IMD  is  down 30 db...end of  story.   We  dont say  Joe hams splatter is  24 db  down  from one tone of a 2  tone signal.
> 
> Jim   VE7RF
> _______________________________________________
> Amps mailing list
> Amps at contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>