Sounds like you need more like 6dB. That would be 88 watts of drive
required.
73
Jim W7RY
-----Original Message-----
From: Steve Bookout
Sent: Monday, November 26, 2012 4:36 PM
To: amps@contesting.com
Subject: [Amps] 8877 cathode impedance
Hello all,
Want to re-do the input matching of an old HB 8877 amp. What should I use
for the cathode impedance when calculating my pi network? I recall it was
something like 50-60 ohms.
Also, thinking attenuating the drive power AFTER the T/R relay and before
the matching network. Right now it only takes 22 watts for 1500 out at 4
KV. A bit touchy to tune (only been like that for 27 yrs.) Would be nicer
to tune at 60, or so, watts out. I saw where Henry radio has some
attenuators on Ebay that might fit the bill.
http://www.ebay.com/itm/New-250-Watt-4-dB-50-ohm-Hybrid-Attenuator-up-2-GHz-/390408415503?pt=LH_DefaultDomain_0&hash=item5ae627a90f
Comments?
73 de Steve, NR4M
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