[VHFcontesting] [Moon-Net] Bob Sutherland 3CX1000A7 VHF Amplifier

[Ron Rogers]

Not to mention that the 3CX1000a7 tube requires 5 volts at 50 amps just to light the filament…..same as a pair of 3-500Zs.  That's 250 watts consumed by the tube just to get it to "light up".

 

And Terry, since you mentioned the Eimac triode breach lock socket (SK-860)…….if you can even find one of those they will cost you $300-500.

 

Ron

WW8RR

 

From: Moon-net [mailto:moon-net-bounces at mailman.pe1itr.com] On Behalf Of Terry Price via Moon-net
Sent: Monday, February 08, 2021 11:57 AM
To: Edward R Cole
Cc: Byron Tatum; Moon-net Amateur Radio Moonbounce
Subject: Re: [Moon-Net] Bob Sutherland 3CX1000A7 VHF Amplifier

 

Ed,

 

A 3CX1000A7 is NOT an 8877, a 3CX1500A7 is. Two COMPLETELY different tubes, different sockets, they are more like a 4CX1000A7 which is a breech lock socket. A 8877 is an indirectly heated cathode and a 3CX1000A7 is a directly heated cathode, like a 3-500z. Drive requirements and input/output capacitance are different. I've built a 3CX1000A7 amp using the classic W6PO 2m output tank but the input is much different. There was even a design using a 3CX1000A7 on 432 but it had poor efficiency and required lots of drive.




Terry Price - W8ZN

Directive Systems and Engineering

703-754-3876

 

 

On Mon, Feb 8, 2021 at 11:43 AM Edward R Cole via Moon-net <moon-net at mailman.pe1itr.com> wrote:

Byron,

Bob Sutherland was W6PO, who's 3CX1000A7 (8877) amp is a classic design.  Here is the link to my 2m-8877 project which I used for several years on eme (sold in 2018).
KL7UW 8877 Amplifier <http://www.kl7uw.com/2m-8877.htm>  page 

There was a company making them at one point (do not know if they still do).  Maybe someone else on this list can assist you on that.  I have the original document as reprint of Eimac Amateur Service News letter in the form of a MHTL document which I could send as attachment by direct e-mail (not thru Moon-net).

The output circuit of my amp is stripline modification done by Harry WA4OFS (sk) who made the RF parts for my amp as a kit.

73, Ed - KL7UW

At 06:35 AM 2/8/2021, Byron Tatum via Moon-net wrote:



Hello-
      A long shot here. I am looking for info on a 3CX1000A7 VHF amplifier by Bob Sutherland (and two other authors in second article) that appeared as a 2 part article in March 1969 HR Mag page 6 and April 1970 page 26. What started my inquiry was discovery of a plate line assembly from the estate of a well known Collins engineer JB Jenkins W5EU. I recognized the assembly as from this 2 part article of which I have studied in past. Mostly for the sake of historical reasons, and learning, I am asking these things:
        1. Does anyone have a copy of the full set of plans that are offered by contacting Bob Sutherland at Eimac as referenced in March 1969 article? I surely would like to have a set to go with this plate line assembly.
        2. Does anyone know if any of the complete amplifiers as offered by Al Roach W6JUK of Dymond Electronics were ever produced? This is referenced in the April 1970 article adjacent to the picture of the modified Henry 2K amplifier (modified by Bob Sutherland at Eimac to incorporated 3CX1000A7 RF deck using Henry power supply).
    I am curious about the history of this 2 part article and if there are any pieces of equipment that survived from it. I don't believe I would care to duplicate the complex output coupling scheme and mechanics but it is interesting to study. I would like to try and find a copy of the construction plans to go with this plate line assembly.
Thanks,
Byron W5FH
936-349-6353 cell

_______________________________________________
Moon-Net posting and subscription instructions are at http://www.nlsa.com/nets/moon-net-help.html

73, Ed - KL7UW
  http://www.kl7uw.com <http://www.kl7uw.com/> 
Dubus-NA Business mail:
  dubususa at gmail.com

_______________________________________________
Moon-Net posting and subscription instructions are at http://www.nlsa.com/nets/moon-net-help.html