[Mldxcc] [NCCC] RTTY & 3-500Z amplifiers

[CATFISHTWO at aol.com]

My tl 922 has a built in fan that runs all the time and  it runs for a  
couple iof minutes after you turn off the amp. I don't know if it is time or  temp 
delayed, but it is about a 2 minute delay or so.
 
 I usually only run the amp at 500 watts for rtty reguardlesst of the  amp I 
amusing.  I have the tl 922, an al 1200, and an 87A, among others and  I 
always use them at 1/3 power for rtty. tubes are getting way to expensive to  have 
them burn out.... even though they say you can run at 50 %
 
Tom
N6AJR


In a message dated 2/2/2009 8:34:20 P.M. Pacific Standard Time,  
wx6v at sbcglobal.net writes:

Hi  Rick,

I also have a Model 422 Centurian which I used in the recent ARRL  RTTY 
Roundup. I've only owned it for a short time and this was also my first  RTTY 
contest. So - I ran mine at 500 watts out for the entire contest and the  amp 
handled this just fine. Even though the amp is rated at 650 watts out for  RTTY, I 
decided to err on the conservative side. I noticed that the tubes  reached a 
dull red glow now and then, but nothing worrisome. I also had a desk  fan 
blowing across the back of my operating desk positioned in such a way that  it blew 
air across the back of my IC-765 and also into the ventilation slots  on the 
side of the amp. With 500 watts out, I had plenty of activity, made  lots of 
contacts, and worked everyone that I could hear.

I gather  that you are preparing for the CQ WPX RTTY contest coming up 
shortly. If so -  I'll see ya on the bands!

Jim   -WX6V-




________________________________
From: "Rick,  W6RKC" <ab1u at volcano.net>
To: mldxcc at contesting.com; nccc reflector  <nccc at contesting.com>
Sent: Monday, February 2, 2009 7:59:53  PM
Subject: [NCCC] RTTY & 3-500Z amplifiers


Hello  all,

after 10 years, I finally got the OK from the XYL to move "SOME"  
radios into a now spare, empty nest syndrome, bedroom. I wired up a  
couple of 20A 110VAC circuit breakers and got on the air last fall.  
Finally got around to wiring up a 30A 220VAC line for an amplifier.  
Since it will work on 160 thru 10 , including WARC, I hooked up my  
Ten-Tec Centurion Model 422  which uses a pair of 3-500Z  tubes.

It works fine on CW & SSB and I have used it on RTTY for the  first 
time in ARRL RU. I set the drive level to give about 700 Watts out  
when using RTTY. It is also located in a spot where I am now able to  
see the tubes. I have noticed that the plates will glow when using  
RTTY. My question is, should I see a dull reddish tint, the color of 
a  Naval Orange or the color one might see when observing the core of the  
Sun?

As I currently cannot afford to purchase another pair of tubes, I  do 
not want to damage these. They will do 1200+ watts out on CW or SSB  
with a nice dull glow, I can however, read a book when doing RTTY as  
they approach sunlight level. There is no external cooling applied  
right now. Just this weekend, I went through a junk box in the garage  
and found a nice DC muffin fan that I will be wiring up. My previous  
attempts at RTTY were with an Alpha 76A. With the ceramic tubes and  
metal cover, it was a case of "what you don't know, won't hurt you"  
when using the Alpha.

Since the 17 & 12 meter WARC bands will  not be viable for a while 
yet, maybe I will just swap it with one of the  Alphas.

Does anyone have any comment on 3-500 plate color and RTTY  operation??????

Thanks & KB

Rick,  W6RKC

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