From: Garey Barrell 
Subject: Re: [drakelist] On or off?


Dan -

I ran four Drake 4 Series lines for six years in the 60's on 
autostart RTTY.  The stations ran 24/7, and transmissions 
(at full power) of 30 minutes or more were not uncommon. 
Each transmitter had a small fan mounted on the back of the 
final cage.  The receivers had no extra cooling, but were 
NOT mounted under a shelf.  The receivers were crystal 
controlled and controlled the transmitters.

The only time the transmitters were turned off was for final 
replacement, which was done when the output power dropped to 
100W on 20M.

Only one _failure_  occurred during this time.  A single 
12BY7 filament opened up.

Power was supplied by TVA, at approx 1.5 cents/kwh.  (Those 
were the days!)

Turn-on surge to cold tube filaments, transformer windings 
and mechanical power switch contacts are the most common 
problems when turning equipment on and off.  With the 
exception of tube filaments, none are easy or inexpensive to 
repair.  Transformers are expensive, and back-of-pot 
switches are nearly impossible to find.  I switch most units 
with external power switches and internal switches are 
operated after external power has been removed.

That said, I use my station every day, and leave the 
receiver on all the time.  I turn the transmitter on when I 
plan to transmit, and then don't turn it off until the end 
of the day.  When I leave town for a few days, I turn the 
receivers off.

A lot of my equipment has been modified with thermistor type 
surge protectors.  I learned this a LONG time ago when my 
little clock radio from Motorola had a similar device in it 
called a "Globar" resistor.  That radio came on five days a 
week for over 25 years, and never had a tube fail!  It 
wasn't on long, typically less than 10-15 minutes a day.

Just my experience.

73, Garey - K4OAH
Atlanta

Dan Ringer wrote:

> I haven't seen this discussed in the archives . . . 
> 
> Several years ago (actually MANY years ago) I ran a Heathkit SB-102. 
> I never turned it off. Generally I put a muffin fan over the finals 
> and pulled air out for cooling. Sometimes I simply opened the lid and 
> let it run with convection cooling. I wanted the LMO to stabilize and 
> to avoid turn-on shock to the components. I never had any problems.
> 
> Now, a few years later (ok, MANY years later), I've put together a B 
> line. I generally turn the T4XB  on a few minutes before 
> transmitting, and use a muffin fan over the finals to exhaust air. 
> The R4B I run continuously, with a fan as an exhaust over the LMO. 
> The R4 LMO is used for frequency control. Everything seems to run 
> cool and is stable.
> 
> Although the LMO's are reasonably stable after a few minutes from a 
> cold start, leaving the receiver on does seem to make a difference. 
> The transmitter runs much hotter and I hesitate to leave it on all 
> the time. (Saves power, too.)
> 
> Am I setting myself up for a problem?
> 
> Thanks!
> Dan, K8WV
> 

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