[RTTY] Amp/Temp

[Rudy Bakalov]

I’d venture to guess that the answer largely depends on the quality of the materials used in a particular amp.

That said, here’s my experience with a similar amp, 2 x GU74, based on the old Alpha 91 platform:

During the recent CQ WW RTTY, the exhaust temp fluctuated between 47C at night and 52C during the day when the shack temp was 27C. Mostly running rather than S&P. The fan was running at the lowest speed and barely audible.

Rudy N2WQ

Sent using a tiny keyboard.  Please excuse brevity, typos, or inappropriate autocorrect.


> On Oct 7, 2017, at 10:58 AM, Courtney Judd <k4wi at k4wi.net> wrote:
> 
> I am looking for any ideas or your thoughts on what would be the safe or maximum operating temperature of a HF amplifier in rtty operation. My setup here is a FT5000 driving an Alpha 86 to about 1200 watts on rtty.... it will do considerably more on cw/ssb and rtty but I felt that I should limit it on rtty. What started all this is that after about 20 years of just sitting up on the shelf doing it's thing, I decided to take the 86 apart and give it's internals a good cleaning. Sure enough, the dust bunnies had been doing their thing. Gave it a good cleaning but when i went to put it back together i noticed that on the back panel where the air enters the amp there was a pre-made place to install a fan. I put a 115 v fan to push air into the amp which goes past the transformer then into the fan below the tubes and then out the top thru the tube shields. On top over the vent holes I built a Styrofoam box with two fans to help pull the air out. Sorta a push-me-pull setup. I bought a couple of digital thermometers with sensors. I placed the probe in the airstream coming out of the amp over the fans in the Styrofoam box and the other the air coming out of the 5000. This is where it got interesting. On rtty when running the 5000 would get up to about 103 deg F. from a resting temp of 79 deg. The amp would go from 90 deg up to a high of 155 deg which sorta made me nervous. I asked my wife if eggs would fry at 155 and she said probably! SO, do you guys monitor your amp's temperature and what do you all think is save? Sorry to be so long winded but I am curious! thanks and 73's Cort K4WI
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