Date: Mon, 10 Sep 2012 11:14:20 -0700
From: "Bill, W6WRT" <dezrat1242@yahoo.com>
To: AMPS <amps@contesting.com>
Subject: Re: [Amps] Amplifier Tuning Device
ORIGINAL MESSAGE:
On Mon, 10 Sep 2012 11:00:42 -0700, N6ML wrote:
>> As I recall, there is some kind of device that is used to tune an amp. It
>> acts like a telegraph bug sending dots.
REPLY:
One thing to be wary of with any pulse type tuning device is they do not load
down the power supply fully. When you go to a full carrier and the PS voltage
drops further, you run the risk of "flat-topping" the RF cycle and causing
distortion.
Just something to keep in mind.
73, Bill W6WRT
### Not quite. Sure, the low duty cycle pulse will not load the B+ supply down
like a dead cxr will,but that will not cause the amp to flat top.... while
running
100% duty cycle modes like RTTY-FM etc. But if the amp is capable of 100%
duty cycle operation, its sorta a moot point anyway. For RTTY-FM operation,
I would suggest just pulse tuning it with a 50% duty cycle 1st,..then switch to
a 100% dead cxr for the final tweak. That way it takes the initial load off
the tubes
if the amp is off resosnance, etc, when 1st tuning it up.
## If you intend to tune up the amp for CW use, then pulse tune with a 50% duty
cycle.
If you intend to tune up the amp for SSB use, then pules tune using a 30% duty
cycle.
If you intend to run loads of processing on ssb, then use a 40-50% duty cycle.
Jim VE7RF
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|