|
But what are you sending with the reduced
power rig ?
SSB ... Normal CW Opera
all have low duty cycles and
result in low heat build up
But if you running at 100% key
down sending qrss and the like ,
then , yes the rig will heat up , in the
early days I always though wspr should of
been named Icarus , with the
number of thermal run a ways caused by 100%
duty over 120 seconds ( not a problem at Hf
where power levels are low, but down here
at 1:400 efficiency's = a lot of heat)
The rig will have a class AB1 or
similar PA with high standing bias to
reduce cross over distortion = splatter on ssb ,
so standing dissipation will be high ..not
much you can do ... add a fan to
cool the heat sink , but be careful of the thermal
gradients , out side cold , wont mean inside is
also at the right temp ..may still be
very hot , if parasitic 'ambient' cooling is
part of the equation and the fan is only cooling
the last part of the heat path ..
73 -G..
Sent: Tuesday, November 06, 2012 4:45 PM
Subject: LF: TRANSVERTERS
RIG/TRANSVERTER HEAT
I have noticed when running a Transceiver at low power for
Transverter or other use the Transceiver PA gets very HOT so it would appear
that this is an inefficient approach except the Transceiver has a dedicated low
power output.
I was wondering what system was used to reduce this power.
It would be better to disable the PA and take the output from the driver
stage.
It is vy noticeable on an IC-706
de G3KEV
| 