[TenTec] O2 output level with PSK aux in

Dr. Gerald N. Johnson geraldj at storm.weather.net
Tue Feb 10 23:57:09 EST 2009

On Wed, 2009-02-11 at 02:54 +0000, Jim M. wrote:
> Using HRD sound card into rear panel auxiliary input.  With speech proc off I get only about 50 watts out with max audio drive measured on rf wattmeter.  The O2 meter shows 100 watts, not 50.  If I turn SP on, I can get closer to 100 watts out.  The O2 power meter appears to be reading 2x what is actually being transmitted?  And or the drive level without the SP is cut 50 percent?  What's going on in the DSP?  Any suggestions on how to get an honest 100 watts on Psk? Jim N4BE
> Jim

You get 100 watts PSK by running 20 watts from the Orion into a 600 watt
amplifier. Otherwise the intermod just kills the BAND you are on, and
the other users will be wanting to shove nails into your coax. You don't
NEED 100 watts to work the world and no radio puts out clean PSK31 at
full rated power. Most do fine at 30 watts or less, and that's enough to
work the world.

Since PSK allows many RF signals in a typical receiver IF bandwidth, its
super annoying to have one super strong signal (which 100 clean watts
would be) to take over the AGC and blank the other signals. So high
power (and 100 watts on PSK31 IS HIGH POWER) is unwelcome and not

Receiving software nearly always shows an intermod level as well as
showing extra spectrum components on the waterfall display. It is
instantly clear who is running the transmitter too hard. Settle for 25
watts and you will make more contacts and friends.

73, Jerry, K0CQ

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