My take and experience on digital modes looks at the folks using
interface
boxes and those that do not use interface boxes. I am one that does not
use
a interface box but connect the sound card input and output direct to the
radio line input and line output. No interface is used. Any of the
current
and popular software packages on the computer work the digital modes just
fine and with no problems. As to RX/TX switching, the VOX handles the
task
nicely. The Windows sound mixer along with the Line gain on the radio
handles the level control. The best thing is that I have none of the
interface problems that others seem to deal with. My philosophy is this;
more boxes, more wires, more cables = more problems.
As to power indication, the display in the radio is very fast thus can
indicate the quasi true PEP power value. Mechanical meters are slow by
nature and without some electronic acceleration will not be able to
follow
or display PEP signal values.
I am not aware of ANY 100 watt radio on the market today that will output
100 watts of clean PSK signal. Typically the output power should be -3
to -6 dB below rated PEP output for digital modes.
73
Bob, K4TAX
----- Original Message -----
From: "Jim M." <jmiller1706@cfl.rr.com>
To: <geraldj@storm.weather.net>; "'Discussion of Ten-Tec Equipment'"
<tentec@contesting.com>
Sent: Wednesday, February 11, 2009 12:29 AM
Subject: Re: [TenTec] O2 output level with PSK aux in
You are right, when I set the drive audio until the ALC just stops
flashing
on the O2 then I get about 30-40 watts out, or in that range, which is
what
has been recommended by others. That's where I leave it for PSK (maybe
PSK
was a bad example to use).... So what about RTTY (AFSK)?. I would like
to
get 90-100W out on that mode, since it is not as sensitive to intermod I
would imagine. But again, the drive from the Navigator won't drive it
fully
to 100W on RTTY. The external wattmeter is a Nye Viking dual meter peak
and
average reading type RFM-003. They don't make it now but it is
accurate:
http://www.eham.net/reviews/detail/2466 SWR is 1.03/1.
I still would like to hear others' experience with the Navigator (or
other
USB interfaces) driving the O2 Aux input, RTTY AFSK as an example. Are
you
getting sufficient audio drive? Thanks to all for the comments. Jim
N4BE
-----Original Message-----
From: tentec-bounces@contesting.com
[mailto:tentec-bounces@contesting.com]
On Behalf Of Dr. Gerald N. Johnson
Sent: Tuesday, February 10, 2009 11:57 PM
To: tentec@contesting.com
Subject: Re: [TenTec] O2 output level with PSK aux in
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
needed.
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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