[TenTec] O2 output level with PSK aux in

[Bob McGraw - K4TAX]

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 at cfl.rr.com>
To: <geraldj at storm.weather.net>; "'Discussion of Ten-Tec Equipment'" 
<tentec at 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 at contesting.com [mailto:tentec-bounces at contesting.com]
> On Behalf Of Dr. Gerald N. Johnson
> Sent: Tuesday, February 10, 2009 11:57 PM
> To: tentec at 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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