[TenTec] Triton IV with digital modes

[Bob McGraw - K4TAX]

Typically on PSK - 31, the 100 watt PEP radios should produce about 30 to 35 
watts output.  AND the speech processor should be OFF and the ALC should 
show NO activity.  This will greatly reduce the heat build up that might 
contribute to frequency instability too.    Should you be running a power 
amp then the output should be 1/4 to 1/3 of the PEP rating of the amp.  Most 
stations are running 20 to 40 watts typically on PSK-31.

If you are trying to drive a MIC input from a sound card speaker output, you 
should have some 20 to 40 dB of loss inserted between the sound card and the 
radio input to prevent overdriving the input stage of the radio and maintain 
a good S/N ratio of the audio signal.  A simple resistive T or Pi or L pad 
will do the job.    If the station you are working will give you a IMD 
report, and most software will as read during idle, then you should get a 
report of some -20 to -30 dB IMD if you have a good signal. If the IMD is 
reported in the  -10 to -20 dB range then it is likely you are overdriving 
the input stage.  The result is that your transmitter signal is wide and has 
2 or more sidebands.  Thus you won't be very popular in crowded bands.  Or 
ask the station you are working if they see any sidebands on your signal. 
There should be none.

73
Bob, K4TAX




----- Original Message ----- 
From: "jim" <jim at itristar.com>
To: <KC2RVD at arrl.net>; "Discussion of Ten-Tec Equipment" 
<tentec at contesting.com>
Sent: Wednesday, December 26, 2007 6:29 PM
Subject: Re: [TenTec] Triton IV with digital modes


>I question whether the Triton's stable enough for sliver narrow PSK, but
> it sounds like
> you're driving the Triton so hard that the supply is nervously
> approaching the current limit
> knee.
> It  might become unstable enough to cause frequency modulation of the
> transmitter. If there is a
> radical DC instability, any dampening caps or voltage amplifier
> circuitry between the meter
> and VSWR detector might be cycling and holding up enough voltage across
> the meter
> coil to cause the erratic deflection.
> If you are running the AFSK signal into the mic jack, set the drive up
> to the normal SSB mode
> setting, then regulate the transmitter to about 25W by adjusting the
> COMPUTER audio level out.
> If you can't get the computer audio level output down low enough to
> properly drive
> the transmitter, you may have to stick a 10dB pad between the computer
> out and mic in,
> as the computer level will often be significantly higher and too low an
> impedance than what
> the transmitter would like to see to develop PEP. A 10:1 T-pad should
> take care of both, and
> help produce distortion free AFSK sigs.  Effective PSK RF power levels
> are typically between
> QRP to 30W.
> Jim WA9Z
>
>
> Louis Ciotti (KC2RVD) wrote:
>> I have been using my Triton IV with PSK31 and RTTY over the past few 
>> weeks,
>> and occasionally something odd happens.
>>
>>
>>
>> I tun up the radio/antenna for about 1:1 using the lock position.  When I 
>> go
>> to transmit using rtty/psk31 I will get a very high SWR reading on the
>> Triton meter, and I get a weird buzzing noise coming from the 262G power
>> supply.  I think the rig may be going into oscillation, but have no way 
>> to
>> verify this.  Anyone else experience this??  I have been able to make 
>> some
>> digital contact with good signal reports, but it this is with the drive
>> turned way down.
>>
>> _______________________________________________
>> TenTec mailing list
>> TenTec at contesting.com
>> http://lists.contesting.com/mailman/listinfo/tentec
>>
>>
>>
>>
>
>


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