[TenTec] Request for check of Orion 1.3xx Behavior - AM

[Ron Castro]

Grant and group:

I ran a frequency response test on the O2 on AM and found the following (all 
controls set flat, modulation at 50%, no compression or ALC):

20    -1 dB
30    +1
50    +1
200    +2
400    +1
600    0
1000    0
1200    -1
1600    -1
1800    -2
2000    -2
2400    -2
2800    -2
3200    -2
3400    -4
3600    -4
3800    -4
4000    -5
4200    -6
4400    -7
4600    -9
4800    -10
5000    -12

If you roll the low end down by 2 dB, you see a variation of +1 -2 dB (+-1.5 
db) from 30 Hz to 3.8 KHz.  The roll-off on the high end is fairly gentle, 
and with a small be of external EQ, can be reasonably flat to 4.5 kHz. 
Looking at the spectrum analyzer while doing the test showed the THD to be 
less than 1/2%  That's a damn good test result!

Ron Castro  N6AHA
Chief Technical Officer
Results Radio, LLC


----- Original Message ----- 
From: "Grant Youngman" <nq5t at comcast.net>
To: "'Discussion of Ten-Tec Equipment'" <tentec at contesting.com>
Sent: Thursday, February 16, 2006 4:33 PM
Subject: Re: [TenTec] Request for check of Orion 1.3xx Behavior - AM


>> I change the TX bandwidth. The audio highs are lost, in the
>> Monitor audio, as the TX bandwidth is reduced from 3900 down to 900.
>
> Thank you (all of you who responded) very much.
>
> I'm not sure if this is no news or bad news.   My presumption on the
> original is that the response could be opened up to about 3.9 KHz on each
> sideband, for a little better fidelity when the band was clear (and yes,
> closed down to 3 Khz or so when things got crowded, but at least at the 
> ops
> discretion).  I never did sweep the Orion on AM, so maybe that wasn't the
> case.
>
> In the Orion II, the AM transmit bandwidth appears to be fixed at 6 Khz 
> (per
> the new manual update).  I'm presuming that means 3 Khz + Carrier + 3 Khz,
> and if that's the case this new version of AM TX is certainly not an
> improvement.  Guess I'm going to have to drag out the audio oscillator and
> sweep the II, to really verify what's going on, before crabbing to 
> ditnsbits
> about ruining a good thing by (1) just messing it up or (2) making a
> political statement in DSP code :-)
>
> Thanks again ... Grant/NQ5T
>
>
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