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@comcast.net>
To: "'Discussion of Ten-Tec Equipment'" <tentec@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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>
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