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Re: [TenTec] [Orion] O2 versus Orion

To: tentec@contesting.com
Subject: Re: [TenTec] [Orion] O2 versus Orion
From: CATFISHTWO@aol.com
Reply-to: Discussion of Ten-Tec Equipment <tentec@contesting.com>
Date: Mon, 9 Jan 2006 21:37:35 EST
List-post: <mailto:tentec@contesting.com>
 
I enjoy this on the orion, but you will never ever keep up with my swan 3  
drifty, now that's accurate freq's
 
In a message dated 1/9/2006 9:42:00 A.M. Pacific Standard Time,  
RMcGraw@Blomand.Net writes:

My  experience tells me that there is a concernable difference in ones 
ability  to audibility and accurately "zero beat" a given signal.  Unless one 
 
can observe the difference in beat of the two signals via the S-Meter  
fluctuations as the frequency gets very close, it is thus below the audio  
passband of the and certainly below the low frequency hearing of most  folks. 
Less than 30  to 50 Hz for example.  Therefore the 1 Hz  resolution or ones 
desire to achieve such is of rapidly questionable  accuracy.

To this end, I prefer to actually measure the transmitter  output or actual 
oscillator frequency with a suitable counter capable of  measuring to 0.01 Hz 
at the desired frequency or better.  Truthfully,  not many hams have access 
to such high accuracy items as their cost is  several times that of an Orion 
II.  Thus we do more "referencing"  than actually measuring of frequency 
values.  In each case, the  reference add a percentage of error +/- to the 
resolution method.

I  took some time to "practice" various zero beat methods this morning and  
then looked at the actual transmitter frequency.  In most cases I was  able 
to get within 30 to 50 Hz of the desired frequency but certainly in  fact no 
closer, as the audio passband fell apart below 30 Hz and there was  simply 
"nothing to hear" coming out of the receiver.   Once I  got closer in 
frequency then I was able to detect the swing of the S-Meter  and bring 
things in a good bit closer.  Still, accuracy of 1 Hz was  questionable.

We must remember that these radios are not designed to be  frequency meters 
or frequency counters and thus the stability and  repeatability is very 
questionable when one gets into the single digit Hz  region.   Then why do 
they put 1 Hz resolution on radios?   To be better than the next fellow and 
to sell radios with  features.

73
Bob, K4TAX


----- Original Message -----  
From: "Martin AA6E" <martin.ewing@gmail.com>
To: "Bill Tippett"  <btippett@alum.mit.edu> > standard for WWV  comparison.
>
> Now that I look at the schematics, I see that the  CODEC has a separate
> "14.360 MHz" clock crystal.  Maybe that's  the problem.  It should be
> generated from the TCXO.  Is that  the birdie I hear at 14,351.770?
> (.05% low)  This would introduce  a minor offset, which is cancelled
> out if you calibrate against  WWV.  Or is there more to it?
>
> Orion's accuracy and  stability are good, but none too high, IMO.  This
> shows up in  netting accuracy at the higher freqs.  Of course, 95% of
> rigs out  there are worse.  The new IC-7000 has a much better spec:
> +/- 0.5  ppm vs Orion's +/- 3 ppm.  Probably cost them a couple of
> bucks  more.  The IC-7800 claims +/-.05 ppm 0-50C "after warmup", for a
>  price.
>
> It would be nice if the master oscillator was at least  upgradeable or
> syncable to an external reference, for the few folks  who are looking
> for very high precision.
>
> 73 Martin  AA6E




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