While it is true that the additional amp stage reduces the dynamic
range, that does not mean that in all situations a problem will be
seen. I've written about this recently here. If your rx is operating
in the vicinity of extremely strong signals, then you're more likely
to see degraded performance. But if one is operating search & pounce
in a CW contest, the 250 Hz filter in the Orion works well, and the
beauty of the O1 is that you can turn the filter off and just use the
600 Hz roofing filter if any DR problems are noticed. It's the best of
both worlds because the 250 Hz filter does a nice job of reducing
noise too.
For your consideration.
73, Duane
Sent from my iPod
Duane C.
On Mar 25, 2008, at 4:29 PM, "pfizenmayer" <pfizenmayer@qwest.net>
wrote:
>
>
> Check schematic - 81910 9 mhz If amplifier in folder A4.
>
> The extra IF amplifier in the 565 Orion is present in both the 500
> and 250
> cycle path - that is why the 600 hz filter originated by W4ZV is put
> in the
> 1 khz slot which does not have the extra IF stage.
>
> The Orion 566 (OII) does not have an extra IF amplifier for the 300 hz
> filter
> (or any other filter) as shown in folder A4 81999 If amplifier for
> OII.
>
> Hank K7HP
>
>
> ----- Original Message -----
> From: "bob finger" <finger@goeaston.net>
> To: "Discussion of Ten-Tec Equipment" <tentec@contesting.com>
> Sent: Tuesday, March 25, 2008 12:05 PM
> Subject: [TenTec] Orion....use of 250 hz filter
>
>
>> John K4NP wrote in part:
>>
>> I had read the info on the insertion loss and increased IMD when
>> using the
>> 250 Hz roofing filter. As a result, I decided to go with the INRAD
>> 600 Hz
>> filter in the 1 KHz slot.
>>
>> Last week, I picked up a model 219 filter at a fair price. My
>> results
>> have been quite favorable.
>>
>> John: The problem is with the 500 Hz slot, thus the work-around
>> with the
>> InRad 600. The 250 Hz slot does not, to my knowledge, have the IMD
>> problem and has no additional gain stage as does the 500 slot. The
>> InRad 600 works so well tho that I find no discernible improvement
>> using
>> the 250 Hz roofing filter even during very crowded contest
>> conditions.
>> Thats why my 250 is turned off in menu. I would suspect your results
>> would be "normal" on the Orion.
>>
>> Thats the reason many of us went to the InRad 600. It works fine and
>> allows one to hear a bit more around the edges when running in a
>> contest.
>> When running 250 Hz is too narrow to ever hear the callers who
>> don't know
>> how to zero beat, or think they have a better chance calling 200 Hz
>> off
>> center. 73 bob de w9ge
>>
>> _______________________________________________
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>>
>>
>
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