Power point

[William Carver]

It would be nice to explicitly give the bandwidth associated with the
dynamic range numbers. Most tests I have seen use 500 Hz but.....

In any case one assumes that all those numbers are obtained with the
same bandwidth, or at least "normalized" to a specific bandwidth.
Without a statement of bandwidth this is just an assumption.

Bill


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[Eric Swartz - WA6HHQ]

All the ARRL numbers are at 400-500 Hz b/w.

73, Eric




William Carver wrote:

> It would be nice to explicitly give the bandwidth associated with the
> dynamic range numbers. Most tests I have seen use 500 Hz but.....
>
> In any case one assumes that all those numbers are obtained with the
> same bandwidth, or at least "normalized" to a specific bandwidth.
> Without a statement of bandwidth this is just an assumption.
>
> Bill
>
>
> ______________________________________________________________
> Elecraft mailing list
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>  

... [show rest of quote]

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[Bill W4ZV]

 > It would be nice to explicitly give the bandwidth associated with the
dynamic range numbers. Most tests I have seen use 500 Hz but.....

 > In any case one assumes that all those numbers are obtained with the
same bandwidth, or at least "normalized" to a specific bandwidth.
Without a statement of bandwidth this is just an assumption.

         ARRL, RSGB (RadCom), W8JI and Sherwood always use 500 Hz or
the "Closest Available to 500 Hz" (per ARRL Test
Procedure).  Sherwood is the only tester who sometimes uses
additional bandwidths but they are always footnoted.

                                         73,  Bill  W4ZV




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[KGØUS]

I agree that most of the time the ARRL radio product reviews are performed with 400-500 Hz bandwidth IF filters installed.  However there is at least one notable exception.  Have a look at the March 1991 ARRL review of the now famous Yaesu FT1000D.  The ARRL tests were conducted with 250 Hz bandwidth IF filters.  This surely helped make the Yaesu FT1000D review results even better.

By just reviewing the ARRL test results, is there a simple way of comparing the FT1000 measured with 250 Hz bandwidth IF filters with other radios tested by the ARRL that were tested with 500 Hz bandwidth IF filters?

73,
Dave

Eric Swartz - WA6HHQ, Elecraft wrote

All the ARRL numbers are at 400-500 Hz b/w.

73, Eric




William Carver wrote:
> It would be nice to explicitly give the bandwidth associated with the
> dynamic range numbers. Most tests I have seen use 500 Hz but.....
>
> In any case one assumes that all those numbers are obtained with the
> same bandwidth, or at least "normalized" to a specific bandwidth.
> Without a statement of bandwidth this is just an assumption.
>
> Bill
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[e-mail]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>  
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... [show rest of quote]

... [show rest of quote]

[Alan Bloom]

On Wed, 2009-09-16 at 20:11 -0700, KGØUS wrote:
...
> By just reviewing the ARRL test results, is there a simple way of comparing
> the FT1000 measured with 250 Hz bandwidth IF filters with other radios
> tested by the ARRL that were tested with 500 Hz bandwidth IF filters?
>
> 73,
> Dave

It makes the noise floor 3 dB lower.  So microvolts sensitivity would be
reduced by a factor 0.707 (e,g, .28 uV at 500 Hz would be 0.2 uV at 250
Hz), blocking dynamic range would be 3 dB greater, and third-order IMD
dynamic range would be 2 dB greater.

Al N1AL



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