[1000mp] FT-1000 with Heil PR-40
Hans Remeeus
hans at remeeus.nl
Fri Jul 28 10:46:26 EDT 2006
Hello Jim,
> Depends what you mean by "normal" SSB purposes.
Local communication or rag chewing. Not DX or contests.
Thanks for the interesting information!
73,
Hans Remeeus (PA1HR)
http://www.remeeus.eu
Communication is about people, the rest is technology.
Jim Smith schreef:
> Depends what you mean by "normal" SSB purposes.
>
> Several decades ago I was a designer of telephone carrier systems. In
> one system I worked on, each channel had a 250 Hz low pass filter and a
> 3400 Hz high pass filter at the transmit end. This system was designed
> to be "toll quality" which means that it would satisfy the end to end
> requirements of the long distance telephone system. So, 3150 Hz
> bandwidth for a telecommunications channel which sounded "natural". With
> guard bands, each channel was allocated a 4 kHz chunk of the spectrum.
>
> There was also a requirement to pass "program material". i.e.
> commercial AM/FM radio broadcasts. We had a way of using 2 channels for
> this. So a program channel, including guard bands, was allocated a max
> of 8 kHz.
>
> It is not obvious to me what normal ham radio SSB purpose would require
> a bandwidth almost 6X greater than a good quality international
> telephone circuit and 10X greater than the bandwidth I routinely use
> when trying to communicate under difficult conditions.
>
> In any event, I would expect that the transmit filters in any ham SSB
> rig would have bandwidths far lower than that of the proposed microphone
> so, if it costs more than a mic with a more restricted bandwidth, you're
> spending money which could be put to a better use.
>
> 73, Jim VE7FO
>
> Hans Remeeus wrote:
>> Hello,
>>
>>
>> The audio response of the PR-40 is 28 till 18,000 Hz. Would this be a
>> bit too wide for normal SSB purposes?
>>
>> Many thanks in advance!
>>
>>
More information about the 1000mp
mailing list