Hello Bill,
The more I thought about it, I'm not so sure about the sidebands
being a problem when looking at the 200 Hz bandwidth limit. You will
always have sidebands, it's a matter of how far down from the
fundamental, in this case two fundamentals 170Hz apart. I've seen
bad RTTY signals that are 170 Hz shift producing noticeable sidebands
on the spectruim more than 200 Hz wide. Yeah, they're probably AFSK
generated.
I'm planning on using the 200 Hz region unless the FCC dictates the
sideband values below a level unattainable by the average amateur
equipment should the ARRL's wachy bandplan be adopted.
No, I haven't done the math as the last time was 45 years ago as an
undergrad. Don't plan on drudging up old memory cells to do the math
as I've got to get the amplifier working better plus build another
for the second radio.
How's the amp. coming along, Bill?
At 06:59 AM 1/16/2006, Mike wrote:
>Hello Bill,
>
>Thanks for pointing it out. That's why I put it as a question.
>
>At 12:00 AM 1/16/2006, Bill Turner wrote:
>>ORIGINAL MESSAGE:
>>
>>At 08:10 PM 1/15/2006, Mike wrote:
>>
>>>Since I use 170 Hz shift (bandwidth) and the DX stations I have
>>>contacted in and out of contests are also 170 Hz shift, the ARRL
>>>proposal should not impacting my operation in the 3520 - 3525 KHz
>>>area and below 7030 KHz and below 3580 KHz. Am I not reading it
>>>correct? Is there another ARRL or FCC document/proposal I should be
>>>looking at?
>>
>>
>>~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>
>>Shift is not the same as bandwidth, as the mathematicians among us
>>will be quick to point out. RTTY is a form of FM, and FM produces
>>sidebands. The bandwidth is a function of both shift and baud rate.
>>
>>I'll leave it to the pros to calculate exactly, but somewhere
>>between 250 - 350 Hz is required for 170 Hz shift.
>>
>>Bill, W6WRT
>
> 73,
> Mike, K4GMH
73,
Mike, K4GMH
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