Jerry with your permission I'd like to reproduce part of your message here.
> I think 2.4 is wider than necessary. I find 1.8 uncomfortably narrow.
Okay, so although K0CQ didn't come out and say it, I will assume that by this
and his previous paragraph, which I cut, he believes that 2.1 kHz is the ideal
bandwidth (hopefully not just because Collins said it was, but because of some
more scientific reason) for SSB communications.
>
> The concepts of spectrum and using the IF shift or bandpass tuning to
> adjust what spectrum is being heard is beyond the
> comprehension of many amateurs.
>
Wow! That is some statement. What do you guys think? IF shift is beyond your
comprehension? I have a much more optimistic outlook on the potential of hams.
I believe there are hams who may not know *how* to use IF shift, but I feel
they could learn if they wanted to.
> Only a FEW DSP transmitters have the capability of changing the
> bandwidth without hardware changes.
Yes, I thought about it later, and I guess K0CQ's right. Ten Tec has only two
or three, and Icom may have two or three, and Kenwood may make one or two. I
don't know about Yaesu. That leaves quite a few rigs made in the last three
years that don't have this capability, I guess.
>
> SSB does use a whole lot more spectrum than CW but uses a lot
> less brain power and that's important for many hams.
Ouch!, that hurts.
>
> The switch over point is where adding bandwidth adds nothing to the
> understanding of the conversation. Not necessarily where
> increasing that
> bandwidth adds naturalness of the perceived voice. The rules currently
> only require using the minimum bandwidth for communications, they say
> nothing about using a wider bandwidth to sound more natural.
>
I have always been perplexed by "the rules" in this matter. It almost seems
like they were intentionally left vague, as if to allow for interpretation and
adaptation to the situation. You know: contesting, use a narrow bandwidth;
ragchewing, okay to widen yourself a little.
I was listening to the Monday night football game last night on the radio. Marv
Albert calling the game from Denver. On a wideband (audio bandwidth = 7 kHz)
receiver, there was audio all the way up to 7 kHz. I thought, "Why broadcast
this wide bandwidth when it's only the human voice calling a game? It's not
music. It would have been perfectly intelligible to cut the bandwidth to 2.1
kHz and broadcast that." So, what purpose does it serve? If you say, "But Part
97 does not apply to AM broadcast stations," you would be right, but we can
still speak philosophically of the purpose served by the wider bandwidth. There
must be one.
Then I adjusted the DSP to a bandwidth of 500 - 2000 kHz, or 1500 Hz total.
Amazingly, I could still understand Marv Albert. So I should say that 1500
should be the max, because any wider bandwidth added absolutely nothing to my
understanding of the football game!
> Then when listening for WEAK signals at the noise level or below
> reducing the receiver bandwidth reduces the noise power and
> so enhances
> the signal to noise ratio improving weak signal communication allowing
> running minimum power as required by the FCC rules. All of
> which reduces QRM.
>
Yes, this is true. Another good point.
It's becoming clear to me that in the minds of many hams spectrum use is indeed
the single most important factor by which to judge a signal's merit. That's
fine. I must have missed the process by which this occurred.
Al W6LX
_______________________________________________
TenTec mailing list
TenTec@contesting.com
http://lists.contesting.com/mailman/listinfo/tentec
|