[Amps] Maximum RF output in practical application: 4-250A

[Joe Isabella]

I'm only going to say that to dismiss something solely because "it's always been that way" is a terribly closed minded way to look at something.  I'm fully aware of why ~200-3.4k was chosen (as I mentioned before) -- it was the best trade-off between speech intelligibility and network resources.  This is not in dispute!!  I also fully realize that when you use a narrow BW, the noise floor drops proportionately.  What *I'm* saying is that when you give the distant end a little more than 400-2.4k, say up to 3, 3.3 or 3.4k, even when they are using a narrow receive BW, it's logical to conclude that they have more there to hear through the mess.  In my (admittedly non-scientific) experimentation, that's what I have found.  It works very well for me, and I think there's something to it.  To morph a phrase from Rich, "Mo' narrower ain't necessarily mo' better".  I would also be the last one to tell you that "pumped up bass and extended highs" are better in high QRM/QRN band
 conditions.  This is separate than wanting to be able to enjoy full-range QSOs in non-crowded bands, and the mechanics of how extended BW improves intelligibility *in good S/N conditions* (which is simple common sense to me).  Let's try to keep the two separated.  Again, there is a time & place for each.  And to claim Bell's research as a reason to use 400-2.4k is off-base since the typical telephone system channel is ~200-3.4k or 3.2k total BW based on the same research.  Which, oddly enough isn't too far from what I found works well for me in high QRM/QRN conditions.  Go figure.

Anyway, I'm off to get that analyzer to capture some data on wider speech BW on my rig's RF performance.

73,
Joe, N3JI

----- Original Message ----
From: Tom W8JI <w8ji at w8ji.com>
To: Gudguyham at aol.com; kdutson at sbcglobal.net; n3ji at yahoo.com; w4tv at subich.com; amps at contesting.com
Sent: Tuesday, July 4, 2006 8:52:19 AM
Subject: Re: [Amps] Maximum RF output in practical application: 4-250A

> All I  can say is that when there is significant noise & 
> QRM, that  extra
> couple hundred Hz of articulation seems to make a 
> difference.
>
> Has anyone else experimented with that?
> Joe,  N3JI

I do all the time, and when there is significant noise and 
QRM **LESS** bandwidth improves copy provided that bandwidth 
is properly centered.

If you listen to widefi AM guys, those with the deepest bass 
and highest highs are the very worse to copy when signals 
are tough. SSB is no different at all.

This has been known a long long time Joe. Not only is this 
thread out of place on an amplifier forum, it has reached an 
impasse. People who want WideFi will go through any extreme, 
including the use of a white paper created by a company who 
sells (no surprise) wide-fi audio systems to replace regular 
telephones. Those who don't swallow all the bean soup will 
stick with the same arguments Art Collins and the rest went 
by, and that any DX'er already knows.

It really is pointless to continue this. It's like trying 
get a guy with a Hummer to admit it is a waste of resources 
or a guy who drive a sports car to enjoy a land-yacht. No 
matter what the technical facts or situation, people will 
find any reason to justify what they think is right. When I 
look at all the banter on Internet or listen to 
conversations, it's clear very few audio affectionos seems 
to grasp the basics of communications systems. W9AC is a 
rare exception who both understands it and has common sense. 
People would be well-advised to listen to Paul if they don't 
trust respected commercial communication sources.

If the band is not crowded and wide-fi guys are away from 
weak signal areas, they can have all the bandwidth they 
want. When the band is busy, even if they are there first, 
they should be smart enough and considerate enough to 
throttle it back to the minimum necessary. The AM guys have 
enough sense to confine activity to areas of the band away 
from potential problems, and the AM guys also have enough 
sense to get off the band when it is crowded.

The only thing I object to is all the nonsense about wider 
bandwidth makes better weak signal or is better at QRM 
cutting.

I hope this thread dies soon. It has NOTHING to do with 
4-250A's. It belongs on a bandwidth forum.

73 Tom 


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