[1000mp] audio filters for the Mark V

[William Shadid]

Garry, and all,

I think all the manufacturers do it. I have experience it with Icom, Yaesu,
and a little with Kenwood (although I don't have much of their gear).



Basically, we are not the main reason for the existence of these companies
and we are treated accordingly. For me, I am glad to get the offerings that
do come our way. But, if I did choose not to buy from a company who had -- 
in the past -- supplied me with an incompletely designed radio I would
certainly have already ruled out Yaesu, Kenwood, Ten-Tec, and Icom!! At the
same time, all four of those companies have provided us with some fine
equipment -- a fact that is hard to deny.


73,

-Bill, WA9MXQ


----- Original Message ----- 
From: "Garry Shapiro" <garry at ni6t.com>
To: "Ian White, G3SEK" <g3sek at ifwtech.co.uk>; "All about Yaesu 1000mp"
<1000mp at mailman.qth.net>
Sent: Tuesday, 01 June 2004 3:07 PM
Subject: RE: [1000mp] audio filters for the Mark V


> Yaesu's posture of denial re problems that are real and widespread has
> convinced me that, when it comes time to buy the next radio, Yaesu is not
in
> my future.
>
> Garry, NI6T
>
> -----Original Message-----
> From: 1000mp-bounces at mailman.qth.net
> [mailto:1000mp-bounces at mailman.qth.net]On Behalf Of Ian White, G3SEK
> Sent: Tuesday, June 01, 2004 12:47 AM
> To: 1000mp at mailman.qth.net
> Subject: Re: [1000mp] audio filters for the Mark V
>
>
> J. Mc Laughlin wrote:
> >    I do not know what "the hiss" is
>
> Just to clarify this point: the "hiss" that everyone talks about is
> noise at audio frequencies *above* the roll-off of the IF filters.
>
> The noise originates in the IF stages after the filters... maybe in the
> 455kHz analog notch filter, which is never completely disabled, only
> de-tuned.
>
> It isn't a serious hindrance to communication, but it is quite
> noticeable in unmodified FT-1000s, and also the FT-990.
>
> Some people don't care about it, while others find it very irritating.
> (I certainly do, because it's a constant reminder of another stupid
> design error that Yaesu refuse to recognise, and that kind of thing bugs
> me. YMMV, of course.)
>
> The audio lowpass filters will kill the hiss completely, but you have to
> adjust the audio cutoff frequency whenever you switch IF filters. The
> Inrad IF amplifier mod masks the IF noise, but causes a permanent
> degradation of close-in IMD performance.
>
>
> --
> 73 from Ian G3SEK
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