[1000mp] MP Roofing Filter from INRAD -- hiss reduction needed?

[Joe Subich, K4IK]

Mike (YO3CTK):  They were taking orders at Dayton.  Contact 
them via their web page (http://www.qth.com/inrad). 


Mike (WB2AJI): Your information matches what I heard from 
George at Dayton.  However, unless one is doing 6 KHz SSB, I 
don't see the 4 KHz filter being an issue for that mode as 
the SSB LO is offset from the filter center frequency.  
Anyone trying to do 6 KHz SSB is a fool (or band hog) in 
any case.  

I do expect that George will eventually see some pressure 
to increase the gain of the post filter amplifier to get 
a bit more "noise (hiss) reduction ... maybe on the order 
of 6 dB of excess gain.  If he doesn't, someone else will 
probably figure a way to tweak the modification (a resistor 
change) and folks will be doing it themselves.  

73, 

   ... Joe, K4IK 
 

> -----Original Message-----
> From: 1000mp-bounces at mailman.qth.net 
> [mailto:1000mp-bounces at mailman.qth.net] On Behalf Of Mihail Mateescu
> Sent: Wednesday, May 19, 2004 1:42 PM
> To: 'All Things Pertaining To The 1000mp Series'
> Subject: RE: [1000mp] MP Roofing Filter from INRAD -- hiss 
> reduction needed?
> 
> 
> Can we open a waiting list?
> 
> 73 de Mike, YO3CTK 
> 
> -----Original Message-----
> From: 1000mp-bounces at mailman.qth.net 
> [mailto:1000mp-bounces at mailman.qth.net]
> On Behalf Of Mike Schatzberg
> Sent: Wednesday, May 19, 2004 7:41 PM
> To: k4ik at subich.com; 'All Things Pertaining To The 1000mp Series'
> Subject: Re: [1000mp] MP Roofing Filter from INRAD -- hiss 
> reduction needed?
> 
> Hello Joe:
> 
> I spoke with George yesterday, and he does indeed confirm 
> that the filter is not going to be switchable.  He wants to 
> make it a straight forward modification, that will suit the 
> particular application for the radio.
> 
> This means that if you listen to SSB wide band, as I do 
> sometimes, to obtain either the best signal to noise ratio, 
> or the best fidelity, you will give up something because it 
> is not switchable, besides giving the AM and FM.
> 
> It appears that you must make your choice between lower 
> noise, with the IF kit, or better IMD numbers with the 
> new kit.  Some people will opt for one over the other, 
> depending on needs.
> 
> The kit right now is still on the prototype board, and has 
> not yet been commercially produced for sale.  The first run 
> will be around 150 units or so, if I remember correctly.
> 
> Regards,
> 
> Mike
> WB2AJI