[R-390] Preselector

[Veenstra, Lester]

With all the tuned RF stages in the front end on the 390(*), it is very
unlikely that an external preselector is going to add a significant out
of band protection.

-----Original Message-----
From: r-390-bounces at mailman.qth.net
[mailto:r-390-bounces at mailman.qth.net] On Behalf Of Dan Merz
Sent: Thursday, August 19, 2004 11:03 PM
To: Bob Camp; Charles B; R-390 HF Receiver List
Subject: Re: [R-390] Preselector


Bob,  I've heard this said before - and I always delight when my
receiver shows noise when the antenna is connected - a good sign.  But
what if the preselector  that I add has narrower bandwidth than the
front end of the receiver I'm using but is still wide enough for what I
want to hear?  Won't I see a benefit by adding this preselector?

another misinformed listener ready to be informed,

Dan.
----- Original Message ----- 
From: "Bob Camp" <ham at cq.nu>
To: "Charles B" <ka4prf at us-it.net>; "R-390 HF Receiver List"
<r-390 at mailman.qth.net>
Sent: Thursday, August 19, 2004 4:28 PM
Subject: Re: [R-390] Preselector


> Hi
>
> One place that a pre-amp might help an R-390 is up on 10 meters. The 
> radio is plenty sensitive enough on the lower bands but as frequency 
> goes up the noise level off a typical antenna goes down. The antenna 
> it's self gets smaller and both the man made and natural noise drop 
> off some as frequency goes up. You can come up with a sub one db noise

> figure pre amp for just about any band from 1 GHz on down. That has to

> be significantly better than the front end of most HF radios.
>
> A simple way to check if it will help:
>
> Listen to the noise out of the radio as you attach the antenna. If it 
> goes up you don't need a pre-amp. Since you have an antenna trimmer 
> involved it's a little more complicated than with a rice box, but the 
> net result is the same.
>
> Take Care!
>
> Bob Camp
> KB8TQ
>
>
> On Aug 19, 2004, at 5:04 AM, Charles B wrote:
>
> > Hi all,
> >
> > What happens if you install a small preselector or preamplifier in 
> > front of an R-390A?  Does it help or hinder?
> >
> > Chuck
> > ka4prf at us-it.net
> >
> > ______________________________________________________________
> > R-390 mailing list
> > Home: http://mailman.qth.net/mailman/listinfo/r-390
> > Help: http://mailman.qth.net/faq.htm
> > Post: mailto:R-390 at mailman.qth.net
> > Unsubscribe: http://mailman.qth.net/mailman/options/r-390
> >
>
> ______________________________________________________________
> R-390 mailing list
> Home: http://mailman.qth.net/mailman/listinfo/r-390
> Help: http://mailman.qth.net/faq.htm
> Post: mailto:R-390 at mailman.qth.net
> Unsubscribe: http://mailman.qth.net/mailman/options/r-390


______________________________________________________________
R-390 mailing list
Home: http://mailman.qth.net/mailman/listinfo/r-390
Help: http://mailman.qth.net/faq.htm
Post: mailto:R-390 at mailman.qth.net
Unsubscribe: http://mailman.qth.net/mailman/options/r-390