] On Behalf Of Pointman
Sent: Thursday, November 26, 2009 9:56 PM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] Re: pre-amp placement
So your suggestion is to get a Band pass/reject cavity instead? Or should I
get 2 for the added isolation?
keep in mind I am on UHF
de
At 11/26/2009 09:39, you wrote:
You might need to add a several DB attenuator
between
the pre amp and the receiver to keep from over
driving
the front end.
Not if you use a good receiver, or not use a preamp with
too much gain.
Bob NO6B
What defines too much gain
At 11/26/2009 10:08, you wrote:
So what is the recommendation to set the loss of the BP cavity? I have a
setting as to 3 db, 1 Db, .5 Db Etc. Running the ARR preamp on a UHF
repeater, it seems the preamp is a little too much and we get a little
desense. I am only running a 4 cavity duplexer
What defines too much gain can vary wildly.
Each install would be different. But too much gain
can be tested for... (measured) and with the proper
construction be fairly easily controlled.
0.1 uV is about as good as you can do with a NBFM RX,
as that's roughly 6 dB above kTB when T=295
At 11/27/2009 11:14, you wrote:
I would have never considered a dual series RF Preamplifier
layout viable until I'd seen one demonstrated against the
single preamplifier version. The properly installed and
setup dual preamplifier layout with system gain well in excess
of 14dB clearly out preforms
On Nov 27, 2009, at 12:14 PM, skipp025 wrote:
There are Northern California site locations in operation
where the Repeater Rx Antenna System contains the desired
pre-selection, two series pre-amplifiers separated initially
by an adjustable attenuator and later a fixed value. It's
beyond
I would have never considered a dual series RF Preamplifier
layout viable until I'd seen one demonstrated against the
single preamplifier version. The properly installed and
setup dual preamplifier layout with system gain well in excess
of 14dB clearly out preforms the rest of the bunch
Hi Nate,
Two or three people have already Emailed me direct so here
goes...
Nate Duehr n...@... wrote:
Nate Duehr, WY0X
I'd love to see how that gets properly measured, if you
ever have the time, Skipp. That one's outside of my
knowledge level, for sure.
Can do:
The measurements
: Repeater-Builder@yahoogroups.com
[mailto:repeater-buil...@yahoogroups.com] On Behalf Of skipp025
Sent: Wednesday, November 25, 2009 10:37 PM
To: Repeater-Builder@yahoogroups.com
Subject: [Repeater-Builder] Re: pre-amp placement
Hello John,
W3ML w...@... wrote:
Hi,
not since high school
k7...@... Mike wrote:
Hi Skipp,
Hello back,
Happy Thanksgiving first off. Go to the Angle Linear
web site and read Chip's documentation he has provided.
I don't know too many people that has a better product
than him and his stuff if installed correctly works
like no other.
@yahoogroups.com
Subject: [Repeater-Builder] Re: pre-amp placement
Hello John,
W3ML w...@... wrote:
Hi,
not since high school... :-)
I have now read two different things about where to put
the pre-amp.
Only two?
One says before the Bandpass and one after.
What I have now is the 6 can
I've got to lay off the hard stuff so early in the
morning... please allow me to correct the following.
I'd venture to say... if your receiver front end is
of decent Q (quality) and reasonably narrow band-width
along with a decent duplexer... then the preamp might
best go after the
-
From: skipp025
To: Repeater-Builder@yahoogroups.com
Sent: Wednesday, November 25, 2009 11:36 PM
Subject: [Repeater-Builder] Re: pre-amp placement
Hello John,
W3ML w...@... wrote:
Hi,
not since high school... :-)
I have now read two different things about
Anyone have a spare bandpass filter tunable for the UHF amateur band like a DCI?
Thanks!
Alan
- Original Message -
From: Mike Dietrich
To: Repeater-Builder@yahoogroups.com
Sent: Thursday, November 26, 2009 10:09 AM
Subject: Re: [Repeater-Builder] Re: pre-amp placement
Hi Eric,
Eric Lemmon wb6...@... wrote:
Skipp,
It seems as if both of your answers suggest that the
preamp be installed in the same place- between the
duplexer and the bandpass cavity.
You caught that just as I was posting the correction.
Perhaps your intent for the second
Mike Dietrich m.dietr...@... wrote:
The main way of thinking is that you want to put the
pre-amp after the band pass filter.
The reason for this is that if it is before the b/p
filter, it amps anything it sees, noise and unwanted
stuff alike. If its behind the b/p filter, it only
Thanks Glenn,
I think I will it where it is since it is a Adv Receiver Research Gasfed.
I don't remember the article mentioning helical resonators.
Was just wondering why there would two different places in the articles.
73
John
--- In Repeater-Builder@yahoogroups.com, Glenn Little WB4UIV
Ralph you bring up a good point of thought.
The ham that built our repeater placed the Decibel Products 4002 Bandpass
behind the Wacom 6 can duplexer and then followed by the ARR Gasfed P144VDG to
the radio.
Now where he built it was his tower site (an old ATT brick building) full of
At 11/26/2009 07:31, you wrote:
Mike Dietrich m.dietr...@... wrote:
The main way of thinking is that you want to put the
pre-amp after the band pass filter.
The reason for this is that if it is before the b/p
filter, it amps anything it sees, noise and unwanted
stuff alike. If its
At 11/26/2009 08:14, you wrote:
Thanks Glenn,
I think I will it where it is since it is a Adv Receiver Research Gasfed.
Good choice IMO. If you want to maximize your sensitivity, just make sure
your pass cavity is very low loss. If the loops are or adjusted for 2 dB
loss, you could easily
You might need to add a several DB attenuator
between
the pre amp and the receiver to keep from over
driving
the front end.
Not if you use a good receiver, or not use a preamp with
too much gain.
Bob NO6B
What defines too much gain can vary wildly. One trick I learned in
At 11/26/2009 08:30, you wrote:
Ralph you bring up a good point of thought.
The ham that built our repeater placed the Decibel Products 4002 Bandpass
behind the Wacom 6 can duplexer and then followed by the ARR Gasfed
P144VDG to the radio.
Now where he built it was his tower site (an old ATT
.
de KM3W
From: n...@no6b.com n...@no6b.com
To: Repeater-Builder@yahoogroups.com
Sent: Thu, November 26, 2009 12:50:18 PM
Subject: Re: [Repeater-Builder] Re: pre-amp placement
At 11/26/2009 08:30, you wrote:
Ralph you bring up a good point of thought.
The ham that built our repeater placed
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] Re: pre-amp placement
So what is the recommendation to set the loss of the BP cavity? I have a
setting as to 3 dB, 1 dB, .5 dB etc. Running the ARR preamp on a UHF
repeater, it seems the preamp is a little too much and we get
Of Mel Swanberg
Sent: Thursday, November 26, 2009 12:40 PM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] Re: pre-amp placement
You might need to add a several DB attenuator
between
the pre amp and the receiver to keep from over
driving
the front end
Subject: RE: [Repeater-Builder] Re: pre-amp placement
A total insertion loss of about 1.0 dB works well, in my experience. With
two 8 bandpass cavities in series, this gives at least 25 dB of isolation
from the transmitter carrier at a 600 kHz split.
Bear in mind that your notch cavity has
Hello John,
W3ML w...@... wrote:
Hi,
not since high school... :-)
I have now read two different things about where to put
the pre-amp.
Only two?
One says before the Bandpass and one after.
What I have now is the 6 can duplexer is hooked to the
bandpass and then on the other
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