More great info from Frank @ SIMREX.
Steve ~ KA1RCI
----- Original Message -----
From: Frank Neuperger
To: [email protected]
Cc: Steven M Hodell ; maqui >> Mike Aquilino ; [email protected]
Sent: Thursday, July 29, 2010 4:15 PM
Subject: Re: [Repeater-Builder] Fw: TKR750 -Preamp
Steve,
That did not post to the list because I don't have membership. I would
appreciate if you would forward to the list on my behalf.
Regards
Frank
On 7/29/2010 3:58 PM, Frank Neuperger wrote:
Steven,
Thanks for the vote of confidence. We sell them to Hams (Ham
frequencies) for $275($25 less than 2-way dealers) as a gesture to Gil Boelke
(silenet key) who developed the preselector and founded GLB (now owned by
SIMREX).
Note that the standalone preselector is still made in house by staff that
were trained by Gil and on tooling built by Gil.
It is also the front end of every SNRDS-II radio. Same radios that are part
of many FAA and other Federal systems.
Standard gain is 8 db
For +$25, you can order it with ~4 dB gain and steeper skirts on the filter
or
~11 dB gain and gentler slope on the filter skirts.
For extreeme interference, one usage of the preselector has been to place
a coax stub notch filter between the antenna and the preselector. I have done
~3MHz spacing of the notches of the comb for a marine radio BASE application
using ~ 35?? feet of LMR 400 for my stub. One of the notches was placed
directly onto the frequency of collocated marine base station giving us an
extra 22dB of suppression at that frequency. Using excessive length of coax
resulting in a comb allows the overallbandwidth to repeak steeply and with
minimal loss between the notches of the comb. A single notch approach (not
a comb) when placed close to your desired carrier will often have unacceptable
insertional loss at your desired frequency. The comb notch filter is just
extra coax and minimizes the insertion loss close to the notch. . The calcs
for length are not too difficult.
Warmest Regards
Frank Neuperger
Simrex Corporation
VE3FNZ
----- Original Message -----
From: Steven M Hodell
To: [email protected]
Cc: [email protected]
Sent: Thursday, July 29, 2010 2:34 PM
Subject: Re: [Repeater-Builder] Fw: TKR750 -Preamp
Another very good choice for this application is the GLB Preselector / Preamp
from Simrex Corp.
I have several of these deployed on 144 / 220 / 440 Amateur repeaters and
they all perform very well. They can be tuned to maximize gain or selectivity
per your requirements and their support is outstanding.
http://www.simrex.com/site/products/special.htm
PRESELECTOR PREAMPLIFER
a.. Low cost solution to interference, intermodulation and desensitization
problems.
b.. Helical Resonator Design.
c.. Preselector Specifications (pdf 63k)
d.. Preselector Example Diagram (pdf 10k)
----- Original Message -----
From: Ken Arck
To: [email protected]
Sent: Thursday, July 29, 2010 2:15 PM
Subject: Re: [Repeater-Builder] Fw: TKR750 -Preamp
At 10:30 AM 7/29/2010, Doug Hutchison wrote:
>
>
>Where does one obtain these and at what cost?
http://www.anglelinear.com
Chip Angle is arguably one of the top 10 RF guys in the world
Ken
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