More great info from Frank @ SIMREX. Steve ~ KA1RCI
----- Original Message ----- From: Frank Neuperger To: fr...@simrex.com Cc: Steven M Hodell ; maqui >> Mike Aquilino ; sa...@simrex.com 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: Repeater-Builder@yahoogroups.com Cc: sa...@simrex.com 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: Repeater-Builder@yahoogroups.com 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 ---------------------------------------------------------- President and CTO - Arcom Communications Makers of repeater controllers and accessories. http://www.arcomcontrollers.com/ Authorized Dealers for Kenwood and Telewave and we offer complete repeater packages! AH6LE/R - IRLP Node 3000 http://www.irlp.net "We don't just make 'em. We use 'em!"