RE: [Repeater-Builder] Trying to test my antenna system (suspect desense..)
Doug, Please advise the make, model, and power of your transmitter, and the make and model of your receiver and duplexer. That information will help the Elmers on this list arrive more quickly at possible causes. It will also be helpful to state the make and model of your antenna, and the type and length of the feedline. What is the transmitter power output (before the duplexer) into a dummy load, and what is the 12dB Sinad sensitivity of the receiver? I hope that the jumpers are all double-shielded cable, such as RG-400 or RG-214; are they? The MFJ antenna analyzer is really useful only to measure the VSWR of the antenna, by itself. Correct tuning of a duplexer is best done with a network analyzer, measuring return loss. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com [mailto:Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com ] On Behalf Of Doug Hutchison Sent: Friday, June 12, 2009 8:26 AM To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Subject: [Repeater-Builder] Trying to test my antenna system (suspect desense..) Suffering from poor receive perfomance and am trying to check integrity of system. Single 3 dB antenna, single output 6 cavity filter, 10w out of filter. Could someone enlighten me, the cavities are factory tuned 145.6875 tx 145.0875 rx and am attempting to check VSWR with an MFJ antenna analyser. The answers I see do not conform to my understanding so, at what frequencies, at the input and output of the filter while connected to antenna, should I see low vswr. I'm seeing 1.2:1 or so at 146.08, should I not see that on 145.08? Just a bit confused! Thank you, Doug - MM0BJA
[Repeater-Builder] Simplex and Repeater on one Antenna
Hi all, this may have been discussed before, but I could not find what I need. I would like to put a 147.06+ repeater and a 144.39 simplex radio on one antenna. I've seen posts here stating that it can be done, but have not seen specific instructions on how to do it, or what parameters to measure while making changes in my (future) design. If possible, I'd like details, such as particular coax lengths, where any T fittings would be placed, and other details. If details are not possible, then I'm looking for the basic concepts to be adhered to when I design this hookup. Thanks. Laryn K8TVZ
[Repeater-Builder] Re: Controller suggestions, TKR-820
You may also want to take a look at the Arcom RC-210 controller. I have had very good luck with Arcom units. I have both Link-Com and Arcom controllers in-service and prefer the Arcoms. I feel they give you the best bang for the buck. From my experiences with the TKR820's I would also recommend using a Angle Linear preamp on the receiver if you have enough duplexer isolation for the increased receive sensitivity. Joe --- In Repeater-Builder@yahoogroups.com, NORM KNAPP nkn...@... wrote: Hi guys, A local ham club recently received a Kenwood TKR-820 repeater. They are looking for recomendations for an external controller. Some of the features needed are to be able to enable/disable up to 3 link radios (2 for sure, one additinonal link radio later) via DTMF. Computer programmable. Don't really need to get fancy with voice anouncemt clocks or temperature or anything like that. May want to hook it up to a 100watt Mastr II later (much later) . Needs to be rack mountable as well... Any and all suggestions are welcome. 73 de N5NPO Norm Knapp
