Jamey Wright
-----Original Message----- From: Mike WA6ILQ [mailto:[EMAIL PROTECTED] Sent: Tuesday, September 14, 2004 10:32 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Voters At 05:13 PM 9/14/04, you wrote: >A while back, there was some discussion on voters. I have read through all >of that. >Have you read the two or three voter articles at www.repeater-builder.com >on the Technical Info page? Yes I have. >>I am looking to install one here. >For what reason? >Some repeater systems that talk further then they can hear decide to >add a voter system to try and match the coverage. Others add a voter >to improve hand-held coverage inside the existing TX footprint, others >just add a two channel voter at the main RX site to gain some diversity >reception. What is your reason? I want to extend portable coverage. We are in an area with lots of hills and valleys. >I am planning on bringing my rx sites back on RF and having the rx >radios at the voter site interface to a status tone (2175 Hz) circuit >and then feed the voter. >You are aware that the 2175 status tone is designed for a wired >system? (where they bring the audio back on leased phone lines). >And that doing it that way will require you to run the link TX on a >7x24 basis? This can get expensive in not only the power bill >but in replacing links TXs (have you verified that you can get the >link frequencies there - one per RX site?). Which band do you >plan on using for the links? 420MHz, 900MHz or 1296mhz? >What equipment do you plan on using for the main channel >RXs and the link radios?? And do you have spares? Running >a link TX 7x24x366 just to keep a tone decoder happy will >quickly determine if your link system is "continuous duty"... What I planned to do is to have the link rx interface to the status tone circuit and when it sees a valid signal from the far end, it will drop the tone. That way the links don't have to run 24x7. I don't maintain it but I know of a public safety system here that does it this way and has done it for a number of years with no problems. I plan on using MASTR II RXs at each site and Maxtrac 900 for the links. >My question is: >Does anyone have a circuit to generate the status tones or know of a >reasonably priced commercially available product. I just don't want to >re-invent the wheel if someone else has already dealt w/ this. >The GE voter used a 1950hz status tone and there was a board that fit >into the EP-39 aux RX chassis that did just what you want. If someone >can post that schematic all you need to do is change the cap in the >oscillator to pick up the Moto tone frequency. If it uses 1950 then that is what I'll use. I have read through the installation/service manual for the voter and apparently misread the status tone part. >There may be a Moto Spectra-Tac card that does the same thing but >I am not aware of the card name or part number. And there are a lot >more GE manuals on PDF floating around that there are Motorola.... I have the PDF of the manual for the voter. I have also been looking for one for the GE MASTR II Aux receivers but I haven't found one yet. >If need be I have a simple audio oscillator design that I can email >you that uses an 88mh toroid and a single transistor. My first voting >panel used this tone gen feeding the normally closed contacts of >the COR. The relay armature fed the link TX and the normally open >contacts was the RX audio. A 10 second carrier delay relay "filled >in the gaps" of tweak signal flutter. The link RX COR dropping out >told the voting panel that the channel was idle. If you don't mind sending me the schematic, I'd appreciate it. I have a design for one but it uses a crystal reference and the crystal is not easy to find and it takes way more parts. Jamey Wright KD4SIY >Mike WA6ILQ Yahoo! Groups Links Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
