HI again, I am using 25 watt (awa rt85/ midland) repeater on 476.550 and 477.300 (750 kHz split)(uhf cb here in OZ). The mast will be 20' ally tube with a fibre glass section near the lower whip (rx). The top of the fibre glass mounted to the ground plains with the TX whip above the ground plain. We use a mobile whip that has 1/4 wave section, phasing coil and then a 1/2 wave section on the top giving 3 db ish, 20 MHz band width. What I figured was 3db TX and 3 db rx sounds good but vertical separation would be a problem. But what about if the TX whip inc a solid ground plain was mounted at the top and the same for rx was mounted directly under but upside down. This would give a solid ground plain between them. Normally you would need about 60' separation. Duplexers for this are very bulky and about $2000. I figure that get rid of the loss in the duplexer add a good double shielded feeder and what you end up with is a 3db 20mhz band width TX and rx antenna system. That can be used on any of the 8 uhf cb repeater channels. This may be an ugly solution but when dollars ($1600 in duplexers) counts this maybe a solution for a rapid deployment multi channel suit case repeater system. I hope this adds to my earlier email. I am very interested in your comments and advise. I am sure there are other applications other than OZ uhf CB repeaters. Cheers all from down under.
----- Original Message ----- From: "Joe" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Friday, August 26, 2005 8:15 PM Subject: Re: [Repeater-Builder] Antenna system 4 short term portable uhf repeater > Hello, > > You need to tell the group the receive and transmit frequencies and the > transmit power level before anyone can venture a guess. Also, type of > equipment would be helpful. You are on the other side of the world, so > you may have to reverse TX/RX antennas to make it work properly seeing as > you are upside-down from this side... ;-) > > Joe > > At 03:25 AM 8/26/2005 +0000, you wrote: >>Hi my learned freinds. >>I am interested if any body has tryed using 3db mobile whips mounted >>on a solid ground plain verticaly 180 degrees to each other and fed >>with separate coax to rx tx ports. > > > > > > > > > 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/
