I normally do not use "ham" antennas, especially cheap dual banders such as Diamond or Comet for duplex/repeater use but a situation has come up where a dual band antenna may be most convenient.
I have acquired a Diamond X-500 which claims 8.3 dB on 144-148 MHz and 11.5 dB on 440-450 MHz. The antenna is just over 17 feet tall, making the gain claims ridiculous.. My guess is it's rated in dBi, therefore, the claim may be a little closer to realistic.. 5 dBd on 2M and 8 dBd on 440 is my guess.. The power rating says 200 watts. I once saw a Comet GP-6 whose power rating also said 200 watts but in the fine print, I saw the "PEP" rating beside it.. it was rated in SSB, which of course, we normally do not use vertical antennas for SSB in those portions on the ham band. We smoked a disc capacitor in the antenna running 100 watts FM into it (combined)... Has anyone pumped more than 100 watts FM combined into a Diamond dual bander without it smoking the matching network? I have heard people say that running dual banders in duplex mode on both band can cause broadband noise, intermond, etc, often causing either severe duplex noise or desence on the repeater unput. I have often wondered has anyone had experience with these types of problems. I have assembled the array and it feels like a wet noodle stick, pretty flimsey, but is rated at 90 MPH.. Some people say the joints work loose inside the antenna. Who can relate to this? I am used to working with Stationmasters, DB-224's, DB-420's, Celwave PD-340's, and so on for repeater use. However, the tower mount I have will not support any of these and we need to run a 2M and a 440 repeater on one antenna if possible. I am looking for overall performance opinions on the Diamond X-500 for serious repeater use and if there's a better dual bander out there with relatively high gain, tell me what it is. I'll be running about 60 watts on VHF and 75 watts UHF into the antenna (after feedline losses).. Thanks, Derek KC4FWC http://www.w4dex.com/kc4fwc/ 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/
