Well you have seen the obvious weaker mechanical construction which can still work well with a side arm made from sch80 electrical pvc tubing, however the power is combined power not per band but you should still have survived if the antenna was held rigid and you were sure it was dry inside. I reworked one of these that came out of service and found a 2pf cap in the base which was very corroded with green slime, copper oxide - I replaced the capacitor using silver bearing plumbers solder, and continued thru the antenna resoldering everything and cleaning the joints as they cooled - then fabricated spiders from rg-213 dielectric as the foam installed by diamond was holding a lot of moisture - the antenna went onto a 120 foot tower with a side arm and about 2/3 up another brace and is being used today. I would be cautious of overpowering the antenna, the club that uses it has a 25 watt uhf and 50 watt 2 mtr machine going into it, with your power levels it should but for how long? The innermod game is just part of operating a repeater in a high rf environment, we all find it and find ways to filter it out - I doubt if any glass antenna will work better than another unless single band, it seems the shunt to ground antennas are less prone to innermod, but they can only shunt one band at a time.
"Derek B. McIntyre" wrote: > > 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/ -- 73...Clark Beckman N8PZD Pursuant to U.S. Code, title 47, Chapter 5, Subchapter II, ß227, "Any and all nonsolicited commercial E-mail sent to this address is subject to a download and archival fee of $500.00 U.S.". E-mailing denotes acceptance of these terms. 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/
