Batboard

Well I think I have finally found a place for an amateur repeater in the town where I live. However, I am stuck with a small problem.

The site will only allow me one coax run for the repeater, yet I am planning on putting the VHF and UHF repeaters at this site. *the site can handle the ice and wind load of two antennas, but the tray for running coax inside has only room for one which is due to the cell companies not planning for expansion.) Due to it's high terrain and outlook this is the best site possible, as all others I have tried or will offer me space are only about 2 to 10 ft above avg terrain. (We live in a small hole town.)

So since I can only put one coax up I was thinking or looking at doing a dual band coupler. Now I know that they make some commercial one for just this purpose. Yet, these do not go down to the ham band or they do on one band and not the other, i.e. 146 - 162Mhz and 450 - 470Mhz.

In talking to the makers of the different ones out there they say that there cutoff is what is printed on the label. Now I also know that /\/\ says you can not take a P1225 and go into the ham band either but we all have.

So has anyone ever done this before and if so what have you used. The other issue I am running into here is fund$, so I am not looking at trying to spend a lot of money. I also do realize that I am looking at one for the top by the antennas as well as one down at the bottom near the equipment.

The repeaters are running at about 100 watts on each band but if I get them on this site i might be able to pull them back to 50 watts after the duplexer.

I know the other option would be to purchase a well crafted/made dual band antenna but I have not been able to find one that can handle a tower type install. Also I have both VHF and UHF antennas already so therefore I am at this cross roads here.

Any help would be great.

We do that at a local site here, a VHF and UHF repeater sharing a dual band antenna at the top. It's a Diamond if i recall correctly, the X500HNA heavy duty repeater version. You could also go with the X50A dual bander, i know some repeaters using it, it has held up remarkably well and is shorter, also cheaper, about $100 or less. The only kicker is you loose some gain, but it depends on the coverage your looking for, if you just trying to cover your town, the immediate area, than the X50A would be plenty.

All you need is a diplexer at the equipment end, though many call it a duplexer. Look here for an example.

http://universal-radio.com/catalog/hamantm/cduplex.html

Connect the diplexer to the coax and then the output from each repeaters duplexer goes to the diplexer, and your done, both repeaters share the dual band antenna. If you can somehow weather proof one of the diplexer's i guess you could in theory have on on each end and run two antenna's but the complications is just not worth it, your better off getting a dual band antenna instead, less connections and future problems to deal with.

We haven't had any problems with this setup and it's been running this way for almost two years now.

Doesnt (Hygain?) make a G6 series that's dual band?

The zero is correct, but, additionally, if done right, you can put a diplexer at BOTH ends. Use at top to split to two antennas of your choice, and at the bottom to split to two radios/repeaters.

Just make sure you get a good one, and properly weatherproof the thing.

Hustler, aka Newtronics, make's the G6-270R, 6db gain on both bands. The benefit of this antenna is it's one piece design, rather than sectional like the Diamond models.

PLEASE don't go installing a typical ham-hump antenna on a Real Site. At best, it'll fall apart rapidly... at worst, it'll cause a problem for the paying users, which causes a problem for you. People who install the latest in antenna technology from Diamond, Comet, etc. on a real site should be flogged.

Typical ham-grade :o is why those of us who do it right can't get site access.

Grab a DB224E, a DB408B, and combine them onto one feedline. Commonly done.

I ran a Diamond duo-band antenna about 300' up a 500' tower for quite some time. It had 1/2" heliax ran to it out of a Comet diplexer. VHF Packet on 145.010 and a 440 repeater. It worked very, very well.
Hurricane Rita took out a top mounted DB-224, but the comet was still on the tower and working after the storm.

And, I am the REAL SITE tower owner!
Sam

No offense, but obviously if your knocking those antennas than you have never dealt with one properly installed and tuned. I have a Diamond X-200A at home, it's been up there for almost three years now, not one single problem, haven't had to touch it since it was put up.

So i don't know what kind of problems you have experienced, but my guess it's not the antenna's fault, it's the installer.

The Decibel Products crap on the other hand... yuck.. They suck, at least the ones i have dealt with. We have on of those 4 dipole antennas on one of the local ham repeaters now, if it was my choice that piece of junk would come down and get replaced with a Diamond or Hustler, it has been causing nothing but trouble.

You didn't say how long your feedline will end up being, or what size line you intend to use. Since repeater talkin range is typically much less than talkout range, feedline loss at 440 is important for repeater receive, and additionally if you use your existing V/Uhf antennas and use diplexers at each end of the transmission line the loss at 440 could be significant enough to reduce your talkin range further.

I'm using TX/RX crossband couplers http://www.txrx.com/product/product.asp ... 66cacba086 to do a amateur U/V system up one cable to two commercial grade DB antennas. Works just fine.

Mark

i agree w/ kb0nly i have had my diamond x200 up for 2 years for my base and a x50A for my repeater. they both work extremley well survived 2 jersey winters w/out fail. by the way i was running the x50 w/ a comet duplexer w/ a vhf and yhf repeaters.

otto