Antenna question

[bwharper78]

I am about to purchase a ft 7900 as my first radio. I am looking at a diamond x50 vertical antenna, mounted in the attic. I have been reading a lot of forums and this seems like a good all around antenna. A few questions I still have:

- at what point would I want to use a yagi for hitting the local VHF/UHF repeater, or is the vertical an okay choice.

- I see a lot of people that have an entire array of antennas. Basic question here, but is it one antenna per radio, or do multiple radios share one antenna or even multiple antennas for a single radio?

- any other recommendations for my first set up?

Thanks

 

[rescue161]

I have an FT-7900 here and it is a great little radio. I'm using mine with a Comet GP-3 dual-band base antenna. No experience with the Diamond X50, but I don't think you could go wrong with either one. I think I got mine from cheapham.com a year or so ago.

I only have that antenna hooked to that radio. No other antenas are connected to it, as it only has one SO-239 on the back of it. People usually have a lot of different antennas as they have a lot of radios to hook them to. I have several antennas, most of them hidden in the attic and all of them are hooked to different radios.

A Yagi will come into play when you are trying to hit a distant station that an omni antenna just can't reach. For local contacts, you should be fine with the X50. If you can put it outside and get it high enough, you'll be pulling in a lot more stations than it being in the attic. I have mine outside and can talk simplex all over the county where I live and into adjacent counties as well. If you're only going to talk through repeaters, then you should be fine with the antenna in the attic as long as you don't have a metal roof...

Other recommendations are make sure that you use great coax. I wouldn't use anything less than LMR400. Sure it'll work with RG-8, but it'll work much better if you don't use that crap... And if you do decide to put the antena outside, make sure that it is grounded!

 

[LtDoc]

Your proposed set up sounds like it ought'a do just fine. I don't have that antenna but do have one similar, it'll handle anything locally. It depends a lot on the terrain and how far repeaters are from you. Basically what's between your antenna and the other guy's antenna. Won't make any guesses about that, but 20 - 30 miles seems a typical number for around here.
A directional antenna is handy for those more distant stations you can't hear with the omnidirectional antenna. Don't expect miracles, but beams do make things nicer at times. Antenna height really is a biggy. Higher is almost always better. Adding another story on your house under that attic would be nice, but not too practical, right? Oh well...
Lot's of antennas on one radio, or lot's of radios too? Yes, it can work either way. About the only way to know for sure is to ask. I have one antenna for each radio. Sometimes I'll switch them around to see if there's any difference in reception, but they usually stay on the last radio I put them. That's subject to change, just depends on what 'wild hair' happens to strike me. That's probably about as 'normal' as it gets.
I second the suggestion about using good coax. The definition of 'good' is sort of variable. If the length of the run isn't all that much, probably less than 50 feet, almost anything will work okay. As the length get's longer so does how 'good' the feed line needs to be. That amounts to how much loss there is per length and the particular coax you may have (or have to buy). The 'worth' of coax depends on frequency of use mainly. The only definite suggestion I'd make with all that is select a 'name' brand, they tend to want to protect their reputation (and sales!) and don't exaggerate their claims much.
Have fun!
- 'Doc

 

[kb0nly]

The X50 is pretty good on UHF, lousy on VHF... A lot of local hams here bought them because they were a one piece design and thought they would be more durable, after time most of them have replaced them after having issues on VHF after a while. One couldn't hit the local repeater 20 miles away. They do work good on UHF though, one of these days i want to tear one apart and see why they suck on VHF.

If you want something better, go to R&L Electronics 800-221-7735 and look up a Jetstream JTB2B for $60, its higher gain then the X50, equal to a X200 but the construction is better. I have owned lots of Diamonds, the Jetstream has surpassed them for survivability and performance, they are a great cheap antenna!

Also check out the Jetstream coax... I use a lot of JT2015F here, its an RG8 sized coax with loss characteristics similar to 9913 and others of that variety. I have tested this coax and i'm more than satisfied with the loss. www.jetstream-usa.com

I don't have any financial interest in Jetstream, just a satisfied customer. And R&L Electronics is one of the better dealers that carry their products.