Antenna Suggestions

AngelFire_91 · Post by **AngelFire_91** » Tue May 27, 2003 10:14 am

Hello,
I'm in the process of looking around for a UHF antenna for a repeater. What I need is the Highest gain around! Without going Yagi. Still would like to stay Omni-Directional. I'm looking for suggestions on Manufactures and makes, personal experiances and any advise people can give. I've been shopping around and have experiance with others but I would like some further input from the peanut gallery. Oh yeah, and cheaper is a plus.

Thanks,
Kevin

nmfire10 · Post by **nmfire10** » Tue May 27, 2003 11:54 am

Do you have a limit on ERP?

Znarx · Post by **Znarx** » Tue May 27, 2003 12:11 pm

Sinclair Technlogies SRL310-C8HD

pattern: Omni
gain: 11dB (dBd NOT dBi)
power rating: 300W
bandwidth : 406-512 wideband
downtilt available: 0, 4 or 6 deg
height: 204 inches (YES 17 FEET!)
weight: 30 pounds (heavy sucker)

approx USD $1500.00

well...you did ask for a lot of gain....Z

AngelFire_91 · Post by **AngelFire_91** » Thu May 29, 2003 6:58 pm

nmfire10 wrote:Do you have a limit on ERP?

Yes sorry, I have a limit of 100W

nmfire10 · Post by **nmfire10** » Thu May 29, 2003 7:35 pm

Well, then you can not you can not use "the highest gain around". Remember, higher gain = higher ERP. 3dB doubles the ERP.

Will · Post by **Will** » Thu May 29, 2003 11:52 pm

Comtelco BS450XL6-x , 6bd TRUE gain and 96" long.. $248. (first choice is the Sinclair, $$$$$$)

And of course Times LMR600 cable, accept no substitutes.

AngelFire_91 · Post by **AngelFire_91** » Sat May 31, 2003 9:56 am

Sorry, duplicate!!

AngelFire_91 · Post by **AngelFire_91** » Sat May 31, 2003 10:04 am

nmfire10 wrote:Well, then you can not you can not use "the highest gain around". Remember, higher gain = higher ERP. 3dB doubles the ERP.

Oh, I know I realized that, I was needing the highest gain for the given ERP. Sorry I left that out. Also if you want to know, it's going to be in the 450Mhz Public Safety band.

We asked for more from the FCC but they said Nope Sorry.

So I was also going to put a 440 Ham Repeater up so really I would look for suggestions for the 100 W one and then a limit of 1500 W one (of course I would never use that much), But the non-Ham one is more important.

Thanks guy's

mastr · Post by **mastr** » Sat May 31, 2003 11:00 am

FWIW, don't get caught up in the idea that high gain = best antenna in repeater service. Since you are ERP limited anyway, a lower gain antenna with a corresponding wider vertical beamwidth might be worth consideration. I would much rather have a lower gain antenna with higher quality feedline, try to keep feedline loss at 2 db or less on all but the highest of towers. Decibel Products is one vendor worth looking at.

wa2zdy · Post by **wa2zdy** » Sat May 31, 2003 11:39 am

nmfire10 wrote:Well, then you can not you can not use "the highest gain around". Remember, higher gain = higher ERP. 3dB doubles the ERP.

Sure you can. You just cut the transmitter power down to meet the ERP limit, and you enjoy the benefits of better receive. Why get a lower gain antenna, have a less sensitive receive condition AND run up a higher utility bill, all for the same ERP?

Remember, antenna gain works on receive too AND cuts down the $$$ you send to the electric utility. Of course you do have to keep in mind antenna patterns and such for your particular situation.

nmfire10 · Post by **nmfire10** » Sat May 31, 2003 12:16 pm

This is true. I only said that because I was getting the impression he was going Tim the Tool Man Taylor and wanted MORE POWER!!

KH · Post by KH » Sun Jun 01, 2003 4:02 am

You're in Colorado, so perhaps this system will go on a tower on a mountain?

There was an 800mhz system here a long time ago that had a really high gain(12 db Bogner) antenna on a 1700 foot tower. When you got close to it the narrow beamwidth shot right over your head---you physically look up at the tower and couldn't hit it.

Point is, if you're constructing way the hell up, a monster gain antenna just might hurt you portable wise.

KitN1MCC · Post by **KitN1MCC** » Sun Jun 01, 2003 10:29 am

i liek the super station master by cell wave my self. seem lik good ant. i have one a vhf and it is a good price

Nand · Post by **Nand** » Sun Jun 01, 2003 1:12 pm

AngelFire_91 wrote:Hello,
I'm in the process of looking around for a UHF antenna for a repeater. What I need is the Highest gain around! Without going Yagi. Still would like to stay Omni-Directional. I'm looking for suggestions on Manufactures and makes, personal experiances and any advise people can give. I've been shopping around and have experiance with others but I would like some further input from the peanut gallery. Oh yeah, and cheaper is a plus.

Thanks,
Kevin

If the highest gain antenna is what you are looking for, then you did get an answer here. But you may get a more useful reply if you indicate the purpose of the system and let us know what type and size of terrain needs to be covered. Also, is the system used for paging? The ERP limit can really screw up the coverage when using a high gain antenna for paging as it can for portable coverage in the nearby area.

Also, cheap is definitely not a plus for a repeater antenna. Cheap antennas degrade sooner and will give you noise problems.

Nand.

AngelFire_91 · Post by **AngelFire_91** » Mon Jun 02, 2003 5:04 pm

Well,
The Repeater will be in a house. it's in a pretty good valley and it's hard to get a good signal out or in. The valley hills around it are fairly high ~300 feet high on three sides and not enough for a tower to clear it. I was looking for Higher gain so I could use a lower power setting and still get out of the valley. I need to be able to get ~20 Miles with a mix of portables and mobiles.

I do have another option but it would take a lot of effort to get that option in place, so we'll have to deal with what I got.

Thanks,
Kevin

Nand · Post by **Nand** » Mon Jun 02, 2003 5:54 pm

The only way to get out of the valley is by placing the repeater on one of the hills. No amount of power or antenna gain will help you if the repeater is surrounded by hills. If you can locate a repeater on one of the hills, a 6 dB gain antenna is likely fine for a 20-mile radius, because you don’t want to overshoot the valley.

To give you a picture of what a repeater in the valley would do, imagine a bright light in the valley and see how much light it produces on the other side of the hills. Light behaves very much like radio waves. Using a gain antenna would be similar to focusing the light toward the horizon where it only concentrates on the side of the hills.

Nand.

mastr · Post by **mastr** » Mon Jun 02, 2003 6:03 pm

It is very unlikely that you will be able to get any where near 20 miles of range without a good amount of elevation, as VHF/UHF signals do not penetrate "mother earth" very well if at all. A modest installation on one of the hilltops will probably outperform an elaborate system down in the valley. Some years ago, I put up a 100ft tower with a good UHF repeater in a low lying area. It worked great until you went over the first hill toward town--about 3 miles. I'm really glad the site location wasn't my decision.

lherronjr · Post by **lherronjr** » Mon Jun 02, 2003 10:09 pm

Maxrad !!!!!!!!!!!!

AngelFire_91 · Post by **AngelFire_91** » Wed Jun 04, 2003 8:35 pm

I realize that the propagation wouldn't be able to get out of the Hills, and that is something I'm going to have to deal with, I was just courious as to some Idea's when it came to getting what I needed out of the Repeater. Site selection is not my doing, If I had it my way I would have put it up on the top of the 14,000ft moutain, where I hope to get my GMRS Repeater going soon, but for this one they said this is what we have to deal with. Thanks for all your suggestions I'll keep you updated as to my progress. and if any of you are comming to colorado I'll let you know what the status is of my GMRS and HAM Repeater on top of the 14,000 ft Peak so you may use it.

Thanks,
Kevin

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