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  #21 (permalink)  
Old 12-25-2013, 6:01 PM
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Originally Posted by Driv3r912 View Post
Hello everyone,

I am getting ready to purchase and install a new UHF repeater in Erie, PA. This area is the home of practically everything 2M, and in being in an urban area like the City of Erie, I feel it would be beneficial to install a UHF repeater for the amateur radio community.

I had my own UHF repeater setup on GMRS and it was kind of rocky at best coverage-wise. So, I am trying to see what other operators have in mind for my setup.

Right now, I will be using two Motorola mobile radios, the transmit radio rated at 45 watts. I want to get a Comet CA-712EF UHF antenna to use on the system. The radios would have a mobile duplexer tuned to the frequencies I plan to use.

Now, I can have the antenna anywhere from 35 to maybe 60 feet safely in the air. My question is, what kind of coverage can be anticipated from a small repeater with an antenna at this height? I'm more concerned about portable coverage than anything else.

The antenna has a rated gain of 9dbi. The place where the repeater antenna is being installed is at my residence, a flat urban area - but with other small obstructions in the residential neighborhood, like houses (no higher than two stories). I am about 20 blocks from the downtown area with large buildings and towers.

So, is this something I should invest money into? Or is it something that won't get a lot of good coverage in ones opinion? I hate to see spending the money, and it becoming a "wannabe-repeater".

Any comments or advice are appreciated, along with any questions! It would be nice to get input from others who may have done a simlar task and their results!

Plese remember, this is a low-profile repeater with the hopes of having some decent coverage -- even if it is limited to mobiles in distant ranges.

I took a look at Erie, PA using Google Earth (GE). GE has tools to see elevation profiles. Using those tools I plotted eight lines extending clockwise from N/E to S/W from Erie and then looked at the elevation profiles for each. Basically my take away was that Erie sits in bowl at about 500 ASL and everything from the N/E to the S/W increases in elevation ~ 1000 feet after about 10 to 15 miles from Erie. Looking up and down the coast (and of course across the lake) it is relatively flat.

Roughly speaking, if you had a 10 watt repeater working properly with an antenna clear of obstacles at 30' or more, I'd estimate your coverage to be 20 miles or so across the flat areas and 10 to 15 miles from the N/E around clockwise to the S/W (basically to the top of the "bowl" excepting canyons).

I will tell you from experience that the mobile duplexer will work, but you will be doing yourself a huge favor by buying a true BPBR duplexer and get it tuned properly.

Good luck.
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  #22 (permalink)  
Old 12-25-2013, 7:59 PM
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ShawnInPaso, thank you for your response. I have drawn up a few coverage maps using RadioMobile also, which seems to be alright for being a low-profile repeater.
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Old 12-25-2013, 9:24 PM
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Here is the coverage map I generated in the Radio Mobile software. As I can determine, very low portable coverage in the reds and yellow. However, the greens cover mobile "receive" coverage. The blues and purples represent fringe areas I take it... So, I guess this isn't the greatest. I'll probably skip the project! Lol.

In summary, this is with an antenna at 40 feet in the air with 9dbi gain and 45 watts of transmission output.
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Old 12-26-2013, 9:39 AM
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How many hams in the green-red shaded area? Count the dots
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Old 12-26-2013, 10:27 AM
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Originally Posted by Driv3r912 View Post
In summary, this is with an antenna at 40 feet in the air with 9dbi gain and 45 watts of transmission output.
Don't forget to account for feedline losses and the losses in the duplexer. In most circumstances, your antenna will not get the full 45 watts that your transmitter produces. The losses are a bigger problem on receive. Many repeaters use specialized pre-amps on the receive side to make up for the feedline and duplexer losses.
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Old 12-26-2013, 2:42 PM
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Default Repeater Coverage / Ideas

Roughly 25-30% of power gets absorbed by a mobile duplexer. For most applications a pass notch is a better option. However, they are quite advantageous for extremely tall lowers or portable repeaters.


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Old 12-27-2013, 11:22 PM
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Go ahead and build the repeater, it will be a good experience. I would cut the transmitter power to about 25 watts, which should get you 12 to 15 out of the mobile duplexer. If the repeater is located at your residence where you can have personal control of it, you won't need a separate radio receiver for a RF control link. The advice on the bandpass/band reject type duplexer really holds for high RF environments. Your residence shouldn't have many radio transmitters in close proximity.

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Old 01-06-2014, 2:27 AM
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Quote:
Originally Posted by Driv3r912 View Post
Hello everyone,

I am getting ready to purchase and install a new UHF repeater in Erie, PA. This area is the home of practically everything 2M, and in being in an urban area like the City of Erie, I feel it would be beneficial to install a UHF repeater for the amateur radio community.

I had my own UHF repeater setup on GMRS and it was kind of rocky at best coverage-wise. So, I am trying to see what other operators have in mind for my setup.

Right now, I will be using two Motorola mobile radios, the transmit radio rated at 45 watts. I want to get a Comet CA-712EF UHF antenna to use on the system. The radios would have a mobile duplexer tuned to the frequencies I plan to use.

Now, I can have the antenna anywhere from 35 to maybe 60 feet safely in the air. My question is, what kind of coverage can be anticipated from a small repeater with an antenna at this height? I'm more concerned about portable coverage than anything else.

The antenna has a rated gain of 9dbi. The place where the repeater antenna is being installed is at my residence, a flat urban area - but with other small obstructions in the residential neighborhood, like houses (no higher than two stories). I am about 20 blocks from the downtown area with large buildings and towers.

So, is this something I should invest money into? Or is it something that won't get a lot of good coverage in ones opinion? I hate to see spending the money, and it becoming a "wannabe-repeater".

Any comments or advice are appreciated, along with any questions! It would be nice to get input from others who may have done a simlar task and their results!

Plese remember, this is a low-profile repeater with the hopes of having some decent coverage -- even if it is limited to mobiles in distant ranges.
Subject already covered
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Last edited by spd640; 01-06-2014 at 2:41 AM.. Reason: Covered already
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  #29 (permalink)  
Old 01-06-2014, 2:39 AM
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I see your point, and agree with it. However, the OP asked if it was worth taking on the expense to put up his own repeater.

Building and maintaining a repeater is a huge undertaking. It's fun and aggravating, enjoyable and a burden, and a great way to expand a ham's knowledge. Getting the repeater is only half of the battle. The other half is having people to put the repeater to use.

In my area there are about 30 70cm repeaters. Some of these are paper repeaters that don't exist, except only to make someone feel good that they have their callsign in the repeater directory. Some of them are linked to other repeaters on 2 meters, and while they are active repeaters - no one uses the 70cm input of the repeater. As for the other 70cm repeaters in my area, the only time you hear any activity on them is when they ID every hour.

So if a ham in my area decided they wanted to put up a repeater on 70cm, the obvious question would be "why?" If there's 30 other repeaters not being used, is it worth the time, trouble, and money to put up the repeater only to have it sit idle?

I believe N0IU brings up a good point, would anyone use the repeater if it was put on the air? The answer to that question can help the OP decide if (as he asked) it is worth spending the money to build a repeater.
Brandon,
I have to agree about the paper repeaters,I am disgusted with it for the simple fact it seems like everyone and their momma has a repeater pair and never uses them.I wanted to find a 2 meter pair for my area but thanks to the paper repeater community up there,every one I looked into getting was grabbed up by someone but you never hear them on the air.I am to the point of doing the 1 meg split just to have one in case ours goes down since it will be on the other side of the county from where our club repeater is.

I think we should always have a back up in case one goes down,guess I will have to do what I have to do to get one on the air.I have only found one frequency that has been inactive I know for 5 yrs and the owners are probably deceased by now since I can't find their call sign.The nearest one to it is over 100 miles from me and I have tried to get it but got shot down for coordination since it has already been spoken for in the past but if it can't be proven remove it.
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  #30 (permalink)  
Old 01-06-2014, 3:49 AM
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Originally Posted by spd640 View Post
I have to agree about the paper repeaters,I am disgusted with it for the simple fact it seems like everyone and their momma has a repeater pair and never uses them.
Check with your repeater council. I believe that once you get a set of frequencies, you have a time frame to get your repeater on the air or your frequency pair is returned to the pool.

I went through this many years ago, I just had to monitor the output frequency for a few months and report to the council there was no repeater on the air.
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Old 01-06-2014, 3:51 AM
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Brandon,
I have to agree about the paper repeaters,I am disgusted with it for the simple fact it seems like everyone and their momma has a repeater pair and never uses them.I wanted to find a 2 meter pair for my area but thanks to the paper repeater community up there,every one I looked into getting was grabbed up by someone but you never hear them on the air.I am to the point of doing the 1 meg split just to have one in case ours goes down since it will be on the other side of the county from where our club repeater is.

.
We had the same problem about 12 years ago when we were trying to get coordinated for a pair for our UHF repeater. We picked a pair that we knew was not in use (the repeater owner moved to Texas and confirmed, in writing, that he took the repeater with him).

the coordinator said and I quote "we are not in the business of de-coordinating repeaters".

So, we contacted Riley Hollingsworth at the FCC. He advised to go ahead, put up your repeater, if you have a problem, contact me personally.

Forwarded this to the coordinator and they all of a sudden changed their minds and coordinated us.

So, if a pair is not being used, and you can prove it- go ahead, put it up. Don't know if Laura Smith will get involved the way Riley was did for us, but it seemed to magically changed the minds at the coordinator who "isn't in the business of de-coordinating repeaters".
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Old 01-06-2014, 6:55 AM
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the coordinator said and I quote "we are not in the business of de-coordinating repeaters".

So, we contacted Riley Hollingsworth at the FCC. He advised to go ahead, put up your repeater, if you have a problem, contact me personally.
Bear in mind that, generally, the FCC only gets involved if a non-coordinated repeater is interfering with a coordinated repeater (Part 97.205(c)). There is no requirement that repeaters be coordinated.
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Old 01-06-2014, 12:14 PM
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Bear in mind that, generally, the FCC only gets involved if a non-coordinated repeater is interfering with a coordinated repeater (Part 97.205(c)). There is no requirement that repeaters be coordinated.
Absolutely correct! My opinion, if you can prove that a repeater pair has been unused for an extensive amount of time and have made every effort to contact the ham that has the unused pair coordinated and cannot reach them, put up the repeater with or without the blessing of any coordination council.

Repeater owners tend to forget that we do not own frequencies. Coordination is a courtesy and is not required. People who hog up pairs for paper repeaters are not being courteous.

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Brandon,
I have to agree about the paper repeaters,I am disgusted with it for the simple fact it seems like everyone and their momma has a repeater pair and never uses them.
Good to see you on here again spd640! Yeah, that's exactly why I don't own a radio that can do UHF. In Huntsville there's probably 15 paper UHF repeaters, 10 that never get used, and 1 that's active but linked to a VHF repeater. Not worth it in my opinion.
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Old 01-06-2014, 7:29 PM
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Check with your repeater council. I believe that once you get a set of frequencies, you have a time frame to get your repeater on the air or your frequency pair is returned to the pool.

I went through this many years ago, I just had to monitor the output frequency for a few months and report to the council there was no repeater on the air.
Already tried this was told no 2 meter were available......
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Old 01-07-2014, 2:03 AM
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Lubbock has 25+ paper repeaters...

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