GMRS Repeater Build - Targeting a 20-30 mile radius

[WRZA597]

Hey everyone, I am both Ham licensed and GMRS licensed.  Wanting to build a GMRS Repeater for my area for community and family communications. Looking for best practices and recommendations on equipment and setup.  We live in Huntersville, NC. Near intersection of HWY 73 and Ramah Church Road. Altitude is roughly 770 above sea level.  There are trees and buildings to contend with.  Have looked at Retevis R97S, Midland MXR10, and the Bridgecom BCR-40DU. Need suggestions on repeater, cabling, antennas, masts, etc.

Any suggestions would be appreciated.

Greg - KK4OHJ, WRZA597

[SteveShannon]

47 minutes ago, WRZA597 said:

Hey everyone, I am both Ham licensed and GMRS licensed.  Wanting to build a GMRS Repeater for my area for community and family communications. Looking for best practices and recommendations on equipment and setup.  We live in Huntersville, NC. Near intersection of HWY 73 and Ramah Church Road. Altitude is roughly 770 above sea level.  There are trees and buildings to contend with.  Have looked at Retevis R97S, Midland MXR10, and the Bridgecom BCR-40DU. Need suggestions on repeater, cabling, antennas, masts, etc.

Any suggestions would be appreciated.

Greg - KK4OHJ, WRZA597

Welcome!  If you take a few days reading through posts on this site you’ll find literally thousands of posts that recommend repeaters, coax cables, and antennas.  Not quite so many on masts and towers.

[WRYZ926]

Use good antennas and get them as high as you can. Also remember that if you use a single antenna and a duplexer that your transmit power will be cut in half. Take the Retevis and Midland repeaters that are advertised at 10 watts. You are only getting 5 watts per RX and TX. Same goes with using two 50 watt radios with a duplexer and a single antenna, your RX and TX will only be 25 watts.

[WRUU653]

Something you may or may not have thought of take a look at the map and click on stale or offline repeaters (small gear upper left). This could avoid choosing a frequency that potentially might come back on line or be on line. I see this one that looks offline near you LAKE NORMAN CORNELIUS and of course this one is active HUNTERSVILLE BIRKDALE 675.

[gortex2]

Location is what matters. Do you have a tower site ? Tall building ? A home repeater in that area will not cover 20-30 miles. 

[BoxCar]

Does your ham club have a repeater? Ask if a GMRS one be added to the site.

[WRZA597]

13 hours ago, WRUU653 said:

Something you may or may not have thought of take a look at the map and click on stale or offline repeaters (small gear upper left). This could avoid choosing a frequency that potentially might come back on line or be on line. I see this one that looks offline near you LAKE NORMAN CORNELIUS and of course this one is active HUNTERSVILLE BIRKDALE 675.

Thanks for this suggestion. Was not aware of the stale or offline repeater option.  I have reached out to the owner of the Huntersville 675 repeater and am trying to get permission, although it is just out of range unless I am in a certain area on my property.

[WRZA597]

12 hours ago, BoxCar said:

Does your ham club have a repeater? Ask if a GMRS one be added to the site.

Great suggestion!  I will look into this.  Thanks.

[WRZA597]

13 hours ago, gortex2 said:

Location is what matters. Do you have a tower site ? Tall building ? A home repeater in that area will not cover 20-30 miles. 

No tower site.  Was thinking about running a mast off of my barn.  I figured that a 20-30 mile range in this area would be a stretch unless I could place the antenna way up on a tower somewhere.  We have family living in Concord and Landis. They are 15 and 16 miles away, respectively.

[WRZA597]

14 hours ago, WRYZ926 said:

Use good antennas and get them as high as you can. Also remember that if you use a single antenna and a duplexer that your transmit power will be cut in half. Take the Retevis and Midland repeaters that are advertised at 10 watts. You are only getting 5 watts per RX and TX. Same goes with using two 50 watt radios with a duplexer and a single antenna, your RX and TX will only be 25 watts.

Yes, I have been watching videos on the Retevis and Midland repeater setup options.  I like your suggestion of using two 50 watt radios with a duplexer.  www.buytwowayradios.com has this video that walks through the setup using two Wouxun KG-1000Gs.  Has anyone used this type of setup? Comments or recomendations?

 

[WRZA597]

Thanks everyone for your time and insight.  Looking forward to getting this up and running.  I will follow up once things are operational.

[SteveShannon]

15 hours ago, WRYZ926 said:

Use good antennas and get them as high as you can. Also remember that if you use a single antenna and a duplexer that your transmit power will be cut in half. Take the Retevis and Midland repeaters that are advertised at 10 watts. You are only getting 5 watts per RX and TX. Same goes with using two 50 watt radios with a duplexer and a single antenna, your RX and TX will only be 25 watts.

I’m sorry, but beginning with talking about RX only getting 5 watts (or saying that your RX will only be 25 watts) this is bad advice.  If you poll the people on this site who actually maintain repeaters (I’m not one) you will find that almost all of them use a duplexer.

1. Although it is possible to construct a repeater with two antennas, the distance between the antennas must be fairly far to provide RF isolation, especially if you attempt to separate the antennas horizontally.  If they are arrayed vertically the distance doesn’t have to be as far, depending on the type of antenna you choose.  It helps to have a tall tower.

2. Yes, it’s true that power is lost in a duplexer.  It’s not necessarily half though.  High quality duplexers lose less power.  Inexpensive duplexers can be very lossy. Power is also lost in coax, so if you choose to use two antennas be sure you use high quality coax because at GMRS frequencies it’s very easy to lose half (or more) of your power.

3. Power should not be the deciding factor.  It’s common for the newly licensed to focus too much on power.  I suspect that if you were to ask experienced radio engineers whether they would prefer a great receiver and midpower transmitter versus a high powered transmitter and just okay receiver they would choose the better receiver every time.  Having more power doesn’t automatically mean greater range.  

Notarubicon (@OffRoaderX) has an informative series of videos where he first built a repeater using two kg1000 radios and two antennas and ended up going to a commercial quality repeater, duplexer, and single antenna.  I encourage you to view them.

[SteveShannon]

23 hours ago, WRZA597 said:

Hey everyone, I am both Ham licensed and GMRS licensed.  Wanting to build a GMRS Repeater for my area for community and family communications. Looking for best practices and recommendations on equipment and setup.  We live in Huntersville, NC. Near intersection of HWY 73 and Ramah Church Road. Altitude is roughly 770 above sea level.  There are trees and buildings to contend with.  Have looked at Retevis R97S, Midland MXR10, and the Bridgecom BCR-40DU. Need suggestions on repeater, cabling, antennas, masts, etc.

Any suggestions would be appreciated.

Greg - KK4OHJ, WRZA597

Start here:

You just got your GMRS license, now you want your own repeater?

 

 

[WRYZ926]

@Sshannon I did watch a lot of his videos. I will also agree that people do focus on power too much at times. But the little 10watt repeaters would not be my choice for a wide area repeater simply because low power radios don't have the range of higher powered radios. Yes a good antenna up high definitely helps.

[SteveShannon]

2 hours ago, WRYZ926 said:

@Sshannon I did watch a lot of his videos. I will also agree that people do focus on power too much at times. But the little 10watt repeaters would not be my choice for a wide area repeater simply because low power radios don't have the range of higher powered radios. Yes a good antenna up high definitely helps.

I absolutely agree that the Midland and Retevis would not be my choice for a wide area repeater.  

I would listen to one of the existing repeater owners and their recommendations for a good condition used Motorola or Vertex or other commercial grade repeater and I would pair it with a decent duplexer and then run at least something like M&P Broadpro 50 (which is like an all-copper shielded LMR-400) coax to a commercial quality antenna.  I hear high recommendations for Laird.  

[WRYZ926]

I definitely pay attention to the people that have done this already. Plus my local HAM club has lots of knowledge for if/when we setup a GMRS repeater.

[shawnvanhorn]

Get an MTR2000 or 3000, a good Sinclair or RFS Celwave full size duplexer. 7/8 heliax and a Db420B at about 200 feet if you want a 30 plus mile coverage.

Sent from my SM-G998U using Tapatalk

[Radioguy7268]

Who are you talking to and what do they carry for a radio? I believe you said you've got relatives 15 miles away. If they carry portables - it is MUCH more important that your desired repeater can hear those 4 or 5 watt portables from 15 miles away than it is for your desired magic repeater to punch out 50 watts so you can reach them.

Pay more attention to how well your repeater can receive - and you'll end up with a better system.

Wouxun mobiles built into a repeater are twice as expensive and half as good as other solutions available. Search up the term desense, and you'll see what's going on.

[OffRoaderX]

2 minutes ago, shawnvanhorn said:

Get an MTR2000 or 3000, a good Sinclair or RFS Celwave full size duplexer. 7/8 heliax and a Db420B at about 200 feet if you want a 30 plus mile coverage.

Beware of the online "experts" trying to spend your money - Using this hardware combination in no way guarantees you will get 30 miles plus coverage.  

[shawnvanhorn]

Beware of the online "experts" trying to spend your money - Using this hardware combination in no way guarantees you will get 30 miles plus coverage.  

No, but this combination gives me close to 50 at my location, though. The other methods suggested so far here won't get him out of his neighborhood. Your answer did not help the op at all.

Sent from my SM-G998U using Tapatalk

[OffRoaderX]

1 minute ago, shawnvanhorn said:

No, but this combination gives me close to 50 at my location, though. Your answer did not help the op at all.

Your location is not his location.  
My reminder to ignore idiots is probably the most helpful one in this entire thread.

[WRZA597]

4 hours ago, Sshannon said:

I’m sorry, but beginning with talking about RX only getting 5 watts (or saying that your RX will only be 25 watts) this is bad advice.  If you poll the people on this site who actually maintain repeaters (I’m not one) you will find that almost all of them use a duplexer.

1. Although it is possible to construct a repeater with two antennas, the distance between the antennas must be fairly far to provide RF isolation, especially if you attempt to separate the antennas horizontally.  If they are arrayed vertically the distance doesn’t have to be as far, depending on the type of antenna you choose.  It helps to have a tall tower.

2. Yes, it’s true that power is lost in a duplexer.  It’s not necessarily half though.  High quality duplexers lose less power.  Inexpensive duplexers can be very lossy. Power is also lost in coax, so if you choose to use two antennas be sure you use high quality coax because at GMRS frequencies it’s very easy to lose half (or more) of your power.

3. Power should not be the deciding factor.  It’s common for the newly licensed to focus too much on power.  I suspect that if you were to ask experienced radio engineers whether they would prefer a great receiver and midpower transmitter versus a high powered transmitter and just okay receiver they would choose the better receiver every time.  Having more power doesn’t automatically mean greater range.  

Notarubicon (@OffRoaderX) has an informative series of videos where he first built a repeater using two kg1000 radios and two antennas and ended up going to a commercial quality repeater, duplexer, and single antenna.  I encourage you to view them.

Will do.  Have already been running through quite a few of his videos.  Funny guy!

[WRZA597]

3 hours ago, Sshannon said:

Start here:

You just got your GMRS license, now you want your own repeater?

 

 

Yep, have already watched that one as well.  Good points to consider for sure.  In this crazy world we are in these days, just trying to nail down alternate communications with family who may not have their ham licenses....yet.  Thanks

[tcp2525]

20 hours ago, gortex2 said:

Location is what matters. Do you have a tower site ? Tall building ? A home repeater in that area will not cover 20-30 miles. 

This is by far the best advice one can get!  I've been playing with a low budget build here that is working out really nicely. Got two Vertex VX-4207 radios for $75 each. Picked up an RFS duplexer for $15 at a hamfest. And an assembled ID-O-Matic controller for about $80 shipped. And few more bucks for 15-pin connectors.

I'm in the testing phase right now and at low power (10 Watts) into the duplexer and 8 watts into the antenna I'm averaging 5-7 air miles of reliable communications. I'm only 50' above sea level and antenna is about 30' above ground. Once I get all the equipment mounted in a case with proper cooling I should be able to run 25 watts safely on long transmissions. Since I have my own spectrum analyzer w/TG, I will spend more time fine tuning the duplexer for optimum performance when everything is permanently mounted.

All that said, I am very pleased with the progress I made so far and everything is working great considering the topography of the area . Just need more altitude!!!!!!!!!

[WRFN864]

Greg, looking at your location and using the RF Line of Site tool, I think you will find that 20-30 miles is going to be a challenge to reach in every direction except to the East and trying to hit Landis is going to be tough since Odell School is in the way.   This is assuming you have an antenna 10m (barn height) off the ground.   You would likely need a 120' tower to clear the obstacles.  But RF can be funny.  Example:  I can hit a repeater with a 4w HT that is 40 miles away from 5' off the ground but can't hit a mobile that is 2 miles away from my Diamond X50 antenna at 30' high with 25watts.

[WRZA597]

Thanks.  Funny that I was just on the phone with Tanner from BuyTwoWayRadios.com and he showed me this very same line of sight tool from www.scadacore.com.  I know that RF can be fickle.  I may be chasing unicorns here.