First time repeater build.

[The_Hawk_Master]

I have done a lot of research on this and would like your opinion with real world experience. This is my first repeater build. Is there anything I’m missing or overlooking?

The repeater it’s self is fixed as I already have it.

I built this looking to cut down on as much loss as possible without breaking the bank. I have picked everything off of my own research and would love to hear your opinion on how I can improve it to get more range.

I am anticipating a total height above the ground level to be about 47 feet with the FG4607 and 44 feet with the FG4605

My mouting location is about 240 ft above sea level but I live in the lower part of my town.

I have considered a tower but that is not in the cards at this time. Maybe a future upgrade.

I am looking to get a minimum of 5 miles range with portables and hope for up to 10 miles. I also have mobiles I would like to use on the system and hope for 15 maybe 20 miles but I know that may not happen with my geography.

I am using a Motorola GR500 with two CDM1250s install and a Zetron ZR310 repeater controller.

I am anticipating 45 watts output of the repeater before duplexer.

The Duplexer is currently unknown at this time next on list to look at.

I am going to use a 1-3 foot Jumper of

LMR-400 with a N-male and N female one of which will have a lightning arrestor on it. I believe I have that in the correct location as the antenna will be on the roof(explained later) I will have a better grounding route at the repeaters location.

I plain on using

CommScope LDF2-50 (3/8" Heliax hardline) for the Main Feedline I am guesstimating I will need about 40 ft

It will have two N-male connectors

Commscope LDF2-50 Cable Assemblies - 3/8 Heliax Hard Line Cable

I will be grounding the unit too with a bout 10 feet of solid copper straight to earth.

The mast I plan on using two 17 -Gauge Galvanized Metal Chain Link Fence Rail they are about 10.5 feet each.

They will be mounted to the Chimney

Which is about 3-5 feet elevated off the roof and the roof is bout 12.5 feet above ground level.

I will use one of those commercially available chimney strap mounting kits



I am looking at one of two antennas but am not sure which one in the real world will give me the best results. I have run simulations but I’m not sure I believe their outcome.

Antenna #1

Laird TE Connectivity FG4607

Gain: ~9 dBi

Length: ~9 ft

Connector: N-female


Laird TE Connectivity FG4607 - GMRS Omni-Directional Base Antennas



Antenna #2



Laird TE Connectivity FG4605

Gain: ~7dBi

Length: ~6.33 ft

Connector: N-female

Laird TE Connectivity FG4605 - GMRS Omni-Directional Base Antennas

 

[prcguy]

Run the radios closer to 15w and no more than 20w, they are not designed for continuous service. The LMR jumpers from radios to duplexer are ok but never in the full duplex antenna path. For a 40ft run use no less than 1/2" Heliax, too much loss in 3/8" like over 2dB loss. Personally I would use 7/8" for that run.

If this is at a residence with no other UHF radios around you could get by with a mobile flat pack duplexer at 20 watts. It would be much nicer with an 85dB or greater Bp/Br if you can find one cheap enough.

The Laird FG4607 is ok with 7dBd gain and I would not go less than that at nearly ground level. You might get 5mi in some directions to a handheld outdoors but it won't be reliable, just spotty and annoying. 5mi to a mobile will be better but not reliable. I had essentially the same setup 40yrs ago in a flat part of town and reliable hand held coverage was about a mile in all directions with some random spots up to about 5mi away. That was using a DB Products DB420 with almost 10dBd gain and 35ft of 1/2" Heliax and a mobile duplexer.

My current home repeaters are about 350ft above average terrain in several directions and with 50w out of the duplexer into 75ft of 1/2" Superflex Heliax (breaking my own rules) into a 4-bay dipole array with 120deg coverage and 9dBd gain I get a good 5mi to handhelds, 15mi to mobiles and in some directions a spotty 75mi to a 50w mobile. In one direction which is mostly over water I have done 100mi to a handheld but I don't travel there very often to test any more. Repeaters are Quantars and duplexers are 120dB isolation Bp/Br. My repeaters on local 5,000ft mountains are a different story.

 

[AK4PY]

I've seen a piece of LMR-400 used as a jumper between the repeater and the duplexer actually be problematic. I do not recommend LMR-400 or anything constructed the same way in any part of a repeater system. Use RG-400, RG-214, 1/4" Superflex, or 1/2" Superflex between your repeater ports and duplexer ports.

 

[popnokick]

I realize your duplexer is TBD but who will be tuning it using what equipment for alignment? Critical detail for a repeater.

 

[MTS2000des]

I realize your duplexer is TBD but who will be tuning it using what equipment for alignment? Critical detail for a repeater.

This part. The biggest factor in a duplex system using a single antenna is the filter, feedline and antenna itself. One can buy the best repeater, but a turdy duplexer poorly tuned with crap feedline (LMR400 is NOT suitable for in band duplex applications) and poor antenna will make it suck worse than a Hoover Elite.

Quality test equipment (e.g. a service monitor with tracking generator) and the skills to actually use it are a must.

 

[prcguy]

This part. The biggest factor in a duplex system using a single antenna is the filter, feedline and antenna itself. One can buy the best repeater, but a turdy duplexer poorly tuned with crap feedline (LMR400 is NOT suitable for in band duplex applications) and poor antenna will make it suck worse than a Hoover Elite.

Quality test equipment (e.g. a service monitor with tracking generator) and the skills to actually use it are a must.

I might add I've never seen a duplexer that was tuned and shipped that arrived still perfectly tuned, they all need to be at least tested on site after installation and more likely the tuning touched up. And that requires knowledge and proper test equipment. Does the OP have that or someone with the skills and equipment available?

 

[W8UU]

I might add I've never seen a duplexer that was tuned and shipped that arrived still perfectly tuned, they all need to be at least tested on site after installation and more likely the tuning touched up. And that requires knowledge and proper test equipment. Does the OP have that or someone with the skills and equipment available?

Agree 100% Excellent advice. I took my Motorola GR1225 (an eBay purchase) to the local Moto shop and had them go through it, despite the fact the seller "programmed the repeater and tuned the duplexer" prior to shipping. The tech found several things wrong in the programming (wideband vs. narrowband receive) and the CW ID had the wrong call sign. Radio putting out 40 solid watts but the duplexer was off. Got that tuned. Radio aligned. He even cleaned the inside with a small shop vacuum and checked the antenna connector. Well worth the one time cost. Machine performs flawlessly after being connected to lightning-protected hardline and a commercial grade antenna, I get the coverage I wanted and more.

 

[prcguy]

Agree 100% Excellent advice. I took my Motorola GR1225 (an eBay purchase) to the local Moto shop and had them go through it, despite the fact the seller "programmed the repeater and tuned the duplexer" prior to shipping. The tech found several things wrong in the programming (wideband vs. narrowband receive) and the CW ID had the wrong call sign. Radio putting out 40 solid watts but the duplexer was off. Got that tuned. Radio aligned. He even cleaned the inside with a small shop vacuum and checked the antenna connector. Well worth the one time cost. Machine performs flawlessly after being connected to lightning-protected hardline and a commercial grade antenna, I get the coverage I wanted and more.

How is that GR1225 holding up at 40w for extended conversations?

 

[W8UU]

How is that GR1225 holding up at 40w for extended conversations?

No issues. I have a continuous duty fan bolted to the back of the box. Runs 24 hours a day. It's a light-to-moderate use machine, so its never been pushed to the limits. If this repeater was used in a highly populated area with a lot of GMRS users, I'd go with a big box machine like an XPR8400.

 

[prcguy]

No issues. I have a continuous duty fan bolted to the back of the box. Runs 24 hours a day. It's a light-to-moderate use machine, so its never been pushed to the limits. If this repeater was used in a highly populated area with a lot of GMRS users, I'd go with a big box machine like an XPR8400.

An XPR8400 is just two mobiles in a box and has reliability issues operating at full power. For DMR the MTR3000 is a purpose build 100w repeater that is an actual big box machine. For analog only there are lots of better choices than the XPR8400.

 

[W8UU]

An XPR8400 is just two mobiles in a box and has reliability issues operating at full power.

My understanding was the 8300 had the reliability issues and the 8400 was fine.

In any case, the MTR3000 is a fine machine. No question there at all.

 

[prcguy]

My understanding was the 8300 had the reliability issues and the 8400 was fine.

In any case, the MTR3000 is a fine machine. No question there at all.

The XPR8400 is still two mobile chassis in a box, I would only run one at reduced power like 20w.

 

[The_Hawk_Master]

This part. The biggest factor in a duplex system using a single antenna is the filter, feedline and antenna itself. One can buy the best repeater, but a turdy duplexer poorly tuned with crap feedline (LMR400 is NOT suitable for in band duplex applications) and poor antenna will make it suck worse than a Hoover Elite.

Quality test equipment (e.g. a service monitor with tracking generator) and the skills to actually use it are a must.

As I am just getting started this set up is just for me and my family to communicate on. As I am just starting I wanted to get one that was preprogrammed for what I am using or have the one i already have reprogrammed. I do not know anyone locally who will do it for my so my only option at this time is to outsource.

Once I get established I will gather the resources to enhance my skills to tune it my self. But it dose not make sense to gather the Materials before I have a use for them.

I do not know if mine is uhf or vhf yet I have to get it out but I need a few days before I will have time to.

I've seen a piece of LMR-400 used as a jumper between the repeater and the duplexer actually be problematic. I do not recommend LMR-400 or anything constructed the same way in any part of a repeater system. Use RG-400, RG-214, 1/4" Superflex, or 1/2" Superflex between your repeater ports and duplexer ports.

I was building the coax I thought would be best. From what I could get, the lightning protection can only be attached to LMR-400 to keep everything inline.
Times Microwave LP-18-400-NF-X
I could not find one made for 3/8 inch Heliax Coaxial Cable.

Run the radios closer to 15w and no more than 20w, they are not designed for continuous service.

No issues. I have a continuous duty fan bolted to the back of the box. Runs 24 hours a day. It's a light-to-moderate use machine, so its never been pushed to the limits. If this repeater was used in a highly populated area with a lot of GMRS users, I'd go with a big box machine like an XPR8400.

@prcguy i plan to run mine like this one. Only personal use between no more than 5 radios at a time. 99% of the time it will be 2-3. With very little talk time anticipated.

For a 40ft run use no less than 1/2" Heliax, too much loss in 3/8" like over 2dB loss. Personally I would use 7/8" for that run.

From the models I ran 3/8 gave me some loss for sure but price per gain for 1/2 and 7/8 was far to high. For a build like this.

The controller in the case is a zetron zr310. I am having a hard time finding the proper software to program it. I have read that the gm300 is the proper software for it but I do not have the controller in front of me yet I can not tell. I open the software up in dos but I do not see the f6 repeater option.

 

[prcguy]

From the models I ran 3/8 gave me some loss for sure but price per gain for 1/2 and 7/8 was far to high. For a build like this.

The controller in the case is a zetron zr310. I am having a hard time finding the proper software to program it. I have read that the gm300 is the proper software for it but I do not have the controller in front of me yet I can not tell. I open the software up in dos but I do not see the f6 repeater option.

Perfect used 1/2" and even sometimes 7/8" Heliax is available free or very cheap with or without connectors all over the country. If you lived near me I could give you 40ft, no need to buy it new.

 

[W8UU]

As I am just getting started this set up is just for me and my family to communicate on. As I am just starting I wanted to get one that was preprogrammed for what I am using or have the one i already have reprogrammed. I do not know anyone locally who will do it for my so my only option at this time is to outsource.

Once I get established I will gather the resources to enhance my skills to tune it my self. But it dose not make sense to gather the Materials before I have a use for them.

It's honestly worth the time to take a day off and drive your repeater to a service shop -- even if that's 50-60 miles away. It's a one time investment in money and time that will make sure you're getting the most out of your equipment. You do not want to be causing unintentional interference to other licensees or have something out of tune and it ends up damaging your repeater system. Shipping the repeater via FedEx, UPS, USPS, or whomever can de-tune the duplexer slightly through bouncing around as the equipment moves through the pipe.

 

[W8UU]

I do not know if mine is uhf or vhf yet I have to get it out but I need a few days before I will have time to.

If you're doing GMRS, you MUST have a UHF (462 MHz) repeater. There are no VHF GMRS frequencies, and MURS (47 CFR § 95.2733) does not allow repeater operation on their VHF frequencies. You'd need a business band license to operate a VHF repeater. Of course, if your repeater station will be an Amateur Radio project, either band will work.

 

[kayn1n32008]

I am looking to get a minimum of 5 miles range with portables and hope for up to 10 miles. I also have mobiles I would like to use on the system and hope for 15 maybe 20 miles but I know that may not happen with my geography.

With out knowing EXACT coordinates of where your repeater will be, we can not accurately predict if ~47' of antenna elevation will give you the ranges you are looking for. Google 'RadioMobile'. make a user name and play around with running some predictions. its not super intuitive, BUT with a bit of time, you can get a good feel for it

I am using a Motorola GR500 with two CDM1250s install and a Zetron ZR310 repeater controller.

I am anticipating 45 watts output of the repeater before duplexer.

Well, throw out the idea of running 45w out of it. A mobile is good for, at best, 10-15% duty cycle. As PRCGuy said, run it at 20w with a good fan. There is zero coverage difference between 20w and 45w. its a shade over 3dB less power and will equate to 0.0m less coverage.

The Duplexer is currently unknown at this time next on list to look at.

While a 'mobile' reject only duplexer may work, do try and find something that is Band Pass/Band Reject(BpBr). It will prevent a TON of headaches. It will allow you to run more power when you get a proper repeater(something NOT made from a pair of mobile radios).

TxRx systems, EMR, Comprod and Sinclair all are excellent manufactures of duplexers.

I am going to use a 1-3 foot Jumper of LMR-400 with a N-male and N female one of which will have a lightning arrestor on it. I believe I have that in the correct location as the antenna will be on the roof(explained later) I will have a better grounding route at the repeaters location.

NO. ABSOLUTELY NO LMR400. The foil shield and braid are disimilar metals and should NEVER be used in a full duplex environemnt. They WILL eventually cause you issues down the road.

RG142, RG396, RG400 or RG214 for your radio to duplexer and duplexer to feedline cables.

I plan on using CommScope LDF2-50 (3/8" Heliax hardline) for the Main Feedline I am guesstimating I will need about 40 ft

It will have two N-male connectors

I strongly recommend LDF4-50 at a minimum. If anything, use LDF2-50 as duplexer jumpers.

Commscope LDF2-50 Cable Assemblies - 3/8 Heliax Hard Line Cable

I will be grounding the unit too with a bout 10 feet of solid copper straight to earth.

Any grounds you place MUST be tied to your existing electrical grounding system.

Antenna #1
Laird TE Connectivity FG4607
Gain: ~9 dBi
Length: ~9 ft
Connector: N-female
Laird TE Connectivity FG4607 - GMRS Omni-Directional Base Antennas

Antenna #2
Laird TE Connectivity FG4605
Gain: ~7dBi
Length: ~6.33 ft
Connector: N-female
Laird TE Connectivity FG4605 - GMRS Omni-Directional Base Antennas

Honestly, Id spend the money on antenna number 1.

For analog only there are lots of better choices than the XPR8400.

Most anything that is modern, not 2 mobiles in a box and is not Icom or Vertex, is better than an XPR8400.

I was building the coax I thought would be best. From what I could get, the lightning protection can only be attached to LMR-400 to keep everything inline.
Times Microwave LP-18-400-NF-X
I could not find one made for 3/8 inch Heliax Coaxial Cable.

Lightning protection should have N connectors on each end, have a directional arrow to show what direction it needs to be inserted. it should be between your antenna feedline and the duplexer.

@prcguy i plan to run mine like this one. Only personal use between no more than 5 radios at a time. 99% of the time it will be 2-3. With very little talk time anticipated.

No. you WILL burn out your transmit radio eventually.

From the models I ran 3/8 gave me some loss for sure but price per gain for 1/2 and 7/8 was far to high. For a build like this.

Spend the money on the duplexer, feedline and antenna. Minimum 1/2" feedline.

 

[The_Hawk_Master]

Perfect used 1/2" and even sometimes 7/8" Heliax is available free or very cheap with or without connectors all over the country. If you lived near me I could give you 40ft, no need to buy it new.

If you will to ship it and it had the right couplers on it I would be willing to cover shipping if cheaper than buying new.

It's honestly worth the time to take a day off and drive your repeater to a service shop -- even if that's 50-60 miles away. It's a one time investment in money and time that will make sure you're getting the most out of your equipment. You do not want to be causing unintentional interference to other licensees or have something out of tune and it ends up damaging your repeater system. Shipping the repeater via FedEx, UPS, USPS, or whomever can de-tune the duplexer slightly through bouncing around as the equipment moves through the pipe.

I would love to find someone localish to me talk to and work with to make it right but I don’t currently so I am learning it my self. That is what the gmrs world is about learning and growing right? Not just give it to someone and have it done right just to do it. I want to learn and become self sufficient. And I feel the only way to do that is ask questions here where this is specialized and through guided trial and error.

If you're doing GMRS, you MUST have a UHF (462 MHz) repeater. There are no VHF GMRS frequencies, and MURS (47 CFR § 95.2733) does not allow repeater operation on their VHF frequencies. You'd need a business band license to operate a VHF repeater. Of course, if your repeater station will be an Amateur Radio project, either band will work.

I do know that. I am referring to the fact that I need to get the system out and look at it. I have the radios to change to to uhf if it’s not already and the duplexer conversation will convert to a very different one… from where to get it retuned to where to get a uhf one or what brand is the best. I WILL know more when I get it out.

With out knowing EXACT coordinates of where your repeater will be, we can not accurately predict if ~47' of antenna elevation will give you the ranges you are looking for. Google 'RadioMobile'. make a user name and play around with running some predictions. its not super intuitive, BUT with a bit of time, you can get a good feel for it

I have played with cloudRF and don’t trust the results I will try that one next time

Honestly, Id spend the money on antenna number 1.

That is the one I have been leaning towards anyway with the height I am at.

Any grounds you place MUST be tied to your existing electrical grounding system.

All grounds in this house are directly to earth. My ground will be routed to the same grounding rod.

Lightning protection should have N connectors on each end, have a directional arrow to show what direction it needs to be inserted. it should be between your antenna feedline and the duplexer

What is you recommendation I think it is very necessary for a lightning rod in the air. But I can find many options on the matter.

No. you WILL burn out your transmit radio eventually.

I would like to see how they handle it. I have heard mixed reviews sense I starred this and if I see the heat show up I will lower it no problem.

 

[prcguy]

If you will to ship it and it had the right couplers on it I would be willing to cover shipping if cheaper than buying new.

Its not fun to ship. Needs a box about 3ft X 3ft X ?? and I don't have anything suitable. Its more of a come and get it kind of thing.

 

[The_Hawk_Master]

Its not fun to ship. Needs a box about 3ft X 3ft X ?? and I don't have anything suitable. Its more of a come and get it kind of thing.

Fair. Unfortunately I don’t think you’re close to me. I’m at 19464