I have a dream of setting up a repeater on the top of my mountain which has not power

[MacJack]

I'm a newbie to GMRS and made a great connection with my local repeater guy and sent him a donation to keep it up.  His repeater is not that busy but I want to add my own on my hill (mountain).  No electric available, good solar view and need to hear how you guys did or would set up your repeater in waterproof Tupperware box... solar, battery, duplexing two radios (40 watts) with cables plus one antenna...  

 

Looking for low maintenance as I will not be going up the mountain that often...  hard hike carrying equipment up the mountain.  I should add the only one repeater in area and not a high traffic area and want to respect my new buddy repeater traffic and his history (friends etc).  

 

So I looked at RT97 https://shop.mygmrs.com/collections/featured-products/products/retevis-rt97-gmrs-repeater-5w  and found out it is not as advertised being 10 watts.  In fact I wanted 30-40 watts unit as using HT 4 watts.  

 

Thanks in advance for your help and if Admin needs to move this to another forum, great... 

 

Jack

WRJX754

[JohnE]

PM sent

[Radioguy7268]

Hopefully you've already read the thread on: "I just got my GMRS License and now I want my own repeater".

 

Solar and high power repeaters don't play so well together if your budget is less than NASA. If you've got a high elevation site, you can talk to everywhere you can "see" at relatively low power. Higher power margins just help to overcome background noise and decrease fading. I'd tell you that 10 watts going into an actual 6 dB antenna is an ERP of 40 watts - and probably overkill if you're using 4 watt portables to talk back. If you really want to make a repeater work better - a better receiver is worth much more than transmit power.

 

If you really do have the idea of "doing it once, and doing it right" you need to forget about Retevis for a mountaintop site, and you also need to forget about using tupperware. A NEMA style weatherized box can be placed outdoors, and will hold up well against the elements if you pay attention to properly sealing up any holes or bulkhead fittings. I've got outdoor sites that have held up for more than 15 years with a NEMA box on a pole - but I wasn't dealing with 8000+ ft elevations or extreme winds/icing.

 

You can buy a high end used commercial repeater like an MTR2000 for about the same cost as a new Retevis RT97 - and you're getting 10 times the quality. Most reputable sellers will even program it for you - saving you the expense of cables and software.

[gortex2]

For a solar setup the RT97 is ideal. If your only planning to use HT's to talk to it talking back at same power should work well. A 50 watt repeater does nothing more for a 4 watt radio trying to talk back. Buy a decent antenna (DB404 or other commercial UHF) and good cable and it will outperform your expectations. Go cheap on cable and antenna and you will loose interest quickly.

[MacJack]

Thank you guys for your comments...  keep them coming as it helping me turn dream to develop a plan...

[MacJack]

JohnE, I looked you up and your post and did not see it... please direct me to that.

 

Hopefully you've already read the thread on: "I just got my GMRS License and now I want my own repeater".

 

[wayoverthere]

JohnE, I looked you up and your post and did not see it... please direct me to that.

https://forums.mygmrs.com/topic/1402-you-just-got-your-gmrs-license-now-you-want-your-own-repeater/

[taco6513]

Get a DB420 for your antenna.

WRCW870

[jerrym58]

There are a lot of engineering details that go into setting up a repeater. I think if your friend’s repeater is serving your needs and you have an amicable working relationship that you are ahead just helping him maintain his repeater. But if you are going to forge ahead anyway here’s some things to think about. Mountain tops get hit by lightning frequently. You need to ground the antenna support structure and ground the coax to the same structure. Surge protection like a Polyphaser is also needed. All ground rods need to be connected with large diameter ground wire. Motorola’s R56 manual is the Bible for site grounding. I agree with another comment on the DB420 antenna but it is very high gain. When you increase the gain you narrow the vertical beam width. I think that antenna’s gain drops in half at about 5 or 6 degrees down so depending on how high your mountain is there may not be enough power and sensitivity left in the valley below. For sites lower to the ground I think the DB420 is the best UHF repeater antenna ever made. I have put many of these up for business repeaters. On a mountaintop site you may have to select a non-standard PL tone or DCS code to stay out of a neighboring repeater’s coverage area on the same frequency.

[WRKC935]

removed

 

[gman1971]

For very high up places you're better off with a low gain, or unity if the altitude difference is too big.

 

G.

[n4gix]

I have experienced a DB420 being used at too high of an elevation in Columbus, Oh.

Commercial repeater owned by a TV station. Had repeater and antenna mounted at 750 foot on a work deck. 

Repeater would talk to Indiana with no problems.  It however would not work at all within the 270 outer belt unless you were in the helicopter. 

Think of antenna gain from an omnidirectional antenna like this.  The pattern of the antenna is like a doughnut.  In order to get gain from it, you have to crush the doughnut.

So as you compress the doughnut, and it spreads out (directional gain) the bottom and teh top get pushed together.  You need to be IN the doughnut in order to talk and hear the signal.

If you raise the bottom of the doughnut above the ground, then you no longer have coverage. 

 

Those antennas can be ordered with the amount of down tilt you need to offset the squished doughnut enough to regain the coverage needed.