Construction / Development site Repeater

[pick]

I have the situation where a long time acquaintance has recently bought 400+ acres of land in the eastern mountains near the Blue Ridge. They will be developing and building on the property over the next two years or so and they have come to me due my experience and background in radio communications. I spent a week at the property site last week and came away with the thought that a well placed repeater should be able to provide good radio coverage. There is some valley and then rising hills with a final high ridge line. All the development will be taking place below the ridge line. There are no services or utilities to the site yet. This is a private / family build and not a commercial development. As such the thought of using GMRS as most of the work will be done by family as they are long time in the construction business themselves. As such a single GMRS license should cover the situation.

This brings me to the purpose of this post. I am looking at what is possible in setting up a good 50 watt repeater site.

At least the first year I see as most likely be a 'trailer' set up with its own generator / solar / battery for power, and if the family likes the repeater and decides to have it full time for the site even after development / construction is completed a permeant tower and radio house with full grid connect.

I am not expecting anyone here to 'design' this for me, but rather point me in the right direction for equipment / suppliers / system providers. Also others experience and advice is welcome.

Sincerely
Robert Pickell
WROM651 / AA3RP

[Radioguy7268]

50 watts is probably overkill if you're talking about just covering 400 acres in a valley - and you're planning to talk back into the repeater with 4 or 5 watt portables.

Less power is more forgiving if you're planning to use solar. You'll be able to get away with smaller panels, fewer batteries. A trailer setup sounds like a good way to do a temporary site, and have the ability to move it around to find your sweet spot - a combination of sun/coverage.

If you're trying to cover a smaller area using portables, I like the idea of a Unity gain antenna. Especially if you're not up on the top of the ridge. Top of the ridge would probably give you the biggest bang for the buck for total coverage area, but you might over-shoot your desired area of coverage down in the valley.

As far as equipment - do you want new? or used?  Quality new repeaters from Motorola or Kenwood are pretty tough to come by in today's semiconductor shortage world. Used is still available. CCR's are still available. Do you plan to put everything together yourself, or are you looking for a local provider who can do all the work?

Final note, the price difference in licensing between GMRS and a 10 year Business/Commercial license is negligible compared to the overall cost of equipment. GMRS might be good for what you want to do, but a Business/Commercial license covers more potential users, and has more available channels - with Frequency Coordination. That doesn't guarantee you exclusivity, but in a rural area, there's a pretty good chance you'll have a business frequency that's not being used the next town over, and not having to share space with FRS equipped hikers/hunters. A Business/Commercial License would also allow you to run Digital and enable Privacy/encryption - which you can't really do in GMRS.

Good luck with it.

[gortex2]

Not exactly sure the location so can't look at the terrain. I can say the Rt97 would be an ideal solar/battery repeater. As long as you have the terrain to get it to a higher point it would work great. I run onei n my motorhome now and its a nice little simple setup for a small group of users. At the race tracks I can get majority of the grounds with no issues. I did use it at a state park and got about 15 miles from the MH on my mobile (Motorhome up on a hill). 

 

If commercial repeater is the route get a GR1225 and spin it down to 25 watts and its a good little package. 

[BoxCar]

A little 5 to 10W repeater on battery and solar with a J-pole would more than meet your needs. I'd put the antenna and solar panel on a pole part way up on a ridge or hill to limit the exposure off the property. Use codes on both the in and out frequencies to limit any unwanted users.

[WRFP399]

On 11/8/2021 at 2:17 AM, BoxCar said:

A little 5 to 10W repeater on battery and solar with a J-pole would more than meet your needs. I'd put the antenna and solar panel on a pole part way up on a ridge or hill to limit the exposure off the property. Use codes on both the in and out frequencies to limit any unwanted users.

This is the exact setup I am running here in AK. Retevis RT97 somewhere between 2200 and 2600 feet up. Mounted the back of a 50 watt solar panel. The battery is a 35 amp/hour SLA which I have stored about 18" under ground to try and protect it from the extreme cold snaps we get. During the summer I can easily run a much smaller battery. A 9 amp hour battery and 30 watt panel was more than sufficient during our summer. The larger battery and panel is needed for cold temps and low sunlight in the winter here. There is a small solar controller mounted to the rear of the panel as well. I have an N9TAX single band GMRS antenna. The repeater can be heard out at 20-25 miles and I can get back into it at that distance with 5 watts. 1 watt under ideal circumstances.  The repeater does suffer from desence a bit as I can always hear it further than I can get into it with an HT. If I drop it to low power it performs almost identically to my HTs (VX-231s and PR400s) in that if I can hear it, I can get back into it with about the same quality.
 

[pick]

Thanks for the replies so far.

I am sure the RT97 would work, but I am looking for a longer term solution. I am not so sure the RT97 would endure non-stop remote day in and out all weather conditions over several years. Also, knowing the family involved as I do there is the very real possible desire to keep this set up and use it beyond just the development and make it permanent. As such I am looking for equipment that enables rack mounting. There is no need to do this on the 'cheap' but also there is no reason to 'throw' money at it either. My thoughts are along the line of repurposed used commercial grade equipment, or if there is are companies doing GMRS purpose built repeater equipment using it.

As Radioguy7268  mentions, 50 watts is most likely much more than needed, though I would want to be able to set my output power. I just do not want to be limited in what I choose to set it to. As those who have worked with radio systems know, power is rarely the main issue of a good and reliable communication solution. To the point of getting a commercial license I agree on the cost and options points made. The reason I would like to avoid it is because this will be a family site / farm / retreat and I foresee it being far easier to have a family member have the license and stay on top of keeping it active then using some commercial entity.

Agree on using codes on both frequencies not only on the repeater but the HT's and mobiles. Just to be clear, I am planning on using HT's that have a high and low power, 0.5 watts low, and 2 watts high.

I have looked at some of the Bridgecomm UHF repeater listed on their web page. Does anyone here have any experience with them and their equipment?

 

[BoxCar]

The Bridgecom equipment is solid. Gigaparts listed an open box unit for $1400 they will tune for the purchaser.

[Radioguy7268]

Count me as not being a fan of Bridgecomm. It's just two mobiles in a box. They used to use Maxon mobiles, not sure if they still do.  My direct experience with Bridgecomm was getting called in to troubleshoot a Hotel's repeater. Unit had been in service less than 3 months, and the original seller had walked away from it, telling the Hotel that they were on their own. The trouble described was that the repeater was "intermittent".

When I arrived, I quickly diagnosed that while the repeater was functional, it was having trouble with the receiver. If I kept a strong -85 dBm signal generated directly into the front of the receiver, it worked well, but once the signal level dropped below that, the repeater would drop. Much further diagnosis led to this only happening with DPL - regular Tone PL codes carried through to -110 dBm. There was also about 3dBm of desense in the unit, so a receive signal on the edge of opening the repeater would quickly lose out once the transmitter kicked in, leading to the repeater cycling back and forth, and the customer's complaint of an intermittent operation.

Phone calls to the company for tech support were quickly answered, firmware upgrades were emailed, problem persisted. The duplexer was eliminated, the trouble still continued. Bridgecomm technical support suggested re-programming the customer's entire fleet to eliminate DPL. When we asked if Bridgecomm would be paying for the cost to reprogram the fleet - crickets.  After 3 weeks of back and forth, the repeater was returned to Bridgecomm for a partial refund and the customer purchased a new (at that time) Motorola XPR8400 repeater, and the problem disappeared. No portables were reprogrammed.

I suppose I could have just played nice and reprogrammed the entire fleet to Tone PL, but I didn't like the internal desense - which would have still been present even on Tone PL. To me, that's just poor design. An acceptable level of desense in a repeater is Zero.

That's been my only direct experience with the brand. I don't know if they've greatly improved since.

[pick]

Thanks for the info that Bridgecomm is really just two mobiles repackaged. That is not what I am looking for in a rack mount repeater. If I was going to have a pair of mobiles as my repeater I would and can do that myself.

Seems it time to start searching / looking for used UHF repeater / pass-notch filters / output amplifiers.  

[gortex2]

For Part 90 gear I would recommend a good used MTR2000. They made high and low power and they are pretty solid. I also ran a Kenwood TKR850 for a bit which was solid for my limited use. 

[WyoJoe]

I like the Vertex VXR-7000 for GMRS. I found mine on eBay for about $400 a few months ago. I bought a programming cable with software for about $50, and could then program it myself. I did purchase a duplexer, and am using it, but you could also use two antennas with appropriate separation between them. With a duplexer, you're pretty much limited to using the frequency it's tuned for. I haven't tried using mine on other frequencies, but it works well on the one it's tuned to.

Of course, two antennas means added cost for the extra antenna, the feedline, and likely, a taller mast to mount them on. These costs can be greater than the cost of the duplexer, so you'd have to look at the circumstances in your particular instance. The advantage to having a two-antenna system is you can change frequencies much more easily as you're not limited to what the duplexer is tuned to.

The VXR-7000 is not a rack-mount unit in basic form. There are rack mount kits for it, though I haven't seen one, and can't comment on it. The unit can easily be placed on a shelf that is installed in a rack if you have one available. You might want to strap it down to keep it in place, but that would be pretty easy to do also.

[PACNWComms]

Used several Vertex VXR-7000 repeaters for remote site use for oil spill response efforts. With the rack mounting kit, they work well with SKB cases, with space for a duplexer, power cords, some antenna coax, and power strip. The only issue we ever had was when a small radio shop attempted to add a 50 Watt amplifier to one, and it never worked the same again. We ended up replacing it with a Motorola XPR8400 which can be found along with the XPR8300 on the used market for reasonable prices. They had a fan issue on early models that was later fixed, but are solid repeaters as well.