mobile repeater battery / setup

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ki5diytex

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Hi!
I recently got my technicians license. I have a very specfic use-case that I'm working towards centered around communication at my ranch. West Texas... tall hills in middle of ranch block reception across ranch. Cell service is rarely available. The hills in the middle are the tallest in the county. Here are my goals:
1) Build a mobile radio/repeater in a Pelican case type box.
2) I want to be able to place mobile unit on top of the hill when I at the ranch, put in repeater mode, so my son and I can talk across entire ranch with mobile radios for safety purposes.
3) I want to also talk to emergency help in nearby town on emergency channels. The largest town in area is about 7 miles away, and is visible/line of sight from the top of the hill at the ranch.
4) When I go back to the city (I live in city full-time), I want to be able to plug my unit into a permanent antennae at the house and use to access repeaters in Dallas.

For a mobile setup, I'm looking at a Pelican case (size unknown yet), with a Kenwood TM-710 radio, a CB radio, PowerGate PG40s 12v supply, Rigrunner setup. Question is what size battery? I won't transmit much. The occasional "are you alive" or "see any deer". I'd like to keep on mountain top for at least 24 hours... but prefer keep it up there for 2-3 days on battery power. QUESTION: What size battery do you recommend? 7amph? 12?. Any other considerations?

Thanks!!!
 

K4EET

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Hi ki5diytex, welcome to Radio Reference!

Jeffrey, be careful that you stay within the FCC Rules and Regulations. You also stated that "I want to also talk to emergency help in nearby town on emergency channels." That will get you a hefty fine and possibly jail time even in a life-threatening situation. Trust me on this. The protocol would be for you as a ham to talk to another licensed ham that can make a landline E9-1-1 telephone call to relay the emergency. Also, quite possibly, your repeater box will be able to "hit" a Dallas wide-area-coverage repeater that has an open or closed autopatch. If it is a closed autopatch, simply apply to join the club. With an HT that has DTMF capabilities, you will then be able to dial the emergency services directly yourself. The main thing is to do everything legally. Like I said, just because it is a life-threatening emergency, you will still be prosecuted. You may also find that nobody will talk to you because bogus units that show up on emergency systems every now and then crying wolf wasting the taxpayers dollars. You do not want to put yourself in that boat!
 

K4EET

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Now for a question on your power plant. With that PWRgate PG40S, what power supply are you planning to use? See this diagram:

 

Firekite

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Are there any other open repeaters in the area? Try that first. With the right radio you could even cross-band repeat from an HT to your mobile rig to reach a local repeater.

How are you going to account for ventilation and cooling if it’s sealed in a pelican box? If you’ve got a solar charger battery powered gate opener at the ranch, you should probably consider taking a similar approach. Maybe get a small Rubbermaid storage shed or an old truck bed toolbox you’re not using or something along those lines that you can more or less seal up but cut holes for ventilation with fine metal mesh covers to keep the critters out. Even an old gate controller box might not be a bad idea.

Get a decent deep cycle (not starting) marine battery or two (wired in parallel to maintain 12V), a decent sized solar panel, and make sure you get a good charge controller. Weatherproof the box, make sure your antenna and coax are well sealed and have drip loops, and of course never forget the importance of grounding.

Also, regarding battery capacity, how many watts do you think you’ll need for it to run? VFH or UHF? You don’t say how big the place is, but the rest of the description makes it sound like fairly low power (like 5W) will get you full coverage of the place. Have you looked for the repeater coordinators in your area to see what they have to say about it? I don’t know what the CB radio part has to do with anything, but depending on anticipated propagation it’s certainly possible you won’t be stepping on anyone else’s toes as long as it’s well coordinated.

I don’t know what kind of repeater equipment you’re looking to use, but unless you want to lug it back and forth every time, you can consider leaving it in place. You could probably even use DTMF to make it active when you arrive and turn it back offline when you leave.

There are lots of ways of doing it “better” but I can get pricey real quick.

The importance of a good charge controller cannot be overstated.

Morningstar SunSaver Charge Controller | World Leading Solar Controllers & Inverters Amazon.com: Morningstar SunSaver Charge Controller | World Leading Solar Controllers & Inverters: Automotive
 

RFI-EMI-GUY

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I tried to send an EXCEL spreadsheet but no joy.

I worked something out using a guess at 10/50/40 duty cycle and a typical CB radio. The TM-710 does not have standby current rated so it might be different. This is to run the station 24 hours.

I have derated by 80% * to account for lead acid storage batteries that really don't like to be deep cycled, even the marine ones. There may be different recommendations depending on battery chemistry etc.

* You need 25% more capacity.

If you dont expect to receive or transmit much, the run time will increase.


Transmit Current 10%Receive Current 50%Standby Current 40%
Kenwood TM-71013A x 10% = 1.3A/HR1.2A x 50%
= 0.6A/HR
0.5A (a guess) X 40% = 0.2AH
Cobra 29 LTD Classic1.5A X 10% = 0.15 A/HR1.2A X 50% = 0.6A/HR0.3A x 40% = 0.12A/HR
Totals = 34.8 + 28.8 + 7.68 = 71.28A/HR /80% = 89.1A/HR1.45A/HR X 24 HR = 34.8 A/HR1.2A/HR X 24 = 28.8 A/HR0.32A/HR X 24 = 7.68A/HR
 
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ki5diytex

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I tried to send an EXCEL spreadsheet but no joy.

I worked something out using a guess at 10/50/40 duty cycle and a typical CB radio. The TM-710 does not have standby current rated so it might be different. This is to run the station 24 hours.

I have derated by 80% * to account for lead acid storage batteries that really don't like to be deep cycled, even the marine ones. There may be different recommendations depending on battery chemistry etc.

* You need 25% more capacity.


Transmit Current 10%Receive Current 50%Standby Current 40%
Kenwood TM-71013A x 10% = 1.3A/HR1.2A x 50%
= 0.6 A/HR
.5A (a guess) X 40% = 0.2 AH
Cobra 29 LTD Classic
1.5 X 10% = 0.15 A/HR1.2 X 50% = 0.6 A/HR.3A x 40% = 0.12 A/HR
Totals = 34.8 + 28.8 + 7.68 = 71.28 A/HR /80% = 89.1 A/HR1.45 A/HR X 24 HR = 34.8 A/HR1.2 A/HR X 24 = 28.8 A/HR0.32 A/HR X 24 = 7.68 A/HR
All,
I'm new to this forum, and can't thank y'all enough for the fast responses!! Good group of folks. And good questions/points you make. Some answers/thoughts:

1) THe point on Contacting emergency personnel directly... good point! It would make sense that I make some friends to allow me to contact one of them -- I should plan on following the law. That said, if my son is attacked by mountain lion or something critical, I'd be willing to be prosecuted... Realistically this scenario won't happen.... but the real scenario is talking to my son.
2) Yes, my son has his technicians license too.. we got them together.
3) Heat ... Yes, I thought about that too. I have a big husky tool box... figure I can open the Pelican, put in the toolbox, and cut holes in the tool box to draw air in/out.. I need to research this more...
4) Power supply... Maybe I'm looking at this wrong... but inside the Pelican I could use the Powergate Epic Series... that takes outside inputs from 1) solar charger/controller and 2) (in basecamp mode, a 30amp powerwerx supply. The powergate would use solar charge to support th battery, and radio runs off battery (rig runner between battery and radio).
 

RFI-EMI-GUY

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I should add that if the TM-710 is being used crossband repeat your RX and TX duty cycle will be the same and so you will have to adjust all three cycles accordingly.
 

K4EET

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Oops... In my post #5 above at:


I failed to state that the "diagram" that I was referring to is seen by clicking on the TAB labeled "Diagram" that is seen just below the picture of the PWRgate PG40S. My apologies for any confusion that I may have caused...
 

Firekite

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I could use the Powergate Epic Series... that takes outside inputs from 1) solar charger/controller
In case it’s not clear, the solar panel connects to the charge controller, and the charge controller connects to the battery. The PowerGate connects to the battery, and the radio connects to the PowerGate.

I’m not sure what the point is of using the PowerGate in general in this application. At home, you’d only use it if you also had a big battery setup in the shack and wanted to have it keep your batteries charged and swap power sources to the batteries in case of a power outage. You don’t need to take it with you to the hill unless you have electrical service on the hill and want to replicate that whole setup. Otherwise just power the radio directly off the battery.

Again, I’m not sure why you’d also have a CB radio involved, as it doesn’t seem to play any useful role up on the hill where no one can hear it or use it, but the radios are all you’d have to take with you, assuming you’ve got your “repeater” setup in place and leave it there, antenna and all.

Just to be clear, you’re expecting to run the Kenwood in cross-band repeater mode, with one of you setting your radio to a UHF frequency and the other to a VHF frequency, right? And you’re certain there aren’t any other existing, normal repeaters in the area you could be using instead?
 

tweiss3

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If this is something you pickup and take down, why not consider a portable inverter generator instead. A Yamaha EF1000iS will run for 12 hours at 1/4 load (250W) (tank is 2/3 gal). It also will ramp up and down as needed, so idle at no transmit, then ramp up as needed.

As for cooling/security of the transmitters, look into vented NEMA boxes. The have some that have thermostat controlled fans to keep electronics in safe temperature ranges.
 

ki5diytex

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Thanks again everyone for your comments: Some responses:
1) Good point on just using a generator. I have a honda that I could use... though the runtime is very small without refill. I'd have to have a bigger tank approach.
2) Good point on existing repeaters. I'll check on that and try to reach them when I go out next time. We have some deep canyons, so my line of sight to long distance is hampered, but ability to hill on my ranch/lease is typically available.
3) PowerGate... I probably was not clear.. I am looking to use this mobile rig for different purposes... the first I'm speaking to is the repeater situation, but I can take home with me, and use at my house as my base radio. Hence the powergate... at home i could plug a powersupply into the powergate, and powergate could control (as I understand), running radio, recharge battery, etc..

I have plenty to run with for now based on y'alls input. Let me do some more investigation based on your comments! Thanks for your help.

Jeff
 

Firekite

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3) PowerGate... I probably was not clear.. I am looking to use this mobile rig for different purposes... the first I'm speaking to is the repeater situation, but I can take home with me, and use at my house as my base radio. Hence the powergate... at home i could plug a powersupply into the powergate, and powergate could control (as I understand), running radio, recharge battery, etc..
You mean you want to take the whole kit and caboodle with you every time, batteries and all? That seems like a lot. But if not, you can leave the PowerGate at home since it serves no purpose for it when the radio is up on batter power on the hill.

Some the details are still fuzzy for me, but I think you’re trying to create a “briefcase repeater“ type setup that you can tote around, plugging it into the mains electrical at home and running as a regular radio and then just lock up the case and take it with you to the ranch to be set up on the hill as a cross-band repeater with each of you using a different band. I’d suggest that if you’re going to do it in general it’s going to be a lot easier (and cheaper) to just bring the radio itself with you. IF (only if) you also want a battery backup in your home shack, the then the PowerGate can stay there. It serves no purpose on the hill. And you’re not going to be able to easily pack enough battery power into a briefcase style Pelican box. If you’ve got the scratch you could put a couple of LiFePO4 batteries in parallel as your best portable option, but that’s still an extra 40 pounds of battery and at a steep price.


A couple of decent AGM deep cycle batteries in an enclosure with a solar panel and charge controller together with an antenna and coax and ground rod and so on, the complete package, could be had for less than one of those batteries alone. So why not just bring the radio with you and hook it up to the batteries on the hill when you get to the ranch? No Pelican case required.

Remember that all the rules of radio still apply no matter which direction you choose.
 

mmckenna

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Thanks again everyone for your comments: Some responses:
1) Good point on just using a generator. I have a honda that I could use... though the runtime is very small without refill. I'd have to have a bigger tank approach.
Running a generator all the time is going to be an expensive solution to an issue that I don't think you have.
The cost of the generator, fuel, oil changes, repairs, rebuild, replacement, etc. is all going to add up.
Solar power is free, and with a properly designed system, it's going to be cheaper, easier and longer lasting.
I've got a network of 3 linked UHF repeaters covering some very rough terrain with deep canyons. All three sites are 100% solar powered and left unattended for 6 months or more at a time. Periodic checking of the systems, repeater alignment, clean the solar panels, cut back grass/brush that grow up near them, etc. has worked well for many years. Every few years batteries get replaced.

Yeah, some cost initially but it's more than paid for itself. And having the repeaters there and always on makes it a much more useful system. No one has to go start the generator, or haul a repeater up to a hill top when needed.

2) Good point on existing repeaters. I'll check on that and try to reach them when I go out next time. We have some deep canyons, so my line of sight to long distance is hampered, but ability to hill on my ranch/lease is typically available.
Doing a repeater right is expensive. The fallacy of cheap repeater systems usually results in disappointment. You can only cut so many corners before the system become unreliable or inadequate.

Also, understanding that you will never get 100% coverage will save you some grief. Learning how to adapt to available coverage is key.

Keep in mind that running more RF power output is not going to solve all your coverage issues. Lower power and proper antennas is a better solution. And don't fall for the "higher gain is better" approach to repeater antennas. If you have deep canyons, lower gain antennas with a more favorable radiation pattern can improve coverage quite a bit.

3) PowerGate... I probably was not clear.. I am looking to use this mobile rig for different purposes... the first I'm speaking to is the repeater situation, but I can take home with me, and use at my house as my base radio. Hence the powergate... at home i could plug a powersupply into the powergate, and powergate could control (as I understand), running radio, recharge battery, etc..
If you do solar, make sure you pay attention to the solar controllers. Some are "rf noisy" and will create issues.
You'll want a dedicated repeater, since you'll need a duplexer tuned to the frequencies you are using. Using it as a base will require reconfiguring your setup depending on where it's used.


This is one of 3 sites.
The lower box holds a couple of 12 volt 100ah gel cell batteries, a charge controller and breakers for power distribution. It's made by SunWize. SunWize Power & Battery | Remote Power Systems for Industrial
Top box houses a low power UHF repeater and a linking controller connecting it to the other 2 repeaters.

This system has been deployed for about 5 or 6 years now and gets exposed to some nasty weather. No issues with it.
 
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tweiss3

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Running a generator all the time is going to be an expensive solution to an issue that I don't think you have.
The cost of the generator, fuel, old changes, repairs, rebuild, replacement, etc. is all going to add up.
Solar power is free, and with a properly designed system, it's going to be cheaper, easier and longer lasting.
You are correct. For some reason, my head goes back to an Ohio farm, sunny about only 30% of the time, and wooded, not ideal for solar. That and the winters tend to kill batteries up here. The solar school zone signs only get about 3 seasons. Him being deep in the middle of Texas, solar becomes a realistic option.

This is one of 3 sites.
The lower box holds a couple of 12 volt 100ah gel cell batteries, a charge controller and breakers for power distribution. It's made by SunWize. SunWize Power & Battery | Remote Power Systems for Industrial
Top box houses a low power UHF repeater and a linking controller connecting it to the other 2 repeaters.
Those are a cool option, and reasonable. I can't believe how off the shelf that system is. Their calculator is nice too. Now I'm kind of pissed off looking at this submittal cost for a solar signs at this school.
 

Firekite

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You'll want a dedicated repeater, since you'll need a duplexer tuned to the frequencies you are using.
I think he’s expecting to run the Kenwood in cross-band repeater mode, with one of them setting their radio (HT?) to a UHF frequency and the other to a VHF frequency.
 

k6cpo

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Hi ki5diytex, welcome to Radio Reference!

Jeffrey, be careful that you stay within the FCC Rules and Regulations. You also stated that "I want to also talk to emergency help in nearby town on emergency channels." That will get you a hefty fine and possibly jail time even in a life-threatening situation. Trust me on this. The protocol would be for you as a ham to talk to another licensed ham that can make a landline E9-1-1 telephone call to relay the emergency. Also, quite possibly, your repeater box will be able to "hit" a Dallas wide-area-coverage repeater that has an open or closed autopatch. If it is a closed autopatch, simply apply to join the club. With an HT that has DTMF capabilities, you will then be able to dial the emergency services directly yourself. The main thing is to do everything legally. Like I said, just because it is a life-threatening emergency, you will still be prosecuted. You may also find that nobody will talk to you because bogus units that show up on emergency systems every now and then crying wolf wasting the taxpayers dollars. You do not want to put yourself in that boat!
In addition, you need to be careful not to cross the line between just conversation on amateur radio while at the ranch and actually using amateur radio to sassist in the operation of the ranch. Once you start conducting daily operations on amateur radio, you've violated the "pecuniary interest" section of the amateur radio regulations. It's forbidden to use amateur radio for commercial purposes.
 

krokus

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If the sites for your repeater are vehicle accessible, consider a small trailer to mount everything to/in. It can give you shade on the equipment, a platform for your antenna, and able to be locked.

Either way, consider a modular approach, since you are wanting a multipurpose radio arrangement. You could take along just the repeater boxes, when using that setup. Look at this site for some ideas:

This podcast has some good ideas, too.

The whole "I want to talk to public safety,in an emergency..." bit has been talked to death on these forums. It is not legal, and not likely to succeed. Look at another avenue of emergency contact, such as Personal Locator Beacon services.
 
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