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GMRS / FRS - Discussions related to GMRS (General Mobile Radio Service) and FRS (Family Radio Service) communications

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  #21 (permalink)  
Old 07-11-2018, 3:11 PM
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"- By old FCC rules, FRS radios are limited to 1/2 watt of transmit power."
That's true, but under the *new* rules, didn't they raise that to two watts?

The "unity gain" aka "no gain" Browning antenna sets about as low a goal as you can find. But the TypeN connector they use *is* actually better than the common SO-239/PL-259 "UHF" connectors. It has less loss at these frequencies, creates less of an impedance bump [more loss] in the cable, AND it has a built-in o-ring to make it fairly water resistant, the bane of UHF connectors used outdoors.

If the goal is really maximizing performance, I'd find a better antenna (I think Laird and Wilson both make 5dbi gain versions for this, among others) that still uses the TypeN connector. And either at the antenna, or still on the outside of the house, connect the cable to a PolyPhaser (brand) lightning arrestor. From that you run one more coax into the building, and one proper grounding cable into the ground. PolyPhaser are what commercial broadcasters use for lightning protection on their towers, the stuff isn't cheap but neither is a new house.

"Range" is a two-way thing. If you are trying to use the base station to work with handhelds? There is only so far that the signal from the handheld can go, and then you won't hear them, regardless of the base station. Your best bet is when the handhelds and the base have equal abilities, or at least "sufficient" ones to make sure it works both ways.

With a five watt (maximum handheld) ham radio, even on the VHF band (which travels better), and a repeater that is literally pushing over 50 watts 100 stories up in the air, with a clear line of sight? A range of twenty miles would be pushing things.

Same handheld can reach the ISS orbiting over a hundred miles dead overhead in the sky though. Physics is tricky that way.(G)
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  #22 (permalink)  
Old 07-11-2018, 5:31 PM
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Seeing that higher gain does not necessarily equal greater distance, what can I do find out which would work best for my terrain?
That's tough. Basically if you can stand on your roof and see all the areas you want to cover, then a lower or medium gain antenna would probably work fine.
If you can't see the areas from your roof, no amount of antenna gain is likely going to fix it.
High gain antennas get their higher gain by focusing more power towards the horizon. That works well out on the plains, or up high.
Lower gain antennas that allow the energy to be spread out more, some up above the horizon, some below, can work better if you have a lot of hills around you.

There are programs that will allow you to model radio coverage. Problem is the are difficult to use if you don't understand what all the input parameter are.

Usually the visual line of site thing is a good way to check.




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Originally Posted by bterrier View Post
I was under the impression that the bearcom bc95/bc130 are re-branded Vertex radios. Can anyone confirm or deny this? If they are vertex, is there a way for me to program?
It -appears- that they are rebranded Vertex radios, but I agree, you'd need someone to confirm that 100%.
Rebadging radios is one thing. Chinese knockoffs are another. There are quite a few imposter radios coming out of China. Kenwood had a big problem with this for a while. Radios looked like current Kenwood models, but the internals were all cheap.



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Originally Posted by bterrier View Post
Thanks for that and info. What is your opinion of the tk-380 and tk-3360? also found some vertex vx-10 radios pretty cheap. Can these be used with repeaters? Are these easily programmed?
Those would work.

Kenwood TK-380 is an older radio. I'm not sure about windows compatible programming software off the top of my head, I'd need to dig into that. This radio DOES have the necessary Part 95 certifications. Again, there are multiple UHF versions of this radio. ONLY the type 1 radio (450-490MHz) will work on GMRS. The other two UHF models, Type 2 (470-512MHz) and Type 3 (400-430MHz) will NOT work on GMRS.

TK-3360 is a good basic radio. However it does not have the necessary FCC Part 95A certifications to be legal on GMRS. Some people choose to ignore that. In reality the radio will work on GMRS.

Not sure about the VX-10. I'm not a Vertex guy. I've got a few hundred Kenwood radios at work, and a bunch of Motorola's that are still in use (slowly being replaced).

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Originally Posted by bterrier View Post
Also what is trunking? I have been reading comments where people are stating some radios can do trunking....I am not sure what they are referring to.
Trunking is a way to take a limited amount of physical radio channels and assign separate talk groups to share them. Think of it like a business phone system. You might have 100 telephones, but there are only 10 trunks going to/from the phone company. Not everyone is on the phone at the same time, so you don't need a 1:1 match of trunks to phones. A trunked radio system does a similar thing. I run a trunked radio system at work. I've got over 400 radios on it. There are about 60 different talk groups (think: virtual channels), but only 5 radio repeaters. The trunked system assigns users to one of those available channels as they need to use the system.

Trunking is a bit complicated and well outside the realm of the hobby user. Also, it doesn't get along well with radio services like GMRS. Not something you'd want, or need, to use. I'm aware that some try to use it on GMRS, but it can be an issue for a shared radio service.

Many radios will support one or more of the various types of trunking. However, for what you are doing, you just need conventional analog capability.
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  #23 (permalink)  
Old 07-11-2018, 5:37 PM
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Yes I would like to find radios that can be easily programmed, but I was curious about the motorolas because I have seen the sm120 and m1225 selling cheap. So it all comes down to programming and the expense associated. I have seen an aftermarket program called “radio doctor” designed to work well for programming
the gm300. Unsure if there is something similar for the sm120.
There are some "aftermarket" (Chirp, etc.) type programming softwares. I'd recommend using the OEM software, however. At least that way you've got a better chance of getting support. Programming software and the specific firmware of the radio is important. Relying on a "free" or after market software can be a headache inducing exercise. Not saying it cannot be done, but if you are just getting started, taking on the challenges of programming with a non-vendor supported software with old, out of date radios, well, you get the idea.

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Originally Posted by bterrier View Post
What about power output? I get that a 1 watt difference may not be very noticeable, but what about a jump from 25 to 40 watts? Should I be searching for radios with higher power output? Or should I focus on features and ease of programming?
Where it makes the difference is way out on the fringes of coverage. A 45 watt radio might get a slightly clearer signal through compared to a 25 watt radio.

In other words, a 50 watt radio will not give you twice the range of a 25 watt radio. There's a lot more involved, math stuff, path losses, etc. Since UHF is line of site, additional power won't necessarily fix a coverage issue problem.
Nothing wrong with running a 45 watt radio. If that's what you can find used, then it's OK. But don't expect a huge jump in performance.

For where you are in this hobby, look more at ease of programming. Even basic radios have a lot of useful features. Programming is a bigger deal.

Also, you might want to consider radios with an LCD display. That can make life a bit easier.
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  #24 (permalink)  
Old 07-12-2018, 10:02 PM
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Thanks for all the help!

At this point Im leaning away from the motorola radios, mainly due to the software/programming issues. Most likely going to start with some kenwoods and maybe Vertex. Not quite sure yet because I am still figuring everything out to make sure I can program the radios once I purchase them, which brings me to my next question.

Do kenwood radios all use the same programming cable? Or is it model specific. It would make much more sense financially if I could keep all the radios down to 1 or 2 programming cables.

I am going attempt to locate the Kenwood software if possible but in the case that I can’t do so, it appears that Chirp works for many kenwood models.
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  #25 (permalink)  
Old 07-12-2018, 10:31 PM
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Originally Posted by bterrier View Post
Do kenwood radios all use the same programming cable? Or is it model specific. It would make much more sense financially if I could keep all the radios down to 1 or 2 programming cables.
Sort of.

There are two primary type of programming cables for portable Kenwood radios:
2 pin type connectors
14 pin connectors.

For mobiles…
Many of the mid tier mobiles can be programmed using the front RJ-45 mic connector.
Some of the higher tier mobiles will require a Kenwood specific round 12 pin connector.

I support a number of models of Kenwood radios at work. I've got the 4 different cables and I can do most radios they've built in the last 20 years or so.

Can't say the same for Motorola, I got a pile of Motorola cables, interfaces boxes, etc.
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Old 07-12-2018, 11:37 PM
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Quote:
"Range" is a two-way thing. If you are trying to use the base station to work with handhelds? There is only so far that the signal from the handheld can go, and then you won't hear them, regardless of the base station. Your best bet is when the handhelds and the base have equal abilities, or at least "sufficient" ones to make sure it works both ways.
Yes I am trying to use the base station to work with the handhelds if possible

[quote] With a five watt (maximum handheld) ham radio, even on the VHF band (which travels better), and a repeater that is literally pushing over 50 watts 100 stories up in the air, with a clear line of sight? A range of twenty miles would be pushing things.[/quote}

The absolute farthest I would want to reach is about 8-10 miles. Being new to this, I'm not sure if its feasible with the terrain but we will soon find out.

I will definitely have some handhelds, but what about if I used some 25-40 watt mobile units in a vehicle. Would that make the distance back to base at 8-10 miles?
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Old 07-12-2018, 11:39 PM
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Quote:
Originally Posted by mmckenna View Post
Sort of.

There are two primary type of programming cables for portable Kenwood radios:
2 pin type connectors
14 pin connectors.

For mobiles…
Many of the mid tier mobiles can be programmed using the front RJ-45 mic connector.
Some of the higher tier mobiles will require a Kenwood specific round 12 pin connector.

I support a number of models of Kenwood radios at work. I've got the 4 different cables and I can do most radios they've built in the last 20 years or so.

Can't say the same for Motorola, I got a pile of Motorola cables, interfaces boxes, etc.
Great, that is what I was hoping. This is one of the many issues that is turning me away from Motorola.
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Old 07-12-2018, 11:43 PM
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And either at the antenna, or still on the outside of the house, connect the cable to a PolyPhaser (brand) lightning arrestor. From that you run one more coax into the building, and one proper grounding cable into the ground. PolyPhaser are what commercial broadcasters use for lightning protection on their towers, the stuff isn't cheap but neither is a new house.
Yea, I definitely want to install things correctly. I took a look at the polyphaser site...how do I match the correct lighting arrestor to my application? There are many to choose from
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Old 07-12-2018, 11:54 PM
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Originally Posted by bterrier View Post
I will definitely have some handhelds, but what about if I used some 25-40 watt mobile units in a vehicle. Would that make the distance back to base at 8-10 miles?
It still depends on the topology of the area. More RF power will not necessarily fix coverage issues at these frequencies.

For mobile use, there is a substantial benefit to using a radio with an external antenna, though.
Inside a car, a portable radio is going to have issues as the metal body of the vehicle will block/absorb signals, both coming in and going out. Some window tinting and defroster wires in back windows will also block signals.
By putting a mobile antenna outside the vehicle, you will improve performance quite a bit.

You also don't need to worry about keeping batteries charged.
Some states have exemptions to hands free laws that permit using a mobile radio, while using a hand held radio may not be permitted.
Louder audio improves intelligibility compared to using a portable radio with a small speaker.

There is no way to know if it's going to cover what you need, but it absolutely will work better than a hand held radio inside the car.
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Old 07-13-2018, 12:18 AM
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Originally Posted by bterrier View Post
Yea, I definitely want to install things correctly. I took a look at the polyphaser site...how do I match the correct lighting arrestor to my application? There are many to choose from

https://www.polyphaser.com/products/...ion/is-50nx-c2
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Old 07-13-2018, 9:56 AM
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Welcome to the fun
It all depends on what you want to do.
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Old 07-15-2018, 11:05 PM
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So... not to keep going back to the Bearcom BC95, but I have a local guy that will sell me a pair for $30. I view that as very cheap, but please tell me if I am wrong about that.

He says they are programmed and can talk to each other but has no idea what the frequencies are. Should I grab them? I am worried about the programming. I have contacted Vertex for the software, but they have sent me to Motorola because they have apparently taken over vertex. (https://businessonline.motorolasolutions.com/)

I signed up for an account, but am still waiting for activation. I read through an earlier post on this site where a member stated to sign up for a vertex account and all the software can be downloaded free of charge. I am hoping this is still the case since Motorola has taken over. (I am willing to pay as well but would need to find it. It would also impact my decision whether or not to purchase the radios)

It has been about 4 days since registering and still haven't hear anything. In the event that I cannot get it from Motorola, does anyone know where I can get it from? Do you know which version of the software I would need? Or do you know if the BC95 is an exact clone of a Vertex model?

If this isn't going to work, I found some used Kenwood's online I think I will probably go with.
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Old 07-15-2018, 11:36 PM
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He says they are programmed and can talk to each other but has no idea what the frequencies are.
This should be a yellow flag. Maybe not a red flag, but it does mean you should proceed with caution.

Any time someone says "they talk to each other" and the phrase "no idea what the frequencies are" usually means they don't know what the have, don't know what they are selling, and won't be of any help if something goes wrong.


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Originally Posted by bterrier View Post
Should I grab them? I am worried about the programming.
Don't blow the $30 until you know for sure you can get the correct programming software for them, and that the cost is reasonable. Try contacting BearCom directly.
If you cannot program them, you'll be out $30.

Also, consider that they will need new batteries at minimum. Everything else should be suspect, make sure you are getting the correct chargers and correct antennas.

Personally, I'd put the $30 towards the Kenwood's. Getting the software for them will be a lot easier and cheaper.
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