Better understanding how GMRS repeaters work

[Guest Templeton]

Hi, I understand how radio works in general. Well, at least a little bit. With GMRS repeaters, there are least 2 scenarios that I can think of.  We have a communications need where we might be slightly outside the range of simplex GMRS handheld radio-to-handheld radio range (mostly flat area, just some open space and general suburbia with typical low buildings). But, if I understand correctly, repeaters can be much further away from the handheld radio, but still be able to receive a signal, and send back an intelligible signal. I think? I understand that repeaters work great in scenario 1 (see image), but would they also work to extend handheld range in scenario 2 ? I looked on the web to try to find an answer to this, but had no luck. In addition to my question, any other related details that I should know? Thanks.

(in this not-to-scale drawing, I am stipulating that all distances shown--handheld to handheld, and handheld to repeater--are slightly outside of the range of handheld simplex communication in these conditions)

 

[gortex2]

This is correct. But a repeater will only work if it can hear the handheld. Normally a repeater antenna is higher up than a handheld. Your case sounds like a good option for the new Midland repeater package deal.

 

[wayoverthere]

Line of sight is a big aspect that's present in the illustrations, but not really a focus. Handheld to handheld, I believe the general number is around 5 miles for simplex. However, for an affective repeater, the antennas are usually placed higher, sometimes hundreds of feet up a tower, or out here they're on the mountain ridges at thousands of feet above the valley floor. This gives them a much further line of sight than at ground level.

The second aspect is antennas; repeater antennas will generally focus the RF energy better outward rather than upward...the usual illustration for this is comparing it to squishing a ball into more of a donut around the antenna. At the extreme this can be a tradeoff if you have large elevation differences where you end up under or over the "beam".

Out here with the high level repeater locations, I have reached repeaters from 60-70 mi out on a handheld.

[Guest Templeton]

If it helps, I am in the flat midwest. So, based on the replies above, is it possible that two GMRS handhelds could be, say, 10 miles apart at ground level (so no simplex communication possible), with one of the radios 15 miles from the repeater and the other radio 25 miles from the repeater (just as shown in the 'scenario 2' situation), but still be able to communicate with one another via the repeater?

So the repeater does not have to be located "between" the handhelds, it can be "to one side" of both of the handhelds, but still facilitate communication if the conditions are suitable? Am I understanding this correctly?

[axorlov]

1 hour ago, Guest Templeton said:

But, if I understand correctly, repeaters can be much further away from the handheld radio, but still be able to receive a signal, and send back an intelligible signal. I think?

Yes, but only because repeaters, usually, located high off the ground, providing longer line-of-sight distances. And also because repeaters, usually, have much more efficient antennas and much better, by many parameters, receivers. There is nothing magical about repeater, and repeater created from two HTs placed at shoulder height will have less reach than same radios on simplex.

[WRQC527]

Also remember that just because your handheld can hear the repeater, the repeater may not be able to hear your handheld. Repeaters put out a lot more wattage than a handheld, and do it through a much better antenna system. The repeater I maintain puts out well over 50 watts and is located at almost 6,000 feet, giving it coverage from Santa Barbara to San Diego. My Handheld at sea level cannot always reach it even if I can hear it, normally due to terrain or obstacles like buildings.

[WRVD377]

4 hours ago, Guest Templeton said:

If it helps, I am in the flat midwest. So, based on the replies above, is it possible that two GMRS handhelds could be, say, 10 miles apart at ground level (so no simplex communication possible), with one of the radios 15 miles from the repeater and the other radio 25 miles from the repeater (just as shown in the 'scenario 2' situation), but still be able to communicate with one another via the repeater?

So the repeater does not have to be located "between" the handhelds, it can be "to one side" of both of the handhelds, but still facilitate communication if the conditions are suitable? Am I understanding this correctly?

To give you my exact test:

1 handheld in my front living room at a window to an identical handheld in my truck. In town Midwest smaller town.  1.3 miles was my max.

Same handhelds with Retevis RT97 antenna 20 - 25' agl, 2.25 miles max.

I did not retry after I went from 5.79W @ 25' and 6.5dB antenna to 25.6 W @ 37' and 11.9dBi (-2.15 ish for dB).

In my case, such that it is with lots of obstacles. 6 foot above ground to 25' above ground only netted me 1 mile more range with same 5W handheld with +19 feet repeater antenna.  Now if both handhelds were 2.25 miles on opposite sides you could have 4.5 miles of possible total range vs 1.3 miles.

All I learned was my power output had little effect compared to my antenna height for getting range.

 

[Guest Templeton]

On 2/14/2023 at 2:16 PM, axorlov said:

Yes, but only because repeaters, usually, located high off the ground, providing longer line-of-sight distances. And also because repeaters, usually, have much more efficient antennas and much better, by many parameters, receivers. There is nothing magical about repeater, and repeater created from two HTs placed at shoulder height will have less reach than same radios on simplex.

Not sure I fully understand. Don't repeaters somehow "copy" incoming transmissions and then re-transmit those same transmissions on a slightly different frequency? That is not magical, but that seems to pretty different from how regular handheld or base units work, no? That said, how would one create a repeater from two handheld radios? And why would such a repeater (at shoulder height) cause a lower range? Do you mean less range from two other handhelds that are using the "shoulder height repeater" as an intermediate connection, vs the two handhelds just trying to communicate directly in a simplex fashion?

[wayoverthere]

27 minutes ago, Guest Templeton said:

Not sure I fully understand. Don't repeaters somehow "copy" incoming transmissions and then re-transmit those same transmissions on a slightly different frequency? That is not magical, but that seems to pretty different from how regular handheld or base units work, no? That said, how would one create a repeater from two handheld radios? And why would such a repeater (at shoulder height) cause a lower range? Do you mean less range from two other handhelds that are using the "shoulder height repeater" as an intermediate connection, vs the two handhelds just trying to communicate directly in a simplex fashion?

There are cables/interface boxes made to link 2 handhelds together. The problem there would the radio doing the retransmittimlng part can overload the receiving radio due to it's close proximity. This would cause this shoulder height repeater to be to hear you from a shorter distance than if you were just going handheld to handheld...while some are worse than others, and some handle adjacent frequencies better than others, almost any radio will desense to a degree to protect the receiver from a strong signal nearby.

You can see the same issue when transmitting from one handheld to another in close proximity;the receiving radio sees an incoming signal, but doesn't receive any audio.

As @axorlovsaid, there isn't anything magical about it, at the most basic it's a receiving radio connected to a transmitting radio. In practice, better filters against adjacent frequencies in mobile and repeater receivers help make it possible, as do things like duplexers that separate the transmit from the receive.

Does that help clarify?

[Guest Templeton]

Yes, that makes sense. Thanks.

So assuming that a local repeater can receive a signals from two particular GMRS handheld radios, that local repeater does not have to be located "in between" the handhelds, it can also be "to one side" of both of the handhelds, but the repeater can still facilitate communication between the two handhelds if the conditions are suitable? Even if the two handhelds are far enough apart from one another that simplex communication is not possible?

Related question: if conditions in flat suburbia are such that two GMRS handhelds can get, say, 1-2 miles of range in simplex communication, is it reasonable to expect that the ~5 watt signal from one or both of these radios could still reach a repeater that is, say, 5-10 miles away? I know that this is highly dependent on the repeater height, but I am not sure how high the towers are of the freestanding repeaters near me. I know that there are no major hills near me, so I think that it is safe to say that the GMRS repeaters are on the top of some kind of radio towers.

And thanks for answering my questions.

[WRQC527]

Templeton, you have been given numerous explanations about how repeaters work. By introducing theoretical and ambiguous concepts and situations, you are confusing yourself. Most repeaters do one thing. They receive your weak HT or mobile's signal, they amplify it, and send it out on a different frequency. That's it. The best ones are high up so they have a massive coverage area. 

[Guest Yeah, I understand. But so]

Yes, thanks for answering my questions. But some of the replies have brought up some interesting new topics about repeaters and about two-way radio communication in general, which I am really curious about. Should I not ask any new questions about any concepts brought up in the replies, or about other questions that I have about radio range, power, antenna height, terrain, obstacles, repeaters, and related topics? I mean, how does one learn more about this vocation/hobby without asking fellow enthusiasts questions? I thought folks on this forum like to help newbies like myself. And I thought that the guest forum said in plain english, "not yet a member of myGMRS but need help or want to ask questions?"  Was I totally wrong to take that statement at face value?

[BoxCar]

Many of the topics you are asking about have been addressed in the past. Several times for some of them.

I suggest you look at one site frequently mentioned on these forums when the subject of repeaters, their construction and use, is asked. That site is https://www.repeater-builder.com.

[WRQC527]

45 minutes ago, Guest Yeah, I understand. But so said:

Was I totally wrong to take that statement at face value?

No. You are absolutely right. The original subject concerned how GMRS repeaters worked, which was covered extensively. Your questions are many, as are our answers. The best way to get answers is to post specific questions and/or look through answered questions and forums. We're here to help. I mean that.

[WRVD377]

3 hours ago, Guest Templeton said:

Yes, that makes sense. Thanks.

So assuming that a local repeater can receive a signals from two particular GMRS handheld radios, that local repeater does not have to be located "in between" the handhelds, it can also be "to one side" of both of the handhelds, but the repeater can still facilitate communication between the two handhelds if the conditions are suitable? Even if the two handhelds are far enough apart from one another that simplex communication is not possible?

Related question: if conditions in flat suburbia are such that two GMRS handhelds can get, say, 1-2 miles of range in simplex communication, is it reasonable to expect that the ~5 watt signal from one or both of these radios could still reach a repeater that is, say, 5-10 miles away? I know that this is highly dependent on the repeater height, but I am not sure how high the towers are of the freestanding repeaters near me. I know that there are no major hills near me, so I think that it is safe to say that the GMRS repeaters are on the top of some kind of radio towers.

And thanks for answering my questions.

Try this site: Radio Line of Sight Calculator for use on VHF/UHF Ham Bands (hamuniverse.com) This gives you some examples. It is all the details that matter.

One of my Handhelds is 5W with a better antenna and it still only got 2.25 miles- So I will jump off the cliff and say it is not reasonable to expect 10 miles from 5W handhelds, maybe on 5 miles. But not for me as I showed above. Again all the details matter as to an answer of which most of us could never give a yes or no answer.

[WRQC527]

41 minutes ago, WRVD377 said:

~5 watt signal from one or both of these radios could still reach a repeater that is, say, 5-10 miles away?

Believe it or not, 5 watt handhelds with decent antennas can reach the receivers or repeaters on the International Space Station or an AMSAT satellite which are around 200 miles up. This is because there is nothing between the handheld and the space station. Those same handhelds cannot reach more than a few miles at best at sea level because the signals are blocked by terrain, structures, foliage, and all manner of other obstacles. It's all about line of sight and how high the repeater is. My repeater is at 5,700 feet, and we can hit it with handhelds from sea level 30 miles away, probably more. 

[wayoverthere]

4 hours ago, Guest Templeton said:

Yes, that makes sense. Thanks.

So assuming that a local repeater can receive a signals from two particular GMRS handheld radios, that local repeater does not have to be located "in between" the handhelds, it can also be "to one side" of both of the handhelds, but the repeater can still facilitate communication between the two handhelds if the conditions are suitable? Even if the two handhelds are far enough apart from one another that simplex communication is not possible?

Related question: if conditions in flat suburbia are such that two GMRS handhelds can get, say, 1-2 miles of range in simplex communication, is it reasonable to expect that the ~5 watt signal from one or both of these radios could still reach a repeater that is, say, 5-10 miles away? I know that this is highly dependent on the repeater height, but I am not sure how high the towers are of the freestanding repeaters near me. I know that there are no major hills near me, so I think that it is safe to say that the GMRS repeaters are on the top of some kind of radio towers.

And thanks for answering my questions.

first question: yes, that's correct.  i'll share a real world example from the ham side (on 70cm, which is nearly identical, signal wise, to gmrs), with the caveat that i don't do much (if any) simplex on GMRS, as the family has ZERO interest.

using my base setup (which is a pair of mobiles and a base antenna in the closet) chatting with someone who lives in the next town up the highway via the local repeater, which is 23 miles from me. discover he's in town shopping at the moment, talking in on his mobile from a shopping center 25 miles from the repeater, and just 6.5 miles from me.  i switched over to the repeater input to see if i could hear him, but not much beyond an occasional burst of static.  i can hear the repeater clearly on a handheld inside the house, and can talk in with no problem from outside in the yard, but going direct just over 6 miles apart was no go.

second question: hard to say on "reasonable"...is it possible? absolutely.  it's going to be very dependent on height, but it's a little bit of a stretch to assume radio towers.  some may be one of the users here, with a 5 watt Retevis 'repeater in a box' on a 20' top rail mast, or mounted on a barn.  dealing with the high level stuff we have in CA, i've talked into a gmrs repeater over 60 miles out from the 3rd floor of a hotel with a handheld, and managed 75ish to a ham repeater in the same area from a high spot in the hills (basically clear line of sight over the valley), but those repeaters i'm working with are on foothill ridges at 3000-4500 ft above sea level. obstructions are the biggest challenge for a largely line of sight signal like gmrs.

here's a quick edit to the diagram in the first post illustrating my example (though i'm using gmrs frequencies in the diagram, illustrating hearing via the repeater was no problem, but listening on the repeater input, no luck.

[WRVD377]

The "reasonable to assume" question was at hand. No mention of a local repeater height. Thus, my answer and condition. The link explains some of those variables. And obviously the extreme exceptions are always out there but are they "reasonable" for an unspecified height, or cabling, or antenna, cable loss, on and on.  So for those with expensive systems, is that "reasonable" the way it was asked? I think not.  Many have answered in alot of detail, but if you read how it was asked with no repeater altitude who will say yes 10 miles is fine on open flat land no buildings or trees (Oh wait that was not specified either). Put an 80' tree line, 10' - 30' infront of any of it. Is it still reasonable? Oh wait put some 5 story buildings right in front of the handheld, is that reasonable? At what power and altitude.  Point being most of you pointed out the variables, exceptions are just that. Ideal perfect designs that most people cannot put in themselves Due to the real costs.  Take my results what does that cost for a reasonable expectation everywhere in the US, then take all the other costs.  I'll bet the examples of 10 miles or more are exceptions compared to most places in the US.  For $800 can you get over 10 miles without knowing repeater height, obstructions, and all the other parts.  My most recent test was at 25W Motorola GR1225, still not over 2.25 miles.

So I leave it at what is "reasonable" at an unspecified repeater height and all real living obstacles that may not have been stated.  Answer: The MFGs handhelds documented answer. Crap. Unless there is absolutely no obstructions of any kind.

 

[SteveShannon]

13 hours ago, Guest Templeton said:

Yes, that makes sense. Thanks.

So assuming that a local repeater can receive a signals from two particular GMRS handheld radios, that local repeater does not have to be located "in between" the handhelds, it can also be "to one side" of both of the handhelds, but the repeater can still facilitate communication between the two handhelds if the conditions are suitable? Even if the two handhelds are far enough apart from one another that simplex communication is not possible?

Related question: if conditions in flat suburbia are such that two GMRS handhelds can get, say, 1-2 miles of range in simplex communication, is it reasonable to expect that the ~5 watt signal from one or both of these radios could still reach a repeater that is, say, 5-10 miles away? I know that this is highly dependent on the repeater height, but I am not sure how high the towers are of the freestanding repeaters near me. I know that there are no major hills near me, so I think that it is safe to say that the GMRS repeaters are on the top of some kind of radio towers.

And thanks for answering my questions.

There’s nothing wrong with having a conversation and sometimes, in a conversation, a person will circle back to a question for more detail or even out of skepticism.  “Maybe I didn’t hear that right?” “But what about this case — it seems different?” And sometimes, those of us who are explaining things answer the question we hear, not the one you asked.  So, go ahead and ask as many questions as you want.  But, understand that we might get testy if you ask the same question over and over in the same way.

Repeaters do not need to be in-between two radios geographically.  They just need to be within range of both of the two radios and the two radios must be within the coverage pattern of the repeater antenna.  That pattern is usually described as fanning out circularly and horizontally.

There are a few characteristics that makes a repeater more effective at achieving greater range:

1. Their antennas are usually placed on high terrain and then installed on towers that raise them even higher, to improve the line of site,
2. Their antennas direct their transmission power outward horizontally (and often slightly downward) to target a specific region.
3. The better commercial repeaters are designed to have better receivers than off-the-shelf GMRS radios, usually much better.  Being better quality makes a big difference. They have more sensitivity to pick up weaker signals and they have greater selectivity to help reject interference from other signals.
4. The commercial repeaters are also designed with better transmitters, but for GMRS they are limited to 50 watts.  What makes them better is the accuracy of their frequency oscillation and the absence of spurious emissions. Having higher power will help increase the range, but less than you might expect. The important thing is visibility, line of sight.

There’s nothing about duplex communications that enhances range over simplex communications.  If you and I each have a radio and we cannot reach each other, placing a repeater where one of us is standing, with its antenna placed down low like our antenna are will probably do nothing to help, but replacing one of us with an antenna that pokes out above all the surrounding buildings and hills will help a lot.

If the repeater antenna is up high enough, and there’s a straight line of sight between your antenna and the repeater antenna, it’s entirely possible to get 10 miles or further.  I live in the mountains. There’s a repeater to the south of me that’s 4000 feet above me and 9 miles away from my house in town.  I can travel 16 miles farther north to my cabin and still easily reach that repeater with a five watt handheld radio, even a very cheap radio.. The people I have talked to using the repeater have been as far south of the repeater as 45 miles, as far east as 70 miles, and as far west as 20 miles. But because of an intervening peak of another mountain there’s one direction that’s probably less than a mile.  It really depends on terrain, topography, structures, and quality.

So the only two correct answers to your questions about flat suburbia and ranges are “it depends” and “maybe.”  If you’re willing to spend the money to install a high quality commercial repeater with a high quality high antenna, it’s highly probable to achieve the range you want.  In fact, simply connecting high quality antennas to your radios and raising those antennas up high might be able get you the range you need. 

So, more specifically, yes, a five watt radio can reliably reach a repeater five or ten miles away if the conditions are right.  Can it work in your instance?  You’re the only one who can answer that.  Try it.  If it doesn’t work with your handheld antenna put an antenna on your car roof.  Or try it with a fifty watt mobile unit and a good mobile antenna on top of your car.  Finally, hook up a fifty watt mobile radio to a base station antenna extending above the roof of your house. Please let us know.

And feel free to ask more questions.

 

[Guest Templeton]

That is amazing that a 5 watt GMRS radio could potentially transmit to orbit ! Does the ISS sometimes take random calls from GMRS operators?!

Thanks for the patience. I know that I have a lot of questions, but I am curious on a practical level how (and if) any local repeaters will work for me. I have never used a repeater before and it is not that I want or need to know the exact physics and electronic theory of repeaters, it is more that I just want to get a general feel for what might work (and what might not work) in my situation. And, yes, I totally understand that the specific conditions matter a lot.

So, to get more specific, based on the repeater map that is here on this website, apparently there is a GMRS repeater about 11 miles to the west of me (flat suburban and rural terrain) that does not have a listed height but it does have an estimated range of 35 miles. So, if I can get 1-2 miles of decent simplex range from my handheld to another handheld located, say, 2 miles to the north of me, is it reasonable (assuming no major obstructions) to expect one or both of my handhelds to also be able to send and receive to this repeater that 11 miles away to the west of my location? Not asking for an absolute or ironclad answer, just trying to get a sense of whether or not this will be possible or likely.

Does "HT" equal 'handheld transceiver'?

Since obstructions matter, does GMRS simplex range typically decrease in summer vs winter when the trees are full of leaves vs bare trees in winter?

[Guest Templeton]

11 minutes ago, Sshannon said:

So, more specifically, yes, a five watt radio can reliably reach a repeater five or ten miles away if the conditions are right.  Can it work in your instance?  You’re the only one who can answer that.  Try it.  If it doesn’t work with your handheld antenna put an antenna on your car roof.  Or try it with a fifty watt mobile unit and a good mobile antenna on top of your car.  Finally, hook up a fifty watt mobile radio to a base station antenna extending above the roof of your house. Please let us know.

 

 

Yes, I will definitely try it. But I don't have any GMRS radios yet. I used some borrowed FRS radios and they were pretty maxed out in my conditions at barely a mile from one another. I just wanted to ask questions here to see if theoretically I get much better real-world range in my conditions if I used a set of GMRS handhelds and a local repeater. But I wanted to get an idea if it MIGHT work before I purchased a set of radios.

But, yes, when I do get the GMRS units, I will of course try it! And I will report here.

New question: one repeater near me says, "permission required" to use. Is there a thread on how to properly get permission from an operator of such a repeater?

[SteveShannon]

14 minutes ago, Guest Templeton said:

Yes, I will definitely try it. But I don't have any GMRS radios yet. I used some borrowed FRS radios and they were pretty maxed out in my conditions at barely a mile from one another. I just wanted to ask questions here to see if theoretically I get much better real-world range in my conditions if I used a set of GMRS handhelds and a local repeater. But I wanted to get an idea if it MIGHT work before I purchased a set of radios.

But, yes, when I do get the GMRS units, I will of course try it! And I will report here.

New question: one repeater near me says, "permission required" to use. Is there a thread on how to properly get permission from an operator of such a repeater?

That background helps.

Some of the FRS channels are limited to only half a watt.  Some use two watts.  You probably will get better range with GMRS.

Now, as far as seeking permission, first you have to get a GMRS license so you can get a full login here.  That will allow you greater access to the repeater page.  There are two different logins: one to mygmrs.com, and one to forums.mygmrs.com.  You must be logged into mygmrs.com in order to request access to a repeater on the repeater pages and you must have a GMRS license, verified to the site via the FCC database, in order to have a login.  Sometimes it takes a couple days for the verification process.

Once you have your login you go to the repeater page and click on the repeater you want to know about.  Then you can click on a link to request access.

[SteveShannon]

33 minutes ago, Guest Templeton said:

That is amazing that a 5 watt GMRS radio could potentially transmit to orbit ! Does the ISS sometimes take random calls from GMRS operators?!

Thanks for the patience. I know that I have a lot of questions, but I am curious on a practical level how (and if) any local repeaters will work for me. I have never used a repeater before and it is not that I want or need to know the exact physics and electronic theory of repeaters, it is more that I just want to get a general feel for what might work (and what might not work) in my situation. And, yes, I totally understand that the specific conditions matter a lot.

So, to get more specific, based on the repeater map that is here on this website, apparently there is a GMRS repeater about 11 miles to the west of me (flat suburban and rural terrain) that does not have a listed height but it does have an estimated range of 35 miles. So, if I can get 1-2 miles of decent simplex range from my handheld to another handheld located, say, 2 miles to the north of me, is it reasonable (assuming no major obstructions) to expect one or both of my handhelds to also be able to send and receive to this repeater that 11 miles away to the west of my location? Not asking for an absolute or ironclad answer, just trying to get a sense of whether or not this will be possible or likely.

Does "HT" equal 'handheld transceiver'?

Since obstructions matter, does GMRS simplex range typically decrease in summer vs winter when the trees are full of leaves vs bare trees in winter?

The ISS doesn’t do GMRS, but it does converse with ham radio operators.

There’s absolutely no correlation between the range between two handy-talkies (HT) going north and the range to a repeater to the west. Different directions, different obstacles. Maybe, maybe not. The best predictor is to tune your handheld radio to the repeater output frequency, leaving tones completely turned off, and listen to see if you ever hear the repeater.  If you never hear it you are probably out of range, or nobody is using it.

You cannot use FRS radios on a repeater. 

Yes, at higher frequencies like UHF, foliage definitely absorbs signals.  So can rain. So can snow.

[Guest Templeton]

3 minutes ago, Sshannon said:

There’s absolutely no correlation between the range between two handy-talkies (HT) going north and the range to a repeater to the west. Different directions, different obstacles. Maybe, maybe not. The best predictor is to tune your handheld radio to the repeater output frequency, leaving tones completely turned off, and listen to see if you ever hear the repeater.  If you never hear it you are probably out of range, or nobody is using it.

You cannot use FRS radios on a repeater. 

Yes, at higher frequencies like UHF, foliage definitely absorbs signals.  So can rain. So can snow.

Ok, great info. And, yes, I understand that FRS does not utilize repeaters. And I understand that it also has lower wattage.

I have applied for a GMRS license, just waiting for it to get approved. (And, boy, a lot of steps to that process!)

Is GMRS on the UHF frequency band? So, in your own experience, you have seen foliage and/or the seasons noticeably affecting your GMRS range?

I understand the different send/receive frequencies used on repeaters. But I do not at all understand the how/what/when/why of the usage of tones and GMRS repeaters. Is there a good thread (or video) you could direct me to that explains all that to a total newbie?

Thanks!

[Guest Templeton]

1 hour ago, Sshannon said:

There’s absolutely no correlation between the range between two handy-talkies (HT) going north and the range to a repeater to the west. Different directions, different obstacles. Maybe, maybe not. The best predictor is to tune your handheld radio to the repeater output frequency, leaving tones completely turned off, and listen to see if you ever hear the repeater.  If you never hear it you are probably out of range, or nobody is using it.

You cannot use FRS radios on a repeater. 

Yes, at higher frequencies like UHF, foliage definitely absorbs signals.  So can rain. So can snow.

Thanks, good info. And, yes, I understand that FRS does not utilize any repeaters and that is has lower wattage than GMRS.

I have applied for a GMRS license, just waiting for it to get approved. (And, boy, a lot of steps to that process!) Is GMRS on the UHF frequency band? So, in your own experience, you have seen foliage and/or the seasons noticeably affecting your GMRS range?

I understand the different send/receive frequencies used on repeaters. But I do not at all understand the how/what/when/why of the usage of tones and GMRS repeaters. Is there a good thread (or video) you could direct me to that explains all that to a total newbie?