[guy57z]

It is a bit of a stretch posting this on this forum, but there appears to be a lot of knowledgeable people here and while my question is not strictly survivalist, it is applicable.

I know this question has been asked many times before. I have been doing a lot of research trying to decide what to do and have read through many posts like this one. The problem is that most posts don't have terrain details and I can't get a handle on exactly how much LOS impacts transmission/receiving at different freq ranges (HF, VHF, UHF).

Most people ask about freq/range and the responses are "it depends". I get that. What I am having trouble with i show much it "depends" vs freq.

My situation is we have a lake cabin on a inland river/lake. We have kids that like to go canoeing/kayaking/fishing as well as some teenagers that are trying to convince us that they are old enough to take the ski boat out by themselves... I am trying to find a reliable means of communications with them in case if problems. It is a rural area and unfortunately cell phone service is non-existant on the shore/dock and spotty on the water. We had an issue late last year where the kids were out and the engine would not start. They had a cell, but we had problems getting calls to go through and being intelligible. It made the starting problem a whole lot more stressful for all involved. We have also had an issue where our youngest was out kayak fishing and a very strong wind came up. He could not paddle back and had to paddle to the closest shore. He had a FRS/GMRS radio so he called us, but what we have is crap and I need to improve on that for that kind of situation. We could not hear him very well and if he was a little bit further out we may not have heard him at all.

The part of the lake we are concerned with is long, relatively narrow (as lakes go, varies between 150-300yrs wide) with steep high shore line. We boat there because it is protected from the wind for the most part, but that same protection creates LOS issues. The surrounding topology varies of course but ranges from 20-80 feet above lake level. Unfortunately our cabin is not at the top of a hill but on the side (facing our cove). What ever we do we will have an antenna on a 40' tower. That will put the antenna above any nearby hills, but right at or slightly below more distant hills between us and various parts of the lake. Of course the problem is that at the other end the lake is in a "valley" of sorts.

I have two use cases. One is canoe/kayak which is short range 1 mile or less but I really wanted to go waterproof HT since they will get wet and likely will go in the water at some time. The second case is on a smallish boat which would need 2.5-3 mile max range. Waterproof HT would be nice, but I could get away without a waterproof HT here.

I have looked at CB, marine VHF, MURS, FRS/GMRS, and a few others. Ham is not really an option because everyone in the family needs to be able to operate the radios. I don't see my wife or the kids getting their license. I would prefer to use one solution, but I am not sure if that is possible. I am leaning towards CB SSB or VHF. I would prefer VHF because of the waterproof/floating HT options but am concerned about it ability to cover 3 miles of hill/valley terrain. I think CB SSB might be better for the terrain coverage but of course I can't find a waterproof HT.

So I know I will have LOS issues. It is definitely not a clear LOS. The question is what option would have the best chance to work reliably up to 2.5-3 miles given the hills and valley I know we have. I can't get a feel for if one freq or another would have a better chance of bouncing off the steep 50-80' lake shore and going down the lake, or if nothing will work given the LOS issues. I am thinking possible CB and the ground wave potential, but I don't know how much you can get around the LOS issue. I am not going to be able to get the antenna at the cabin any higher. We will be limited to HTs on the kayaks. I had hoped to use HTs on the boat too, but I suppose I could look at an external antenna setup.

So bottom line, Given a challenging LOS (hills/valley) what option would be most likely to work? Challenging LOS (at least I think it is challenging) means that the base antenna is maybe 10' above the nearby hills, but roughly 10-15' below the elevation of hills ~ 1/4 mile away and trying to reach down to a valley/lake with a max 80' vertical elevation differential on the other side of distant hills. Again, I am not looking for 10 mile range, I just need ~3 miles. I am not sure if scattering or reflection would help get over and around and if it would be more or less likely at different freq. I had hoped for a single solution for the longer range boat as well as the shorter range kayak (waterproof HT), but if that is not possible, I might consider two setups.

In the end I know I will just have to "try it out". but given the cost and work to put up an antenna, I am trying to increase the odds of getting a working solution the first time.

Thanks

 

[ommega]

The longer the wavelength the farther the signal will go.
Horizontal is better than vertical.
More power is better.
SSB is better.
The best compromise should be a 11 meter CB hand held with a good antenna, or a shorter 2 meter Boefang duel band from Amazon with free shipping for under $40 that gives you more than 2,000 channels some that are even outside the legal band limit.

 

[endl3ss]

I don't know if this will help you at all, but it might be worth looking into.
I've made two posts about this quite a bit back, and the relevant posts are these two:

http://www.survivalistboards.com/showpost.php?p=4466346&postcount=7

http://www.survivalistboards.com/showpost.php?p=4467077&postcount=8

Short version is, you can register at this site, Radio Mobile Online. Click on the Create new account link down to the left, and then you can log in and get some analysis done.

Once you set up with an account, you just log in, and you'll see this main menu:

Once there, you need to register a new site (the position you wanna calculate coverage from). Click on "New site", and you'll see this window:

From there, you can click and move the red marker to your area, zoom in until you get more precise location for you, and then save that site as on of your sites. Once you've done that, you'll end up in the main menu again.

Then, you can start calculating your first coverage. To do that, you'll click "New Coverage", and you'll see the following screen:

Here you can select what site you wanna use to calculate from, tweak frequencies, antennas, power output, calculation distance and gain, to see what frequency you'll need to reach those areas you need to communicate with, and that will give you what type of radio you'd need.
Not the easiest and most intuitive, but if you mess around with it for a bit, you'll get an idea in the end.
Coverage analysis results will be like you can see in my two previous posts.
You could start out with ommega's suggestion, and check how those freqs work in your area.

Final disclaimer: I've used similar tools extensively, and while they're tools that will give you a good indication of how it's gonna be in real life, real life always trumps software, no two ways about it. So the propagation calculation is no guarantee.

 

[PBR Streetgang]

Do cellphones work in the area?

 

[becyn]

I vote for CB ground wave. Use a good antenna for best results.
I'd try wire dipoles cut for the CB band aimed at each other
Unfortunately NVIS is a non-starter on 11 meters. That would be what you actually need.
2 meters will be useless station to station without LOS. No problem, though, with a high altitude repeater.

 

[azrancher]

Do cellphones work in the area?

They had a cell, but we had problems getting calls to go through and being intelligible.

Nope apparently not.

Rancher

 

[radiomaster]

Cb ssb

The part of the lake we are concerned with is long, relatively narrow (as lakes go, varies between 150-300yrs wide) with steep high shore line. We boat there because it is protected from the wind for the most part, but that same protection creates LOS issues. The surrounding topology varies of course but ranges from 20-80 feet above lake level. Unfortunately our cabin is not at the top of a hill but on the side (facing our cove). What ever we do we will have an antenna on a 40' tower. That will put the antenna above any nearby hills, but right at or slightly below more distant hills between us and various parts of the lake. Of course the problem is that at the other end the lake is in a "valley" of sorts.

Use CB SSB radios. They will easily cover the kind of area you describe.
It is doubtful that UHF or VHF will work well into the valley/canyon unless you put up some type of repeater, or use a multi-element yagi beam on a high tower at the base station.

-RadioMaster

 

[Jerry D Young]

Without going Amateur, I think the best legal option is MURS, in protective waterproof bags. For emergencies, you can put together a kit for a small helium balloon to lift a copper wire up high that can be wrapped around the hand held antenna to extend the range.

http://www.gas-depot.com/products/d..._genx/105-95-cc-helium-cylinder.html?sef=hcfp

there are CB SSB handhelds, but they are few and far between, but they would work well if you can find them. Also need the water proof bag, which might be a bit difficult because of the length of the antenna. There is still some discussion if any of those that are available are actually legal on the CB band, even though they sure do work.

Just my opinion.

 

[Todjaeger]

I've been working on a similar problem, determining radio coverage and placement for a road race with intervening terrain.

Honestly I'd first start out mapping the area out, first in Google Maps to plot specific locations, and then use the National Map Viewer to get topographic data.

Link for National Map Viewer.

In some testing I've participated in, a coastal hill blocks transmissions between sections of the roadrace. Specifically two points about 3,000 ft apart, one at 7ft elevation and the other at 10 ft, are blocked using a VHF STOCS channel (like MURS but a state system) at 5w. The hill itself rises to about 88 ft elevation in a span of 1,200 feet from the water on one side, and over 1,800 ft rises up from a salt marsh (elevation 5ft) on the other side.

It doesn't appear to take much to block the RF signals. Looking at topo maps might give an area of just how 'much' hill might be in the way.

Another thing which might be worthwhile, would be to invest in a GMRS license, which can cover the entire family. Then get the endorsement for a GMRS repeater, and have that positioned somewhere to allow LOS the areas where you want radio coverage. Depending on circumstances you might have one setup in a vehicle, or possibly even up a tree, depending on location. Something to think about at least.

I personally have reservations on relying on a CB handheld, just because the antenna length is going to be only a fraction of what's really needed for effective comms.

 

[JDH]

I've been working on a similar problem, determining radio coverage and placement for a road race with intervening terrain.

What track/course?

 

[merlinfire]

2 meter ham handheld: cheap baofeng $50

5/8 wave antenna, SMA connector, and magnetic mount: $50

give you 10-20 mile range.


you can get a telescoping antenna for a handheld which will when extended give you nearly this range I believe, maybe more like 10 miles reliably. might be the thing

 

[Todjaeger]

What track/course?

Not sure the exact course this year. The road race is a 13 mile loop that runs more or less parallel to Long Island Sound in SW Connecticut. Some years it goes into a neighboring town but sticking by the beach, other years part of the loop heads inland where it starts to climb some hills that are part of a series of ridgelines.

 

[JDH]

Not sure the exact course this year. The road race is a 13 mile loop that runs more or less parallel to Long Island Sound in SW Connecticut. Some years it goes into a neighboring town but sticking by the beach, other years part of the loop heads inland where it starts to climb some hills that are part of a series of ridgelines.

That will be a challenge. I need to talk to the rally guys to see how they cover their spread out courses through the woods. GP Houston was a PITA this year. It was confined to the Astrodome parking lot. They ended up doing the Marshal post on a land line to have any type reliable communications.

 

[guy57z]

I've been working on a similar problem, determining radio coverage and placement for a road race with intervening terrain.

Honestly I'd first start out mapping the area out, first in Google Maps to plot specific locations, and then use the National Map Viewer to get topographic data.

Link for National Map Viewer.

In some testing I've participated in, a coastal hill blocks transmissions between sections of the roadrace. Specifically two points about 3,000 ft apart, one at 7ft elevation and the other at 10 ft, are blocked using a VHF STOCS channel (like MURS but a state system) at 5w. The hill itself rises to about 88 ft elevation in a span of 1,200 feet from the water on one side, and over 1,800 ft rises up from a salt marsh (elevation 5ft) on the other side.

It doesn't appear to take much to block the RF signals. Looking at topo maps might give an area of just how 'much' hill might be in the way.

Another thing which might be worthwhile, would be to invest in a GMRS license, which can cover the entire family. Then get the endorsement for a GMRS repeater, and have that positioned somewhere to allow LOS the areas where you want radio coverage. Depending on circumstances you might have one setup in a vehicle, or possibly even up a tree, depending on location. Something to think about at least.

I personally have reservations on relying on a CB handheld, just because the antenna length is going to be only a fraction of what's really needed for effective comms.

Thanks. Your numbers are helpful. I have looked at the topo in my area and I know exactly how much hill is in the way and how much it various for reaching the different areas of the lake. The problem I am having is getting a feel for how much signal loss (or total blockage) I will see due to the poor LOS. My case may not be quite as bad as yours. While my one point would also be at 7ft elevation, my other point would have an antenna at 70ft elevation with a hills of a max 85ft elevation in between.

I am still concerned that since I can not get above the highest point, VHF/UHV may be blocked.

 

[Rabt]

If you have any cell signal at all text messages of 12 charaters or less should go through. ie - RUOK, WhereRU, NeedHLP, etc. Try it.

Regarding radios the first cheapest alternative before you buy new units:

Before you abandon FRS, GMRS, try mounting frequency matched antennas on the boats. You can unplug the handheld unit from the coax when not in use. The rubber ducky antennas on the radios are pretty pizz poor.

 

[azrancher]

You may want to experiment with the Motorola i355 push to talk cell phones, they are cheap on Ebay and they may work for you right out of the box, other wise there is a thread here on making them into a repeater and adding amplifiers to the radios, these radios will work even without cell coverage.

Rancher

 

[Todjaeger]

Thanks. Your numbers are helpful. I have looked at the topo in my area and I know exactly how much hill is in the way and how much it various for reaching the different areas of the lake. The problem I am having is getting a feel for how much signal loss (or total blockage) I will see due to the poor LOS. My case may not be quite as bad as yours. While my one point would also be at 7ft elevation, my other point would have an antenna at 70ft elevation with a hills of a max 85ft elevation in between.

I am still concerned that since I can not get above the highest point, VHF/UHV may be blocked.

This might not be what you want to hear, but your problem might be able to be calculated using trig, to at least determine how much of the hill would actually be between the two antennaes. In my case, there was about 3,000 ft or so of hill. No way a VHF signal would punch through something like that.

You might get lucky if your base antenna is high enough that you might only have 100 ft to punch through, which a UHF signal might be able to manage.

Or if the angles are right, you can try reflecting a RF signal off of a hill into a canyon or valley. That might require a dish or Yagi antenna to do effectively though.

 

[jblewis007]

A lot of if's, and's and but's. CB is just too hard at the scale you need. To put a CB mobile in a canoe or on a boat would require a battery and the handhelds are just too big and unreliable, not to mention the water aspect killing the electronics. Small handheld GMRS in a water proof bag is a good idea. Get the one with the longest range possible. It's not set in stone and varies according to conditions, but a rule of thumb to go by.

 

[Sky1950]

I have a similar problem at my "farm", 65 acres in a topographic "bowl". No cell, VHF,UHF, etc, No nearby repeaters high enough to catch the signal. Eventually I will have to look into installing a repeater on my highest elevation on a 70 ft a mast. Always check the topography and repeater locations before you start planning. But my HF NVIS works great LOL