Retevis RT97S Repeater

[LeoG]

Well that was disappointing.  I went over to the shop and put the antenna on a makeshift mast, a 16' board and raised it up on the same bollard and now I can't get reception from the repeater from the same areas near my home.  I'm sure the metal building right next to the antenna has something to do with it LOL

The angle of the building does allow the signal to get to my house.  Surprising it worked better nearly on the ground. 

Coax should be coming tomorrow.  Maybe I'll get it up on the mast.

[SteveShannon]

39 minutes ago, LeoG said:

Well that was disappointing.  I went over to the shop and put the antenna on a makeshift mast, a 16' board and raised it up on the same bollard and now I can't get reception from the repeater from the same areas near my home.  I'm sure the metal building right next to the antenna has something to do with it LOL

The angle of the building does allow the signal to get to my house.  Surprising it worked better nearly on the ground. 

Coax should be coming tomorrow.  Maybe I'll get it up on the mast.

Sometimes RF from an antenna lower to the ground doesn’t have to struggle to get through as much foliage as when the antenna is raised to the same level as the thickest leaves.

[LeoG]

Well that's a reasonable explanation.  I'm going to see if I can get an extra 10' mast attached to the existing mast and get more height out of it on the roof.  Maybe I'll get 35-37' off the ground.

[WRXB215]

7 hours ago, SteveShannon said:

Sometimes RF from an antenna lower to the ground doesn’t have to struggle to get through as much foliage as when the antenna is raised to the same level as the thickest leaves.

That's my problem. I do better on the ground than on top of the house. To get above the thick part of the foliage, I'm going to have to get a lot higher than I can afford right now.

[LeoG]

Well the LMR400 came in.  Not exactly bendy is it?  Back in my CB days I was use to using RG8 which probably isn't quite as thick but close.  But at least that seemed flexible.  How small of a radius can I put on this?  Anyone care to gander a guess?  It's the real stuff, Times MIcrowaves Systems.

[Borage257]

Data sheet says 1” but I wouldn’t do less than 3” or 4”

 

https://timesmicrowave.com/documentation/lmr-400-coax-cables-datasheet/

[Davichko5650]

On 5/29/2024 at 3:54 PM, LeoG said:

I have a clothes line pole in my backyard.  The coax might be a killer.  Have to look up flagpole pricing.  The shop height is 26' to the top of the roof and I have 4-5' above that for now. 

I used our unused clothesline pole, it  was perfect for mounting a collapsible 33" Channelmaster stainless mast. Up atop that is my Comet CHA250B 80-6 meter antenna. The Pole has a 3 foot concrete base and has withstood sustained winds of 74 mph unguyed.  It was $165 well spent.  Contemplating a side arm below the 33' mark to put a GMRS antenna up for better simplex base to mobile coverage. Installation took 2 of us; my ancient self and my younger son, but was very easy to do...

[LeoG]

Well no joy for me.  I got the antenna up and it showed 1.02 for SWR while outputting 6.58 watts off the repeater.  Apparently it's still not high enough.  Signal drops off at nearly the same point as you go towards my house.  I'm still below the tree line which I assume is the main issue.  Probably work better in the winter.  I drove around and north of me is the sweet spot, 3.69 miles which was barely audible though the static.  Using the OEM antennas which aren't great, got a pair of Smiley Rubber Duck antennas coming but they won't be here for a week.  I don't think they'll make any significant difference.  It seems to be about 90% of the Nagoya 771G of what I've watched on some videos.

But likely I will take it down and put it on my house so I can use it as a local area repeater and extend the range of the HTs some.  I don't think I have a real option to get it up significantly higher.  I think in the shop area it would need to go up another 15-20 feet.  I can probably get another 2' higher with what I have.

[LeoG]

Well I took advantage of the small bit of height I could gain.  Looked to be about 16"  Who knows, maybe it'll peak over the trees  LOL.

 

That was a joke son.  I doubt it'll do anything.

 

[gortex2]

What is the leangth of the LMR400 you used ? Shorter the cable the better it will work. If you copuld mount the repeater just inside the shop 10' below the antenna I would think you would have much better results. Remember its still 3db of loss per 100' so even 50' of cable you will loose some power to the antenna. At 50' of cable you only getting about 4 watts to the antenna. 

[LeoG]

I was doing some Radio Mobile calculations and man oh man I wish.  I had to downgrade the parameters severely to get my real life results.

My real specs are 6.25 watts out, 7.2dBi gain antenna at 12 meters high, 2db loss (probably less) with a HT radio receiver with a .25uV sensitivity at a height of 1 meter.

What I had to put in to get my real life results was much different.

1 watt out from the transmitter, 7.2dBi gain antenna at 1 meter high, 2dB loss and a HT receiver with a .75uV sensitivity.

 

Either something isn't right or tree leaves really hamper the single very dramatically

 

Here is what comes out with the real specs

 

And here are the results that pretty closely resemble my results

 

Lots of trees. I put the antenna on the back building in orange.  I don't think I could get it high enough to get over the trees successfully.  Probably need a tower 60-80'

 

[gortex2]

Personally I'd focus on feedline and antenna. I dont trust dbi numbers as they are normally no where near what they list. But then again this is normal in many areas.Those that talk about 200 miles on a hand held are talking to repeaters 5000' in the air or full of doggy do. In another thread I talked about my RT97 that I installed in my motorohome. I used a FG4500 antenna on my ladder at about 12' in the air. I had 10' of LMR400 down to the repeater. From Charlotte Motor Speedway Turn 4 camping I could get about a mile south and maybe 1 1/2 north of the track to my hand helds in a vehicle. My JK Midland 15 watt radio with 1/4 wave on fender mount could go about 2 miles south but could get almost 3 miles north. Looking at the terrain in that area you would see why. UHF is line of site as you know. More power at the antenna the better, but its also a balance. Your HT needs to get back there. People think a 25 watt repeater will make there hand helds talk 20 miles and they may hear but that doesn't mean they can get back to the repeater. In the LMR world we will balance the repeater. If a customer only has 4 watt UHF radios in a warehouse we will lower the repeater power to 5 or 6 watts.  

[Borage257]

Strong signal margin is usually the value I adjust to change coverage plot. It better reflects the environmental factors than changing the more fixed variables. Your area in the summer thru foliage may have a signal margin over 20dB while in the winter it may be in the single digits. 

[LeoG]

3 hours ago, gortex2 said:

Personally I'd focus on feedline and antenna. I dont trust dbi numbers as they are normally no where near what they list. But then again this is normal in many areas.Those that talk about 200 miles on a hand held are talking to repeaters 5000' in the air or full of doggy do. In another thread I talked about my RT97 that I installed in my motorohome. I used a FG4500 antenna on my ladder at about 12' in the air. I had 10' of LMR400 down to the repeater. From Charlotte Motor Speedway Turn 4 camping I could get about a mile south and maybe 1 1/2 north of the track to my hand helds in a vehicle. My JK Midland 15 watt radio with 1/4 wave on fender mount could go about 2 miles south but could get almost 3 miles north. Looking at the terrain in that area you would see why. UHF is line of site as you know. More power at the antenna the better, but its also a balance. Your HT needs to get back there. People think a 25 watt repeater will make there hand helds talk 20 miles and they may hear but that doesn't mean they can get back to the repeater. In the LMR world we will balance the repeater. If a customer only has 4 watt UHF radios in a warehouse we will lower the repeater power to 5 or 6 watts.  

Well I have two repeaters in my area that I can reach that are on mountain tops.  One is 22 miles away and the other is 17 miles away (50 watts).  And my little 4 watt HTs with its OEM antenna reach both of them fine and I can hear myself pretty good with them.  Some static but there is a good amount of quieting.  And of course these are professional, likely commercial repeaters that costs 10s of thousands to put up.  But the HTs do reach them.

So I do really think it's foliage that is killing me off in my particular situation.  The fact that a nearly ground level antenna goes as far as my antenna up 38' likely tells you that it's getting blocked by the same things.  When I had it down on the ground I was using RG58/U and it still made it the same distance as using LMR400 with the antenna up 38'.  Both coaxes are 50' long.

[LeoG]

2 hours ago, Borage257 said:

Strong signal margin is usually the value I adjust to change coverage plot. It better reflects the environmental factors than changing the more fixed variables. Your area in the summer thru foliage may have a signal margin over 20dB while in the winter it may be in the single digits. 

I've already said that to my wife.  If I had put this up in the winter I would have gotten much better results. 

As I've said before I have a small cell phone amp/antenna system because the inside of the metal building is pretty bad for cell signals.  I have it pointed towards a telephone mounted cell tower.  They usually cover an area about a 1 mile diameter circle.  In the winter I pick up the airport cell tower, which is horrible for data because of how crowded it is.  On the order of 10-20Kb/sec down, which is slower than a telephone modem.  In the summer when the leaves get on the trees the signal from the airport is blocked much more and I pick up that pole mounted tower and my download speeds are 20-40Mb/sec down, cable speeds.  So I do know of the effects that the leaves can cause on high freq signals.  I've taken advantage of them.  But unfortunately now they are hindering my signal I assume.

[LeoG]

In this direction I was able to tag the repeater at 6.25 miles out.  Other than going through a Sheraton hotel and a small patch of trees it followed the road so fairly free from interference.

But as you can see the trees in my area are non existent in this direction.

[LeoG]

On 5/30/2024 at 4:40 PM, Borage257 said:

Data sheet says 1” but I wouldn’t do less than 3” or 4”

 

https://timesmicrowave.com/documentation/lmr-400-coax-cables-datasheet/

Bent pretty easy.  It's stiff but still flexible.  Nice stuff.

[LeoG]

OK, now I have a question.  When I set the repeater up it was at squelch level 5 and I moved it down to 3 apparently.  I was thinking about it last night when I went into the settings program and saw that default was 5.  I actually didn't realize that I had put it down to 3.

So today I put it down to 1 and low and behold I got more distance.  Makes sense because it makes it more sensitive to input levels.

Now is there a proper squelch level for a repeater?  Should I have it at zero?

 

And I tried the eliminate squelch tail function in the repeater and it did exactly that.  Killed it 100%.  But that also means I can't hear when I'm connecting by myself so I put it back to it's default off position.

Any insight on what the squelch should be set at would be helpful.

[SteveShannon]

42 minutes ago, LeoG said:

OK, now I have a question.  When I set the repeater up it was at squelch level 5 and I moved it down to 3 apparently.  I was thinking about it last night when I went into the settings program and saw that default was 5.  I actually didn't realize that I had put it down to 3.

So today I put it down to 1 and low and behold I got more distance.  Makes sense because it makes it more sensitive to input levels.

Now is there a proper squelch level for a repeater?  Should I have it at zero?

 

And I tried the eliminate squelch tail function in the repeater and it did exactly that.  Killed it 100%.  But that also means I can't hear when I'm connecting by myself so I put it back to it's default off position.

Any insight on what the squelch should be set at would be helpful.

You could set it to zero because you also have CTCSS or DTCSS, don’t you? But you’ll have a few more low level transmissions. 

[LeoG]

Right now currently I am running a CTCSS tone on my channel.  I have the repeater setup for 16 channels, really 8x2 channels and each has a different setting so when I change (while experimenting) I can see what might work better.  Currently I am on 725 and a 100Hz tone with my squelch at 1.

The basic wonder for me is if I set it to zero is there the possibility of the repeater triggering on the noise.  I expect no, because it's waiting for the tone.

And does setting the squelch give me more range because it can now "hear" my HT further out.  Not saying that my range will increase like it has more power.  I guess just saying because it's more sensitive to the input signal therefore it will respond to the weaker signal.

 

I think I've already proven it because I can tag my repeater farther out, nearer to my house.  But it still has a tough time getting down to the middle of the hill I'm on reliably.  At this point I'm sure the signal will be almost worthless full of static.  But I'm getting there and starting to understand some things I didn't know I needed to know LOL.

[SteveShannon]

1 minute ago, LeoG said:

The basic wonder for me is if I set it to zero is there the possibility of the repeater triggering on the noise.  I expect no, because it's waiting for the tone.

I agree that’s how it should work, but try it to be sure. 
As far as more range, it will now trigger on a weaker signal. You might find that it doesn’t drop the transmission or something like that. 

[LeoG]

I had a very specific spot where it stopped responding to the HT.  I perceived that as range of the repeater.  I thought it should go farther but there's those trees.  And after seeing the squelch level default it occurred to me that the squelch setting might be what is limiting me and not the transmitter power and leaves. 

I'm at the shop right now and I'm going to set it to zero and see what happens.

 

Thanks Steve

[LeoG]

No go on the Ze-ro

 

The repeater says it's transmitting but has no power output.  I can't key in with an HT.  Just sits there dead with static on the speaker of the repeater.  As soon as I set it back to 1 all is good.

So much for that experiment.  But squelch on 1 has helped significantly.  I am still going to need that antenna up higher.

[LeoG]

On the way home (of course) I thought it might work with a Digital tone instead of a frequency tone.  With white noise all tones are there all the time, so maybe it's being triggered.  I really doubt it, but it's something that can be tried.

I'm figuring that setting 1 is as good as it's going to get.  This is where digital has the disadvantage.  Whole numbers vs continuously variable with a squelch knob.  Instead of whole number 1 squelch.  If it had a knob you might be able to get away with .5 or .7 squelch in analog.

[SteveShannon]

28 minutes ago, LeoG said:

On the way home (of course) I thought it might work with a Digital tone instead of a frequency tone.  With white noise all tones are there all the time, so maybe it's being triggered.  I really doubt it, but it's something that can be tried.

I'm figuring that setting 1 is as good as it's going to get.  This is where digital has the disadvantage.  Whole numbers vs continuously variable with a squelch knob.  Instead of whole number 1 squelch.  If it had a knob you might be able to get away with .5 or .7 squelch in analog.

I don’t know much about the settings in the Retevis, but for some radios (Baofeng in particular ) the discrete squelch settings may be assigned to different levels on a wider spectrum. Randy talks about that at about the 10 minute mark in this video:

And he posts a link to an article about it here: https://www.miklor.com/COM/UV_Squelch.php

I don’t know if your repeater has a setting like that