Retevis RT97S Repeater

[Borage257]

Might be good to enable a river beep on the repeater for your testing. I’d leave the squelch on 1. Get some friend (or family) to help you test various ranges too

[LeoG]

The Retevis software is pretty basic.  Squelch settings include going from 0-9 and that's it.

[LeoG]

39 minutes ago, Borage257 said:

Might be good to enable a river beep on the repeater for your testing. I’d leave the squelch on 1. Get some friend (or family) to help you test various ranges too

Ya, if there was a beep I would have engaged it.  But nothing of the sort unfortunately.  Thanks for the suggestion anyway.

[LeoG]

The only difference between the tone and the digital was the digital didn't pretend to transmit.  But with either activated and zero squelch it wouldn't receive a signal and re-transmit it.  So squelch level 1 it is.

[yqtszhj]

Good topic you started Leo. I’m working on a similar setup as you. I tested mine with my base station antenna that’s up in the attic and get 4 to 6 miles with my mobile and 3 to 4 with a handheld. That will cover the little town I live in. I plan on a solar panel and a battery for power eventually.
 

Im hoping to get my mast up next week if ups can ever get it here. I’m going the flag pole route (with an extension) since I live in a neighborhood. Should get me to 40 feet. That was some inspirational pictures posted here. I’m at about 250 ft. elevation and the town is below me about 60 ft so adding 40 more feet may help. We will see if it does.

With my base station and attic antenna I can get 15 miles easy at 50 watts to my mobile but need something for when I’m not sitting at the radio desk and in the car. I figure the repeater will allow 2 HT’s to talk when they normally wouldn’t be able to due to obstacles. So far, so good.

[LeoG]

Well I plan on doing a testing phase since I think the trees are killing my signal.  It rained and the distance after the rain ended was really reduced.  Thinking all the water hanging on the leaves.

So I am going to take some 16 ft 2x4s and join them together to get 48 ft off the ground.  And if that doesn't clear it I'll add another 16 ft to that.  And if that doesn't work the repeater system will go to the house and just be local for me and my family.  I got permission from my landlord at the shop to put up a 50 ft mast if I wanted to.  Concrete pad and then attached to the building near the peak and another 24' free standing if the specs say it'll work.  It's something similar to one of the Rohn tower parts.  10' tower pcs put together to reach to the sky.  If it needs to be guyed then that's out too.

[LeoG]

OK, I seem to have an issue.  After I lowered the squelch to 1 and had much better results we had a rain storm.  No lighting or anything like that, just rain.  My SWR stayed the same.  The power output from the repeater went from 6.4 watts to 7.8 watts.  The distance I was able to achieve dropped dramatically.  Down to something like 1/4 mile, even in the direction with no trees which I had about 5+ miles.

Any guess to what might be going on here?  The antenna has a SO239 connector as well as its mate on the LMR400 coax.  The MA-09 antenna has an aluminum tube that covers the connectors/connection and I would say it would protect it from rain.  Was there something I should have done to seal the connection?

[Borage257]

Check out this video on sealing coax connections. 

I have found Temflex Rubber splicing tape with a layer of electrical tape over top to work well.

3M 3/4 in. x 22 ft. Temflex Splicing Tape, Gray 2155 - The Home Depot

Generally more atmospheric moisture/humidity can cut signal range as much of it can be absorbed by the water. Alot of guys in my area see some degree of signal drop during and after rains as the pines pull the water into the needles. 

[LeoG]

1 hour ago, Borage257 said:

Check out this video on sealing coax connections. 

I have found Temflex Rubber splicing tape with a layer of electrical tape over top to work well.

3M 3/4 in. x 22 ft. Temflex Splicing Tape, Gray 2155 - The Home Depot

Generally more atmospheric moisture/humidity can cut signal range as much of it can be absorbed by the water. Alot of guys in my area see some degree of signal drop during and after rains as the pines pull the water into the needles. 

Well it's been the weekend and the problem still persisted.  When it was raining I was doing some testing and the signal waned.  I expected it.  After it stopped I wasn't sure what to expect because all those trees in my way now had wet leaves.  But I came back from visiting my grandkids over the weekend and the problem still existed.  In my CB days I never sealed the fittings.  And I know CB and UHF are drastically different.  So I'm just running on antiquated knowledge.

[WRPQ991]

just my $0.02  maybe the rain helped ground your mast? Or the wet ground acted as a ground plane?  I have a chimney mounted Nagoya I had some welding cable I used for a ground, overkill but it's what I had.

[LeoG]

So it made my performance much worse?  Right now I don't have a physical ground.  It's a metal building, metal mast with a metal support.  Not sure if the side of the building actually has ground contact in any manor but I'm betting it does.

I was using the ground plane as my ground until I get the setup permanent at which point the system was going to get it's true ground.

[SteveShannon]

2 hours ago, LeoG said:

Well it's been the weekend and the problem still persisted.  When it was raining I was doing some testing and the signal waned.  I expected it.  After it stopped I wasn't sure what to expect because all those trees in my way now had wet leaves.  But I came back from visiting my grandkids over the weekend and the problem still existed.  In my CB days I never sealed the fittings.  And I know CB and UHF are drastically different.  So I'm just running on antiquated knowledge.

CB is HF and much, much, much less affected by atmospheric moisture than UHF. 
The tube at the bottom of your antenna that surrounds the connection should have provided a measure of protection. 
PL-259 connectors are not waterproof so rain can get into your coax cable dielectric.  Once it does, the only thing you can do is cut off the end of the cable to get rid of the portion of cable that moisture has infiltrated. The cables used “in the CB days” were a completely different type and perhaps didn’t allow moisture to enter the dielectric or the lower frequencies weren’t affected as much by moisture. 
The radials on your antenna serve as the ground plane. Having the mast grounded should have no effect on RF, but is helpful to reduce interference and protect against static electricity. 

[LeoG]

All of what you said are how I've based my thoughts, back from my knowledge of installing CB stuff.  Other than not realizing the RG8 cable was more waterproof than the LMR400.  I expected quite a bit of protection from the tube.  I made sure the coax was centered and had no contact with the tube also.  I thought it would be very difficult for water to actually get into the fittings with the setup they provided.  I thought maybe air moisture might be able to get in there eventually but not physical rain getting into the connector itself.

As for grounding my thought was it's mainly for lighting/static protection and not really an antenna ground.  That the ground plane provided what the antenna needed to function properly.

[LeoG]

If I were to take a resistance reading on the coax with the antenna connected I assume it should read open, of course disconnected from the repeater. 

Not exactly much I can do from the ground.  And access to the antenna is difficult right now being up there.  But I have a feeling if this persists it's going to have to come down to be inspected.  At that point I'll put my power meter terminated with a dummy load at the end of the run to see what's actually getting there.

[LeoG]

Well, this isn't encouraging.  I checked the resistance and it bounced a lot but more or less settled at around 10 ohms.  Checked my mobile and it's open circuit.  The cable was acting like a capacitor to a point sweeping up and then down to settle at 8.9 ohms.  That sounds like the resistance of 50' of wire to me.  Wish I had an old fashion analog meter with a needle.

[SteveShannon]

1 hour ago, LeoG said:

If I were to take a resistance reading on the coax with the antenna connected I assume it should read open, of course disconnected from the repeater. 

Not exactly much I can do from the ground.  And access to the antenna is difficult right now being up there.  But I have a feeling if this persists it's going to have to come down to be inspected.  At that point I'll put my power meter terminated with a dummy load at the end of the run to see what's actually getting there.

Yes, measuring resistance should indicate open with no antenna, but I assume you’re using a multimeter which only measures DC resistance. With an antenna like a j-pole you would see a dead short at DC.
The problems you’re experiencing are with ultra high frequency AC. A multimeter is useful to detect an electrical short, but really won’t tell you much about problems that appear at UHF. For that you need an antenna analyzer or VNA. 

[LeoG]

Ya, I know.  Just doing what I can with what I have.  No idea on how the MA-09 is setup and I really have no idea if it's a J pole style antenna or not.  It definitely looks like a short as I am reading resistance that looks to belong to 50' of wire.  But it's also not really steady, jumps around a bit - there is wind out there.

So I guess this means I'm back to square one, not knowing a darn thing LOL.

[SteveShannon]

10 minutes ago, LeoG said:

Ya, I know.  Just doing what I can with what I have.  No idea on how the MA-09 is setup and I really have no idea if it's a J pole style antenna or not.  It definitely looks like a short as I am reading resistance that looks to belong to 50' of wire.  But it's also not really steady, jumps around a bit - there is wind out there.

So I guess this means I'm back to square one, not knowing a darn thing LOL.

Do you have a different piece of coax to try?  

[LeoG]

Well, ya I do.  But it's the RG58/U cable they sent with the kit.  Pretty lossy stuff.

Were you going to suggest hooking that up bypassing the LRM400?  Or something else?

Because that would entail taking the antenna down which is something that is quite the chore.

[SteveShannon]

9 minutes ago, LeoG said:

Well, ya I do.  But it's the RG58/U cable they sent with the kit.  Pretty lossy stuff.

Were you going to suggest hooking that up bypassing the LRM400?  Or something else?

Because that would entail taking the antenna down which is something that is quite the chore.

First, see if that piece of cable acts the same way when you hook up to it with your meter. 
If it doesn’t, then yes, you’re going to have to take down your antenna so you can diagnose the problem. Right now you don’t know if the problem is with your antenna or the feed line. 
Or decide it’s not enough to worry about and leave it alone. 

[SteveShannon]

35 minutes ago, LeoG said:

Ya, I know.  Just doing what I can with what I have.  No idea on how the MA-09 is setup and I really have no idea if it's a J pole style antenna or not.  It definitely looks like a short as I am reading resistance that looks to belong to 50' of wire.  But it's also not really steady, jumps around a bit - there is wind out there.

So I guess this means I'm back to square one, not knowing a darn thing LOL.

It’s definitely not a j-pole, but it might have some coils and capacitors that could look like a DC short. 
Or you might just have a loose fitting that’s giving you problems with the wind. 

[LeoG]

It essentially doesn't work.  I can get 1/4 mile out.  I can get a mile and a half with the HTs with 4" antennas going through a forest and a highway embankment.  So I think their just might be a slight problem.....LOL

[LeoG]

Measured the cable with no antenna and it's a total open, which it should be.  Ya, I think it's gonna have to come down.  Maybe I'll email Retevis and see what they have to say about how their antenna might react to a dc ohm test and other such related questions.  Because after doing the 1.5 mile test with the HTs, I don't think this has been working right since the beginning.

[LeoG]

OK, played some games.  Went home and gave the wife an HT.  Came back to the shop and used the microphone on the repeater to transmit out.  I was able to get to her, barely.  Probably 5% quieting but she could understand what I said.

Now I'm wondering... if the duplexer has slipped.  When I got the repeater I did a dummy load test on it and it was 6.4 watts, same thing on the antenna +/-.  Now it's saying 8.5 watts into the dummy load and 7.8 watts into the antenna.

With the tiny duplexer this thing has there's no way it's doing 85% pass through into the dummy load.  That's why it says it's a 10 watt transmitter with 5 watts out from the duplexer.

And so I'm getting more wattage out but my reception is very limited (?).  It's still set on Squelch of 1 but I'm not able to receive the HTs from anywhere near as far as I was before, nearly to my house.  Now I can only activate the repeater about 1/4 mile away from it using an HT.

 

It's a real befuddler.

[SteveShannon]

6 minutes ago, LeoG said:

OK, played some games.  Went home and gave the wife an HT.  Came back to the shop and used the microphone on the repeater to transmit out.  I was able to get to her, barely.  Probably 5% quieting but she could understand what I said.

Now I'm wondering... if the duplexer has slipped.  When I got the repeater I did a dummy load test on it and it was 6.4 watts, same thing on the antenna +/-.  Now it's saying 8.5 watts into the dummy load and 7.8 watts into the antenna.

With the tiny duplexer this thing has there's no way it's doing 85% pass through into the dummy load.  That's why it says it's a 10 watt transmitter with 5 watts out from the duplexer.

And so I'm getting more wattage out but my reception is very limited (?).  It's still set on Squelch of 1 but I'm not able to receive the HTs from anywhere near as far as I was before, nearly to my house.  Now I can only activate the repeater about 1/4 mile away from it using an HT.

 

It's a real befuddler.

I doubt that the duplexer has slipped, but that is confusing. 
It should be easy enough to check the duplexer. Bypass it and have your wife transmit from the HT.  How does it work on receiving with the duplexer bypassed? If you don’t want to fiddle around with the connections to the duplexer I understand.

Try hooking a handheld to your MA-09 to see if the antenna works any better.