GR300 UHF Help

[glideslope]

Major Issue: Range of GR300 has gone from approximately 1.5 miles to about 1000 feet using my HT750.

This repeater is by no means an ideal setup and, according to most of the users on these boards and the responses they've given to other help threads I've searched, It's probably pretty bad. However, let's understand that I'm not looking for a 30 mile range but, I am looking to understand why the repeater went from 1.5 miles to 1000 feet. This repeater is a GR300 Shell with a Motorola HLN3333B RICK, Radius M120 (xmt), D34LRA77A5DK Radius (rcvr) powered by Astron SL-14. This setup has a cheap chinese duplexer and 12 feet of RG58A/U braided coax to a Browning 450 5/8th wave antenna, the antenna sits about 30 feet up on top of a 3 story house in a rural area.


As I previously said, I know this setup is far from ideal but, was a budget repeater meant for local use. It's turned into extremely local use now and using 5w portable simplex works better. This repeater has not been used at all in the last 2 months. Yesterday, I decided to fire it up and make sure things were still working okay which, its not! I have a feeling this problem is with the Chinese duxplexer but I'm hoping its not! Whats your diagnosis?

[guy being a guy]

We have to find whats "bad" first .
Use this repeater as a base station. Go grab a mic and send a portable out in the field .
Have him start at the base of the repeater and drive away .......
Won't be long before we find the problem is TX or RX of the "base" station equipment .
Suspect TX .........Go around the duplexer on the TX side . I realise you now dont even have an RX side, but keep a portable maybe on simplex or something ........TX side fixed ?
Can you swap antennas to isolate that ,or is it too difficult ?
YOU CAN...........Take a multi meter, on DC measuring, and just HOVER ( don't touch ) the center pin of the connector going to the antenna itself...........If you have any kinda TX power coming out it will make your meter go crazy . Again ,don't touch the center connector and don't key it a whole bunch while doing it.
I suspect ( after reasoning with limited information ) that the SM120 being used for TX has no power out. The cause of its failure could be luck of the draw and bad timing, OR the antenna has high reflected power ( lots of rain in the last 2 months of inactivity ? ) Hit by lighning and you did not know ? It may have had hi refleted power since it was put in and it just now caused the TX radios PA to fail ................Hard to tell ,but hope I helped Bad TX and RX while testing then further suspects a bad antenna OR duplexer just needs to be realigned and not nessecarily "bad". To test the duplexer there really is no other way than test equipment - Sorry
YOU can, and I have done it ..............Swap ( reprogram both and swap RICK cables ) the 2 radios. Make the SM120 the RX radio and the GM300 (?) the TX radio now. Takes some doing , but have done it many times.
Don't forget narrowbanding.

[guy being a guy]

Oh yeah ........
If you suspect something on the RX side ( no antenna issues ) but RX side duplexer or radio ........Thats not very easy to shade tree troubleshoot the RX. Again easier and better with test equipment - sorry
I did however forget the power supply - you never know. Could have surged in the last two months .
14 amps is enough , but myself would have gone to 20 and been safe. The xmitter will draw about 8 amps or so - If you actually set up your multimeter and read the actual amps you risk the fuse in your meter. Some low tier multimeters can't read that. Try a car battery if you suspect the power supply to have voltage but no current . Just transmit while in line on the red 12 volt lead. No current draw also can be the PA on the TX radio is tits up

[glideslope]

Thanks for the replies. I took the tx, rx radio and rick out of the gr300 shell and connected them to my QJE 30 amp power supply. According to the power supply, when xmitting there is a 8.5amp draw and 0.7amp at rest. I setup my scanner next to another ht750 in front of th power supply lcd scrren and left a webcam on and drove around town. The repeater dropped off well before simplex did. I noticed there was no amp draw on the power supply from the repeater anymore at about 2000ft where simplex communication would still work. So, its not even keying up. That makes me think its more an antenna, coax, rx radio or duplexer issue?

[escomm]

So, its not even keying up. That makes me think its more an antenna, coax, rx radio or duplexer issue?

Sounds about right to me

[guy being a guy]

Take the antenna and connect it directly into the back of the RX radio.
Aim your webcam for the red LED on the RX radio and go for a drive. Audio off the cam would be awesome !
Good RX sens ?
Antenna and RX radio are OK then . If not, suspect antenna and do a FULL visual inspection . Ohm out the coax cable.
After seeing your post on amperage we can assume that yes indeed we have some TX power.
You need to take the duplexer to get it tuned properly. I think the tuning is off and you have desense occuring as soon as the xmitter kicks on.
You probably had this problem all along as I think not even 1.5 miles is that great for your set up.

Gonna be duplexer ( my vote ) or your antenna system .

[guy being a guy]

I guess you could even do it maybe a better way.........
Simply turn off the TX radio. This then tests the antenna, RX side of duplexer, and the RX radio !
Plenty of sensitivity and range on JUST the RX side ?

Xmitter is "desensing" the repeaters RX . Tune duplexer correctly and enjoy !

[guy being a guy]

Oh yeah ..........We have assumed that the TX and RX jumper cables to the duplexer is correct .
100% sure the RX cable goes to "High" or RX connector on dulexer and to the RX radio ?
TX is connected to "Low" or TX side and also going to the TX radio ?
These jumper cales are nice, clean , and void of Scotch tape and Elmers glue right ?

50 / 50 shot that they are simply reversed .
Unsure .........Swap cables and then go for a ride again. Won't take 15 minutes just to check .

[glideslope]

Thanks for the replies again. I'm sure the TX/RX Cables are correct. Curious if this is cause for concern as well, I turned the repeater on without actually supplying power to the RX Radio but it still powers up. I'm assuming power is carried through the RICK controller cable to the RX Radio, Is this normal? Also, I can't shut the RX radio off individually. Only if power is cut from the power supply.

[glideslope]

I've noticed the TX Radio will do a self test beep when I power up the repeater but nothing else. The RX Radio will make no noise at all. If I click the repeater enable button on the RICK and set it to disable, any radio txmit audio will come out of the TX Radio. Is this normal?

[guy being a guy]

Yeah , the power up stuff using this set up varies . I don't pay it much mind really.
It can get power thru the 16 pin connector sometimes . One radio will have audio the other won't . One speaker is disconnected , the list is long ..............
BUT ...............
Make sure the large PA connector on the RX has power on it. Use alligators clips if you have to . Simple to do and try ,as the PA on the RX radio does have some pin diodes that need power to "open" up the antenna path - I can't remeber where they get their power from, but just ensure BOTH radios have power on the large PA connector.
Did you ever test the range of just the RX side ?
However you have to configure power to JUST having the RX radio fired up and going thru the duplexer and antenna system . If the RX side is fine, then when you introduce a xmitter into the equation and it craps out ..............desense !
If the RX range proves to be bad ( no TX ) then we have a bad antenna , cable , connectors , duplexer or actual RX radio.
The "history" also tell us a lot. I assume it was a good functioning repeater ( although the 1.5 mile was pretty bad in my opinion ) and did not get used for a few months and NOW when you went to use it it sucks ?
I think the basic set up is funtional - something happened to the antenna in 2 months, AND the duplexer was really not that great from the outset.
This will tell us a LOT !!!
Any pictures would help as well.

[Will]

Warning on the R.I.C.K. setup. The dammed R.I.C.K. passes the RX radios power to the transmit radio and can burn out the RX radio's fuse on the logic board. FIX: remove the wire on pin 13 of the R.I.C.K. to TX radio cable.

[glideslope]

Warning on the R.I.C.K. setup. The dammed R.I.C.K. passes the RX radios power to the transmit radio and can burn out the RX radio's fuse on the logic board. FIX: remove the wire on pin 13 of the R.I.C.K. to TX radio cable.

I'll do this once I'm back at home in front of the repeater. Are you aware a burnt fuse causing any of these other issues?

[glideslope]

I tried searching batlabs but can't find a picture of the cable end that shows which pins are which, would anyone have that?

[Will]

I tried searching batlabs but can't find a picture of the cable end that shows which pins are which, would anyone have that?

Look here: http://batlabs.com/images/maxacc.gif

[glideslope]

I removed PIN 13 from the RICK to TX cable, both sides of the cable however, the RX radio is still powered without being plugged in.



I find it odd that I can turn the TX Radio on or off using the power&volume knob. Also, the radio makes its own self test noise when its turned on. However, the RX Radio cannot be turned off unless the RICK is unpowered.



I'm lost with this setup.

[Will]

"However, the RX Radio cannot be turned off unless the RICK is unpowered."

The R.I.C.K. should only get it's power from the RX radio on pin 13. The RX radio gets it's power from the two pin power connector and that goes thru the on-off switch in the radio out on pin 13. We use a two amp fuse for the RX radio power cable.

Check the RX radio with it connected to the R.I.C.K. The TX radio disconnected. Does the on-off switch work?

GM300 series accy connector: http://batlabs.com/images/gmacc16.gif

[glideslope]

With the RX Radio connect to the Astron PS and the RX Cable from the RX to RICK. Yes, the on off switch works.

[Will]

With the RX Radio connect to the Astron PS and the RX Cable from the RX to RICK. Yes, the on off switch works.

Does the R.I.C.K. turn on and off with the RX radio? From what you posted I think it does.

Some quirky things happen in the R.I.C.K. boxes. What I do is to remove the unused pins and wires in the R.I.C.K. to radio cables.

So only pins 7, 9, 2 and 3 are used in the TX radio cable.

And only pins 7, 9, 8, 11 and 13 get used in the RX radio cable.

And pins 7 and 9 are actually tied together in the R.I.C.K.

If you want the speaker in the radio, jumper pins 15 and 16 at the radio end.

[glideslope]

Thanks! I'm thinking of just getting the IDM2 (AE) CWID Repeater Controller from mre1032 on eBay. Think this is a better solution for a simple GMRS Repeater? I've had a lot of issues with this GR300 setup and I just don't have enough knowledge to keep up with it.