Help With Repeater

[speedway_navigator]

All good advice. Also consider the short jumper cable between the repeater receiver and the duplexer should be a double-shielded silver-plated cable with silver plated connectors. This cable is the most important when using a duplexer, as it reduces the likelihood of any RF from your transmitter leaking into the receiver and causing desense. Some quality RG cable types for jumpers are 214 ,142, 223, 400.

I had a piece of RG142 on a duplexer cause intermod at a Bearcom event. When I setup my duplexer with 4 repeaters on a combiner it tested fine on the Bearcom channel but a few minutes later 2 different users were on at the same time and it sounded like crap. I wiggled each one as I was TXing and found it.

This was before VNA days and I didn't bother to test the cables because 'they worked fine in the shop' before they shipped.
I tell techs who service mobile repeater trailers to watch for vibration damage, we tend to make too may assumptions it will work this time because it did last time.

 

[prcguy]

I had a piece of RG142 on a duplexer cause intermod at a Bearcom event. When I setup my duplexer with 4 repeaters on a combiner it tested fine on the Bearcom channel but a few minutes later 2 different users were on at the same time and it sounded like crap. I wiggled each one as I was TXing and found it.

This was before VNA days and I didn't bother to test the cables because 'they worked fine in the shop' before they shipped.
I tell techs who service mobile repeater trailers to watch for vibration damage, we tend to make too may assumptions it will work this time because it did last time.

The key point here is Bearcom, who is to say the combiner was tuned properly or even had isolators.

 

[freddaniel]

I also exclusively use crimp connectors and attempt to pull them off after the crimp. This is to make sure they do not fail later. I use American Made crimpers as I have had trouble with crimpers from China.

 

[ramal121]

And I have seen this more than I'd like, does anyone check to see if the center pin is seated properly before crimping? C'mon.

 

[speedway_navigator]

I bought some N connectors from Lcomm and didn't realize their center pins have a ring at the end. I mis-crimped the first one because I assumed it was the same diameter all the way and crimped the ring which crunched it, it would not fit in the connector.

 

[freddaniel]

SILVER-PLATED Type-N connectors for RG-214 are RFN-1006-3F and Type-N connectors for RG-55, 142, 223, 400 are RFN-1005-3C1 made by RF Industries for about $5.25 each. Search Google for best prices. The least expensive double-shielded silver-plated cable is RG-223

​

 

[dickie757]

@freddaniel Your info is accurate and useful, but in this case they're trying to get the transmission line away from the type that needs crimp type connectors. They are trying to get em to use a hardline feedline that has a solid copper shield, instead of foil and mesh. That type of feedline uses a different connector with gaskets and compression flares. When assembled, the outer plastic jacket is just a protector, not a real part of the cable. In the case of crimp type, the jacket, while not part of the radio system, is very important. It keeps moisture and water away from the foil/braid/mesh. The hardline is corrugated solid copper, therefore, waterproof.

 

[speedway_navigator]

I used RFS connectors on half and 7/8" for some VA hospital projects, got really good return loss readings with them.

 

[tlemke940]

the reason why it is not recommended to use LMR on a repeater is its PIM rating as as compared to the better PIM rating of RG and HELIAX cables. it is not as bad on a single repeater but when you start moving up into multi repeater systems and multi radio sites you want the better cable and it DOSE help on even a single repeater system.

just FYI once you start going down the rabbit hole of PIM you start looking at your whole repeater system in a new light. if anyone has taken a PIM class you know what i mean.