Need to rework all jumpers at repeater site. What cable would be the best fit for my situation

[vsp5151]

Our amateur repeater site was constructed using left over cables because we had little money. It is not pretty. Yes we had connector issues over the years. We now want to update all the internal jumper cables. We have a 2M Quantro, 2M Quantar, 440 Quantar and a spare, GMRS repeater and a 220 repeater and associated duplexers. I would like to purchase a roll of small flexible cable and replace all the jumpers over a period of time. Most of the cables will be Type N male on each end but a few will need PL-259 connectors. I will also buy the tool to prep the cable along with the proper crimping tool. None of the cables will get wet. I don't want to use any adapters so I anticipate using right angle connectors. Again 1 type cable for everything. I have an account with TESSCO so I can use them as a supplier. All entrance cables come to a polyphaser in a water proof cabinet all my connections will start from there. I was a radio technician for 50 years but have been out of the business and am not familiar with the newer cable and connectors.

 

[cavmedic]

Our amateur repeater site was constructed using left over cables because we had little money. It is not pretty. Yes we had connector issues over the years. We now want to update all the internal jumper cables. We have a 2M Quantro, 2M Quantar, 440 Quantar and a spare, GMRS repeater and a 220 repeater and associated duplexers. I would like to purchase a roll of small flexible cable and replace all the jumpers over a period of time. Most of the cables will be Type N male on each end but a few will need PL-259 connectors. I will also buy the tool to prep the cable along with the proper crimping tool. None of the cables will get wet. I don't want to use any adapters so I anticipate using right angle connectors. Again 1 type cable for everything. I have an account with TESSCO so I can use them as a supplier. All entrance cables come to a polyphaser in a water proof cabinet all my connections will start from there. I was a radio technician for 50 years but have been out of the business and am not familiar with the newer cable and connectors.

RG400 for or 3/8 hardline is probably a good start for your jumpers between filters and equipment in the rack. Possibly 1/2” hardline for longer runs between the poly phasers and duplexers.

 

[Project25_MASTR]

I've always worried about long term the applicability of a .195" coax on the transmit side of a Quantar since the VHF/UHF models are rated at 125W. I'd probably go with something like a .240" diameter coax at a minimum.

If limiting to a single coax type, I'd run LMR-240-UF between the repeaters and filters. On combined antenna ports I would use the PIM rated variant. If not limiting, RG-214 on the transmit side, RG-179 for RX. Of course, you could go to 3/8" Superflex but unless you are really trying to ink every last dB of savings the price of the connectors is difficult to justify.

 

[prcguy]

RG-142 dual shield silver plated with teflon dielectric has been a standard for many duplexer mfrs and will handle more power than you can come up with. Silver plated or low PIM connectors are cheap and easy to install. However you can use lower loss but high PM coax like LMR400 on the non duplex paths like transmitter or receiver to duplexer and between filters on a non duplex path. The Times EZ series connectors are a dream to install using the Times prep tool.

 

[jcop225]

How long is the run from your duplexers to your surge protection? If it is 10' or more I would start to question the wisdom of sticking with one type of cable.

RG-142 is a no-brainer for everything within the rack but I would want something corrugated from the duplexers to the SPDs if longer than a few feet to avoid the loss. You can usually find pre-made assemblies for standard lengths.

If you're insistent on a single cable type for everything, a 1/4" flexible corrugated cable like Commscope FSJ1-50 would be the best compromise.

I'd avoid any LMR, sure you can get away with it in certain places in a repeater system but it's not a good look especially if it is a shared site.

 

[prcguy]

How long is the run from your duplexers to your surge protection? If it is 10' or more I would start to question the wisdom of sticking with one type of cable.

RG-142 is a no-brainer for everything within the rack but I would want something corrugated from the duplexers to the SPDs if longer than a few feet to avoid the loss. You can usually find pre-made assemblies for standard lengths.

If you're insistent on a single cable type for everything, a 1/4" flexible corrugated cable like Commscope FSJ1-50 would be the best compromise.

I'd avoid any LMR, sure you can get away with it in certain places in a repeater system but it's not a good look especially if it is a shared site.

I would try and limit the length of RG-142 runs to about 4ft at VHF and 2ft at UHF. Same for RG-214. For longer runs between duplexer and lightning protection, etc, inside the building I like 1/2” Superflex Heliax jumpers. You can sometimes get those very cheap on eBay or ham swapmeets.

 

[vsp5151]

My shortest runs from surge protection to the duplexers 5 feet. Some radios in the next rack will be about 8 feet. 8 feet is the longest run. I had no plans to replace duplexer cables. Thanks for all the replies. There is a lot of good information there.

 

[kb5udf]

I feel the need to revive this thread. Working on a ham 70cm repeater project. I will probably need to make up a harness for the Duplexer.
I understand the need for half wavelengths in that context. We will use at least 1/2 inch hardline to the antenna (it will be a rather short run), but for the jumpers to and from the repeater and in the duplexer harness, is LMR240 double shield appropriate? I ask b/c at uhf frequencies, I would prefer the apparently lower loss over RG142.

 

[jcop225]

The jumpers from the repeater to the duplexer are generally considered short enough that the loss of RG-142 is acceptable. If you are particularly concerned about loss in your jumpers you could use a 1/4" corrugated cable such as FSJ1-50 as suggested above. There should be enough reading both on this forum and other places on why you should not be using LMR-240 or any other non-silver covered braided cable for a repeater if you are looking for an explanation.

 

[kb5udf]

10 4. thanks.

 

[TurboTony]

You shouldn’t use LMR for any repeater stuff. The dissimilar metals will cause issues.

 

[mmckenna]

The RG-142 is the right stuff. There isn't enough length in the jumpers to make any noticeable difference between that and LMR-240 anyway. The superflex heliax might be a good option, but again, I doubt you'd notice any real difference in performance.

 

[prcguy]

You shouldn’t use LMR for any repeater stuff. The dissimilar metals will cause issues.

LMR is fine in the receive only or transmit only path. Its to be avoided in any full duplex path that includes a transmitter. If the OP has any ham radio swap meets in his area there can be really good deals on new factory RF cables. At Dayton the last couple of years people were selling various length FSJ4-50A 1/2" superflex Heliax jumbers for $10 each and tons of very expensive 18GHz rated jumper cables for as little as $2 per cable. I've bought many perfect and new RF cables at my local ham swap meet very cheap.