Repeater antenna and cable advice

[WRYN359]

I'm going to be using a Retevis RT-97S on about a 25-30' collapsable pole for a repeater while camping. Since this is going to have to be at least partially disassembled when travelling, cable flexibility may be an issue due to repeated bending. I'm not going to be trying to cover a 50 mile area with this, just make it easier to hear over hills etc when we go hiking one way and the kids go biking a different way. I'm leaning towards a Tram 1486 because it seems to be cost effective and capable of doing what I want it to do (and probably more). For cable I've got my eye on Messi & Paoloni Ultraflex 10 that I can get premade with UHF connectors and seem to have no dissimilar metals. I figure a 50' section should be sufficient. I keep reading that LMR-400 is great but isn't good for repeaters due to dissimilar metals, and that for repeaters I should be going with Heliax 1/2". Since my transmitter definitely has and my antenna will likely have UHF connectors anyway, would the db savings from no adapters make up for the slightly higher db drop from the cable over such a short span (I don't see heliax UHF connectors and would probably need to do n to UHF adapters)? I also like that the M&P is stranded so (in my mind) it won't mind being coiled and uncoiled every week.

I'm open to ideas on both the antenna and cables and. I did go through the cable loss thread as well as doing several other threads here and elsewhere, but I didn't really see the M&P cables mentioned and no one was talking about the effects of need to move the antenna on a regular basis. I also don't know what I don't know, so there may be other considerations I'm missing.

[SteveShannon]

13 hours ago, WRYN359 said:

I'm going to be using a Retevis RT-97S on about a 25-30' collapsable pole for a repeater while camping. Since this is going to have to be at least partially disassembled when travelling, cable flexibility may be an issue due to repeated bending. I'm not going to be trying to cover a 50 mile area with this, just make it easier to hear over hills etc when we go hiking one way and the kids go biking a different way. I'm leaning towards a Tram 1486 because it seems to be cost effective and capable of doing what I want it to do (and probably more). For cable I've got my eye on Messi & Paoloni Ultraflex 10 that I can get premade with UHF connectors and seem to have no dissimilar metals. I figure a 50' section should be sufficient. I keep reading that LMR-400 is great but isn't good for repeaters due to dissimilar metals, and that for repeaters I should be going with Heliax 1/2". Since my transmitter definitely has and my antenna will likely have UHF connectors anyway, would the db savings from no adapters make up for the slightly higher db drop from the cable over such a short span (I don't see heliax UHF connectors and would probably need to do n to UHF adapters)? I also like that the M&P is stranded so (in my mind) it won't mind being coiled and uncoiled every week.

I'm open to ideas on both the antenna and cables and. I did go through the cable loss thread as well as doing several other threads here and elsewhere, but I didn't really see the M&P cables mentioned and no one was talking about the effects of need to move the antenna on a regular basis. I also don't know what I don't know, so there may be other considerations I'm missing.

If your mast is strong enough mount the repeater box closer to the antenna and make sure you select one of the “ultra-flex” types of cable. 
M&P is fine. Both layers of shielding are copper, unlike Times-Microwave’s LMR400 which has aluminum and copper.

[WRYZ926]

You don't need Heliax for your uses. LMR 400 Ultra Flex and similar will work just fine. And you shouldn't hurt LMR 400 Ultraflex as long as you don't loop it too tight when you are finished with it. 

[WRYN359]

17 minutes ago, Sshannon said:

If your mast is strong enough mount the repeater box closer to the antenna and make sure you select one of the “ultra-flex” types of cable. 
M&P is fine.

It won't be, and the repeater will likely be inside the camper so I can also use it as a base station and won't always need to have an HT on when the kids are out doing their thing.

[gortex2]

Howdo you use the RT97 for a base radio ? Mine only had a power plug on one side and antenna jack on other side. No mic/speaker. Maybe the new ones do. As for cable I'd just go with LMR400 with the closest leantgh you need. Remember the RT97 is only 4-5 watts at the antenna connector. The more loss you can eliminate the better. I'd focus on a way to mount it near the top of the mast with a 3' jumper to the antenna. 

[SteveShannon]

1 hour ago, gortex2 said:

Howdo you use the RT97 for a base radio ? Mine only had a power plug on one side and antenna jack on other side. No mic/speaker. Maybe the new ones do. As for cable I'd just go with LMR400 with the closest leantgh you need. Remember the RT97 is only 4-5 watts at the antenna connector. The more loss you can eliminate the better. I'd focus on a way to mount it near the top of the mast with a 3' jumper to the antenna. 

The 97S model has an extra port which can be used for an external mike or an IDer. But I absolutely agree about just mounting it to the top of the mast with a short piece of good cable.

[WRYZ926]

I have to agree that using good cable (LMR400) as short as possible.

[Pjshaw]

The Tram 1486 antenna is a good one. You might want to pick up a Tram-Browning  BR6140. It will have a higher radiation angle to get over hills.

[WRYN359]

23 hours ago, gortex2 said:

Howdo you use the RT97 for a base radio ? Mine only had a power plug on one side and antenna jack on other side. No mic/speaker. Maybe the new ones do. As for cable I'd just go with LMR400 with the closest leantgh you need. Remember the RT97 is only 4-5 watts at the antenna connector. The more loss you can eliminate the better. I'd focus on a way to mount it near the top of the mast with a 3' jumper to the antenna. 

It’s an RT97S. It has a DB-9 connection and you can buy an speaker/mic for it.

[WRQG411]

Here's my setup, works well.  I have a 25-ft piece of LMR400 and run it on my trailer batteries.

[WRYN359]

On 1/16/2024 at 3:58 PM, WRQG411 said:

Here's my setup, works well.  I have a 25-ft piece of LRM400 and run it on my trailer batteries.

Looks very similar to what I have in mind.

[WRYZ926]

I am running my Comet CA-712 with a 32 foot run of LMR400 Ultra flex. The base of my antenna is about 18 feet above ground.