Premium coax

[kmartin]

I need to know what kind of premium 50 ohm coax i can use for my outdoor yagi antenna. I will be running if through the slide out on my travel trailer. I was currently using RG66 quad shield but i am ready to invest in a premium outdoor cable. Something that is close to the same diameter or smaller because of slide out. I will be running about 50 ft. I monitor frequencies in the 700 and 800 MHz range
Any suggestions ?

 

[kmartin]

I meant i was using RG6 not RG66

 

[trentbob]

A popular coax is lmr400. You're only receiving. It is thick and if bent can break but just use the jumper coming into the house. Good low loss coax for 7 - 800 megahertz and 50 feed is not that long of a run.

 

[kmartin]

Thanks Trentbob. I was worried about the cable breaking when i close the slide out. I would like to keep it one piece without any patch or jumpers

 

[prcguy]

Why such a long run in a travel trailer? 50ft of LMR400 is close to 2dB loss at 800MHz and that's getting to be excessive. Any way to change the coax route to shorten it?

Thanks Trentbob. I was worried about the cable breaking when i close the slide out. I would like to keep it one piece without any patch or jumpers

 

[trentbob]

I can certainly understand that but usually a 3 foot jumper isn't going to make that much difference but definitely keeping it all in one piece is the way to go. I'm sure you're going to get other suggestions here also, it's a very effective coax for me. You can coil it, you just don't want to bend it. It also holds up well to the weather. I use coax – seal to weatherproof the connections. Be sure to apply tape first before molding the sealant around the connections and it'll make it easy to remove instead of having a goopy mess.

 

[kmartin]

Why such a long run in a travel trailer? 50ft of LMR400 is close to 2dB loss at 800MHz and that's getting to be excessive. Any way to change the coax route to shorten it?

My antenna is 30ft high using top rail fence sections. These sections are mounted to a sturdy 10ft wooden deck post 10 feet from my trailer. And then after running it through slide out and to the location of my radio radio is about 45 ft

 

[kmartin]

I can certainly understand that but usually a 3 foot jumper isn't going to make that much difference but definitely keeping it all in one piece is the way to go. I'm sure you're going to get other suggestions here also, it's a very effective coax for me. You can coil it, you just don't want to bend it. It also holds up well to the weather. I use coax – seal to weatherproof the connections. Be sure to apply tape first before molding the sealant around the connections and it'll make it easy to remove instead of having a goopy mess.

Ok. Thanks for that info. I'm wondering if if the a quality 50 0hm cable would make that much difference compared to using RG6 quad shield cable ?

 

[trentbob]

I think it's really close LOL

 

[prcguy]

You would have a little less loss with LMR400 and it might take a little static out of weaker signals.

Ok. Thanks for that info. I'm wondering if if the a quality 50 0hm cable would make that much difference compared to using RG6 quad shield cable ?

 

[kmartin]

I thank you for all you're help good information

 

[JoshuaHufford]

If you can't get anything larger than RG-6 through your slide out I would run as much as possible with at least LMR-400, or possibly something larger in the "UltraFlex" option, then have a short run of LMR-240 to get inside your camper. I know you want to avoid adapters but that is what I would do.

Another possible option is to have a preamp at the antenna, then you could get by with smaller coax for the entire run.

 

[jcop225]

If you actually want premium at that approximate size there is Commscope FSJ1-50 or LDF1-50 (depending on the bending radius you need)

Best practical cable at that size is LMR-240 as others have stated.

 

[Ubbe]

It's probably not worth the cost and work to replace a RG6 with LMR400.

RG6 has 3dB attenuation at 900MHz and LMR400 has 2dB at a 50ft lenght and LMR400 are thicker and not as flexible as RG6.
If you want zero attenuation you can put a $25 low noise amplifier at the antenna and a 10dB-15dB attenuator at the receiver.

/Ubbe

 

[JoshuaHufford]

It's probably not worth the cost and work to replace a RG6 with LMR400.

RG6 has 3dB attenuation at 900MHz and LMR400 has 2dB at a 50ft lenght and LMR400 are thicker and not as flexible as RG6.
If you want zero attenuation you can put a $25 low noise amplifier at the antenna and a 10dB-15dB attenuator at the receiver.

/Ubbe

Do you know why the Times Microwave coax loss calculator shows 4.9db loss for RG6 at 900MHz on a 50Ft. run?

Coaxial Cable Attenuation and Power Handling Calculator | Times Microwave Systems

Calculate the attenuation and power handling capability of coaxial cables using the online calculator by Times Microwave Systems. Choose from a variety of cables and get started now!

www.timesmicrowave.com

 

[mmckenna]

Do you know why the Times Microwave coax loss calculator shows 4.9db loss for RG6 at 900MHz on a 50Ft. run?

Coaxial Cable Attenuation and Power Handling Calculator | Times Microwave Systems

Calculate the attenuation and power handling capability of coaxial cables using the online calculator by Times Microwave Systems. Choose from a variety of cables and get started now!

www.timesmicrowave.com

There are different grades of RG-6. RG-6 is a military specification, but individual manufacturers can adjust it a bit. Depends on a number of variables.
If you trust a specific manufacturer, you can look up the specs on their website. If it's some no-name Chinese brand, I'd take their "specifications" with a grain of salt.

 

[JoshuaHufford]

So is it safe to say we can't assume that the OP currently only has 3db of loss with his current setup?

 

[mmckenna]

So is it safe to say we can't assume that the OP currently only has 3db of loss with his current setup?

One should never assume.

RG-6 is a general specification for a type of coax. The individual manufacturers can use different materials, designs, etc. So, using X dB per foot might get close to what the reality is, but it's unlikely to be exact. Then figure in coaxial connectors, how many, adapters, how carefully the connectors were installed, and all the other variables.

We can assume there is some loss. We don't know how much unless one was to know the specifics.

Same goes for LMR-400. If it's true Times-Microwave LMR-400, then we know what the loss per foot is. But there are a number of companies that produce "LMR equivalent" cables where the specifics can vary. And again, connectors, skill at which they were installed, adapters, etc. It's all variables.

What matters is the end user can receive what they want to receive. Better coax, higher gain antennas, amplifiers, higher sensitivity receivers, it's all things that can improve performance.