High quality RG6? High frequency RG6?

[seans1212]

After reading a lot about how RG6 can be used for a scanner feed, I was wondering if there are different versions or quality levels of RG6 in terms of loss as well as upper-frequency range.

After many years of building my own scanner antennas, I am about to upgrade to a ScanKing royal discone, possibly an LNA to compensate for the 30 meters of RG6.

I scan anything really but mainly Air/Mil air but would like to scan up to 6GHz if possible. I know the discone mentioned does not cover those frequencies, but I may try some UWB directional TEM antenna and an 18GHz antenna relay to see what I can pick up.
Currently, I am running about 25 meters of RG213U which 'almost' is very similar to RG6, to a DIY air/mil air antenna and seem to be fairly deaf at above 2.5GHz.

Your input would be appreciated.

 

[prcguy]

I've tested coax for the largest direct to home satellite company in the US and helped specify what they used. Some of the better RG-6 will be advertised as "3GHz swept" meaning they connected a TDR or other instrument to the entire roll of coax and tested it. For the satellite industry we specified 3GHz swept and solid copper center conductor over copper plated steel because satellite systems have DC power on the coax and you can run out of power before your run out of signal on long runs.

There are also dual, triple and quad shield types which are used when lots of cables are bundled tightly together and leakage between cables is a problem. The loss specifications are the same for dual, triple or quad shield and there is no advantage to using it for single satellite runs or for scanner use.

There are lots of brands to choose from with Belden and Commscope being two of the larger US companies. For scanner use you probably won't notice any difference using the cheapest brand out there except for maybe the outer sheath breaking down a little faster in the sun.

 

[gtaman]

PPC perfect flex tri shield is the easiest. You can spend the money on BNC compression fittings or just use normal PPC fittings and F to BNC adaptors.

I use RG-58 but it’s a very special and expensive cable which is Beldon 9167. I have a large quantity so I use it often.

Any good RG6 will work even the Southwire Trishield from Lowes is excellent.

Quad shield is a bit thicker but if you have the right fittings they slide on nicely.

 

[seans1212]

Thank you both for your inputs

I am presuming the cheapest RG6 is not tested to 3GHz, but is there much of a difference for a scanner, would it still feed high frequency down, in which case that would be the easiest to find here in the UK.

 

[W4EMS]

Used a 40 foot run quad shield for a scanner with no problem on 700/800.

 

[seans1212]

Thanks, but are there any specific part numbers for the quad shield or the 3GHz version of RG6 or do you just have to take the seller's word for it?

 

[seans1212]

I came across a post, I am guessing this is what they are called; RG-6U & RG-6 Quad.
Thanks again

 

[prcguy]

Just search for RG6 3GHz and you will find various brands. Why do you want quad shield?

Thanks, but are there any specific part numbers for the quad shield or the 3GHz version of RG6 or do you just have to take the seller's word for it?

 

[gtaman]

Any PPC/Beldon/Commscope brand. PPC Perfect Flex 77 tri cable is used all over the world and in the UK.
It does not have to say Swept up to 3Ghz. That just means that they swept the cable and verified the length/loss matches at certain points up to 3Ghz.
The PPC cable will easily do 3Ghz.

 

[seans1212]

Just search for RG6 3GHz and you will find various brands. Why do you want quad shield?

Will do. message #5 mentioned they use quad shield. I am not running my cable next to any other or through any noisy area, so not strictly necessary.

 

[seans1212]

Will have a search around, thanks.

 

[Ubbe]

As a quad shield are more expensive they usually put more care also to the center lead, and you can often see that those coaxes has less attenuation, but it probably doesn't matter at lower frequencies than a sat dish's 2-3GHz.

/Ubbe

 

[prcguy]

I've tested most brands of RG6 and there is no difference in loss over single vs quad shield. There can be a slight difference in loss between brands but not between their different shielded products. The only place you might need multi shield is with L-band signals and tightly bundled cables where cable leakage is worse at 2GHz vs 500MHz.

As a quad shield are more expensive they usually put more care also to the center lead, and you can often see that those coaxes has less attenuation, but it probably doesn't matter at lower frequencies than a sat dish's 2-3GHz.

/Ubbe

 

[gtaman]

RG6 is 6 dBmV loss per 150ft at 600Mhz.

 

[seans1212]

I've tested most brands of RG6 and there is no difference in loss over single vs quad shield. There can be a slight difference in loss between brands but not between their different shielded products. The only place you might need multi-shield is with L-band signals and tightly bundled cables where cable leakage is worse at 2GHz vs 500MHz.

I am not so much worried about shielding as I think whatever shielding RG6 comes with is good enough for my environment. I am, however, interested to get a cable that has a higher freq handling, 3GHz is good enough and the reason is I want to see if I can receive anything around 5.6-6GHz, thats the only reason I am looking for a better quality of RG6.

 

[seans1212]

As a quad shield are more expensive they usually put more care also to the center lead, and you can often see that those coaxes has less attenuation, but it probably doesn't matter at lower frequencies than a sat dish's 2-3GHz.

/Ubbe

Ubbe, you are right, as long as I can get anything out of the cable at around 6GHz, that would be great. I am sure the standard RG6 would do. My current coax run of about 25m has a top freq of 1GHz but I get a very strong 2.4GHz signals when I tune my radio to that range, so a 3GHz rated cable should do OK.

Thank you all.

 

[prcguy]

RG-6 will pass frequencies well past 3GHz, the testing they do simply insures it meets specs to 3GHz which is higher than you will encounter in any satellite system. The installation of the connectors will become very critical at or above 3GHz but it should pass 6GHz ok and with a predictable amount of attenuation that will be close to twice the loss at 3GHz. You could also consider RG11 which is a larger lower loss 75 ohm cable with similar easy to install connectors.

Why are you using 75 ohm cable vs 50 ohm? LMR240 and LMR400 are spec'd well past 6GHz and so are the connectors.

I am not so much worried about shielding as I think whatever shielding RG6 comes with is good enough for my environment. I am, however, interested to get a cable that has a higher freq handling, 3GHz is good enough and the reason is I want to see if I can receive anything around 5.6-6GHz, thats the only reason I am looking for a better quality of RG6.

 

[KMG54]

I use Perfect Vision solid copper quad shield for my scanners. I use quad because my c and Ku band dishes are bundled with them. My CB and my 10 meter ham run LMR400 perfect flex. Everything works just fine.

 

[merlin]

I have used Belden supershileld. A dual 100% shield. For runs to 30 meters, it is low loss up to 1.2 Ghz. Higher frequency it doesn't work well at all.
@ 1296 Mhz it is like 10 Db loss. Barely usable.
In the industry, it is common practice to downconvert at the antenna. Theoretically, no limit to frequency then. Block converters have a typical output of over 0Dbmv, enough to run 60 meters.
Bundeling runs has been no problem at all.
If this will be followed with switches and splitters, you will want a preamp ahead of that with very low noise. 15 Db is common, but can be too hot for scanners so consider some attenuators.
Cheers

 

[seans1212]

As a quad shield are more expensive they usually put more care also to the center lead, and you can often see that those coaxes has less attenuation, but it probably doesn't matter at lower frequencies than a sat dish's 2-3GHz.

/Ubbe

Thanks Ubbe, I will either go for RG6 standard 3GHz or quad, depending on cost etc.