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Best Coax Cable For Scanner

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#1
Hello everyone. I have a delema that I've been trying to figure out and decided to post my question here. I currently run a Radio Shack 652 scanner and have a ST3 Antennacraft on the roof of my house. The problem is that I need approximately 100ft of cable as my scanner is on the opposite side of the house. Currently I have 2 50ft sections and the RX is poor. What do you suggest I do, run 100ft of RG58 or should I go RG8 or even LMR coax? Thanks for you Time.
 
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#2
Best Cable

U didnt mention the freq but from being noisy running 2 pieces of coax leads me to believe it might be

800mhz which vhf connectors are like a brick wall. my idea is to run the best as is piratical RG/8 being the

minimum and if you are trying to receive 800 mHz dont use vhf connectors . i have found the short 800 on

my scanner works better at the radio rather then the long run but for low band and vhf the antenna on the roof

is better for far away stations I am running 100 feet of RG 213 but i wish it was something better but it is all i

have and a 250 feet roll of it given to me.
 
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#3
If at all possible, move the scanner and antenna closer together.

If that isn't possible, it really comes down to how much money you want to spend. Lower loss coax cost more.
A receive pre-amplifier is an option, but keep in mind that they will increase noise as well as the signals you want to hear.

You can look at the different options here, and how they will affect the signal:
Coax Calculator
or
Welcome to Times Microwave | Coaxial Cable - Attenuation & Power Handling Calculator

I can tell you that for a 100' run, you really don't want to use RG-58. RG-8 would be the minimum, LMR-400 or LMR-600 would be a better choice. It won't be cheap, though, so consider all your options.
 
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#4
It is easy to look up the attenuation of each of the types of coax you listed on each of the frequency bands you want to hear. You pretty much listed them in the order of preference. RG58 would be the least desirable with the LMR (400 and up) being better with 7/8-inch (and up) hardline being the best. Your choice will be determined by how much you want to spend and how much you want to hear.
BB
 
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#5
For HF, almost any quality coax will be fine. For VHF & UHF, you'll need some good quality low loss coax. For 800 MHz frequencies, you'll need some good quality very low loss coax. For longer runs (100+ feet), move up at least one level. Use the highest frequency you use as what type you need. Use the best coax you can afford for the best results.

Use a Coax Loss Calculator to help you choose. Coax Loss Calculator

Assuming typical scanner user needs, typical choices are (lowest to highest loss @ 860 MHz for 100'):
* LDF4-50A (2.05 dB loss - lower numbers are better!)
* LMR-400 (3.79 dB)
* RG-8, Belden 9913 (4.101 dB)
* RG-8, Belden 8237 (6.718 dB)
* RG-213, Belden 8267 (7.427 dB)
* RG-8X, Radio Shack (11.846 dB)
* RG-8X, Belden 9258 (12.809 dB)
* RG-58, Belden 8240 (13.269 dB)
* RG-58, Radio Shack (14.414 dB)
* RG-58, Belden 9201 (14.894 dB)
* RG-58, Belden 8219 (16.253 dB)
* RG-58, Belden 8259 (20.481 dB)

As you can see from my chart there are different kinds of coax with the same or very similar names. RG-8 and RG-58 are fairly generic names for styles of coax so pay attention to the specific names after these. I list the Belden numbers for many and the generic "Radio Shack" for what you'll typically find in that store. Also be aware that RG-8X (also know as Mini-8 or RG-8 Mini) is a totally different kind of coax than RG-8, although the name sounds very similar.

Be aware, though, that many companies may sell their coax using just the generic name and the coax you get may vary greatly from batch to batch. What you get may be great one time you order and total crap the next time. This is because they buy whatever may be cheapest for them when they order their lot. One time it may be left-over spools from a quality maker and other times it may be from a cheap junk maker that calls their 1/2" 50 ohm coax RG-8 if you want RG-8 or call it LMR-400 if you want that even if it may not actually match the specs for either type (they may even print the desired type on the coax prior to shipping it out!).

Oh, I almost forgot. If you really want the absolute best, they make some 6 1/2" (perhaps even 8") diameter solid coax with very minimal loss. Turns are made using solid elbows and you must hang them using springs since the copper from the coax expands/contracts at different rates than the aluminum or steel towers. They're also very heavy (think hundreds of pounds per section (generally 16' or 20' per section). This is often used on those 2000' television transmission towers so very low loss (and power handling) are very important.
 
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gewecke

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#7
I use 75' of RG6 Quad shield and it has very low loss up to almost 800mhz and is reasonable in price. ;)

73,
n9zas
 
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#9
I second RG6.

Its cheap, readily available and low loss from DC-3GHz
Unless you are designing your system to receive on one specificfrequency, matching wont do much.
The impedance at the antenna is going to vary very very widly from 50Mhz-2Ghz that the scanner covers.
It wil vary quite a bit just 100Mhz away from the tuned frequency.

Dont worry about the matching for wide band receiving, low loss is the key.
 
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#10
Thank you everyone who responded. Yes, Im basically looking to cover 30mhz-800mhz bands. It looks like rg6 or lmr will be the way to go. Eventually I'd like to move the antenna to the other side of the house (closer to the scanner) but for now Ill buy that cable. Those charts helped out a lot too, thank you.


Jay
 
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#12
LMR Cable

being used for a base scanner with a Tram 1400 Aluminum 6dBd Gain VHF 135MHz-174MHz Base Station Antenna . The antenna will used on a porch of my apartment. along with a 800 mg antenna. which coax lmr should I use?
 

dlwtrunked

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#13
I use 75' of RG6 Quad shield and it has very low loss up to almost 800mhz and is reasonable in price. ;)

73,
n9zas
Agree as the difference for a hundred feet between that RG6 and LRM-400 is something like 2 or 3 dB at 900 MHz despite what some would have you think. Another consideration though is how well the cable will weather over the years and what sorts of bends you may have to make (the less the better of course).

Ignore the inevitable responses about impedance difference as the effect on reception is negligible.

RG-11 is another possibility.

The real truth as your antenna model and it height will have a greater effect. And if not good enough, a pre-amp at the antenna end might be considered if there are no nearby transmitters to overload it.
 

wa4dou

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#16
Jefatech ll400

Considering the cost of RG-8/RG-213
cable, these days, I don't use them anymore, choosing instead, LMR400 type cable. I've used several thousand feet of LL400 from JEFATECH, in Maryland, at 900 mhz, with complete satisfaction as regards its loss characteristics and longevity in UV sunlight. It's available in 2 varieties, the stiffer is 59 cents per foot and the more flexible is 89 cents per foot. I'll add that the braid is tightly woven, probably 97%.
 

wa4dou

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#18
How much difference is there between LMR-400 and something I've seen called LOW-400? They claim it's the same and cheaper.
Can't say with any certainty, unless you order and try a product and see if it meets specs. I had occasion to order a roll of Times Microwave LMR400 and it came sporting a 40% braided shield, which caused me to look for another vendor. I suspect they had a vendor that slipped one by on them. Tried a roll of Jefatech LL400 and it had a nice tight braid and good loss measurements and never looked back. Used several thousand feet of it and grew to trust them. Did a search on LOW-400 and it's $.55 a foot. That 4 cents a foot advantage might or might not be eaten in shipping, depending on where it's coming from.
A first purchase from an unknown vendor can always be "iffy", but we all have to take our turn in the barrel, eventually. I did it with Jefatech about 10 years ago, and was happy. Now some hams around my area buy it by the 500' roll and divy it up.
 
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#19
How much difference is there between LMR-400 and something I've seen called LOW-400? They claim it's the same and cheaper.
Probably a red flag.

There's a lot of people out there selling cable that is "just as good" as LMR400. Or so they claim.

Not sure I'd risk it. Looking at the website that sells it doesn't give much information. They talk about "global sourcing", which probably translates into "Made in China" knock off stuff. I'd be interested to get my hands on some and compare it side by side with the real stuff to see if it's as good.
Their claim that Times Microwave LMR-400 is $1.15 a foot is high end list price. Easy to find it much cheaper. A quick look showed $0.86/foot from one of my suppliers.

Ideally, you'd want to look at coaxial cable as a long term investment. It's a really important part of your system, and going cheap to save a few bucks now might bite you in the rear later on.
If you have a really long run that paying less for the likely Chinese stuff is attractive, then you might actually need something better than LMR-400. If you are looking at something like a 50 foot run, the $20-$25 price difference probably isn't worth the risk.
 

wa4dou

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#20
Probably a red flag.

There's a lot of people out there selling cable that is "just as good" as LMR400. Or so they claim.

Not sure I'd risk it. Looking at the website that sells it doesn't give much information. They talk about "global sourcing", which probably translates into "Made in China" knock off stuff. I'd be interested to get my hands on some and compare it side by side with the real stuff to see if it's as good.
Their claim that Times Microwave LMR-400 is $1.15 a foot is high end list price. Easy to find it much cheaper. A quick look showed $0.86/foot from one of my suppliers.

Ideally, you'd want to look at coaxial cable as a long term investment. It's a really important part of your system, and going cheap to save a few bucks now might bite you in the rear later on.
If you have a really long run that paying less for the likely Chinese stuff is attractive, then you might actually need something better than LMR-400. If you are looking at something like a 50 foot run, the $20-$25 price difference probably isn't worth the risk.
Same argument with RG-6 cable. Belden wants $.62 a ft. I'll stick with my LL400 known commodity or in some cases Andrew LDF 4/5-50A. Wise shopping and knowing folks can sometimes produce real deals.
 
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