Coax Question

[outtacontrol]

Currently I am useing RG-8. Im looking at RG-6 Quadsheid, and RF-9913 . There is quite a difference in price which is fine, but the difference in loss is what my question is. From what I can find, RG-6 will lose about 3 db in a 50' run around the 800mhz range where RF9913 is loseing around 1.5 -2 dB . Is the difference here something I'll notice or would the RG-6 be sufficient .

 

[LordJ]

http://www.ocarc.ca/coax.htm

that should help...

 

[zz0468]

It's always better to go for the lower loss cable if you can, but it's highly doubtful that you'd actually notice a 1 or 2 db difference. The money you'd spend on more cable isn't going to bring a bunch of previously unheard signals.

 

[mjthomas59]

If your measurements are correct and you would only lose 1-1.5DB then you have to ask yourself how much money do you have/are you willing to spend? I seriously doubt you will notice 1DB difference when it comes to receiving, and probably not when transmitting either. That being said, i'd check the ohm rating on any of the cable you select, i believe the RG-6 quad-shield is 75ohm?

 

[outtacontrol]

Yes the RG 6 IS 75 OHM and the 9913 is 50 OHM

 

[mjthomas59]

Not sure if this thread is related to your other thread you posted here in the antenna thread but i did want to check.

If you are having trouble picking up a system the first place i would look before i changed anything is what antenna you have. There are those systems(especially the 800mhz systems in my area) that no matter what i've tried i still can't pull in.

Spending the money on a good high gain antenna(or possibly directional antenna) in the frequency range you need is going to do far more good than just simply changing from RG8 to Rg-6. I would hate to see you drop the money for modestly better coax to find that you still can't bring in what you are wanting. Changing coax is a good way to reduce static and another annoyances but i don't think it going to change from not getting a system at all to bringing it in clear.

Just my thoughts, but as someone said in your thread, moving your antenna is free so i would do that first, and then i would look into a better antenna(unless what you have happens to be made for the band you listen to), and then think about changing coax. Its only a 50' run, if we were talking 100+ then i would think differently.

 

[outtacontrol]

Update, through alot of research and a few questions Ive decided to go with Radio Shacks quadshield RG6. So far I noticed a little bit of a difference, but I still have to get my ears outside, I'll be doing that this week. Thanks everyone for your feedback on this. Alot of good points were made.

 

[GTR8000]

Wait a second...you went from RG-8 to RG-6QS? Are you sure you had RG-8 and not RG-8X or RG-58? Big difference! RG-8 is good coax (provided it's quality cable in good condition with good quality, properly installed connectors), and has LESS loss than RG-6QS.

RG-6QS will work just fine for RECEIVE ONLY applications (don't transmit on 75 ohm cable), but not all coax is created equal. Do not buy coax at Radio Shack, their quality is less than desirable. If you're dead set on using RG-6QS, and don't want to order online, then go to WalMart and pick up the Philips brand they sell that has the compression F connectors already installed.

http://www.radioreference.com/forums/showthread.php?t=94388

That alone will reduce your loss quite a bit. Looking at the numbers on the loss charts and calculators is a good starting point, but again, not all coax is created equal. If you're using a quality brand like Belden or Times Microwave, then you can be assured the coax is meeting the spec they publish. Anything else is a crapshoot, especially Radio Shack's stuff.

Please check the coax that was already installed and verify if it was RG-8 or not, and what brand and condition it was in and if it had properly installed connectors.

 

[Taloniilm]

I got 100 ft of Phillips RG-6 Quad Shield at Walmart for 45 bucks. I cut it in half and used the factory connections at the antennas. It was a bit of a pain to get the compression type connectors on the radio ends of my two runs but the strong connection I acheived was worth the hassle. I always used dialectric grease in all my connection to prevent corrosion. So far it's working great for me.