Coax for Wide Band Discone Antenna

Status
Not open for further replies.

bb911

Member
Joined
Sep 30, 2006
Messages
251
Location
Southern California
It depends on your area . I lived in an area of strong signals, including two NWS mountain top transmitters. I didn't waste my money on LMR-400. Overkill. As far as RG6 being 75 ohm, like fasteddy64 stated, it doesn't matter.
(BTW, I occasionally transmitted 2 watts on 2m with RG6 to J antenna (used for scanner and 2m) with no problems. You can Google "RG6 amateur radio use").

Aluminum is fine unless you insist on the need to solder connectors. You can crimp/buy quality crimped RG6, and use adapters. Given all of the above, you can lighten your wallet, but is it worth it if you live in an area where most signals are strong enough as is? Will it make any change in what actually reaches your ear?
 

prcguy

Member
Joined
Jun 30, 2006
Messages
10,513
Location
So Cal - Richardson, TX - Tewksbury, MA
RG-6 in general is much better than RG-58 despite the impedance problem. There is absolutely no advantage using quad shield over regular CATV/satellite type single braid over foil RG-6.

For a 50ft run I would absolutely use LMR-400. You go to all the trouble of putting up an outside antenna, so why give up much of the signal its picking up with cheap coax?

RG-6QS is a lot better than RG-58.
 

jonwienke

More Info Coming Soon!
Premium Subscriber
Joined
Jul 18, 2014
Messages
12,990
Location
VA
At 900MHz, RG6 has about 3dB more loss than LMR400 on a 100-foot run.
 

k9wkj

Member
Joined
Feb 18, 2015
Messages
372
Location
where they make the cheese
Cheap and compromise are two words that come to mind when I hear RG-6 discussed for scanner antennas. It cost more for LMR400 but why not do it up right?
At 900MHz, RG6 has about 3dB more loss than LMR400 on a 100-foot run.
ohh I knew I would get in trouble :)
all said, I come from a land where public service digital is scarce
and anything above T band is unheard of (except for the prison down the highway)
so my response is tilted towards whats needed for my needs
I have over 500ft of Commscope 3227 (think LMR 400 with a solid copper center)
and almost 400ft of LMR600 on hand
and have no current need for any of it ( I hope to need it next year!)
as RG6 pays the bill for my VHF/UHF needs
its all about balancing what you want V/S what you need
I am currently feeding a VHF/UHF vertical with RG6 as the antenna is a FB match with out the feedline
and its a very good match with the 35ft or so of RG6 feeding it
 

jonwienke

More Info Coming Soon!
Premium Subscriber
Joined
Jul 18, 2014
Messages
12,990
Location
VA
I think you misunderstood me. 3dB is a difference, but not one that is going to make the difference between hearing something and not in most cases. It's not best practice, but will work reasonably well for runs under 100 feet.
 

prcguy

Member
Joined
Jun 30, 2006
Messages
10,513
Location
So Cal - Richardson, TX - Tewksbury, MA
Your not adding in the extra loss for 50/75 ohm mismatch and that is not a constant number, it will change over frequency and at different points down the coax.

I think you misunderstood me. 3dB is a difference, but not one that is going to make the difference between hearing something and not in most cases. It's not best practice, but will work reasonably well for runs under 100 feet.
 
Status
Not open for further replies.
Top