Towertalk
[Top] [All Lists]

## Re: [TowerTalk] Coax Question

 To: "Tower and HF antenna construction topics." Re: [TowerTalk] Coax Question Ken Boasi "Tower and HF antenna construction topics." Tue, 13 Apr 2010 00:50:14 -0400 mailto:towertalk@contesting.com>
 ```Steve, You can find W3LPL's coax attenuation charts here: http://www.k1ttt.net/technote/coaxloss.html I have found this to be a handy reference. You can also add in the loss for the LMR series cables by going to Times Microwave's website- they have an attenuation calculator to which you enter the type of cable, frequency, and length and it will calculate loss. Ken N2ZN On Apr 13, 2010, at 12:38 AM, N7KA@comcast.net wrote: > > > Steve > > > > It that is a foot foot run from rig t ante4nna you have some serious > work to do. > > > > You need t study what loff you will get in 500ft of what ever feed > line you use. > > > > Here is some very basic info on loss, TX power vs power at the antenna > > 0.0 db loss = 100% to TX power reaches the antenna > > 1.0db loss = 89% of TX power reaches the antenna > > 2.0db loss = 79% of TX power reaches the antenna > > 3.0db loss = 50% of TX power reaches the antenna > > 4.0db loss = 40% of TX power reaches the antenna > > 5.0 db loss = 32% of TX power reaches the antenna > > > > Now look up loss per 100ft of any coax and multply by 5 (for 500ft > of coax run) and you will get the loss in that LONG run of coax. > Remember this long run also works against you on RX as well. > > > > Compare coax all coax at same freq, I woul d use highest band. SO > if you plan to have 10M that far away, I would use 30MHz as the > comparison frequency. > > > > Here is some 500ft loss info at 30MHz: > > > > RG-213 = 5.0db loss > > LMR-400 = You find info > > 1/2in LDF4-50A = 1.785db loss > > 7/8 in LDF5-50A = .975db loss > > > > \I am too lazy at this point to look up LMR-400 so you look up the > 100ft loss at 30MHz and multiply by 5 for the loss. > > > > I will NOT be cheap to run a coax 500ft and NOTloose a lot of power > in the coax (its resistance) so get out the loan application papers, > you are gong to need it or else you will be running QRP and NOT by > choice. Get the biggest coax you can possibly afford. > > > > Hope tis provides info and perspective of the issue you face getting > the TX power through 500ft of coax to the antenna. > > > > I would never consider any coax loss greater that 1 db to be > acceptable. I use 1/2 inch 50 ohm hardline on all my antennas above > 80M > > > > Arne N7KA > > > ----- "Steve Bagley" wrote: >> This may be a little off topic but I would appreciate your input. >> I am putting up a tower and will need to run about 500 feet of >> coax. Should >> I go with LMR-400 or 213? Any comments or input would be greatly >> appreciated! I am of course looking for the lowest loss. >> 73's >> Steve, N2MAI >> _______________________________________________ >> _______________________________________________ >> TowerTalk mailing list >> TowerTalk@contesting.com >> http://lists.contesting.com/mailman/listinfo/towertalk > _______________________________________________ > > > > _______________________________________________ > TowerTalk mailing list > TowerTalk@contesting.com > http://lists.contesting.com/mailman/listinfo/towertalk _______________________________________________ _______________________________________________ TowerTalk mailing list TowerTalk@contesting.com http://lists.contesting.com/mailman/listinfo/towertalk ```
 Current Thread Re: [TowerTalk] Coax Question, (continued) Re: [TowerTalk] Coax Question, jimlux Re: [TowerTalk] Coax Question, Roger (K8RI) Re: [TowerTalk] Coax Question, Ryan Jairam Re: [TowerTalk] Coax Question, Steve Hunt Re: [TowerTalk] Coax Question, Jim Brown Re: [TowerTalk] Coax Question, F.R. Ashley Re: [TowerTalk] Coax Question, D Calder Re: [TowerTalk] Coax Question, Gene Fuller Re: [TowerTalk] Coax Question, Rick Karlquist Re: [TowerTalk] Coax Question, N7KA Re: [TowerTalk] Coax Question, Ken Boasi <= Re: [TowerTalk] Coax Question, Cqtestk4xs Re: [TowerTalk] Coax Question, Roger (K8RI) Re: [TowerTalk] Coax Question, K7LXC Re: [TowerTalk] Coax Question, Jim Brown Re: [TowerTalk] Coax Question, Cqtestk4xs Re: [TowerTalk] Coax Question, john Re: [TowerTalk] Coax Question, john [TowerTalk] Coax Question, Jim Thomson Re: [TowerTalk] Coax Question, jimlux Re: [TowerTalk] Coax Question, Roger (K8RI)