Tower Antenna transmission lines

[N1IOR]

I am installing a new tower and plan on putting up a multiband (mosley)HF beam (10, 15 and 20M) and a Cushcraft A627013S beam with 6m, 2m and 70cm. I would like #suggestions for feeding both antennas. #Thank you in advance for your assistance.

[K6BTM]

Andrew 7/8 hardline for the VHF-UHF. RG-213 for HF should be fine. YMMV.

[WB2WIK]

I'd say it depends on how long each line needs to be, and what kind of tower you're using.

Can't use hardline or Heliax on a telescoping tower, for example. But you can on a fixed-height design.

The Cushcraft VHF-UHF beam referenced is a pretty low-performance model without much gain, so I wouldn't take the line that seriously. But "length" matters, and so does the tower design, in feedline selection.

WB2WIK/6

[W5JO]

Check your Mosley book. I think it specifies the feed line be RG 8U/213 with polyethylene and says this is important. It has to do with the feed system.

As for VHF/UHF, it depends on how much margin you need. If the receive is critical, then very low loss, if it is not, then most anything will work fine. Many times you need not spend a lot of money to work the stations you want to hear. If you can hear them, you can talk to them.

[KD7WHQ]

How long would the run be from either antenna to the shack?

LMR-400 is quite a bit better than RG8/U or RG213 as far as loss on the higher bands.

Under 100', it would be my choice..

[K9STH]

There is a problem with LMR-400 and that is it isn't flexible enough to be used around a rotor. It would fail in a very short period of time.

For the Mosley antenna RG213/U is fine all the way. For the VHF / UHF LMR-400 would be OK to the top of the tower. Then use a jumper of RG213/U around to rotor to the antenna.

Of course 1/2 inch or 7/8 inch Heliax would be even better for the VHF / UHF. But, in most applications the LMR-400 will work fine.

All of my antennas are fed with 1/2 inch Heliax including the ones that I use on 160 meters. But, I got the Heliax in 100 foot lengths (with connectors on both ends) for free and it is almost exactly 100 feet from the top of my tower, across the back of the house, and into the shack. To use anything that isn't as good would actually require me having to purchase something. Once at the top of the tower then RG213/U goes around the rotor to the yagis. For the side mounted vertical dipoles (for 10 meters and 6 meters) the Heliax stops at the yard arm and then either RG8/X or RG213/U goes to the antenna.

Glen, K9STH

[kc2jga]

Quote[/b] (WB2WIK @ Dec. 16 2005,12:14)]The Cushcraft VHF-UHF beam referenced is a pretty low-performance model without much gain, so I wouldn't take the line that seriously. #
WB2WIK/6
I wouldnt exactly call this antenna low performance. Yet it may only have 3 elements for 6mtrs and 5 for 2mtrs and 70cm. I have netted quite a few contacts with this antenna. Even from NY to Florida I picked a station out on 2 meters couple years ago with this antenna.

Just my 2 meters worth.

[WB2WIK]

Quote[/b] (kc2jga @ Dec. 17 2005,07:09)]Quote[/b] (WB2WIK @ Dec. 16 2005,12:14)]The Cushcraft VHF-UHF beam referenced is a pretty low-performance model without much gain, so I wouldn't take the line that seriously. #
WB2WIK/6
I wouldnt exactly call this antenna low performance. Yet it may only have 3 elements for 6mtrs and 5 for 2mtrs and 70cm. I have netted quite a few contacts with this antenna. Even from NY to Florida I picked a station out on 2 meters couple years ago with this antenna.

Just my 2 meters worth.
It is a low-performance antenna, compared to serious stuff. When measured at the CSVHFC on the antenna range, it had such low gain that most homebrew antennas made with coat hangers and bamboo booms outperformed it easily.

However, everything works when propagation's good!

I remember working into the Bahamas (WA1JXN/C6) on 2m SSB from my portable QTH in Vermont (about 1300 miles) using 3W PEP and the built-in 19" whip on the IC-202 battery-operated portable rig when I was sitting on the porch at the Skyline Inn on Mt. Equinox. Tough to beat that one.

Of course in that case, propagation was doing all the work and I just happened to be there.

I only mentioned the low performance because someone suggested using expensive Heliax as a feedline. Great idea, but expensive and heavy and one could achieve much greater station performance improvement just using ordinary RG-213/U coax and going to longer boom, monoband VHF yagis which are cheap and lightweight. So, I'd do that first, and then if further improvements are desirable, go for the Heliax!

WB2WIK/6

[k9kjm]

Belden RG-213 is the coax for HF use.
Times LMR-400 comes in several "versions" if it is to go around a rotor, Just get the LMR-400 "Ultra-Flex" (Costs more than the standard LMR-400) #
As pointed out, Length matters at VHF/UHF. If longer than 70 feet or so, A good used length of 7/8" from a swapfest is the best way to go.
And also as pointed out, That antenna is not much. "Jack of all trades, and master of none" was an old saying that applies to antennas too. Try to get one to do too many things at once and it is not real good any any of them.

[KC2MDP]

Quote[/b] (k9kjm @ Dec. 17 2005,21:59)]Times LMR-400 comes in several "versions" if it is to go around a rotor, Just get the LMR-400 "Ultra-Flex" (Costs more than the standard LMR-400) #
This is some real good low loss cable. The only problem I encountered with the LMR-400 Ultra Flex is getting the coax connectors on the ends of the cable due to it's rubbery jacket. not impossible, just a bit tougher than a traditional RG-8 type cable

[k9kjm]

It is a very tough rubber type outer jacket on LMR 400 Ultra Flex. A small dab of silicone grease will allow your connector to screw right on with little effort.