I recently asked this newsgroup and the antenna newsgroup a question
about what feedline I could use for a Beverage. Here is the summary of
the replies I received. Enjoy! 73/DX Henry WA0GOZ
To: <topband@contesting.com>
Date: Sat, 19 Oct 1996 16:15:32 -0500
knoll003@gold.tc.umn.edu wrote:
>
> Is there any reason I can't use the 75 ohm coax that is available
> from Radio Shack and other such places for the feedline for a Beverage?
> Should I spend money for good feedline like 213?
From: Mark Fossum <n0nsv@amsat.org
I just assembled a beverage antenna the other day in a field adjacent to
my house. I had the same question as you. I questioned the boys at
I.C.E. (the people who made my terminators and matching box) and they
said just use whatever you have as long as you're staying under 150' to
the beverage. Loss is minimal at such low frequencies. 73 Mark
From: Merv Schweigert <k9fd@htc.net
Henry no reason in the world not to use 75 ohm coax for the
feed of a beverage, only precaution is to use decent coax such as
tv cable drop line or any other good shielded coax to prevent pickup
of unwanted sigs on the shiled. I use cable tv 75 ohm stuff for
years , its cheap or free, works just great. Good luck and see
you on the low bands 73 Merv
From: nw6n@juno.com
There is absolutely no reason why you can't use other types of cable for
feedlines to a beverage, We've all used all sorts of different types of
cable over the years! 73, Bob NW6N
From: Bill Hider <n3rr@erols.com
Henry, there is no reason you can't use cheap 75 Ohm coax. For best
performance, use a 6:1 (or close to that) for the impedance tansformer.
Also, unless your feedlines are extremely long, there is no reason to
use RG-213 either. I use RG-58 equivalent cable for feedlines 300 feet
long. Since the Beverages have loss, not gain, a few more dB loss makes
no difference, just use a preamp in the shack if you really need it.
From: abowen@nettally.com (Bowen, Arlan)
I use RG 6 which has quite low loss, depending on quality. I buy mine at
ham radio flea markets for as low as 4 cents per foot, in large quant-
ities. Lots cheaper than trying to use RG58 or 59. Using the large stuff
is a waste of money. INK N4OO
From: Bill Hohnstein <k0ha@navix.net
RG-6 is a good choice for beverage coax and what I use on all
six of mine. 73, Bill K0HA
From: N6DX@aol.com
No reason at all. nearly all my Beverage feed lines are 75 ohm. A good
source is the local cable TV company. They usually have many roll ends of
100 to 300 feet of 75 ohm hardline. It is better than coax since the
aluminum jacket is 100% shielding. I still use 9:1 transformers at the
antenna and no attempt to match the receiver end. However a tunable preamp
helps. Good luck. Darrell, N6DX@aol.com
From: Mandy Wright <Mandy@mrwolf.demon.co.uk>
Any coax will do (except audio lead). The losses are minimal, and the
gain is irrelevant at these frequencies. Directivity and Signal/noise
ratio are all that matters. Locate as far away as possible from buildings
or other noise sources, even if this means using a longer coax feed.
Ground the coax to a earth spike near the antenna and not at the receiver
end or the receiver will pick up noise.
To: <topband@contesting.com>
Date: 20 Oct 1996 22:11:09 -0400
From: w8jitom@aol.com (W8JI Tom)
<Mandy@mrwolf.demon.co.uk> writes:
I agree fully with this....
>
>Directivity and Signal/noise ratio are all that matters. Locate as far
>away as possible from buildings or other noise sources, even if this
>means using a longer coax feed.
I disagree completely with this.....
>Ground the coax to a earth spike near
>the antenna and not at the receiver end or the receiver will pick up
>noise.
The feedline needs to have isolating common mode chokes placed at the
antenna end, and perhaps a small distance from the antenna end. Grounding
at the receiver actually will help S/N ratio, because common mode
excitaion of the coax will be reduced.
For example, if the power mains are carrying conducted RFI, and this RFI
is bypassed to the receiver chassis, the shield of the cable can become
the new path for this unwanted noise. It will follow the shield out to the
antenna, and can "pump" the less tahn perfect ground stake up and down.
Since the feedline responds to the voltage difference between the ground
stake and the aerial, the feedline sees this ground pumping as a real
signal. Right back down the cable it goes, to the receiver.
It can also be field coupling, from induction or radiation fields, that
pumps the ground stake up and down with unwanted signals or noises. Or
field coupling that couples the shield of the cable to the antenna itself.
A common mode choke, as well as independent (unconnected to other
grounds) ground stakes spaced along the line will choke and shunt these
unwanted signals to ground.
It is VERY desirable to ground (or earth) a low noise receiving array
feedline at several points along the line, as well as to use common mode
chokes. The receiver should absolutely be grounded. 73 Tom
From: Lee Hiers AA4GA <aa4ga@contesting.com
75 ohm stuff works great. W4WA (ex-AB4RU) uses a double-shielded or
solid shield 75 ohm coax which is FB because it reduces the
possibility of any stray noise pickup. And he got it really cheap
somewhere. I've got a bunch of the 75 ohm cable TV hardline laying around
I'm probably gonna use for my beverages...since you can usually find it
free, you can't beat the price! 73 de Lee Hiers, AA4GA
From: n5ia@juno.com (Milt Jensen)
I use 75 Ohm CATV cable extensively. My Beverage "headend" is
4,000 (yes, 4 thousand) feet from my shack. I use RG-59 flooded cable
for all the connection runs to the remote antenna selector. For the main
runs to the shack I use 1/2" hardline. Just under 3 dB of loss in the
whole run. Works great, even up to 20 meters. Good luck with your
system es 73 de Milt
From: K8GG
I have successfully used cable tv 75 ohm coax for quite a while on bev-
erages. They provide a good match through a 9:1 UnUn for a beverage ten
feet above poor ground. Some purists then do a 75:50 ohm UnUn in the
shack. Others simply plug the 75 ohm coax into their transceiver or pre-
amp. One of the caribbean contest stations has had cable TV coax running on
the ground out behind a cottage for years. I am sure there is a mismatch
since the beverages are only 4-5 feet off the ground, but so what. If you
can hear a UA9 from the caribbean, I guess it works OK. 73, George, K8GG
From: Pete Smith <n4zr@contesting.com
Henry - RG58 or 59 are fine for beverage as long as they are appropriately
matched to the antenna. 73, Pete Smith N4ZR
From: CATALANO_DENIS_E@hq.navsea.navy.mil
I use 75 ohm coax. No problems. 73 Denis, WD4KXB
From: jfarber@sprynet.com
For runs up to several hundred feet, RG-59 or 58 is fine. Some ops favor
RG-8 or even TV hardline, but others tell me it really isn't all that
critical unless you have a run of 1000 ft or more. (some guys do) Hope this
helps. 73 John Farber, KG6I
From: kaufmann@ll.mit.edu (John Kaufmann)
Coax lines like RG-59 can certainly be used. For very long runs, there
will be more loss than for RG-213, but since you probably won't be
transmitting into your Beverage, this should not be a problem. You'll
see more attenuation on receive, but if you impedance match the Beverage
to the feedline, there should be enough signal that your overall SNR
won't be effected. I happen to use 75-ohm CATV line to feed my Beverages
because it's a lot cheaper than RG-213. The longest run is around
300-400 feet. The only drawback to the smaller coax is that animals can
chew through it more easily. I've had this happen several times with
my feedlines lying on top of the ground in the woods. They must find
the stuff tasty. 73, John W1FV
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