what coax is good to 900mhz? i am looking for something as thin and
supple as i can find. i tried a hunk of coax off of an old cb antenna
(wishful thinking) with no luck. should this work? or is hf coax no
good at 900 mhz? i built a ten element yagi off a plan i found on the
net. it should be a rocket ship but its not as good as a wide band
rubber ducky that i have. i am trying to receive a 900mhz wireless
microphone from a distance of about 200 yards. any ideas?

1/2" Superflex (FS4J-50B) is pretty low loss at 900 MHz, but it ain't
exactly supple. How long is the coax run? RG-142 might be OK for
semi-short runs and is fairly flexible (about the same size as RG-58)...

Scott


Jim wrote:

what coax is good to 900mhz? i am looking for something as thin and
supple as i can find. i tried a hunk of coax off of an old cb antenna
(wishful thinking) with no luck. should this work? or is hf coax no
good at 900 mhz? i built a ten element yagi off a plan i found on the
net. it should be a rocket ship but its not as good as a wide band
rubber ducky that i have. i am trying to receive a 900mhz wireless
microphone from a distance of about 200 yards. any ideas?

Scott wrote in
:

1/2" Superflex (FS4J-50B) is pretty low loss at 900 MHz, but it ain't
exactly supple. How long is the coax run? RG-142 might be OK for
semi-short runs and is fairly flexible (about the same size as RG-58)...

Or if the system can play at 75 ohms, satellite TV grade RG6 is pretty fair
and cheap to buy.



--
Dave Oldridge+
ICQ 1800667

On Sat, 12 Nov 2005 19:41:36 -0500, (Jim)
wrote:

what coax is good to 900mhz? i am looking for something as thin and
supple as i can find. i tried a hunk of coax off of an old cb antenna
(wishful thinking) with no luck. should this work? or is hf coax no
good at 900 mhz? i built a ten element yagi off a plan i found on the
net. it should be a rocket ship but its not as good as a wide band
rubber ducky that i have. i am trying to receive a 900mhz wireless
microphone from a distance of about 200 yards. any ideas?

Unless you go for exotica thin low loss coax at 900mhz is a
contradiction in terms.

RG58 at 900mhz is a dummy load after about 15ft. (20db/100ft)
Belden 9914 is around 8db/100ft (.400inch size)

RG8X is a low loss .242" cable thats only 12db/100 at 900mhz
so if you use that and stay under 20ft the loss should be be under
3db still lossy but manageable. Generally if you want low loss cable
at 900mhz you are talking about fat or very expensive cables.

Allison
KB1GMX

On Sat, 12 Nov 2005 19:41:36 -0500, (Jim)
wrote:

what coax is good to 900mhz? i am looking for something as thin and
supple as i can find. i tried a hunk of coax off of an old cb antenna
(wishful thinking) with no luck. should this work? or is hf coax no
good at 900 mhz? i built a ten element yagi off a plan i found on the
net. it should be a rocket ship but its not as good as a wide band
rubber ducky that i have. i am trying to receive a 900mhz wireless
microphone from a distance of about 200 yards. any ideas?

LMR195 uses the same connectors as RG58, and has about 11dB loss /
100' at 900 MHz. You should find it stocked in the WLAN outlets, with
or without connectors.

Another thought is to salvage some foil/foam RG58 style cable from a
car mobile phone antenna.

Owen
--

thanks guys for your input! ok, forget about thin and supple. i need 50
ohm impedance coax at 900mhz into a uniden scanner(bnc connector) with a
15 foot run. what coax of any size is commonly available that would be
suitable?

"Jim" wrote in message
...
thanks guys for your input! ok, forget about thin and supple. i need 50
ohm impedance coax at 900mhz into a uniden scanner(bnc connector) with a
15 foot run. what coax of any size is commonly available that would be
suitable?

Hi Jim

I wonder why you would not use the RG-6 as suggested by Dave Oldridge.
Even Home Depot has the cable and the BNCs for it.
RG-6 is good transmission line at 900 MHz.

I submit that nothing in the system from the antenna all the way to the
receiver will be 50 ohms, no matter what transmission line you choose.

Jerry

Jim wrote:
thanks guys for your input! ok, forget about thin and supple. i need 50
ohm impedance coax at 900mhz into a uniden scanner(bnc connector) with a
15 foot run. what coax of any size is commonly available that would be
suitable?

LMR-1700 looks pretty good on the loss charts. It's about
$10 per foot, 1.67 inch diameter - not sure about the BNC
connector :-)
--
73, Cecil http://www.qsl.net/w5dxp

I suggest you look at a BNC cable assembly available From AAA RF Products of
San Clemente, CA The AAA1003-180 Cable Assembly uses RG213/U cable with BNC
male connectors, lenght is 15 feet and loss at 900 MHz would be about 1.6
dB. Cost about $30. See www.aaarfproducts.com for email & phone #

Murray, W6KRC




"Cecil Moore" wrote in message
om...
Jim wrote:
thanks guys for your input! ok, forget about thin and supple. i need 50
ohm impedance coax at 900mhz into a uniden scanner(bnc connector) with a
15 foot run. what coax of any size is commonly available that would be
suitable?

LMR-1700 looks pretty good on the loss charts. It's about
$10 per foot, 1.67 inch diameter - not sure about the BNC
connector :-)
--
73, Cecil http://www.qsl.net/w5dxp

If you need a nice low-loss coax for 900 MHz, there's not much better
than a 1" outside diameter cable with a 0.3" diameter inner conductor.
Or something like that.

If you cannot find such a line then the best thing to do is re-design
the whole system such that you don't need it.

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