Dick Green WC1M wrote:
> However, some comparisons between RG-213
> and Buryflex revealed that the latter is actually
> more flexible. It also has much lower loss. You
> can get Buryflex from Radioware
> (http://www.radio-ware.com/).
I looked up this Bury-Flex stuff on the above-stated website -- they call it
"RF-9914F" -- and compared its specifications to those of Belden 9913F7 (the
"flexible" version of 9913). I'm currently using Belden 9913F7 on all my
antennas. As far as I can see, "Bury-Flex" and Belden 9913F7 are virtually
identical in concept and construction: .405" jacket, .108" stranded center
conductor, 100% coverage foil tape shield, 95% coverage tinned copper braid
shield. Some comparative notes:
a) Belden uses their own proprietary direct-burial jacket material (Belflex(R)
PVC blend) on 9913F7, while Bury-Flex claims only "PE" (polyethylene) as the
jacket material.
b) The capacitance per foot and velocity factor specs vary slightly, probably
due to a different formulation of the dielectric material.
c) Up to about 200 MHz, the claimed losses per 100 ft are essentially
identical -- but above that, the Belden 9913F7 starts looking better and better
compared with the Bury-Flex, which isn't even spec'ed above 1 GHz. (Belden
9913F7 is spec'ed up to 4 GHz.) At 1 GHz, for example, the Belden 9913F7 is
spec'ed at 4.6 dB / 100 ft, while the Bury-Flex is spec'ed at 5.3 dB / 100 ft.
So my theory is that "Bury-Flex" is a knock-off of Belden 9913F7, but uses a
cheaper dielectric material, which accounts for its differences in velocity
factor and capacitance (both dependent on dielectric constant), and for its
increasingly poorer loss performance in the UHF range. While no specs are given
for flexibility, the virtually identical construction of the two cables suggests
that the flexibility should be about the same, also.
The cost differential -- in small quantities, anyway -- is quite significant.
100 feet of Belden 9913F7 from AES costs $79.99, while the same quantity of
Bury-Flex from Radioware costs only $59.50. It certainly looks like the
Bury-Flex is the better "deal" if you're going to be using it at HF or low VHF
frequencies (6M and 2M).
Question is -- I don't see any data on where they get this stuff from, who makes
it, etc. Do I really want to go with a no-name cable when I could pay a few
dollars more and get Belden? I suppose it depends to some degree on how tight
your finances are, but for me, I would feel more comfortable going with a cable
whose manufacturer I know and trust.
I'd be interested in hearing any other data, opinions, testimonials, flames,
etc. Has anyone tested Bury-Flex, both when it's new and after it's been
installed for a while, to see how good it really is compared to Belden?
Bill / W5WVO
>
> 73, Dick WC1M
>
>> -----Original Message-----
>> From: Tower (K8RI) [mailto:tower@rogerhalstead.com]
>> Sent: Monday, April 26, 2004 10:11 PM
>> To: coulter@bellsouth.net; towertalk@contesting.com
>> Subject: Re: [TowerTalk] Using Belden 9913 on a crankup?
>>
>>
>> I used 9913 for years and then gave it all away after one
>> lightening strike blew off the water proofing. I figured it
>> just wasn't worth the risk.
>>
>> OTOH 9913 is not a good cable to use where flexing is
>> encountered. The center conductor can migrate off center and
>> it needs to make wide radius bends if long life is expected.
>>
>> I much prefer LMR 400 to 9913. It's slightly cheaper, or has
>> been. It's one or two tenths of a db less loss and fits the
>> same connectors. Both fit PL259s. LMR 400 is more rugged and
>> can make relatively short radius bends. Much shorter bends
>> with reliability than 9913. I believe (without taking the
>> time to look it up) that LMR-400 extraflex has about the same
>> loss as regular 9913, but is more expensive.
>>
>> I used 9913 for years without a problem, or at least I never
>> noticed any. I liked it, but finding water running out of my
>> rig after the lightening blew off all the water proofing was
>> enough to cause a rapid switch to something better. I'd
>> probably still be using it had that not happened.
>>
>> You'll also most likely find hams who have used the stuff in
>> flexing situations with no problems (there are usually
>> exceptions to most any set of
>> circumstances)
>>
>> Good Luck,
>>
>> Roger Halstead (K8RI, EN73 & ARRL Life Member)
>> N833R, World's Oldest Debonair (S# CD-2)
>> www.rogerhalstead.com
>>
>>
>>> Could somebody tell me if Belden 9913(not 9913 flex)is usable on a
>>> crankup tower. What I am interested in, is if it is bendable enough
>>> when the tower
>> is
>>> cranked down or will it bow out too much? Should I go to a more
>>> flexable
>> cable
>>> for the run up the tower, or is it workable? This is for a 51 ft.
>>> crankup. Thanks for your help.
>>>
>>> Todd
>>> N4JRZ
>>>
>>>
>>> _______________________________________________
>>>
>>> See: http://www.mscomputer.com for "Self Supporting Towers",
>>> "Wireless
>> Weather Stations", and lot's more. Call Toll Free,
>> 1-800-333-9041 with any questions and ask for Sherman, W2FLA.
>>>
>>> _______________________________________________
>>> TowerTalk mailing list
>>> TowerTalk@contesting.com
>>> http://lists.contesting.com/mailman/listinfo/towertalk
>>>
>>
>>
>>
>>
> _______________________________________________
>
> See: http://www.mscomputer.com for "Self Supporting Towers",
> "Wireless Weather Stations", and lot's more. Call Toll Free,
> 1-800-333-9041 with any questions and ask for Sherman, W2FLA.
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
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