Steve,
Can you comment on when plenum rated coax should be used and which ones are
best for HF and UHF? I know it is frequently specified for commercial
installations- in one job it was required to be used inside a roof-mounted
monopole- and may be code required in some installations. Should plenum
rated coax generally be used inside monopoles?
I am planning a run inside a hot air heating duct for about 20 feet from
basement to attic in a residence- any thoughts on residential use? Is there
a plenum rated coax that is also good for outdoor use so the same cable can
be used in a plenum, then continue outdoors and up a tower?
Larrie
W2UL
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of Steve Davis -Davis RF
Co.
Sent: Thursday, May 29, 2008 11:06 AM
To: r_bakalov@yahoo.com; Tower Talk
Cc: Kyle; aKay; Jeff; astaceyjones; aaaNicole
Subject: [TowerTalk] LMR400 vs BuryFlex, Response DAVIS RF,Designer of
Bury-Flex ^^
Hi Rudy,
Possibly this will help you and others: We sell LMR, and also Bury-Flex
Tm, which I designed over 10 years ago. Bury Flex Tm has become one of our
best sellers and is bought by many hams as well as NASA, Lockheed Martin,
SPAWAR, etc., as our core business is commercial.
Outer jacket on both: Polyethylene ("PE") of very similar if not
virtually the same chem. composition, 400 and Bury-Flex. If you are also
thinking of LMR-400 UF (ultra flex), that outer jacket is TPR, not PE, and
will not last as long as PE in UV. TPR, on avg. in USA might be 15-18 yr
life, approx, whereas quality PE will go at least 25 yr and more.
Attenuation and MUF: Although Times spec is 16 GHz, and not to chide
them as they do a great job, we don't recommend it over 8 GHz, for various
reasons. Bury-Flex Tm: I don't recommend it over 3 GHz. For up to 3 GHz,
both attenuations are very close to each other. For HF, not even worth
comparing, virtually the same.
Flexibility: Bury Flex definitely has it over LMR 400 and is only a
slight perception less flex than Ultra Flex 400....again, not a distinctive
difference.
NOTE: the TPR jacket of Ultra Flex ("UF") is not nearly as good for
low-friction to metal, i.e., to the tower, etc. In fact, Bury Flex is
EXCELLENT for a coil around the tower for crank ups. UF is not.
Pricing: We have quite low pricing on LMR 400 and UF (presently .81
avg for Bury Flex vs. .75/ft LMR 400 (400 UF is $ 1.13) List on 400 is
.88 and 400 UF is 1.33) Prices can vary periodically primarily due to
copper fluctuations and mfr. price changes.
PE vs. TPR or PVC: PE is relative rodent resistant, a strong
application point for many hams. This is why we were first to convert our
control cables (not all) for rotators, etc., to PE outer jackets. And the
cost difference is minimal.
Bottom line: PE is much tougher (higher durometer) than PVC or TPR. You
will quickly learn this when cutting into a PE jkt with a new razor blade:
PVC will be like butter, PE much tougher (but not a pain if you use a sharp
safety razor), thus PE is much more abrasion resistant , and can be laid
thru ponds/rivers, etc..... PVC can not be as so, it is only "moisture
resistant"...not "water proof" (varies with mfrs., some mfrs ref. their PE
to be "highly moisture resistant")
My strict advice over the years: don't "skimp, save a dime, etc." on
your
cable and connectors. It is not worth the hassle of repair/replace in the
middle of winter, up a tower, in the middle of that contest or contact with
rare DX. Your best system results/success, as all members of this forum
know, is first with the antenna system, working back from there. Lastly,
make SURE that your connectors are installed properly (we can do that for
you if you are of many who can't stand the process, N, BNC, UHF, etc etc)
AND that they are sealed extremely well from the elements (again "moisture
proof" vs. "water proof", doesn't hack it in my book...needs to be "water
proofed").....plenty of archive info on TT ref this subject.
Bury-Flex has been extremely popular over the years with hams, and the
commercial biz. But again, we have excellent prices on LMR types, same to
next day shipment 99% of time on either (tend to have back orders
occasionally on Bury Flex) and excellent customer service...we smile, never
blasé....HI
Soon to be released to TT, etc: I have promised many of you the following,
now done and just in line to get onto the site (I can't respond to email
requests for this now, will let you know when on DavisRF.com: Decision
criteria for choosing between various options of 1/2" and 7/8" OD Hard
line... all product options avail, and which give similar
electrical/mechanical results: one fairly new product which is a DISTINCT
cost savings in the 7/8", equal performance to LDF5 (Now AVA5) Andrew
Heliax product.
I will check with Steve to see if I can attached is a spec to a TT
submission ( ref. Bury-Flex Tm), also will be on DavisRF.com I hope in near
future (many site priorities).
Please support your dealers who know what they are doing, are there for
you, and not simply clerical reps who dispense price per part #. There is
a lot to be said for "you get what you pay for".
As usual, feel free to contact me with any question or input you can share
with me...always welcomed.
Cheers, Steve K1PEK
978-369-1738
~ Davis RF Co., Div. of Orion Wire Co.,Inc.
Distribution to numerous industries, Andrew
Heliax; Times Microwave LMR; RFS Celwave and others.
Cable design engineering. RF Peripherals.
www.davisRF.com
Tel: 1-800-328-4773 (1-800-DAVIS RF) Tech'l: 1-978-369-
1738, Fax: 1-978-369-3484
~ DAVIS/ORION Marine Wire and Cable Co., Distribution and Design: UL/USCG
Marine Stds. Tel: 877-242-2253 Fax: 603-787-2221 (Direct tel to Steve
Davis: 978-369-1738 or Fax: 978-369-3484)
~Orion Wire Co., Inc., Design Engineers of Specialty/Custom Cable
Tel: 1-800-328-4773, 1-603-787-2200 Fax 1-603-787-2221,
email: j_stimson@davis-orionwiregroup.com
www.davisRF.com
From: Rudy Bakalov <r_bakalov@yahoo.com>
Subject: [TowerTalk] LMR400 vs BuryFlex
To: towertalk@contesting.com
Message-ID: <114702.13331.qm@web43137.mail.sp1.yahoo.com>
Content-Type: text/plain; charset=iso-8859-1
Tel: 978-369-1738 Fax: 978-369-3484
NOTE: Please include all past email history with all followup emails until
your order or inquiry is complete. Thank you.
Steve Davis, Jeff Stimson and the staff of the
DAVIS/ORION Group of Companies
Where Customer Satisfaction is our Premier Goal
~ Davis RF Co., Div. of Orion Wire Co.,Inc.
Distribution to numerous industries, Andrew
Heliax; Times Microwave LMR; RFS Celwave and others.
Cable design engineering. RF Peripherals.
www.davisRF.com
Tel: 1-800-328-4773 (1-800-DAVIS RF) Tech'l: 1-978-369-
1738, Fax: 1-978-369-3484
~ DAVIS/ORION Marine Wire and Cable Co., Distribution and Design: UL/USCG
Marine Stds. Tel: 877-242-2253 Fax: 603-787-2221 (Direct tel to Steve
Davis: 978-369-1738 or Fax: 978-369-3484)
~Orion Wire Co., Inc., Design Engineers of Specialty/Custom Cable
Tel: 1-800-328-4773, 1-603-787-2200 Fax 1-603-787-2221,
email: j_stimson@davis-orionwiregroup.com
www.davisRF.com
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