[BC] LED obstruction lights

[Warren Shulz]

Mike,
 
When I rebuilt the lighting conduit runs on the 70 yr old WLS tower I looked long and hard at options.  After pricing and all consideration I stayed with incandescent lamps.  Need to inspect tower once a year and change lamps.  When you are pulling 100 kva from the utility a few kw more is not significant.  Big loss is Austin ring coupling transformer.  Did add step-start on light circuit and did add photo cell for night off.  For the first 60 years of life the tower lights were on 24x7.  With step-start and annual re-lamp no outages to report in a 10 year period.  Its not the power bill, or fixture cost that was an issue.  Its tower down time and tower climbing labor that was an issue.
 
Warren Shulz
WLS CGO

________________________________

 on behalf of Mike McCarthy

The problem with any of these systems (strobe or LED) is generally not the
system itself without external influence...such as AM towers circulating
currents.  Even FM towers if the cable runs through a LONG multi-bay
array.

If you place the conductors in a suitable GRC conduit, the RF currents are
stripped off the conductors by the closely coupled conduit. Additioanlly,
the shield used on those specialty cables creates a folded loop unless
bonded at points along the tower withing the higher RF fields. That's not
necessary in the conduit.

The manufacturers won't tell you that as they want to sell their system as
low cost alternatives. Adding conduit is a costly proposition. Especially
on a multi-tower DA.  But if you want a stable low maintenance system, GRC
conduit is needed.

Would I put a typical system on a 180 deg. 50KW tower, I don't know.  But
high relibility low power AM is possible and is reality using GRC conduit.
 BTDT.

If Austin will warranty them on a high impedance high voltage tower,
that's an interesting premise/option which I need to explore as I have
site approching the need to replace fixtures on a super wild tower.

MM

> Ah yes, now that Bobby mentions it, Austin is who I was trying to think
> of.  They stated that high RF was not an issue (I had that discussion due
> to TWR claiming RF damage to failed beacons--Austin didn't think that was
> why the TWR beacons failed--reinforcing my opinion).
>
> --
> Brian Urban
> Chief Operator
> KUT Radio
> TEL 512-471-1085
>
> On 4/21/10 9:02 AM, "Bobby Cox" <bcox at kintronic.com> wrote:
>
>>Austin Insulators has some new LED lighting that is very solid in high
>>RF environments.  They've proven them on high power Navy LF and VLF
>>sites.  Now they're offering them to the broadcast market.  They showed
>>them in the Kintronic booth at NAB last week.  I can get you more info.
>>if you contact me offline.
>
>>Best Regards,
>
>>Bobby Cox , Ph.D.
>>Senior Staff Engineer
>>Kintronic Laboratories, Inc.
>>Phone:  423-878-3141
>>Fax: 423-878-4224
>>Email:  bcox at kintronic.com
>
>>-----Original Message-----
>
>> From: Gary Peterson
>
>>I've got a tower with a Hughey & Phillips (marker) obstruction fixture
>>that needs repair. It is functional, but severe weather can force
>>moisture into it.  I'm thinking that rather than trying to find a new
>>gasket and porcelain socket for this old incandescent beastie, I should
>>just replace it with a new LED unit.  As a matter of fact, I'm planning
>>to replace all the incandescent fixtures, other than code beacons, with
>>LED ones.
>
>>I would be interested in any caveats or comments, negative or positive,
>>about any of the various brands available.  On or off list is fine.
>>Thanks in advance!
>
>>Gary, K0CX
>>CE KFXS, KOUT, KKMK, KRCS, KKLS & KBHB