[TowerTalk] Fwd: Old Hardline

jimlux jimlux at earthlink.net
Thu Nov 14 21:26:38 EST 2019


On 11/14/19 6:08 PM, Robert Harmon wrote:
> Interesting stuff.  I got on the Trilogy website, they have a corrugated copper outer conductor too.  Can't
> find loss specs for lower HF freqs.  Also suppliers and cost.

For HF, the loss is dominated by the skin effect in the shield and 
center conductor - especially for hardline, which has almost no 
dielectric.  So the loss will go as sqrt(f).   If the loss is, say, 
10dB/ft at 10 MHz it will be 3.2 dB/ft at 1 MHz.

More details here:
https://www.microwaves101.com/encyclopedias/coax-loss-calculations



> 
> Bob
> K6UJ
> 
> 
> 
> 
>> On Nov 14, 2019, at 12:57 PM, Michael Clarson <wv2zow at gmail.com> wrote:
>>
>> Has anyone checked out Trilogy Cable? It is like catv Hardline, but 50 ohm.
>> Water migration is a non issue, cheaper than copper and tough as hell. The
>> Al outer conductor is pretty thick. As a bonus, it is made in USA.
>>
>> On Thu, Nov 14, 2019, 13:58 Steve Maki <lists at oakcom.org> wrote:
>>
>>> LDF4 is the same as it always was.
>>>
>>> It's the larger sizes where they are using a thinner shield. AVA5 took
>>> the place of LDF5, AVA7 is the new 1-5/8", etc.
>>>
>>> AVA cable has lower loss, but you can't drive a car over it like you can
>>> LDF cable.
>>>
>>> Still it's not THAT fragile - we've installed many thousands of feet on
>>> cell towers and never had a problem.
>>>
>>> OTOH RFS is still making the robust cable, and at a very good price, so
>>> if you're buying new, it's a no brainer.
>>>
>>> -Steve K8LX
>>>
>>> On 11/14/2019 10:48 AM, Rob Atkinson wrote:
>>>
>>>> The feedback I get from industry now is that the Andrew (Commscope)
>>>> line is no longer of the quality it once was.  The shield is thinner
>>>> and more fragile.  The RFS Cellflex line is found to be better, like
>>>> the old Heliax.  I have no first hand experience though because my
>>>> supply of old LDF4-50 and LDF4-75 are not yet used up.
>>>>
>>>> 73
>>>> Rob
>>>> K5UJ
>>>
>>>
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