Topband: spacers for ladder line

[Garry Shapiro]

Hardy,

I thought about that choice of THHN as I was concerned also about the 
cracking of the outer, clear plastic insulation. I don't think that 
applies to the underlayer of (colored) insulation. It seems possible 
that the points of contact between the spreader and the wire will not 
crack or flake because they are under pressure and not directly in the 
weather. If so, the line may start to look a bit ragged after a few 
years but still be completely functional wrt to the grip of the 
spreader. Unfortunately, the only way to find out is to try it.

There must be other #14 insulated wire that is more suited to outdoor 
use and has the same O.D. as THHN. And if there is nothing sacred about 
a nominal 600 ohms, #12 wires could be used with a reduction in surge 
impedance.

I am sure ham ingenuity can deal with this.

Garry

On 5/20/2010 8:41 AM, Hardy Landskov wrote:
> Garry and others,
> Yes his insulator looked good and was pricey IMHO but there is one 
> more thing to consider. Out here in AZ that THHN wire insulation will 
> crack and fall off within a year so the grip on the insulator will  
> probable be reduced noticeably and may not even be strong enough to 
> grip the wire.
> Case in point: I put up a window line Beverage using DXE's insulators 
> with the snap in pegs. They are starting to crack will probably have 
> to be replaced after this Summer. The 551 window line has lasted about 
> 15 years but it too will have to be replaced. RG213 is the same way, 
> about 15 years outside and it's done.
> The only coax that looks brand new after 25 years is the LDF4-50A.
> YMMV.....
> 73 Hardy N7RT
>
>
> ----- Original Message ----- From: "Garry Shapiro" <garry at ni6t.com>
> To: <topband at contesting.com>
> Sent: Wednesday, May 19, 2010 6:47 PM
> Subject: Re: Topband: spacers for ladder line
>
>
>> Re ladder line:
>>
>> At Dayton, one exhibitor was a small outfit called TennaMax,
>> _http://www.73cnc.com/_
>>
>> Offered were weighted knobs for various radios---and a very handy spacer
>> for open-wire lines. The black Delrin spacers--trademarked as
>> LadderSnap-- are designed for #14 AWG THHN house wire, which snaps into
>> the spacers, which are repeated every 18" or so. Spacing between wires
>> is 4" for a nominal 600 ohms. They are offered in bags of 70 (100') for
>> $35 and 175 (250') for $80m plus shipping; these are domestic prices.
>> See the website.
>>
>> At roughly half a buck each, these spacers are a bit pricey, IMHO, but
>> they do the job painlessly and efficiently. OTOH, the price per foot of
>> finished line, including the THHN wire, is less than $.40/ft, which
>> compares quite favorably with good coax.
>>
>> I have no connection to the vendor, but remembered this thread when I
>> saw their display.
>>
>> Garry, NI6T
>>
>