Re: Antenna Mounting
- At 03:05 07/04/27, Digest Number 1715 wrote:
> Posted by: "davemynatt" dave@... davemynattA side issue, but the wire clothes line I've seen in Europe &
> Date: Thu Apr 26, 2007 11:30 am ((PDT))
>My apt ... manager .. antenna .. roof ... wants me to use clothes line,
>instead of the nylon rope I have.
>The clothes line is wire covered with rubber and is UV 'proof';
UK is stranded stainless steel in a PVC or polythene jacket.
Strong, but less conductive than one would like for an antenna
wire and far too conductive for an un-insulated guyline :-(
>[snip]If you have to use this wire rather than the polyester
>Will this rubber coated wire be okay? Any advice as to what to use
>from the end insulator to the roof mounting post?
recommended by Chris, it's not just the end insulator
you need to worry about.
ARRL HANDBOOK 2001 Chapter 30 page 53 has a table
of guy wire lengths to avoid for the eight amateur bands
3.5MHz to 28MHz, based on resonance within 10% of any
frequency within the band.
[Most of these are quite long (minimum 13' on 28MHz) so
you may not have a problem if your roof space is constricted.]
If one of your support wires would fall on any of the prohibited
lengths for your choice of bands, than you should add an
insulator to split it into two lengths that don't resonate there.
You might also keep a lookout for existing metallic structures
on the same scale, though you may not be able to do much
about them except keep well clear. If you think you have a
problem with other cables on the roof you might consider
clamp-on ferrite suppressors for them, or the steel wool kind,
to avoid transmitting into other equipment.
ARRL Antenna Book [**] ch20 "Antenna Materials and Accessories"
has general guidance on construction including wire tension
and insulator strain.
[** Which you may find online as "ARRL ANTENNA HANDBOOK",
if you know enough Spanish to invite yourself in as guest.]
A: Because it destroys the flow of the conversation
Q: Why is top-posting bad?