[UK-CONTEST] UK-Contest Digest, Vol 87, Issue 28

[David Ferrington, M0XDF]

Wow, haven't seen them or used one since the early 80's.

The half wave point on the freq. used for thick net is approx. 1m, so the cable is made with a black ring at the half wave point all along it's length. You must put the end connectors on at the marker (I don't remember what type they are, N I think).  Then, when you want to tap into the cable to connect an Ethernet device, you use a special Ethernet device with has a block with a channel and an insulated pin in the centre. You use a tool to make a hole in the the sheath, through the braid, then through the dielectric. each hole getting progressively smaller so the brad does not short to the inner. Then you clamp the block over the cable, the pin goes into the inner and a ring of pins goes into the braid. An Ethernet 'D' type connector then connects a multi-core cable from the block to an Ethernet card in the computer.

That's a vampire trap!

:-)

Unlike thinnet, where to use BNC and T pieces - don't know if you could use traps with that.

-- 
73 de M0XDF

On 21 Mar 2010, at 13:05, John Wilson wrote:

> Steve, please enlighten us. What is a vampire tap?
> John G3UUT
> 
> Steve White wrote:
>> Yellow (Ethernet) coax is suitable for amateur radio use, but the outer 
>> jacket deteriorates in sunlight. Consequently it is only suitable for use 
>> indoors or in ducting. If you buy some at a rally or equipment sale, inspect 
>> the black rings that are at 2.5m intervals along the cable for holes 
>> (vampire taps). Cover any you find with self-amalgamating tape.
>> 
>> Steve, G3ZVW
>> 
>> 
>>> Message: 4
>>> Date: Sat, 20 Mar 2010 18:46:31 +0000 (GMT)
>>> From: ALEX LISTER <alexcom22 at btopenworld.com>
>>> Subject: [UK-CONTEST] ] Buried coax
>>> To: uk-contest at contesting.com
>>> Message-ID: <232612.91613.qm at web86306.mail.ird.yahoo.com>
>>> Content-Type: text/plain; charset=utf-8
>>> 
>>> 
>>> If using Duct
>>> Don,t forget the mouse bait for the rodents.
>>> Incidentally I am using some large diameter 50 ohm Yellow ethernet,
>>> With a solid dielectric for a long run to HF vertical , Been in ground 
>>> some time
>>> Sleeved with Plastic conduit . Seems OK.
>>> 
>>> If ur going to do job properly and have a non solid dialecric.
>>> Then Squirt some dried clean air up it.
>>> Or for EME RX some gas !
>>> But you will need to find a friendly cable contractor for the air bits !
>>> Alex Lister
>>> G8FCQ
>>> Member Leicester Radio Society G3LRS/G2AA
>>> Member DMUARS
>>> 0753 120 1640