[TowerTalk] 2 questions

[K8RI]

On 7/7/2012 11:00 PM, Joe Subich, W4TV wrote:
>
>   > First question. I have an Ameritron RCS-10 that doesn't seem to work
>   > on all positions. Mine only works on 1-4 with no connection on the
>   > other positions. What would cause that? It almost seems like 2 and 6
>   > are hooked together and 1 and 5 too!
>
> RCS-10 uses a "binary tree" arrangement of relays.  You will probably
> find the input relay has been arced so that both the normally open and
> the normally closed contacts are connected at the same time (all the
> time).


Using double pole relays in binary trees is normally considered a very 
unreliable way to go in industry.  Solid state logic is much more 
reliable and only takes 4 lines to count to 10 (BCD) and is simple to 
decode with one chip.  I can't imagine why anyone would use relays in a 
binary tree.  I've never seen an RS10 so I can't verify the 
construction, but I have used the more conventional RCS4 and 8 that use 
the second set of contacts on each relay to prevent any other relays 
being active other than the one selected.

73

Roger (K8RI)

>
>   > Second question is about the need/benefit of grounding coax cables at
>   > the bottom of a tower.
>
> It's called lightning protection.  You want the shield of all cables
> connected at both the top and bottom of the towers so that a lightning
> strike can't cause a high voltage between the tower and cable shield
> which would "puncture" the insulation and put the high voltage on the
> chassis of any connected equipment.  There is a lot more in the literature.
>
> 73,
>
>      ... Joe, W4TV