National Contest Journal:
2004 November/December issue,p.8, Improved Stack Switching with Invisible
Stubs by N4TZ
1980 November/December issue,p.12, Upper-Lower-BIP-BOP Switch by K1GQ
1980 September/October issue,p.7, More Tricks With Coax Upper/Lower/Both
Switching by N4SA
1980 July/August issue,p.9, Tricks With Coax Upper-Lower-Both by K2TR
73, Ted W4NZ
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com]On Behalf Of Joe Subich, W4TV
Sent: Friday, June 18, 2010 11:29 AM
To: towertalk@contesting.com
Subject: Re: [TowerTalk] upper/lower/both box
For monoband stacks I like the N4TZ "Invisible Stub" design
from NCJ a few years back. You will need to add an extra
box/relay with half-wave coax for the out of phase condition.
The N4TZ design avoids the un-un and/or L/C networks and
is arguably more reliable due to the lack of discrete parts
that can break down.
73,
... Joe, W4TV
On 6/18/2010 10:22 AM, Jim Thomson wrote:
> does anybody remember how these box's were configured ?
>
> Buried some where in mu old W2PV material... there is a diagram of
> one. Think it used a pair of P+B DPDT relays. This is for 2 x
> identical 40m yagi's... that's it. It only has to be configured for
> one band.
>
> Last time round... I designed a simple LC box for a buddy who has 2 x
> 40m yagi's. The 2 x ant's were always drioven in phase. The LC box
> was simple.. just a mess of shunt NPO 5 kv doorkno caps at left end.
> [ hot to grnd] followed by a series cu tubing coil. 50 ohms
> in... and 25 ohms out. The 25 ohms consisted 2 x coax connectors..
> wired in parallel. 2 x identical length 50 ohm cables... one per
> yagi.
>
> I was going to suggest adding bip/bop capability... since that only
> involves adding 1 x spst vac relay.. and one x 1/2 wave of coax.
>
> IMO... I think BIP /BOP would be plenty. However.. there maywell
> be cases where the top ant by itself would be louder than both in
> phase..... and ditto with bottom yagi [vs BOP]
>
> Is the U/L/B box in one of the books ? If it is..it's buried good.
> This is just for one band... no broadband xfmr's required.
>
> Tnx........ Jim VE7RF
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