Since you already have the balun in the tuner, I think I'd try it first. 
You have nothing to lose.  Then, if you don't like the results, you can 
always get the external balun later and run coax from the shack.  As we all 
know. RF is tricky and there's no way to know what it will do in your 
particular situation without trying it.
Lou Kolb
Voice-over Artist:
Radio/TV Ads, Video narrations
Messages On-hold:
www.loukolb.com
----- Original Message ----- 
From: "Tom Behler" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Monday, December 24, 2012 1:16 PM
Subject: More on interfacing Cobra Ultralite Senior with Tentec 238A manual 
tuner


> Hi, again all.
>
> My apologies:
>
> I should have given more complete info in my last post.
>
> First of all, the Tentec 238A is rated for up to 2000 watts, so I would
> think  I'd be ok in that regard, since the most my Ameritron AL811H puts 
> out
> is about 600 watts.
>
> Second, here's a more complete set of instructions about antenna
> connections:
>
> For balanced feedline systems, adding a
> jumper from SINGLE WIRE to one of the
> BALANCED LINE terminals as shown on the
> rear panel is required. A tin-plated steel
> jumper for this purpose has been provided.
> It is attached to one wing nut connector on
> the back; if balanced line will be used, attach
> the other side of the jumper to the other
> wing nut. Then connect the feedline to the
> two BALANCED LINE terminals.
> ANT position 4 can be coax, single wire, or
> balanced line. ANT 1, ANT 2, ANT 3 must
> be coax only.
> Please note that 238C does NOT allow for
> the connection of either coax-fed and
> balanced line or single wire antennas to the
> ANT 4 connection at the same time. There
> is no switchable configuration for ANT 4 -
> any antennas connected to these jacks will
> be in use. If you have a coax fed antenna
> and a balanced line or single wire antenna
> connected to ANT 4 at the same time, both
> of these antennas will be in use when ANT 4
> is selected from the front panel."
>
> In light of this new info, would I still be ok without the Balun Designs
> balun, as far as anyone can tell?
>
> On the negative side, would using just the tuner and the antenna without 
> the
> additional Balun Designs balun possibly lead to more stray RF in the 
> shack?
>
> 73 from Tom Behler: KB8TYJ