I bet all that paralleling and unparalleling as you change frequencies and bands
is really fun stuff. Wonder why they aren't around anymore? 73 Paul N4XM
> I know they are no longer made, but the TenTec Models 229 and 238
> tuners are not all bad. Being L-network tuners, they cover a very
> wide range. They have an internal 500 pf 2 KV air variable capacitor
> and padding in four steps of 440 pfd, so the internal capacitors can
> have a total value from 40 to 2260 pfd. Also both models have an
> external terminal for another 1000 pfd parallel padder for 160 meters
> which raises the total shunt capacitance up to 3360 pfd!
>
> The roller inductor is good quality and covers 20+ uhy.
>
> So, although QST cannot review it, these models make sense, and have
> the ability to be used effectively on 10 through 160 meters.
>
> There is a Collins model 180-U reversible L network tuner in a smaller
> box that is about the same, but only up to about 10 uhy and 1500 pfd.
> Using a coaxial T on the capacitor side, another 1000 or 1500 pfd can
> be paralleled across the internal capacitor. They were rated, by the
> military, for 500 watts SSB and RTTY, and have been used for a KW by
> hams. The model 180-S has a vacuum variable of similar construction,
> but uses plugs and jacks to add capacitive padders, instead of a
> ceramic rotary switch like the 108-U and TenTec models.
>
> I am also reminded that someone made a "Unique Wire Tuner" It had a
> series capacitor and shunt inductor L-network inside. It could be
> rewired to shunt capacitor and series inductor, if one is willing to
> add capacitance externally across the internal 2 KV air variable, it
> would work OK on 160 as well. The current in the coil would be the
> limiting factor. It should be good for 500+ watts.
>
> Hope this helps.
>
> 73 George K8GG
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