[Amps] SB-200 input.
w5ifp at gvtc.com
Sat Jul 26 12:24:33 EDT 2014
The Dentron CM1,2 & U series of external input tuners are fixed broad
It uses a parallel circuit on 160m and PI-L on 80/40/20 with PI on 15/10.
The manual only specifies a "length" of RG-8 or equiv.
This works ok on my Clipperton-L (4x572B) when driven with an IC-735
However I get a better input SWR using the Internal tuner on my FT-920.
Besides it is autotune.
Someone mentioned different cores. The CM uses T-94-2 on 160m, T68-2 on
80/40/20/15m and air on 10m
Jim w5ifp at gvtc.com
On 7/26/2014 9:52 AM, Bill Turner wrote:
> One way to add a tuned input with little fuss is to place a "tee"
> connector at the input of the SS amp and connect a parallel resonant
> LC circuit at the tee. Make the LC circuit have a Q of between 3 to 5
> at 50 ohms and you're in business. Use a variable cap such as an Arco
> compression trimmer and tune for minimum SWR. This does not need to be
> a pi network if you do not need any impedance transformation. If you
> do need a pi network, it can still be done externally, but it gets a
> bit more complicated.
> To multiband it, run a short piece of coax to a switch which selects a
> separate LC circuit for each band. This is essentially what I have in
> my homebrew 8877 amp, although the circuitry is inside the amp instead
> of external to it. You might want two LC circuits on 80 and 160 to
> cover the whole band, depending on the Q you choose.
> 73, Bill W6WRT
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