On Thu, 2009-05-21 at 20:37 -0500, Stuart Rohre wrote:
> Inherently in theory, the L match is less lossy, because you have one
> less physical component. Since real components are not perfect, the
> more you have, (like the 3 in the T circuit, vs. 2 in the L), the more
> loss in the larger component count circuit. This neglects loss that may
> come from undersized switch contacts, poor layout in the enclosure,
> etc. One can only evaluate true losses by measuring power in and power
> out of any tuner.
>
> Stuart Rohre
> K5KVH
>
>
Its not so much the added parts, because capacitors have very low
losses, its the increased coil current caused by the higher loaded Q of
the pi and T over the L that makes the loss greater. And that can be
compensated to any desired extent by making the coil physically larger,
except it gets hard to keep the inductance low enough for 28 MHz when
its wound of water pipe. The biggest coil I've ever tested for Q was
wound of 1-1/2" copper water pipe. Quite low loss!
73, Jerry, K0CQ
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