Just a small clarification:
A 3 dB pad will increase the return loss byt 2*3dB = 6dB.
A 2.0:1 SWR is equivalent to a reflection coefficient of .333 and a
return loss of 9.542dB. Therefore it takes a 4.77dB pad to guarantee a
input SWR of <= 2.0:1.
However let's think of it like this: Assuming an original SWR of 3.0:1,
then a 2 dB pad will produce a resulting SWR of 1.922:1. A measly 6 ft.
piece of RG-58 coax between the transmitter and the amp will have less
than 0.2dB of loss at 28MHz which will not improve the input SWR much at
all. Even if the 6 foot piece of coax is made from RG-174 the loss at
28MHz will only be 0.3dB which still won't do much. Am I missing
>One simple way to improve the input swr to any amplifier is to add a 1 or 2
>db attenuator at the input. The greater the attenuation, the greater the
>improvement in swr. It does not make sense to do this if you barely have
>enough drive power, but the Alpha 87a drives easily.
>A 1 db attenuator only needs a 15 watt continuous rating for most
>amplifiers. Either a T or pi type will work.
>A 3 db pad would mean that you would never have greater than a 2:1 swr into
>any amplifier, although the power dissipation would climb dramatically for
>And, Happy New Year
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