On lower frequency bands, you can sometimes see an
improvement..............the reason for this is because you will be tuning
out the reactance in your antenna system, at the receiver end. If you have
capacitive reactance, you can insert inductive reactance of an equal
magnitude............if you have inductive reactance, inserting capacitive
reactance will cancel out that component, leaving just the resistive factor.
You can sometimes see a difference of 1 or 2 S-Units.
Because you are providing some selectivity with this tuned filter network,
receivers with a less than optimum front end can benefit, because of the
rejection of out of band signals that could otherwise cause some IMD
products.
With a good receiver, the benefits will not be so apparent.

Pete

David wrote in message
...
BTW, the 956 is a preselector, not an antenna ''tuner''.

On Fri, 24 Oct 2003 13:38:35 GMT, "Martineau Gauda"
wrote:

Hi, have IC-R75 with 30 ft random wire antenna. Would an antenna tuner
such
as MFJ-956 significantly improve reception on 80-20meters.

Thanks

Martineau Gauda