View Single Post
  #12   Report Post  
Old June 6th 05, 02:34 PM
Reg Edwards
 
Posts: n/a
Default


"Cecil Moore" says -

There's no such thing as a 100% efficient tuner.

====================================

Cecil, not a very surprising statement.
There's nothing which is 100% efficient.

What is the typical efficiency of a typical tuner with a typical
antenna.
Does it differ significantly from 100% ?
Yes or no?
----
Reg.



Well, at the risk of David going into conflict with the Goliaths of

the
newsgroups, I would reckon that a tuner (matcher ?) must be a pretty

efficient
device as it doesn't get very warm from wasting energy as heat - or

perhaps my
aerials are a reasonably good match and the tuner isn't doing any /

much work.
Also a tuner, I would suggest, is a fairly useful bit of kit in that

it enables
the transmitter to see the sort of load it wants to and allows it to

deliver
more power to the antenna system without the internal protection

devices
limiting the power it produces (to avoid self destruction) even if

not all
arrives at the antenna.......

Is this a fairly correct understanding of what is going on, Reg /

Cecil ?

Nick

====================================

Nick, your response indicates a 'perfect' understanding of what goes
on inside tuner boxes. If it runs cold or cool with 100 watts there's
nothing to worry about.

Most Guru's over-exaggerate the importance of tuner losses. But in a
practical case they never state what the efficiency actually is. Such
omissions illustrate their ignorance of the subject.

From the frequency of occurrence at which 'tuner loss' appears in
these columns, novices and even experienced amateurs can gain the
frightening impression that tuner loss is the most serious loss in the
system and is to be avoided at all costs, even to the extent of
dispensing with the tuner.

In answer to my own question, the efficiency of a typical tuner when
used with a typical antenna does not differ significantly from 100
percent. Even if it is as poor as 90% this corresponds to an
undetectable loss in signal strength of 0.5dB or 1/13 of an S-unit.
Less than the thickness of the S-meter needle. So forget it.
----
Reg, G4FGQ