Setting aside your deep-seated need to resort to gratuitous abuse at the
bottom of your post, you seem to be confused, for the discrepancy in
radiation
has got nothing whatsoever to do with the feeder or with Z0.

"Brian Reay" wrote in message
...

Consider the Radiation Resistance, Loss Resistance, and reactive element
which determine the eff., and Zo.
(The reactive element represents the energy 'stored' in the field around
the antenna- just like the energy stored in an inductor or capacitor, both
reactive components.)

No, it does not, for a 1/2 wave dipole has such energy stored in the near
field,
but it is not reactive.

The apparent reactivity is because the wave reflected from the end of a
shprt antenna
is well out of phase with the feed.


A short dipole, for example, will be a poor match but RRLR.

That is not true, especially in the case of those down at 137 kHz, where the
loss resistance is higher than the apparent radiation resistance by an order
of magnitude, which is why the published designs feed 1kW from the TX to
get 1W erp.

Provided the feeder loss is low, either by good matching or the use of low
loss feeder (assuming the PA is 'happy')

The feeder has now to do with the performance of a short antenna.


the RF only has one place to go, to be radiated.

Or reflectd back from the open end, just as happens with the standing
wave that is the 1/2 wave dipole. A short antenna does not have a standing
wave.

A short dipole has other issues, in particular if matching is used to
overcome the issue of the Zo, then the matching network plus antenna will
have a very narrow bandwidth (compared to a full sized dipole) and
adjustment will be essential to maintain efficiency if the frequency of
operation is changed.

not relevant.

Remember, the use of 'standard' Zo of 50 or 75 ohm is not essential, nor
is maintaining a feeder SWR of 1.5, provided the PA can cope and feeder
loss can be tolerated/reduced (eg by using open wire feeder).

not relevant


Those who don't really understand what is going on get all 'hung up' re
SWR. In fact it really causes two real issues. If the PA is forced to
operate outside of its safe area of operation, damage may result. (RF does
not 'go back into' the PA, as some think, the impedances are all wrong for
that)

Nonsense. the reflected energy can cause the maximum operating
characteristics
of the PA to be exceeded. How else could damage be caused?


As to the 'postulate', pure nonsense. Some terms he has read, thrown
together so as to try and give the impression he understands things.

Once again, it is you who originates the gratuitous abuse. You really cannot
help yourself, can you, Sonny?


When it this was pointed out, he got riled and start his tirade.

Untrue.

As normal. You know as well as I do the pattern, even if you refuse to
admit it due to you leftie bias against anyone who dares not to be a
leftie.

Oh, for god's sake, sonny, that is completely random and out of place.