"Christian McArdle" wrote in message
.. .
The existing aerial's a sort of '4 dipoles and a single mesh
reflector' arrangement - not a Yagi

Can you identify it? 95% of all TV aerials are Yagis. (And 95% of
statistics are made up on the spot).

Christian.


Chipping in, again, I can't quite parse what you're saying; is the aerial
array; -

query
Case A:

-- -- -- -- four off dipoles
--------------------------- mesh reflector


or;-

Case B:
--
--
-- four 'dipoles' = one dipole
and three directors(?)
--

------------- mesh reflector

/query

In both Case A and Case B the transmitter is normal and on the 'dipole' side
of the mesh. BTW, the 'mesh' (reflector) is theoretically infinitely large
and stops all signals from behind ... luckily for us, the Lord ensured that
the reflectors could be attacked with tin-snips and didn't need infinite
dimensions; turns out that one only _needs_ the reflector to be this* big
and the mesh only has to be this* far behind the dipoles

[*this is a function of frequency]



Case B would be normal and what RTE intend when they call for a UHF Band A
aerial; CASE A is highly unusual - what RF Engineers describes as a phased
array
with 'intriguing' possibilities of gain, bandwidth and beamwidth as a
function of frequency!


--

Brian