Hillsborough
Sheffield
S6 2LL
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Main Page List
The subjects on this page are listed on the following order,
ATV`s Aerial Array
Amateur Radio Aerial Arrays
ATV`s Aerial Array
The transmitter of choice is Emley and the (bottom) unamplified Log 40 gives good
pictures on all channels. At the top of the 16ft semi-
on CH31). The XB10A in the middle is amplified as well and is on Belmont. Depending upon
climatic conditions we get poor or almost reasonable results. The fact that it faces East
(i.e. toward the Continent) means that in certain weather conditions co-
In addition we have an FM dipole horizontally polarised on Crosspool. This works fine on
the latter TX because with VHF "line of sight" is not so critical. We would normally advise
an FM dipole to be vertically polarised (to enable it to work more omni-
Picture of our shop`s aerial array.
We need some kind of signal off all the
main transmitters around here in case
we have to repair a TV for which we
have no remote (to retune it) so we
didn`t put up this array just out of
interest !
Note the way we have used side
poles to mount the two Horizontally
polarised aerials which are aligned
on Emley Moor (bottom aerial) and
Belmont (middle aerial) respectively.
Doing this enables the antennas
cradles to be mounted perpendicular
to the dipoles and we found this
made a big difference on the
Belmont aerial.
We have actually experimented with
incorrectly mounted cradles to see
how much difference it makes.
The difference is significant.
Amateur radio aerial arrays show the differences in element size most clearly as there is such a huge difference in the frequencies used. The top antenna on the array is for transmitting (and receiving) at a frequency of 1.3GHz which has a wavelength of 23 cm.
The next one down does the same thing but on 14 to 28MHz which equates to wavelengths of 10 to 20 metres. It can be seen that as the frequency rises (and the wavelength
shortens) the antenna dipole/elements become smaller. By the same token an A group TV (UHF) aerial has a larger dipole and elements than a C/D group, see aerial groups.
Just to emphasise the differing size of the elements, the smaller 1.3GHz antenna (at the top) is a 44 element, whereas the huge aerial below it is only a 3 (three ! ) element....
Amateur Radio antenna array. Note the rotator to “aim” the array where required.
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