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Appendix
Where I put stuff when I can`t think of anywhere else to put it.......
Appendix Index
UHF Channel Numbers to Frequency etc
Test results (full) of Group A aerials
Test results (full) of Group B aerials
Test results (full) of Group C/D aerials
Test results (full) of Group K aerials
Test results (full) of Group E aerials
In the UK television transmissions are usually referred to by a channel number as opposed
to a frequency. Both the channel number and the frequency are given on all our Channel
Allocation Guides (e.g. the one for Crystal Palace) but the frequencies are rounded down
by 0.25MHz. For example the exact frequency for CH21 is 471.25MHz.
The table below also shows channel number v frequency (and also the wavelengths).
In the case of analogue the channel number is related to the frequency thus :
Fv = 8n + 303.25
Where Fv = Frequency of the vision carrier in MHz and n = Channel Number.
For digital the channel number is related to the frequency thus :
Fc = 8n + 306
Where Fc = Centre frequency of the MUX, and n = Channel Number.
As an approximation, good enough for most tuners, the digital frequencies are 3MHz
higher than the analogue (although it`s actually 306 -
Since most tuners use channel numbers this 3MHz difference is not usually significant, but if you are trying to enter the actual frequency to yours it obviously might be for you !
Some digital MUXES are transmitted with a channel offset and these are + or -
These offset frequencies can be found in the relevant Ofcom documents :
The vast majority of digital TVs or STBs can still tune in to a MUX even if it has an offset
and this is also the case in manual tuning. If you have trouble trying to tune in your
MUXES its always worth checking that the tuner is not being sidelined by an offset, though
this should be very rare.
Such is the Black Art nature of RF all aerial test readings are approximate, in fact
as far as I`m aware
no lab will guarantee accuracy better than +/-
It must be admitted that these particular results are less accurate than that (unlike our TV aerial tests) but they still give a pretty reliable indication of the relative performance of the various antennas.
UHF TV frequency wavelengths
To calculate the wavelength (in cms) divide 30,000 by the frequency (in MHz).
This should be accurate to 0.07%, which is accurate enough for most RF applications....
The “variable” figures result from the directional nature of the particular aerial.
This doesn`t apply to the TV aerials, they`re variable because they`re not even designed to
pick up VHF frequencies ! Note that if the 3 element aerials were pointing directly away
from the transmitter you`d probably lose more than the -
Though you would be pretty unlucky if you were to align your aerial like that !


Log Periodic Polar Response
Typical 10 Element Wideband Yagi Polar Response

XB14 A Group Polar Response
XB14 Wideband Polar Response

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