What are the different frequency blocks? What is a block?
What are the different UK frequency blocks?
Frequency Blocks: Basically radio frequencies get assigned to blocks / Banks of frequencies for the purposes of coordination. Now in the UK it is very easy to remember the block because we only have 1 legal block of frequencies that cover 606.000 up to 631.500. If you have Lectrosonics IFBs you can figure out what the frequency is using this frequency finder chart. Now frequency blocks are also semi based on tv channels that take up a block of individual frequencies due to the strength needed to broadcast their signals. The TV channel covered by Block 606 is UK TV channel 38. Also UK TV Channel 70 at 863-865 MHz is licence free, you will find most radio mics are going for just channel 38 (frequency block 606)
In summary for skim readers: UK Legal Frequencies On UK Block 606 or on little bits of US Block 23+24. Covering 606.000 - 631.500.
What are the different US frequency blocks?
Now our American friends have a bit of an easier time in terms of choice, though they can only now buy wideband radio mics like the Wisycoms that cover more than 1 block. So let's go through them via Frequency Block name/number - US TV Channel - Frequency range
Frequency Block 470 - US TV 14 > 16 - 473.300 > 485.700
Frequency Block 19 - US TV 16 > 20 - 486.900 > 511.300
Frequency Block 20 - US TV 21 > 25 - 512.500 > 536.900
Frequency Block 21 - US TV 25 > 29 - 538.100 > 562.500
Frequency Block 22 - US TV 29 > 33 - 563.700 > 588.100
Frequency Block 23 - US TV 33 > 36 - 589.300 > 607.700 (Legal UK Block 606 Starts at 606.000 > 631.500)
Frequency Block 24 - US TV 38 > 42 - 614.900 > 639.300 (Legal UK Block 606 Starts at 606.000 > 631.500)
Frequency Block 25 - US TV 42 > 46 - 640.500 > 664.900
Frequency Block 26 - US TV 46 > 50 - 666.100 - 690.500
Frequency Block 27 - US TV 50 > 55 - 691.700 - 716.100
Frequency Block 28 - US TV 55 > 59 - 717.300 - 741.700
Frequency Block 29 - US TV 59 > 63 - 742.900 - 767.300
How can I easily find out what my countries frequency block is in US frequency blocks?
You can find out what individual frequencies will fit into what US frequency block using some maths. Take the first part of the frequency in MHz (606.000 mHz is the first legal UK frequency) so lets use 606.000 and make it just 606 then get your calculator out and do 606 divided by 25.6 and the resulting number you will get is 23.671875. Now forget about the decimal numbers and now you know it is in block 23.
So UK frequency block 606.000 = 606.000 rounded to 606 divided by 25.6 = 23.671875 rounded = 23 = US Block 23
Try it with any frequency you have around the world to see if it fits into a US Block.
How do I coordinate frequencies within a block?
In the UK you can only use Channel 38 which is 25.500Mhz of bandwidth. You want to try to spread your radios apart from one and other so you don't get interference or intermodulation between radios. To help calculate when you have over 10 radios (including camera links and directors headsets) you can use apps like FreqFinder and enter in all the frequencies you have and see if there will be intermodulation. Basically the more space the easier it will be from a self intermodulation point of view, but remember other people maybe operating similar frequencies.
How do I coordinate frequencies with other people?
Often in news and other events you will be sharing blocks like 606 with other sound mixers. If you are able to book a licence to use another TV channel (39/40) then that will be less crowded. Otherwise try talking to the mixers on the event and coordinate to help each other out.