VHF Radio Transmission

[palman]

Hi,

Twice a year I provide a PA system at a sheep dog sale in a field in North Wales. Five boxes on sticks along a 100m ish fence down the middle of said field, with vehicles parked on one side and dogs and sheep on the other, all good.

I sometimes get requests from the people that are near to the speakers to “turn it down a bit” but of course the don’t care about those that are not near a box.

So it got me thinking about transmitting on VHF so that they can tune in with their car radios and everyone can have their own desired level.

I’ve no intention of using more speakers with lower levels, I’m just looking into the feasibility of doing this.

Is it possible to do this legally, and what kit would I be looking at to hire or possibly bye?

 

Thanks in advance

[paulears]

As far as I know - the only legal way is to apply for a RSL licence which will allow you to do what you need to do - but the restrictions and costs are prohibitive for something that generates little spare cash. However, maybe you could use a number of the low power devices intended to connect MP3 players to car radios? They're very low power, but I wonder if one on each loudspeaker pole mighty get you to the nearby cars? Might be worth trying?

[bruce]

A very similar discussion here: http://www.blue-room.org.uk/index.php?showtopic=68386

[palman]

Hi Paul, I really don’t want to complicate things, I was thinking more in the line of one tx to cover the entire field.

For two six hour sessions a year its not going to be cost effective to do it legally.

Bruce, thanks for the link.

Ah well, it was just a thought.

[TomHoward]

£400 application fee for a £25 licence (as would be required for 1W / 1 day FM is a bit steep, seems like there should be a reduced application fee for the 1W licence.

 

It almost encourages you not to bother applying for the licence and just using the cheap Aliexpress transmitter unlicensed, which is a bit silly as they could recover more of the £25 fees were the application process more reasonably priced.

[Owain]

I think quite a lot of farmers in rural areas still have CB radios.

 

A low-output hand-held transmitter wouldn't be picked up very far away.

 

Not a permitted use of CB, and anyone could break in and disrupt the announcements.

 

I think I'd just use taller sticks so the speakers are a bit further away from the nearest people's earholes.

 

 

[Jivemaster]

There is the unpermitted use of PMR446, or CB, the incorrect use of "in car" FM transmitter, or the licensable use of a VHF RSL with fee and consultation fees payable.

 

The simple answer has to be "same again as before", improvements being speakers further from the crowd line, Speakers on higher poles, or more speakers (which can impinge on inteligability).

[TomHoward]

The only other thing similar would be a webcast / internet radio stream but that has all sorts of problems of its own as well.

[sunray]

I haven't used a 'music link' for a number of years so I'm out of touch with licensing, The allocations I used to use were from JFMG on frequencies like 52.3, 48.45 etc and IIRC the minimum fee was £25.00.

[MarkPAman]

Apparently over 87% of new cars are being fitted with DAB this year and it was well above 50% 4 years ago.

 

So you need to think about what age of car your spectators tend to turn up in, though I suspect that there's a complete mix at this type of event.

 

E2A - Though I guess many still receive both?

[sunray]

I haven't used a 'music link' for a number of years so I'm out of touch with licensing, The allocations I used to use were from JFMG on frequencies like 52.3,  48.45 etc and IIRC the minimum fee was £25.00.

Oops I missed the salient point listen on the 2nd harmonic, 2x52.3 = 104.6, 2x48.45 = 96.9.