Re: Low power FM transmitters legalised in UK

In article <5%1vg.15522$EK1.1557@xxxxxxxxxxxxxxxxxxxx>, Richard Evans <R.P.Evans.NoSpam@xxxxxxxxxxxx> writes
DAB sounds worse than FM wrote:
Richard Evans wrote:



Perhaps they want to keep the power levels low enough to avoid any
chance to causing interference to the neighbors.
Yes, no doubt, but it seems a bit low if you ask me.

Yes rather low. I would think they would have to use an attenuator to achieve power levels so low. If reckon if you tried to just turn down the output of an oscillator to those sort of levels, the thing would probably just stop oscillating all together.

The problem of designing a very low power oscillator is eliminated if the limit is 50nW ERP, a very short aerial or just a coil in the oscillator should keep the radiated power low enough.

There may have been another option Ofcom could perhaps have gone for. I read somewhere on the Ofcom site about a idea of using intelligent low power transmitters, that automatically use only channels that are not in use in the area. Perhaps a device that can automatically scan to look for a clear channel, and then always checks that this channel is still clear every time it is switched on. If they licensed a device like that, they could make sure it only transmits on available channels, and that way a few milliwatts would be easily possible without interfering with broadcast services.

The problem with that is the higher cost. Oh, and if the UK is the only market who will develop and manufacture it.

I see Ofcom's move as an attempt to legalise an offence rather than go to the expense of enforcing the law.


--
Ian G8ILZ
.

Relevant Pages

  • Re: 5mW boost converter
    ... but cross-conduction in the oscillator stage. ... They aren't suitable (Idd close to a mA for slow ... input stage of the oscillator inverter. ... I have used the CD40106 as well as the 74HC14 in low power PWM ...
    (sci.electronics.design)
  • Re: Range and low power draw mutually exclusive?
    ... Well strictly speaking such a low power transmission shouldnt be a huge problem in design and build. ... You'll find lots of designs for that all over the web. ... Your first step though is to find out what the rules and regs on unlicensed low power HF devices is in your country. ... The next biggest problem is how you modulate that oscillator in a very narrow band mode. ...
    (rec.radio.amateur.misc)
  • Re: AM receiver chips?
    ... >> frequency) with great sensitivity, selectivity, and low power. ... and tacked a low-value cap accross the tuning cap ... > tune 475; just retweak what's there. ... Note that you will need a much smaller capacitor for the oscillator than the ...
    (sci.electronics.design)
  • Re: Selkirk analogue switchoff process
    ... > of all the analogue and digital channels between the 15th November ... The BBC used to list the digital multiplex transmitters and their ... possibility of a low power seventh multiplex and in some locations even ...
    (uk.tech.digital-tv)
  • Re: Winter Hill since Switchover
    ... to get those channels, who are far enough out, will have a nothe year or so ... Note:- In order to reduce spam, any email without 'Brian Gaff' ... Winter Hill's mux will have to remain on low power until SC's DSO in 2011. ... Please replace invalid and invalid with gmx and net to reply. ...
    (uk.tech.digital-tv)