[cma-l] AMCR

[Associated Broadcast Consultants]

Sadly Tony, SDR won't help, it's about the laws of physics.

To make an efficient antenna you typically need one quarter of a
wavelength.  For FM/VHF thats about 75 cm - faily easy with a bit of copper
pipe or suchlike.  For medium wave a quarter wave can be as much as 139m -
that's 456ft - meaning serius steelwork and/or guy wires that take a large
area of ground..  Moreover at lower fequencies the "ground plane" becomes
more important - which often means burying loads of copper in the ground to
increase its conductivuity.

So a 400ft mast plus digging up an acre or two of ground gets quite
expensive!  Or build a less effecient antenna, but put-up with having to
use a bigger transmitter and possibly having reduced audio
bandwidth/quality.  Or put your transmitter on a boat in the north sea - a
technically perfect location for a AM transmitter, but the Offshore Radio
Act tends to suggest you shouldn't do it, et alon the tendering costs!

And all that to provide a 20th century transmission arrangement that's days
are numbered.  Finacial suicide!

Glyn

-- 
Glyn Roylance - Principal Consultant
Associated Broadcast Consultants <http://www.a-bc.co.uk/>



On 14 September 2015 at 19:53, Tony Bailey <ravensound at pilgrimsound.co.uk>
wrote:

> Reading this thread may explain why none of the last London tranche AM
> licensees (new not existing) got on the air.  There are a number of LRSLs
> around the country on AM although of course they only have to radiate 1
> Watt.  Maybe it's a job for the SDR black box brigade to take on now that
> they've finished playing with DAB?  DRM anyone?
>
> Regards,  Tony Bailey
>
>
>
>
>
>
>
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