[cr-india] Fwd: Re: connecting our studio to the transmitter...
Vickram Crishna
v1clist at yahoo.co.uk
Fri Nov 30 10:46:27 IST 2007
Superb and neat solution, very low cost, and - although this may not really be all that much of an advantage - no computers/digital devices needed. Using WiFi for the same purpose will certainly need additional costs of about 40k - however, since those 40k devices can be used for other work also, one should be cautious about considering the entire cost.
My recommendation for 27MHz is to build a dedicated link, for which the components can be sourced from the local market. Using matched crystals, the cost of the circuits will be very low, and if the studio and station are reasonably within line of sight, then a suitable antenna pair will not be expensive either.
Things to watch out for:
interference from other CB users in the area (this could be accidental or deliberate, so remember your crucial link is not all that difficult to compromise)Real-time transfer of content (ie only 'live' transmission os a serious option): with digital transfers, you can programme your studio-transmitter link to ensure your entire content is locally cached before broadcast.
Vickram
http://communicall.wordpress.com
http://vvcrishna.wordpress.com
----- Original Message ----
From: Ramnarayan.K <ramnarayan.k at gmail.com>
To: MAHESH ACHARYA <cr_4_agriculture at yahoo.com>
Cc: cr-india at sarai.net
Sent: Thursday, 29 November, 2007 10:26:23 PM
Subject: Re: [cr-india] Fwd: Re: connecting our studio to the transmitter...
Dear Mahesh,
Hi
Thanks for your mail,
i think your mail was not marked to cr - so for the benefit of others
its below.
My responses and queries are below that
On 11/29/07, MAHESH ACHARYA <cr_4_agriculture at yahoo.com> wrote:
> Hi Ram and others.
>
> Answer to first part of the technical question is yes and no. Yes
you can
> broadcast in FM provided you use 27-28MHz of the FM band.
>
> The no condition applies only if you broadcast in the commercial
band of
> the FM that is 88-108MHz.
>
> As I understand location of the studio and transmission are
separate, you
> will have to connect them either physically through cable or VIA
wireless.
> Cost benefit analysis of both the options would be ideal keeping
following
> points in mind.
>
> 1. Distance between the locations.
> 2. Cost factor of connecting locations through cable (Rs 20-50\ per
feet)
> vs wireless ( 802.11 transceivers cost 8-10k, approx range is
10-15Km)
>
> If you have not selected the transmission site. You could use
topographic
> map of that area/google earth or GIS of the terrain to locate the
highest
> point.
>
> You will face this situation. Receiving the programs in FM radio
set. My
> knowledge on legal implication of converting to FM frequency (802.11
is in
> the Gigahertz range that is 2.4 and FM is in Megahertz range that is
for
> commercial 88-108MHz.) is limited.
>
> Alternatively 27MHz (Citizen Band Radio) does not need license. So
you can
> convert the 2.4GHz into 27MHz and behold! any body with the CB radio
can
> listen to the program.
>
> My few cents:-)
>
> cheers!
> mahesh
> VU3MBV
>
>
Again a clarification:
> Answer to first part of the technical question is yes and no. Yes
you can
> broadcast in FM provided you use 27-28MHz of the FM band.
> Alternatively 27MHz (Citizen Band Radio) does not need license. So
you can
> convert the 2.4GHz into 27MHz and behold! any body with the CB radio
can
> listen to the program.
I think what Phuntshok (and i ) are saying is that the actual FM
transmission will be regular - through the regular licensed process
and broadcasting in the allotted FM band 88 to 108 Mhz. *Not* to use
some other means to broadcast.
> You will face this situation. Receiving the programs in FM radio
set. My
> knowledge on legal implication of converting to FM frequency (802.11
is in
> the Gigahertz range that is 2.4 and FM is in Megahertz range that is
for
> commercial 88-108MHz.) is limited.
actually the idea is not to convert the 2.4 Ghz signal into a FM
frequency signal -
The studio would connect wirelessly to a wifi enabled device at the
remote antenna / transmitter location which in turn would feed a
regular audio signal to the designated, approved FM transmitter.
Am assuming that how the transmitter recives the final feed is not so
relevant - it could be a tape recorder, a cd player, a digital audio
player, a computer or a live mike feed. If this is true then it would
not matter. A suitable device would recieve the signal from the studio
and the transmiitter would get an appropriate audio signal from such
device.
> Cost benefit analysis of both the options would be ideal keeping
following
> points in mind.
>
> 1. Distance between the locations.
> 2. Cost factor of connecting locations through cable (Rs 20-50\ per
feet)
> vs wireless ( 802.11 transceivers cost 8-10k, approx range is
10-15Km)
The cost benefit would really depend on the site - again with
Phuntshok , and other who are resident in Himalayan terrain - it would
make sense to optimize a coverage by choosing a good high point (which
may or may not be inhabited). Second the cost of the wire even for a 1
km link is not just far too expensive but prone to may other problems
(laying the wire is one) securing it from miscreants (mainly human and
some time other creatures as well). Then the problem of powering say
even a 1 km ethernet link (no idea what it would do to the signal). In
this case wifi (802.11 b/g ) would be really useful.
The wifi range of 10 - 15 km is more than adequate - and very doable
with very simple equipment.
> If you have not selected the transmission site. You could use
topographic
> map of that area/google earth or GIS of the terrain to locate the
highest
> point.
Radio mobile software http://www.cplus.org/rmw/english1.html would be
a very useful (maybe) better tool.
***
> Alternatively 27MHz (Citizen Band Radio) does not need license. So
you can
> convert the 2.4GHz into 27MHz and behold! any body with the CB radio
can
> listen to the program.
Are you saying we can broadcast on this CB range without any approval
etc. if so why is this not already being used and why can;t we use
this instead of the long process FM transmission.
***
thanks
ram
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