Announcing 'hifi-am', to discuss High Fidelity AM tuners and hobbyist transmitters...
 

Hello,

I've created a discussion group (mailing list) to discuss high
fidelity AM tuners and hobbyist transmitters. Appended below is the
more detailed group description.

To subscribe to this group, either go to the group home page (at
Yahoo) and subscribe there (you will need a YahooID):

http://groups.yahoo.com/group/hifi-am/

Or, if you don't have a YahooID, send a blank email to:




Looking forward to seeing you there!

Jon Noring


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Group Description for hifi-am:
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The purpose of hifi-am is to explore the possibilities of high
fidelity AM tuners and hobbyist transmitters for medium-wave (or
better known as the broadcast band, appr. 520 to 1720 khz.)

Although most commercial AM broadcasts are definitely not high
fidelity (due to various factors including, in many countries, audio
bandwidth restrictions), there are nevertheless a few commercial
stations which broadcast with audio quality approaching high fidelity.
For example, in Australia, because the number of stations is fewer and
the country quite large, many stations broadcast with quite wide audio
bandwidth, approaching 15 khz.

There is steady growth in interest (in the U.S.) for non-licensed
hobbyist broadcasting in the BCB (per FCC "Part 15"), which is
restricted to 100 milliwatts and a three meter antenna (among a few
other minor restrictions). With a high efficiency antenna, it is
possible for such neighborhood broadcasting to be heard about 1/2 to 1
mile from the transmitter. There are quite a few progressive and
alternative stations broadcasting this way. For a wonderful example,
see Radio KMTZ.

More importantly, it appears there is no specific restriction on audio
bandwidth for Part 15 transmissions. Thus, if this is true, the
broadcasts can approach high fidelity (15 to 20 khz audio bandwidth.)

Although discussion can focus on the general topic, it is hoped this
group will catalyze the development of hobbyist kits for high fidelity
AM tuners (digital, solid state, and tube) and for high fidelity
low-power (Part 15) AM transmitters. It should be fun to consider the
many possibilities.
....