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- November 30, 2007 at 6:11 am #7036
Here is a good site for lots of part 15 info & specs http://www.tvwiki.tv/wiki/The_Master_List_of_Part_15_Radio_Stations_of_North_America
December 2, 2007 at 12:25 am #16118mlr
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Total posts : 45366and if you’d like to see what it looked like when it was originally published: http://web.archive.org/web/20060831162219/http://home.att.net/~weatheradio/part15.htm
December 3, 2007 at 12:13 am #16119DarkStar
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Total posts : 45366Is there anyone here that has done any Part 15 broadcasting on the 22 meter band like that web page above describes?
No antenna restrictions, 1.8 mW into a 1/2 wave dipole, enough bandwidth to do AM on 13.560 mhz… Sounds like a cool place to experiment!
Unfortunately, I don’t know a whole lot about creating a working circuit from a schematic, but if someone was to create a kit I would buy it in a heartbeat!
–Chris ^_^
December 3, 2007 at 3:10 pm #16120radio8z
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Total posts : 45366No antenna restrictions, 1.8 mW into a 1/2 wave dipole, enough bandwidth to do AM on 13.560 mhz… Sounds like a cool place to experiment!
This does not appear to be the case. According to the FCC rules:
Section 15.225 Operation within the band 13.110 – 14.010 MHz.
(a) The field strength of any emissions within the band 13.553-13.567 MHz shall not exceed
15,848 microvolts/meter at 30 meters.and so on for the frequencies involved. There is no mention that I could find in the rules of antenna or power alternatives to the field strength limit. The power and antenna would have to be adjusted together to produce a field strength meeting the limit. Any antenna and any power would be legal as long as the field strength limit is observed and perhaps the numbers you cited would achieve this, or perhaps not.
Neil
December 3, 2007 at 4:05 pm #16121scwis
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Total posts : 45366A bit more info about alternate approaches is on Jon Smick’s legendary Part 15 site here:
http://home.att.net/~weatheradio/HFtransmit.htm
However, the link to the oscillator test page noted in Jon’s writing is obsolete. The new location for the oscillator test page is here:
http://www.mlecmn.net/~lyle/epson/epson.htm
And what do you know, but Lyle’s reference to the Epson site is also 404, but I found a current copy here:
http://www.eea.epson.com/portal/pls/portal/docs/1/503460.PDF
Lyle provides additional transmitter info here:
http://www.mlecmn.net/~lyle/proto/LFproto.htm
Then there is this interesting piece from a completely different source about using crystal oscillators in AM broadcasting, modulating with a transformer, here:
http://sci-toys.com/scitoys/scitoys/radio/am_transmitter.html
Note that the Smick/Koehler unit is CMOS, while the Sci-Toys unit is TTL
Experimental broadcasting for a better tomorrow!
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