On Thu, May 8, 2008 at 8:44 PM, Michelle <<a href="mailto:w5nyv@yahoo.com">w5nyv@yahoo.com</a>> wrote:<br><div class="gmail_quote"><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<div><div style="font-family: times new roman,new york,times,serif; font-size: 12pt;">...<p>USA band plan<br>144.300 - 144.500 MHz Satellite<br>145.510 - 145.790 MHz FM simplex, digital, and Satellite. Channels are spaced 20kHz apart (145.510, 145.530, 145.550).<br>
145.800 - 146.00 MHz Satellite</p>
<p> ...</p><p>2. "...A RTTY, data or multiplexed emission using an unspecified digital code under the limitations listed in §97.309(b) of this Part also may be transmitted. The authorized bandwidth is 20 kHz."</p>
...<br><p>I think that the 20 kHz is what applies here, because of the "using an unspecified digital code"... </p>
<p>Did I interpret that correctly?</p></div></div></blockquote><div>Sounds right to me. <br></div><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<div><div style="font-family: times new roman,new york,times,serif; font-size: 12pt;"><p></p>
<p>Next I considered 70cm.</p>
<p>In the US and Australia...420 to 450 MHz...in Canada...430 - 450 MHz; in the UK...430 - 440 MHz.</p>
<p>ARRL US band plan</p>
<p> 435.00 - 438.00 MHz Satellite only (internationally) </p>...<br><p>1. ...A RTTY, data or multiplexed emission using an unspecified digital code under the limitations listed in §97.309(b) of this Part also may be transmitted. The authorized bandwidth is 100 kHz.</p>
<p>Using the same reasoning as for 2m, it sounds like the digital mode bandwidth for 70cm would be 100kHz, since we are not using one of the specified digital codes.</p></div></div></blockquote><div>Hypothetically, then, it's<br>
<br>20kHz for a single signal within 145.8 - 146. Is 20kHz wide enough to exploit FHSS? Is there any merit to the claim that a single hop must be limited to 20kHz, but successive hops can cover a wider range? Hopping within 20kHz can be implemented entirely on the Siren. Hopping over 200kHz needs to be external.<br>
<br>The same arguments would apply, mutatis mutandis, to 435 - 438, except that the Siren could not cover 100kHz in any configuration by itself.<br><br><br>73<br>Frank<br>AB2KT<br></div></div><br clear="all"><br>-- <br>The only thing we have to fear is whatever comes along next. -- Austin Cline