<p><pre><code>  2 miles is amazing range. Bear in mind, these aren&#x27;t 
  huge towers hundreds of feet above the ground with 
  50kWh power sources and million dollar price tags, 
  they&#x27;re battery-powered, handheld, and consumer-priced
</code></pre>
This guy did 7,600Km at 10mW on the 30m band, using a raspberry pi and a couple passives: <a href="https:&#x2F;&#x2F;gerolfziegenhain.wordpress.com&#x2F;2013&#x2F;04&#x2F;13&#x2F;raspi-as-wspr-transmitter&#x2F;" rel="nofollow">https:&#x2F;&#x2F;gerolfziegenhain.wordpress.com&#x2F;2013&#x2F;04&#x2F;13&#x2F;raspi-as-w...</a><p>Of course, the antenna was 44 feet long, and he was transmitting at 1.46 baud, using WSPR: <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;WSPR_%28amateur_radio_software%29" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;WSPR_%28amateur_radio_software...</a><p>As Shannon proved in the 40s, you can get great range if you can sacrifice bandwidth: <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Noisy-channel_coding_theorem" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Noisy-channel_coding_theorem</a>