<div dir="auto"><div>hey adam, this is rad!</div><div dir="auto">fyi there's also a disaster.radio mailing list (fwd'ing)<br><br><div class="gmail_quote" dir="auto"><div dir="ltr">---------- Forwarded message ---------<br>From: Adam <<a href="mailto:me@adammunich.com" target="_blank" rel="noreferrer">me@adammunich.com</a>><br>Date: Wed, Apr 25, 2018, 21:39<br>Subject: [sudo-discuss] diaster.radio modulation scheme tests<br>To: Sudo room <<a href="mailto:sudo-discuss@lists.sudoroom.org" target="_blank" rel="noreferrer">sudo-discuss@lists.sudoroom.org</a>><br></div><br><br><div dir="ltr">Hi all, <div><br></div><div>I ran some tests on LORA modulation schemes to get the best results I could on a 100mW TX power budget. </div><div><br></div><div><div>I nearly ran out of gas during this latest test, and unfortunately I managed to screw up my data logging, so I don't have RSSI or SNR data, but this map contains all the places I stopped and got a two way signal on my jet ski.</div><div><br></div><div><div>The transmitter was in my hand, the receiver was at pier 50, SF. </div><div><br></div><div>DIY half wave dipoles were used, with a center freq of 900MHz with a +/- 100MHz 3db roll off. </div></div><div><br></div><div><a href="https://www.google.com/maps/d/u/0/edit?mid=1dE2QZS9cgX_oHLWyzmUNAYrjlbX0wJpE&ll=37.75708554224248%2C-122.33675183183021&z=13" rel="noreferrer noreferrer" target="_blank">https://www.google.com/maps/d/u/0/edit?mid=1dE2QZS9cgX_oHLWyzmUNAYrjlbX0wJpE&ll=37.75708554224248%2C-122.33675183183021&z=13</a></div></div><div><br></div><div>I found that quarter wave antennas are no good (see the red markers). The blue markers are today's test, using RFM95's from HopeRF.</div><div><br></div><div>To get the very long range, I used the following modulation scheme using the RadioHead library.</div><div><br></div><div><div>RH_RF95::ModemConfig modem_config =</div><div>{<span style="white-space:pre-wrap">                                                                                                          </span></div><div><span style="white-space:pre-wrap"> </span>/*Reg 0x1D: BW=125kHz, Coding=4/8, Header=explicit*/</div><div><span style="white-space:pre-wrap">     </span>(7 << 4) | (4 << 1) | (0),<span style="white-space:pre-wrap">                                                  </span><span style="white-space:pre-wrap">        </span></div><div><span style="white-space:pre-wrap"> </span>/*Reg 0x1E: Spread=4096chips/symbol, CRC=enable*/<span style="white-space:pre-wrap">       </span></div><div><span style="white-space:pre-wrap"> </span>(12 << 4) | (1 << 2),<span style="white-space:pre-wrap">                                                                       </span></div><div><span style="white-space:pre-wrap"> </span>/*Reg 0x26: LowDataRate=On, Agc=On*/<span style="white-space:pre-wrap">                            </span></div><div><span style="white-space:pre-wrap"> </span>(1 << 3) | (1 << 2)<span style="white-space:pre-wrap">                                                         </span></div><div>};</div><div><div><br></div><div>RF95.setModemRegisters(&modem_config);<span style="white-space:pre-wrap">                                  </span></div></div><div><br></div></div><div><div>In other news, you can still jet ski if your core body temp is 88F. Little unpleasant though.</div></div><div><br></div><div><img src="https://mail.google.com/mail/?ui=2&ik=725aaff29f&attid=0.1&th=163195aaa89e9e68&view=fimg&rm=163195aaa89e9e68&sz=w1600-h1000&attbid=ANGjdJ9k3mPUS8h1rftZYk4iOhj1Vw6zpdn7wx3op8QjBUnXc9YIDRgqgxQR7P7axc5Qleq-UVbT6aUgJN2eFjMHepBShxlIHpk_iaVb4sAgpX--myjEATrUmWpugwA&disp=emb&realattid=ii_jgg1929l0_163003a2b7629d78&zw" width="544" height="408"><br><img src="https://mail.google.com/mail/?ui=2&ik=725aaff29f&attid=0.2&th=163195aaa89e9e68&view=fimg&rm=163195aaa89e9e68&sz=w1600-h1000&attbid=ANGjdJ8lV8ZQqKXj6qwyH6kv31nIXXJu5vUB-WszbvciDcQikNWWr35b5hbX2wlnIDrnnAqFG2VneC8s_4V7T2PX20pD02B5iI363z752QdibQ3xy3UWKemAslnt0bw&disp=emb&realattid=ii_jgg19bg11_163003a4f9b205eb&zw" width="408" height="544"><br><br></div><div><div><div class="m_32284542532022902m_-6884852068765213517gmail_signature"><div dir="ltr"><div><br>- - - - Begin automatically generated footer - - - -<br><br>I seek to understand, and aim to create.<br>Weblog: <a href="http://adammunich.com" rel="noreferrer noreferrer" target="_blank">http://adammunich.com</a><br><br>PGP Public Key: <a href="https://pgp.mit.edu/pks/lookup?search=adam+munich" rel="noreferrer noreferrer" target="_blank">https://pgp.mit.edu/pks/lookup?search=adam+munich</a></div></div></div></div>
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