SCCARC Talk on Digital Speech Decoder, LTspice filters, and cellular technology

By Jeff Liebermann Sept 20, 2013 V2.3

This file can be found at:

http://802.11junk.com/jeffl/SCCARC-talk-2013-09-20/

 
 
· Digital Speech Decoder (DSD)
o http://wiki.radioreference.com/index.php/Digital_Speech_Decoder_(software_package)

o Narrow banding. No changes to ham radio. Choice of technologies.

o Trunking versus non-trunking. Speed of transmission for public safety.

o Demo of scanner and DSD decoder

o http://www.scan-ne.net/DSD/DSD4WinTutorial.pdf

o RTL-SDR Tutorial: Decoding Digital Voice (P25) with DSD

o http://www.rtl-sdr.com/rtl-sdr-radio-scanner-tutorial-decoding-digital-voice-p25-with-dsd/

o Requirements – discriminator audio.

§ http://www.discriminator.nl/index-en.html

§ CPU burner. 1.8GHz P4 minimum.

§ Linux, Windoze, Mac. Open Source.

§ Virtual Audio Cable (optional)

· http://software.muzychenko.net/eng/vac.htm $25

· http://www.vb-cable.com shareware

o Digital Mode Samples

§ http://www.w2sjw.com/radio_sounds.html

§ http://www.kb9ukd.com/digital/

o What doesn’t work:

§ Dstar. AMBE2020 vocoder vs P25 AMBE+2.

§ DVSI patent. Mbelib.

§ Trunking, encryption, data. (note on interoperability)

 
 
 
· LTspice, filters, and intermod hunting:
o FM Broadcast Intermod at W6JWS-2m 146.745. 
§ http://802.11junk.com/jeffl/SCCARC-talk-2013-09-20/LTspice-FM-Notch/W6JWS-2m-intermod.pdf
§ http://802.11junk.com/jeffl/SCCARC-talk-2013-09-20/LTspice-FM-Notch/WR6JWS-2m-intermod.htm
o Where to download LTspice. 
§ http://www.linear.com/designtools/software/
o Sample circuits
§ http://www.linear.com/designtools/software/demo_circuits.php
o Ideal inductors versus real inductors.
§ Files: http://802.11junk.com/jeffl/SCCARC-talk-2013-09-20/LTspice-FM-Notch/
§ Ideal: http://802.11junk.com/jeffl/SCCARC-talk-2013-09-20/LTspice-FM-Notch/FM%20broadcast%20band%20notch%20filter%20%28ideal%29.jpg
§ Real: http://802.11junk.com/jeffl/SCCARC-talk-2013-09-20/LTspice-FM-Notch/FM%20broadcast%20band%20notch%20filter.jpg
 
 
 
· Cellular tech, towers, and goodies.
o 1G = 2Kbps, 2G = 64Kbps, 3G = 2000Kbps, 4G = 100,000Kbps
o New technologies and frequencies
§ 700, 1700, 2100 Mhz 4G bands 
§ http://www.4gamericas.org/index.cfm?fuseaction=page&sectionid=361
§ http://www.apple.com/my/iphone/specs.html
§ Data only cell phones (VoIP).
§ Microcellular, DAS, Small cells. UCSC DAS system.
o Graham Hill Verizon tower (proposed)
§ http://802.11junk.com/jeffl/coverage/VZW-water-plant/
§ Data supplied by VZW 
· http://802.11junk.com/jeffl/coverage/VZW-water-plant/205061-%20RF%20EME%20Compliance%20Report-2.4.13.pdf
· http://802.11junk.com/jeffl/coverage/VZW-water-plant/VZW.Brookdale.Drawings.pdf
· http://802.11junk.com/jeffl/coverage/VZW-water-plant/ProposedVerizonTowerWTPOpti.pdf
· http://802.11junk.com/jeffl/coverage/VZW-water-plant/VZW.Brookdale.Drawings.pdf
§ Field Intensity and power Density:
· http://802.11junk.com/jeffl/coverage/VZW-water-plant/Picture11a-google-earth.jpg
§ Calculated exposure and coverage
· http://802.11junk.com/jeffl/coverage/VZW-water-plant/RF%20Radiation%20Levels%20at%20T-Mobile%20Taper%20Avenue%20Cell%20Tower.pdf
· http://802.11junk.com/jeffl/coverage/VZW-water-plant/Field%20Intensity%20and%20Power%20Density.pdf
§ Capacity versus coverage.
§ Politics.
o Hwy 1 to Davenport DAS system (10 miles).
§ http://802.11junk.com/jeffl/coverage/VZW-water-plant/Hwy35_Draft_ISMND_Sept2011web.pdf
o Big Basin Tower
§ http://stopsmartmeters.org/2012/08/14/california-coastal-commission-votes-unanimously-to-approve-big-basin-state-park-verizon-cell-sites/
o Micro and Nano Cellular
§ http://www.wireless.att.com/learn/why/3gmicrocell/
o Cellular repeaters
§ http://www.wi-ex.com/homeOffice.aspx
o Tower Ordinance 13.10.660 thru 13.10.668
§ http://www.codepublishing.com/ca/santacruzcounty/