Category: Radio

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SSTV in Max

Slow scan television simulation using Jitter.

See this Cycling 74 forum post for an explanation of how frame rate is limited by audio sample rate and  horizontal resolution: https://cycling74.com/forums/topic/jit-poke-vertical-bars-at-high-scan-frequencies/

Download

https://github.com/tkzic/max-projects

Screen Shot 2015-04-09 at 7.24.11 PM

Folder: sstv

Patches:

  • raster-scan4.maxpat (original)
  • raster-scan5.maxpat (better frame rate by lowering screen resolution to 160 x 120)
  • raster-poly-wrap5.maxpat (even better frame rate – up to 15 fps – by up sampling to 384 KHz)

Note – set your audio sample rate to 96KHz if possible, to get the results described above.

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RF converter circuits

Notes and links.

down converters (shortwave to medium wave)

HF to CB/AM Broadcast Receive Converter kit, great for QRP!

Vectronics VEC-101k http://www.vectronics.com/Product.php?productid=VEC-101K

Shortwave converter for AM radio: https://books.google.com/books?id=rZDbnQ0siCYC&pg=PA307&lpg=PA307&dq=how+to++Intermediate+frequency+output+of+am+radio&source=bl&ots=sMJHJ1BecU&sig=QemPm07_g2Tyqk-SVrCD3CEAnpE&hl=en&sa=X&ei=pMsYVdeCH_i1sQTtp4L4DQ&ved=0CDYQ6AEwBTgU#v=onepage&q=how%20to%20%20Intermediate%20frequency%20output%20of%20am%20radio&f=false

40 meters to CB by vk3ye (includes BFO): https://www.youtube.com/watch?v=hCdt0aXj7bc

upconverters

kf7lze roundup of up converters: http://blog.kf7lze.net/2012/09/14/round-up-of-rtlsdr-upconverter-choices/

 

W9RAN Ranverter Pi: http://www.hayseedhamfest.com/ranverter_sdr_261668310.html

ct1ffu upconverter: http://www.ct1ffu.com/site/?option=com_content&view=article&id=178&Itemid=104

IF converters

455kHz -> AF Converter (DRM): http://users.belgacom.net/hamradio/schemas/DRM_455kHz_to_LF_Converter_FRG-100.htm

Any SDR that will receive 455 KHz (or whatever the IF is) plus a R-Pi would work. The Pi would need to  boot automatically into an SDR app with the frequency set to the IF.

455 kHz BFO Kit – Receive ssb and cw on an am receiver!

RADI0KIT-2 DRM SSB RADIO BROADCASTS DECODER KIT / IF CONVERTER.

 

IQ converters and panadapters

FST3253 is a commonly used chip for Tayloe mixers.

Babel Fish IF SDR Radio 1st IF I /Q software conversion module: http://www.ebay.com/itm/Babel-Fish-IF-SDR-Radio-1st-IF-I-Q-software-conversion-module-/231292143562

A Binaural IQ Receiver by Rick Campbell: http://www.arrl.org/files/file/History/History%20of%20QST%20Volume%201%20-%20Technology/QS03-99-Campbell.pdf

QSD By Ray Ring: http://circuitsalad.com/2013/12/30/my-phasing-receiver-is-a-success/

Thomas Nylund Tayloe detector and SDR http://tuomasnylund.fi/drupal6/content/software-defined-radio

Softrock Lite II 06 mixer: http://www.wb5rvz.com/sdr/sr_lite_ii/06_mix.htm

Other

1KHz to 33MHz Adjustable Oscillator Module, LTC1799

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RF mixer simulation in Max

Audio simulation of an RF circuit.

Screen Shot 2015-03-29 at 4.49.36 PM

The simulation serves no purpose, but its fun. There are 4 versions. I think the third one sounds best (rf-mixer-sim3.maxpat). Its interesting to hear how much spectral distortion happens from multiplying sawtooth waves.

Screen Shot 2015-03-29 at 4.46.55 PM

Download

https://github.com/tkzic/max-projects/

folder: rf-mixer

patches:

Note: please set the signal vector size to 1 (or as low as possible) and enable overdrive and audio interrupt

Screen Shot 2015-03-29 at 5.22.30 PM

Four versions:

  • rf-mixer-sim.maxpat (initial attempt)
  • rf-mixer-sim2.maxpat (uses sah~ and rate~ objects)
  • rf-mixer-sim3.maxpat (uses gate~ objects with a phasor~ clock)
  • rf-mixer-sim4.maxpat (bandpass filter on RF input)