1 files changed, 42 insertions, 0 deletions
diff --git a/gr-uhd/apps/hf_explorer/README b/gr-uhd/apps/hf_explorer/README
new file mode 100644
index 000000000..57f45ceba
--- /dev/null
+++ b/gr-uhd/apps/hf_explorer/README
@@ -0,0 +1,42 @@
+hfx.py is meant to be a full-featured Long Wave / Medium Wave
+and Short Wave (250kHz to 30Mhz) AM and Single Sideband receiver.
+It uses the USRP with a Basic RX board, and will need an
+antenna and some preamps, about 30db gain will work. See the
+'Help' menu or hfx_help for more info.
+
+----------------------------------------------------------
+
+Powermate knob supported but not required, tooltip frequency display,
+single click tuning, AGC, record to disk, play from disk and record
+audio.  Ability to tailor the audio passband with two sliders over the
+spectrum display. The sliders almost align with the actual
+frequency. Preset filter settings for LSB (-3000 to 0kHz), USB (0 to
++3000kHz), CW (-400 to -800Hz) and AM (-5kHz from carrier to +5kHz).
+
+AM now switches in a synchronous PLL detector with the carriers at
+7.5kHz. The PLL carrier is displayed in the bottom display and helps
+show where on the upper spectrum the demodulated signal
+lies. Everything gets shifted up 7.5kHz in AM, center frequency,
+tooltips, etc.  The target AM carrier needs to be closely tuned in, it
+will have a hollow sound untill it is locked, and then the PLL carrier
+in the bottom display will jump up and remain relatively
+constant. There is a slider "AM sync carrier" to play with different
+levels to mix with the signal for demodulation.  The filter in AM is
+preset to 2500/12500 (7.5kHz +/- 5kHz) and is handy for removing
+adjacent channel interference.  Change AM_SYNC_DISPLAY in script for
+whether to show AM Sync carrier or not.
+
+Run with "-h" for command line help with setting USRP ddc center
+frequency, decimation, rf data record, playback and audio data
+recording.
+
+There are some controls for controlling a varactor and tuning an
+antenna - just ignore them unless you want to build a voltage tuned
+antenna to track frequency.
+
+There is also code for Web based control of frequency and volume - so
+I can tune the radio with an Ipaq from bed.  Disabled by default - it
+takes a web server, some directories and scripts to use.
+
+
+