Wednesday, March 16, 2016

Apache Labs - Hermes - Hears Birds

For almost the entire winter I've been playing around with building beacons, and using various forms of up and down-conversion of RF signals in all sorts of tests.  Mostly I'm just trying to learn more, and learn how various 'tweaks' can make a difference with my various RF projects.

The past few days I've been returning to playing around with my Apache Labs "Hermes" SDR.  This little software defined radio never ceases to amaze me.

It's funny to me how so many of my projects I putz around with can somehow intermingle with each other.  If you follow this blog then you know I've been recently playing around with Arduino's to accomplish things like acting as a CW beacon, used as an LO in a RF chain, or used as a device to read and display RF Power levels.  These things can be used with so many projects and they're seriously cheap.  The Arduino UNO I'm using cost me < $20 USD, and the Si53531A Etherkit breakout board is super handy for generating RF signals between 0 and 160 MHz (and a little higher).

So...I decided since I was waiting for money and parts to work further on my multi-band beacon project that I'd reuse some of that stuff to make a simple down-converter actually it's able to operate as a full transverter.   Meaning for example, if I want to operate on 145 Mhz I connect an antenna for that to a mixer's RF port.  Then I connect the output of an Arduino driving the Etherkit board at 100 MHz as an LO into the LO port of the Mixer.  The IF port connects to the Apache Labs Hermes SDR.  And wha-lah!  I can receive from about 128 MHz to about 160 MHz.  

This morning I was listening to aircraft between 128-135 MHz roughly.  

All afternoon I was listing to 2 meter repeaters around 146-147 MHz, and then 911 Dispatchers 154 MHz (around here).  

This evening I decided to see if I could hear any Satellites.  And sure enough I copied NOAA-18 easily during one pass around 137.620 MHz.

After that I listened for CAMSAT which is "XW2" and I heard that as well.  Here is a video of XW2 reception.

It's kinda long, and it's a little noisy and the signal was fairly weak.  But even CW-Skimmer was able to copy "CAMSAT" and "XW2" down in the noise.

So it's actually hearing pretty darn well.  My antenna is just an omni 25-1300 MHz "Discone" up about 20 feet on a chimey.  Nothing fancy there, and about 45 feet of LMR-400 Coax.  Just real basic listening stuff.

I'm using an LNA-3000 which is good from DC-3GHz.  It's good for about 18dB roughly.  But I probably really don't need that, especially where it's mounted down in next to the radio.  BUT anyway... :-) (I like to play)

Here's some helpful 'stuff' for tracking and listening for this stuff: