What is this transmission?

Digital, SSB

I checked in to W6VVR Vaca Valley Radio Club net this evening and they said post-net they’d be hopping on to 7.190MHz. Quickly set up my bugcatcher for 40m and listened, but nothing heard, except for a QSO in progress on 7.192 from Arizona to Los Angeles.

So I thought I’d tune around on the new Extra sections of 7.075-7.100MHz (Hawaii and Alaska can use this for voice, but we mainlanders can’t.) Was expecting CW and perhaps some blurty digital sounds.

Instead I found this:

What is this? I imagine it’s a digital mode (somewhat like Olivia) but I’ve never heard anything like it. Makes me think of a harmonic alien transmission.

APRS iGate


Last night I set up an Automatic Packet Reporting System (APRS) iGate to listen on 144.390 MHz for packets and report them to APRS Internet Service (APRS-IS). This is like a listening station that will improve my area APRS coverage.

My receive-only APRS station on https://aprs.fi

This can be done relatively inexpensively with a Raspberry Pi (~$35), a RTL-SDR receiver (~$26), and some opensource linux software available online.

The latest RTL-SDR v3 is a capable little Software Defined Radio (SDR) receiver that can even receive to HF frequencies. For much cheaper than a standalone HF receiver, you can get the kit that includes a whip dipole, extension SMA cables, and mounting hardware. I lengthened the whips to 2m resonance (~19 inches each side).

Using software in linux: rtl_fm and direwolf, one is able to listen for APRS traffic on 144.390 MHz, decode it, and with the Raspberry Pi  connected to the Internet, can send what it hears to the main APRS servers for visibility on aprs.fi.

Note one guy here sharing his heart rate and blood oxygen levels while on the road.

Now that this is up, I can monitor the firehose of digital packet information that is constantly on the frequency, and relay some close-by transmissions to the rest of the world.

Special thanks goes to my friend briandef (who is studying and may soon become a ham) for his insight and pre-struggle with SDR opensource software to help me debug out how to cleanly set up the RTL-SDR dongle.

Being a Ham Means Figuring Things Out

CW, Digital

A setback day today, as I finally received a USB audio cable for my attempts to use fldigi with my mac laptop (one of the few SDR programs that works on macOS). I was so looking forward to CQ’ing on my available bands with CW in an automated sense, but no luck.

The USB audio cable I ordered (manufactured in Greece, no less), doesn’t seem to work. It is quite frustrating to wait forever for the requisite parts only for me to once again face the world of failure and non-support on Apple Mac computers.

The ham software world is very driven by Windows software, something hams really need to change. For the most part, most hams I talk to are using old versions of Windows, and rarely know much about computers– a direct opposite of my life. Had I the desktop software skills, I would totally try to port many of these apps available to the Mac realm.

So today has been a setback on several ham fronts: CW was a hard study today, I found the bands empty when searching, and now my foray into digital modes has been halted by technology.

But, I am not despairing (too much). Part of being a ham is persistence in the face of a problem. Trying different ways and different configurations until you get the setup right and are able to talk to others.

Ham Code Guide

CW, Digital

Spurred by the previous post, I’m using the Koch method for learning Morse code (CW). I’m attaching here a document I made back when I first became a ham in 1999 that is a quick reference for prosigns and Q-Codes. Morse is also there, but I do not recommend CW by sight, has to be reflexive by sound.

A good iOS mobile app for this is Ham Morse by AA9PW.

Here is my reference document: Ham Code Guide by KF6UJS.