How I Monitor HF Reports
OK, so I’m sitting at my desk which has my trusty receiver on it and my computer monitor, keyboard and mouse but most importantly a pen and some paper.
I have my receiver tuned to an interesting frequency depending on propagation of HF signals on any given day. So let’s say I’m monitoring 8843kHz today which will give me a split of either Hawaii to CONUS traffic and vice versa or Flightwatch for Austarlia.
I mostly wear headphones to cut down the ambient household and traffic noise and find a good pair indispensable in this hobby.
My computer browser has a number of tabs already open and they include:
- RZJets for good decoding of received SELCAL codes
- SkyVector for hunting down waypoints reported by the pilots
- FlightAware to confirm a flight number, and
- FlightRadar24.com to confirm track details
As an aircraft calls the ground station, let’s say its United 1182. Aircraft reporting standards are pretty much the same throughout the world so I’m expecting the following once communications is established between aircraft and ground station, in this case it will be San Francisco. The call from the aircraft will normally be in this order:
- (Optional) Registration
- (Optional) Type
- (Optional) Destination
- (Optional) SELCAL code
- First position and time (UTC) to be reported
- Flight Level
- Next position and time
- Following position (no time is normally provided)
- Temperature, normally a negative value
- Wind components, direction and speed
- Any requests for deviation or climb/descent
So when I hear: “United 1182 hitty 0810 Flight Level 360 sisal 0900 domas next, temperature minus 33, wind 240 diagonal 45, go ahead” I normally write what I hear down even if it makes no sense and sometimes I even record on the computer using Audacity the audio output from the radio so I can replay the two way comms later to make sure I transpose it correctly.
After I have the comms written down I look to see if the waypoints make sense. This is because just about all the waypoints on oceanic tracks and across remote areas are five character strings that can be pronounced. Sometime ground stations will ask the flight to spell phonetically the waypoint word and this often helps in making sure I get it right.
Knowing the routes planes fly is a good skill to get and only by studying the routes on charts did I ever learn where the planes were and what the waypoints were called. These days we have online tools to help and this is where SkyVector comes into it. Prior to using SkyVector I will have checked FlightAware to make sure I got the callsign correct. Once again experience will get you there in determining what callsign belongs to which airline. For example British Airways do not identify their flight in radio communications by announcing they are British Airways 123, they use the callsign Speedbird, which is a reference to the old BOAC logo of a bird in flight at speed. However, that said most airlines’ callsigns are normally the name of the airline such as New Zealand, QANTAS, Delta etc.
So in our example above, I would search FlightAware with the airline and flight number I wrote down, United 1182 to check that it is where I expect it to be and that’s either going to or coming from the US and Hawaii together with the origin and destination airports normally in IATA code format (AKL-SYD instead of NZAA-YSSY). So long as it’s showing airborne and a valid flight then I’m reasonably confident I got it right. The example below (for a different flight) also shows that FlightAware even has the flight plan in detail.
The next thing is to confirm the first waypoint because after that you can use SkyVector to more easily check the spelling and pronunciation of the other waypoints. Check the lines on SkyVector to find what sounds like the waypoint you heard and then go along the line to the next waypoint to see if that sounds like what the next waypoint the pilot said. It may take some going back and forth particularly if you are not familiar with the routes. In the example above it wasn’t hitty it was FLITY followed by FIZAL and FOMAS.
Decoding Asian English transmissions over Asian air routes is the hardest not just because of the language difficulties but also because there’s a whole lot more flight routes in that part of the world and deciphering the waypoints is a little more difficult.
Once you’ve nailed the waypoints the next thing is to try and identify the aircraft, this can only be done really on HF if either the aircraft advises their ‘tail’ number or their SELCAL code. Looking up the SELCAL code using RZJets web site will often get you the aircraft registration. Here’s an audio clip of a SELCAL, the code is AGJQ:
In the Auckland oceanic area aircraft don’t normally advise ATC of their registration as they will already have it on the flight plan. US airspace is different! Another way to get the registration and then details of the aircraft is by using a SELCAL decoder so that when the ground station sends the SELCAL check to the aircraft the tones can be decoded and passed through RZJets. Personally I like to use Airnav SELCAL Decoder because its reliable and I get good decoded results.
So now I should have all the information to make a value added log of the aircraft’s communication with the ground station and that’s what goes into my B(log).