Anyone who spends enough time playing with radios, knows that propagation can be your best friend or your worst enemy. Everything on the SW bands is at its mercy and it and can bring fantastic openings or kill a band stone dead (sometimes for days at a time).
Working out the way a certain frequency is performing can save much dial spinning and waiting because lets face it, listening to static is never a great way to pass the time (unless your a bit odd) 🙂
There’s a bewildering amount of free online resources that will tell you whats meant to be happening, but for a more immediate approach (for me) its all about fixed point and fixed power radio transmissions.
Airband VOLMET Network
VOLMET’s are still in abundance on the HF part of the radio spectrum (even though a number have been shut down over the years) and these certainly fall squarely into the fixed point/fixed power role.
Having a bunch of these on presets allows a quick scan through to show the condition on separate SW bands. They’re nicely spread out over the hf bands with many of them transmitting the same information over multiple frequencies (very handy).
An example of this is the Gander VOLMET, which transmits on various frequencies across the shortwave bands.
To me this dual (of more) frequencies aspect makes VOLMET transmissions always seem more accessible than purpose built propagation beacons. Each VOLMET has a schedule or window of operating time and its crucial to take note of these (converted into your local time), if your going to get the most out of this resource.
For a good list of available VOLMET beacons (and discontinued ones) you can head over to http://www.dxinfocentre.com/volmet.htm
Utilities or Broadcast?
Of course, if your time sat in front of the radio is spent listening to broadcast stations, then you already have all the fixed point/fixed power signals your need (even though the high power doesn’t always make the job any easier).
If you know what broadcast stations should be where and when, it wont take you long to realize that part of the band just isn’t doing it for you.
Listening to utilities and other stations that don’t run into the 1000,s of watts and have no regular (or continuous) schedule means its important to know the chances of reception before spending wasted time in front of the radio.
Band Openings of all Kinds
Range isn’t always the issue and you may be looking for an opportunity where a band swamped by signals preventing you from hearing your target station, changes and gives the weaker signals a chance .
This is the reverse side of propagation and depending on your listening pleasure can be very important when weeding out those overly strong and unwanted transmission sources.
On a side note, I recently found a great blog post (which I sadly didn’t bookmark) about a SWL who suffers with the usual day to day locally generated interference that we all battle against.
Given a few days notice of his power company shutting down the mains supply to his surrounding area, he took the time to get all his equipment powered up on batteries with the sole purpose of playing radio without all that radio hash.
The results were amazing with stations heard from his home QTH that were never possible before and highlighting what we as radio users just get used to when it comes to interference.
Taking the time to check the airband VOLMET service may turn you on to the wider range of aircraft transmissions on HF (of which there are many) and add another side to your shortwave hobby (if your not monitoring these already).
I’ve only touched on the VOLMET subject and if you want further reading, wiki.radioreference.com has some more information on their website.