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Propagation Predictor

Hi all,
Although VOAPROP and similar propagation predictors work well at determining the HF propagation and likelyhood of a path over a range of 2000miles plus they do not seem to cut the mustard for >1000mile paths. This is not quite the same as NVIS “Near Vertical Incidence Skywave” where we generally think about ranges of 100miles max. Within the UK and into Europe, it has also been interesting how, from one day to the next, propagation on 40m /60m has fluctuated during the past summer.
I think the factors affecting this mode of propagation are the critical frequency (now available almost instantaneously on line) and the D layer absorbtion.

Is anyone aware of a programme that takes these and possibly other factors, into consideration when determining the likelyhood of a path and band?


David G0EVV

http://www.ips.gov.au/HF_Systems is a fabulous resource.

For UK stations:

http://www.ips.gov.au/HF_Systems/6/7/1 (Select LAMP chart for UK cadets and hit display)

www.ips.gov.au/HF_Systems/6/6/1 (Select London and hit display)

Use your skill, judgement and experience to adapt the London displays to your UK location. For non-UK stations, select accordingly from the dropdown menus.

Hello David,

Propagation can change quite quickly so in terms of forecast predictions not so sure about them.

In terms of real time I always look at WSPR:



Hi Mike, as well as WSPR, I find the following site (that is driven by spots on DXCluster I believe), gives a reasonable indication of realtime long distance propagation conditions.


I predict what i can hear

simples :smile:

Mind you 28mhz last night 18:30hrs utc last night hearing LW5 coming in loud and clear from Buenos Aires. He no wanna talk to me. Enough said.


Hi Ed,
The trouble about DX-cluster driven sites is that you could have a QRO station(s) which gives a false impression.
With WSPR the monitor station are less than 1w so I reckon if a WSPR picks up another at less than a watt then propagation might be ok.
Night night.

Does a QRO signal travel further than a QRP signal?

Hi Mike,

As I monitor both DXMaps and Wspr, I have seen the same indications of paths being open, or not, so one seems to confirm the other. There are other factors of course while wspr stations tend to have omnidirectional antenna, those logging onto DXCluster may have beams but as as far as I have seen, when one system indicates no, or very little traffic between specific regions, the other system confirms this. When there is a lot of traffic indicated between two Europe and another region, there’s a good chance I may hear something.

There could be an element of self-fulfilling prophecy about this: rather than waste precious time tuning around, many people wait until a propagation predictor says a band is open; they then start activating on that band, and the clusters report their presence on the band. Hey presto: the clusters “confirm” the predictors.

In practical terms “Yes”.

A QRP signal is lost below the noise before the QRO signal is so on multihop paths with significant attenuation QRP doesn’t get there but QRO does.

With QRP you are more likely to get a “nil heard” report. :wink: