HF Radio propagation table

[GILow]

Originally Posted by Sailmonkey

True, but the article is titled SSB for idiots.

That’s me covered nicely.

[GILow]

Originally Posted by coopec43

Maybe the following chart will helps will help.


Also Noonsite has information on Radio Nets which I have yet to come to terms with (Just type in the country)

https://www.noonsite.com/report/paci...of-radio-nets/


Tropospheric propagation describes electromagnetic propagation in relation to the troposphere. The service area from a VHF or UHF radio transmitter extends to just beyond the optical horizon, at which point signals start to rapidly reduce in strength. ... Such conditions are related to the current state of the troposphere

http://archive.hnsa.org/doc/radio/chap21.htm


http://www.cruiserswiki.org/wiki/World_MM_Nets


https://en.wikipedia.org/wiki/Radio_propagation

Thanks mate, but I wasn’t looking for a list of Nets, I was looking for approximate propagation distances.

[S/V Illusion]

Originally Posted by GILow

Nailed it! Thank you, that’s precisely what I was looking for.

While your effort to simplify choice of frequency is good, that chart is useless.

Every day experience with minimal antennas and 100 w shows some of those ranges are wildly optimistic, I.e., 20Mhz and above while below 14 MHz, the range is typically in the hundreds to thousands and even greater below 10 MHz at night. Generalizations included both here and in any chart can be misleading at best.

[n5ama]

Propagation is actually more complicated than a simple chart can address. Solar cycles, ion layers that reflect signals (some of these go away at night hence differences in night versus day propagation), atmospheric noise, man made noise on either end of the path and a multitude of other factors.

Frequency beacons are used to study these factors. The government provides a very handy and free resource to predict some of these highly variable propagation factors.

Charts that address frequency and propagation distances also don’t predict azimuth. If you have a directional antenna versus a vertical omnidirectional antenna, you may have north/south propagation but not much if any East/west.

Use the chart as a starting point but don’t get upset if it doesn’t work well.

The chart should be more reliable at night. 😁

[Cadence]

I'm dumb as a rock. Does it not depend on atmospheric conditions ounce over the horizon?

[Sailmonkey]

Originally Posted by Cadence

I'm dumb as a rock. Does it not depend on atmospheric conditions ounce over the horizon?

It does, That chart I posted is from, essentially, an oversimplified beginners guide to HF.

[GILow]

Originally Posted by Sailmonkey

It does, That chart I posted is from, essentially, an oversimplified beginners guide to HF.

Yes, it is over-simplified, but it's a good starting point.

This about having a strategy for establishing contact with a listening station. If I were doing all that HAM stuff chasing long distance contacts I'd be looking for something very different. But when choosing which of the three main listening frequencies to try first I think it will be ok.

[JPA Cate]

Don't knock back the net list quite so fast. If you're wanting to contact someone, trying where you already know someone is listening--especially for a maritime mobile--will get you a faster contact, assuming propagation will support 2 way traffic.

Ann

[Cadence]

Originally Posted by JPA Cate

Don't knock back the net list quite so fast. If you're wanting to contact someone, trying where you already know someone is listening--especially for a maritime mobile--will get you a faster contact, assuming propagation will support 2 way traffic.

Ann

I may be wrong? In this day and age it seems like a hobby. Is the network of hams still alive and well. They seemed invaluable at one time but it seems technology may has diminished that, until the satellites die ?

[Annie in WA]

Here in Pacific Mexico ham and marine SSB are still very much in use by many cruisers. Satellite links and phone line are not much use for regional networking like a daily radio net. Sure you can get weather and call someone without HF radio but hearing about weather conditions from someone who is there and how different ports and areas are dealing with virus restrictions the nets are perfect. Last year a buddy of ours had his starter give out and was on the net when another boat 60 miles away had a spare starter, another boater offered his vehicle to deliver the starter to the remote anchorage. There are many ways to cruise and installing a HF radio is expensive and a pain but I wouldn't cruise without one.Much of our circle of close friends are active on HF radio it enriches our lives particularly during social distancing.

[ChrisJHC]

The guys at WICEN seem to be still relevant.

https://wicen.org.au

[coopec43]

Originally Posted by S/V Illusion

While your effort to simplify choice of frequency is good, that chart is useless.

Every day experience with minimal antennas and 100 w shows some of those ranges are wildly optimistic, I.e., 20Mhz and above while below 14 MHz, the range is typically in the hundreds to thousands and even greater below 10 MHz at night. Generalizations included both here and in any chart can be misleading at best.

+1

When TV first started in Australia, TV stations were broadcasting in the Eastern States (2000 miles away) but there was no TV Station in Western Australia at that time. Yet one day when I was watching the "snow" on our TV I could see a poor picture of the start of the Sydney/Hobart Race. Two thousand miles away!! The experts just said it must have been very unusual atmospheric conditions.

[coopec43]

When I get my yacht in the water I most certainly plan to use radio nets.

HF radio nets are the lifeblood of the long-distance cruising community. They exist to keep cruisers connected, allow them to pass along vital information and call for assistance in the event of an emergency.

(Article 2018)
https://www.oceannavigator.com/atlantic-hf-radio-net-formed/

[JPA Cate]

Originally Posted by Cadence

I may be wrong? In this day and age it seems like a hobby. Is the network of hams still alive and well. They seemed invaluable at one time but it seems technology may has diminished that, until the satellites die ?

It is definitely a hobby....also. As soon as there is a bad earthquake, tornado or cyclone damage, anything that takes out local communications, the hams are there helping out.

Even our little ham radio net that we participate in most days first priority is to ask for emergency, medical, or priority traffic; then we go to vessels under way, and then we go to people at anchor (usually propagation is poor in marinas, due to a combination of radio noise and parasitic absorption); or who are land based.

Young people can get ham licenses and be the communications officers for their boats, too. Lots of ways to involve youngies.

You may remember when the Rebel Heart was in distress. Their satphone had quit working due to a billing error. With SSB, once you have the radio and the modem, you are self sufficient for text e-mails, weather information, and you can talk to another human being, propagation willing.

Ann

[Cadence]

Originally Posted by coopec43

+1

When TV first started in Australia, TV stations were broadcasting in the Eastern States (2000 miles away) but there was no TV Station in Western Australia at that time. Yet one day when I was watching the "snow" on our TV I could see a poor picture of the start of the Sydney/Hobart Race. Two thousand miles away!! The experts just said it must have been very unusual atmospheric conditions.

I've spoked to Australia and Norway from coastal South Carolina with a SSB CB
What's that 13 watts. Would I rely on ever doing it again maybe not the same people. Skip is unpredictable.