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I’m in Sacramento and have an EFHW antenna about 30’ up. I expected to be able to hear the W6WX 14.100 beacon without issue but I cannot. The distance is about 140 miles and the beacon transmits its call at 100w.

I’m trying to determine if I have an antenna issue (I can hear some 20m CW signals) or if my expectations are just wrong.

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    $\begingroup$ Hello and welcome to ham.stackexchange.com! $\endgroup$ – rclocher3 Sep 8 at 17:12
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140 miles is too far away on 20m for groundwave propagation and the "skip" zone or first hop distance, given 20m's general DX capabilities, is much longer than 140 miles. So, I wouldn't expect to hear it "without issue". However, when you're tuned to 14.100, you should be able to copy other beacons in the rotation, if your antenna works.

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  • $\begingroup$ Thanks for the answer. I assume my antenna has some functionality as I’ve made CW contacts on 40m and do hear other 20m stations. Unfortunately I can’t hear any of the 20m beacons. Maybe my 20m noise floor is too high? It’s around S5. $\endgroup$ – nall Sep 7 at 18:39
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    $\begingroup$ That is hard to say without knowing station details etc. You could just call CQ a few times on 20m CW, maybe at different times throughout a day, and check with RBN where your signal is being copied. That should give a fair indication of how you're "getting out". $\endgroup$ – henryflower Sep 7 at 19:22
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    $\begingroup$ @nall it's hard to deal with numbers like that out of context, but an S5 noise floor on a high-HF band like 20 is probably terrible, yes :) $\endgroup$ – hobbs - KC2G Sep 8 at 1:04
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Rather than just answer your question, I'll show you how to answer it yourself.

VOACAP is a good tool for all kinds of HF propagation questions. Entering your location and the location of the beacon into the point-to-point predictions tool, with parameters set to CW, 100 W, dipoles at 33 feet, and "Residential" noise, clicking on "Prop Charts" and then selecting only the 20 meter trace yields this:

enter image description here

With these parameters, this shows that at best you'll be able to hear the beacon 5% of the time, and only between 05:00 and 15:00 UTC, optimally around 11:00 UTC. So it is not unusual that you are unable to hear the beacon.

Clicking "REL map" (REL means reliability) at the bottom generates this insightful image:

enter image description here

This is only valid for one time of day and year, and one band, which you can see in the text at the top. At this particular time (September, 19:00 UTC, 20 meters) you have good coverage of the Midwestern United States, Mexico, Central America, Central and Western Canada, and a lot of the Atlantic Ocean, with fair coverage of Northern Africa, Europe, and some of the Middle East. I'd wager you can find beacons in those regions that you can hear.

That big blue area (indicating unreliable communication) around your station at Sacramento is called the "skip zone". 20 meters doesn't travel too far by ground wave, so to communicate with a nearby station you'd have to reflect the signal off the ionosphere almost directly overhead. But at this time of day, at these frequencies, the ionosphere isn't reflective at those angles: all the radiation at near vertical angles simply escapes to space.

You can also see a 2nd skip zone (passing through Ohio and Kentucky) where 1 skip is too short but 2 skips is too far, and 3rd skip zone through the middle of the Atlantic Ocean.

Decreasing the frequency shrinks the skip zone as the ionosphere becomes more reflective at nearly vertical angles. This is the same map, only for 30 meters:

enter image description here

Notice how the the ring around your station is smaller. Your maximum distance is less, but the skip zone is smaller. This is because during the day, absorption of lower frequencies is higher (limiting the maximum range) but reflection at high angles is better (shrinking the skip zone).

At 40 meters, the skip zone is pretty much gone, but it's also quite useless for long-distance communication:

enter image description here

But if you did want to communicate over long distances on 40 meters, you only need to wait for night. This is 40 meters 12 hours later, at 07:00 UTC:

enter image description here

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  • $\begingroup$ Phil, all I can say is a huge thank you for "teaching me to fish"! This is very helpful! $\endgroup$ – nall Sep 8 at 19:05

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