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Because of my living situation I am using a Par EndFedz Mk II Trail Friendly antenna with my IC-7300, since it can do 40m and 20m and is only 41 feet long. However, it can only handle 25W.

Now, for FT8 25W is sufficient for all sorts of contacts (living in the northeast US I've had a number of EU and South American QSOs on FT8 at 25W on 40m and 20m).

But SSB is an entirely different beast since it requires a much much higher SNR than FT8 does.

Can one reasonably make SSB contacts with 25W? Or will that pretty much have to wait until I'm in a situation where I can use an antenna that can handle at least 100W?

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    $\begingroup$ voacap.com $\endgroup$ Sep 5, 2021 at 3:12
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    $\begingroup$ ^^^ What Phil said about VOACAP. @PhilFrost-W8II I'm pretty sure that you nicely expounded on this in an answer. IMHO it would be good to link to it here. :) Also, this Q seems like it's been asked before; but if so, I could not find it. $\endgroup$ Sep 5, 2021 at 22:23

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All things are possible (if a bit harder). The CQ WW SSB contest has a QRP category (maximum of 5 watts of power), and the top scorers in that category in 2020 worked more than 100 countries in 48 hours. Probably not with a portable antenna, but then again, you've got 7dB more power than them to help even things out! There is no "range limit" on HF. Lower power requires more in the way of planning and patience, but logarithmically, 25 watts is closer to 100 than to 5.

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Depends on ionospheric propagation conditions (sun spots, solar flux index, time-of-day, direction, and etc.).

People have completed QSOs at well over a thousand miles with a few milliwatts in CW. A SSB QSO typically requires 100X to almost 1000X more power than CW to complete a QSO, which still comes to less than 25 W. On the other hand, on some days I can't get an HF signal heard anywhere that is not line of sight due to electromagnetic disturbances (A and K indexes, solar flares, etc.)

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Can one reasonably make SSB contacts with 25W?

Yes you can, I have. In fact I have transatlantic QSO's with 10 W.

Already mentioned prior: the lower the power the more the challenge, and more it depends on all factors of propagation, noise levels, antenna-system including feedline, and so on so forth.

In my opinion: 25W is not much, but certainly not low.

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You can make SSB contacts with 25W (I managed a transatlantic SSB QSO with 10W PEP).

It's also possible to look at your FT8 received signal reports from your QSO partners to get a sense of whether SSB would have been possible if you'd both been working phone instead of data; if your received signal report from a partner when you transmit at 25W is a positive number (not negative) then SSB contacts to people in the same area are likely possible at the power you're using. You can, of course, adjust this if you're running at less than 25W - for example, if you're transmitting at 2.5W, a signal report of -10 or higher is a sign that SSB contacts are probably possible if someone's listening in the same area as your partners.

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