Pure signal and digital modes

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Tony EI7BMB
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Pure signal and digital modes

Postby Tony EI7BMB » Tue Jun 18, 2024 7:59 am

Sorry if this is a dumb question , is there any benefit to using a sampler/pure signal on digital modes like Ft8 ?
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w-u-2-o
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Re: Pure signal and digital modes

Postby w-u-2-o » Tue Jun 18, 2024 10:30 am

Yes, certainly. Anything that improves transmitter linearity is a good thing.

However, not all digital modes will play well with PS on automatic. You can use the Single Cal feature to obtain a PS correction then just let that ride until you change VFO frequency. Transmit two-tone, then use Single Cal repeatedly until you are happy, then let it ride.
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Tony EI7BMB
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Re: Pure signal and digital modes

Postby Tony EI7BMB » Tue Jun 18, 2024 3:53 pm

Thanks Scott, think I'll get one of those VK samplers
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w9ac
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Re: Pure signal and digital modes

Postby w9ac » Mon Jun 24, 2024 1:27 pm

Tony EI7BMB wrote:Sorry if this is a dumb question , is there any benefit to using a sampler/pure signal on digital modes like Ft8 ?

Not when operating most FSK modes like FT8 unless you operate in "Fox" mode where up to five carriers are generated, 60 Hz from each other. Otherwise, FT8 is a single frequency, constant amplitude modulation mode that under typical operation, isn't subject to IMD degradation.

FT8 is used successfully with Class C and Class D amplification. For example, look at the QRP Labs QDX data transmitter specifications. It operates only under Class D modulation.

Paul, W9AC
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Tony EI7BMB
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Re: Pure signal and digital modes

Postby Tony EI7BMB » Mon Jun 24, 2024 6:13 pm

Thanks for the info Paul .
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w-u-2-o
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Re: Pure signal and digital modes

Postby w-u-2-o » Mon Jun 24, 2024 8:07 pm

The same would not be true for any multi-tone/multi-carrier mode like VARA, WINMOR, PACTOR, MT63 and others.

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