Using another band

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EA5IYL
 

Posts: 4
Joined: 12 May 2022, 12:12

Using another band

Post by EA5IYL »

I have the 20-30-40-60-80 m version of the (tr)uSDX, which I bought assembled, and I'm having fun with it.
I have managed to tune it to a frequency in the 17 m band, and the radio reported to be transmitting about 1.5W there (maybe 1 W measured at the meter). Is it really working QRPp out of the intended bands? I started from the 20 m band relay setting, of course.
Cheers!
DL2MAN
 

Posts: 706
Joined: 30 Dec 2021, 19:18
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Re: Using another band

Post by DL2MAN »

A class E Device is a resonant circuit. We have one per Band in (tr)uSDX.
Like an Antenna - if used out of Band- it will work to some degree, but with a lot of disadvantages.
In case of "out of Band" use of (tr)uSDX, the Output Power will be lower, while input power will stay roughly the same. This means: A lot of Power is dissapated somewhere.
Basically the same as using an Antenna with real bad SWR..... So you´re asking for the PA FET´s to blow.

In Addition to that: RX Sensitivity is Lower out of Band, and Harmonic Suppression is random at best.

So I would not advise you, to use (tr)uSDX out of Band. At Least not to Transmit !

73 Manuel, DL2MAN
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