The front end discussion (V4 vs V3X)

[DB9JG]

My result of some tests comparing a Theremin‑modded V4 versus a V3X:

Short story: The V4 wins.
Long story: The V4 still wins.

I really have to admit that the V3X does a good job as long as it is not exposed to a loud RF environment at the short telescopic whip or a „real“ antenna.
When simultanously listening to the same signals on two earphones, both radios performed well with no significant audible difference.
The result shifted clearly in favor of the V4 when the signals became stronger and especially when using external broadband antennas via a splitter.
There is a lot of signal distortion on the V3X, apparently caused by cross‑modulation with strong LW and MW signals.
This distortion is not audible with the V4 (the same good result was also observed with a V3S).

One minor pro for the V3X: There is absoluteley NO Theremin effect as the RF-amplifier isolates the FMI from the antenna input.

My personal winner is the V4xxl (formerly known as V4).

But for people who weren’t born with a soldering iron in their hand, the V4B is preferable, as demonstrated in other threads.

For the video demonstrating the large signal behavior:

https://www.facebook.com/groups/629443686140117/permalink/897861035965046/?

[Ilja-code-art]

where to bay?

[ghplw]

This page lists the places you can buy it but currently there's no guarantee that you'll get the 4B.
https://atsmini.github.io/

I ordered mine from this store a couple of weeks ago and go the 4B.
https://www.aliexpress.com/item/1005008683589611.html

[DB9JG]

V4 vs V3X @147kHz

A V3X and a V4 (with Theremin mod):

• Frequency: 146.72 0kHz, LSB
• Telescopic whips: 40 cm
• No ground connection
• H. J. Berndt firmware, default settings (AGC on)

Result:
• V4: reception sufficient
• V3X: no reception, only some off-frequency neighboring LW signals

Notes:

• The video compares the received audio signals of both MiniRadios.
• The photo shows the test setup.
• The screenshot displays the spectrum observed simultaneously at a nearby MiniWhip antenna. Signal level at the MiniRadios’ telescopic whips is about 10 dB weaker than the MiniWhip spectrum.

For the video: https://m.facebook.com/groups/629443686140117/permalink/898598929224590/?