Narrow band antenna.

Disbalance mean in-phase signal on gate 1 FETs. differencial will not amplify this signal.

I have. I just did now how them because this is trivial.

I did not show varicaps because this is trivial. Sorry.

I did not show varicaps because this is trivial. Sorry.

I did not show varicaps because this is trivial. Sorry.

Which defeats the choking.

That makes no sense whatever.

That is trivial. However, you can bias for less because you don't need that much drain current.

Sounds like a lot of unnecessary complexity. The one thing you repeat is varicaps, but I don't see them.

This is still a strain in language as you have done nothing to describe what the "compensation" is for. The circuit of your schematic is fully differential in a bridge configuration, so saying it will not amplify still makes no sense. To offer a deliberate imbalance to a balanced circuit gives rise to astability which is the first hallmark of oscillation - especially in an amplifier with too much gain, and too much current drain - or a lockdown.

I get every impression that this bridge configuration arrived from some sense of "ground" that then drove the need for the cross piece to the midpoint of the loop. That point is "ground", but only as an electrical neutral to the loop. It carries no other "ground" distinction and you could have as easily built a single MOSFET amplifier rather than a bridge configuration. A split shield around the loop (or integrating it into the design) would have simplified AGC and control lines too.

You tried to incorporate some of the split shield design into this when you enclosed the amplifier and made a socket connection, but you defeated the benefit of the choke at the same time with a zero net gain (the choke, as built, has no use).

They are not shown in your schematic. I don't see them in your photos. Making them operational is adding yet more lines, although I can see they would be necessary for your purposes.

Providing the decoupled varicap bias into a balanced circuit is not trivial at all, and offers the prospects of returning to that self oscillation. There will be something like half a dozen components for that alone.

HOWEVER, this is all beside the point unless your design breaks into oscillation again. You haven't informed us how you cured that since you announced you had solve all your problems.

It will not amplify signal in-phase signal. It's same like differential amplifier.

Yes. It's "Ground" only for bridge amplifier.

It's more difficult for me. It's looks more simply for me to build fully symmetrical amplifier.

I have.

Please see the US ARRL frequency chart here:

I'm in Europe. We have only 7000....7100.

This still makes no sense. You have not described what you are "compensating" for, and differential amplifiers amplify without distinction to "in-phase" or "out-of-phase." If it did, you are not using the right topology because you are using operational amplifier terminology - the circuit is not an operational amplifier, even by discrete components.

Nice close-up. Choking of some of the lines seems OK, but not the coax. So, now where is the schematic of the biasing for these varicaps? If those two clear insulation lines are going to the loop, it is going to be hard to apply DC to a dead short - or does that black shroud cover more than the varicaps?

Could you find in this picture choke?

It's lines from resonance loop to amplifier.

Now my Antenna in broken. I will fix my antenna mad make a web for schematics, software for calculation? etc.

PS: Could anyone know, What I can receive in QRSS, 7 MHz in Europe on this

The most effective antenna for size and gain in this range would be the DDRR or variations of it such as the normal mode helix. They both are single loops of copper pipe tuned at the end with a capacitor (probably a "real" capacitor rather than a varicap would work better.) The Helix is basically the DDRR with the ground plane removed and the image side constructed. For more information go look at my article in a VERY old issue of QST (May 76) and somewhere about that time you'll also find two articles on the DDRR which are very detailed and excellent! Note that these are often called "hula hoop" antennas. They are basically transmission line antennas.

What material is used in the ferrite?

Does this mean the varicaps are across the loop?

If so:

You've done it by parts already, so, sure.

For transformer - low magnetic permeability (50) for chokes - high.

I'm use USSR ferrite 50HH.

Unless you can be more specific, this sounds like the wrong material (which you have not specified - do you know what you used?).

Google reveals all of one page in the entire Web that responds to that as a search term - and that page refuses to load.