On Mon, 24 Mar 2008 07:59:50 -0700 (PDT), Artem
wrote:

I think that some disbalance should compensate differencial amplifier
on transistors.

That makes no sense whatever.

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

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).

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

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

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.

73's
Richard Clark, KB7QHC

On Mar 24, 10:02 pm, Richard Clark wrote:
On Mon, 24 Mar 2008 07:59:50 -0700 (PDT), Artem
wrote:

I think that some disbalance should compensate differencial amplifier
on transistors.

That makes no sense whatever.

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

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

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

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"

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

distinction and you could have as easily built a single MOSFET
amplifier rather than a bridge configuration. A split shield around

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

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).

I have.


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

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

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.

http://img245.imageshack.us/my.php?image=d3du5.jpg

On Mon, 24 Mar 2008 15:40:53 -0700 (PDT), Artem
wrote:

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

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

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.

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.

http://img245.imageshack.us/my.php?image=d3du5.jpg

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?

73's
Richard Clark, KB7QHC

On Mar 25, 9:33 pm, Richard Clark wrote:
On Mon, 24 Mar 2008 15:40:53 -0700 (PDT), Artem
wrote:

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

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

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.

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.

http://img245.imageshack.us/my.php?image=d3du5.jpg

Nice close-up. Choking of some of the lines seems OK, but not the
coax.
http://img370.imageshack.us/my.php?image=d2eb0.jpg

Could you find in this picture choke?

So, now where is the schematic of the biasing for these
varicaps? If those two clear insulation lines are going to the loop,

It's lines from resonance loop to amplifier.

it is going to be hard to apply DC to a dead short - or does that
black shroud cover more than the varicaps?

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
http://www.radiointel.com/review-degende1103.htm
receiver?

On Tue, 25 Mar 2008 13:55:16 -0700 (PDT), Artem
wrote:

Nice close-up. Choking of some of the lines seems OK, but not the
coax.
http://img370.imageshack.us/my.php?image=d2eb0.jpg

Could you find in this picture choke?

What material is used in the ferrite?

So, now where is the schematic of the biasing for these
varicaps? If those two clear insulation lines are going to the loop,

It's lines from resonance loop to amplifier.

Does this mean the varicaps are across the loop?

If so:
it is going to be hard to apply DC to a dead short - or does that
black shroud cover more than the varicaps?

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

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

73's
Richard Clark, KB7QHC

On Mar 26, 12:26 am, Richard Clark wrote:
On Tue, 25 Mar 2008 13:55:16 -0700 (PDT), Artem
wrote:

Nice close-up. Choking of some of the lines seems OK, but not the
coax.
http://img370.imageshack.us/my.php?image=d2eb0.jpg

Could you find in this picture choke?

What material is used in the ferrite?

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


So, now where is the schematic of the biasing for these
varicaps? If those two clear insulation lines are going to the loop,

It's lines from resonance loop to amplifier.

Does this mean the varicaps are across the loop?

http://img524.imageshack.us/my.php?image=antjy3.jpg

On Wed, 26 Mar 2008 04:15:20 -0700 (PDT), Artem
wrote:

What material is used in the ferrite?

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

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

73's
Richard Clark, KB7QHC