On Mar 24, 4:59 pm, Artem wrote:
I just did now how them because this is trivial.
I did not show varicaps because this is trivial.
Sorry.

On Mar 24, 4:59 pm, Artem wrote:
I just did now how them because this is trivial.
I did not show varicaps because this is trivial.
Sorry.

On Mar 24, 4:59 pm, Artem wrote:
I just did now how them because this is trivial.
I did not show varicaps because this is trivial.
Sorry.

On Mon, 24 Mar 2008 04:32:39 -0700 (PDT), Artem
wrote:

I've observed that, and I have observed it is not enough from your
photo - if you still have self-oscillation. Your pictures do not
reveal any choking of the RF Out cable.

It's inside. Nearby BNC socket.

Which defeats the choking.

As for the diagonal arm for "ground." This is fine insofar as it
being placed in the electrical middle of the antenna loop (a ground),
but all this rat's nest of wiring throws the concept of balance out
the window.

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

That makes no sense whatever.

another invitation to problems when a 9V battery would
solve that too. Local power would discard the need for the ground

Yes. But FETs draw more that 10ma each.

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

coming from the loop's perimeter, eliminate unnecessary AGC, reduce
the complexity of choking, lower gain (it obviously has too much), and
give you only one coax coming from the antenna.

Cable length is not problem. I'm living in apartment. I can put
antenna outside the window. But not on the roof.

I can make power supply over coax cable. I can put Atmega8 (en
example) to amplifier and add DACs for operate varicaps, AGC. I can
add rectifier and filter for detect self-oscillation and automatics
reduce AGC. But it's not necessary.

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

73's
Richard Clark, KB7QHC

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 Sun, 23 Mar 2008 12:39:35 -0700 (PDT), Artem
wrote:

On Mar 22, 8:48 pm, K7ITM wrote:


15 floor of 16-floor building. But I think that in this case "ground"
are building walls.

There is a hint he it is common that tall buildings incorporate a
lot of steel, and that will likely act as a shield. I hope this
antenna is not mounted inside!

It's not mounted at all. But for tests I'm put this antenna outside.




vertical) -- -- where "close" means relative to a wavelength. So the
small balanced loop is especially good for LF and VLF work.

my reason was make narrow-band antenna. For reject all out of band
noise.

A reasonable thing to do, though a good receiver with a low-distortion
and fairly narrow-band front end should not have trouble with out-of-
band signals (noise). Do you have a quantitative measure of just how
strong this out of band noise is?
Not. Just not received.

I'd personally much rather use a
preselection filter separate from the antenna, and close to my
operating position, to reject out-of-band signals. Even though the
antenna you have described has very high Q, I believe I could do
better with a two or three resonator filter running at lower Q, since
the slope of the attenuation versus frequency is much greater.

I will receive QRSS at all. And I think that it would be best way is
using
narrow-band antenna - filter - synchronous detector.

there was some especially strong signal in the band, I would at least
consider a fixed-tuned bandpass filter that covered my band of
interest, assuming that band is fairly narrow such as 7.0-7.1MHz.

Can you tell that you are getting the expected antenna bandwidth,
about 3kHz at the 3dB points at 7MHz?

I'm just testing. I will purchase RF generator in next week and test.
Now I have only self-oscillation frequency.

Antenna looks like working. I'm receiving a lots of Morse signals at
7.000 - 7050 Mhz. But I cant recognize any voice signal.

This is receiving signal. Looks like narrow-band enough. This is not
self oscillation. In self oscillation voltage a few volts.
http://img148.imageshack.us/my.php?image=ds0000bu6.png

This is schematics. I'm not sure that I'm correct use gual gate
transistors.
http://img210.imageshack.us/my.php?image=schbr1.jpg

I'm not sure that using shielded cable and ferrite chocks is good
idea.
http://img171.imageshack.us/my.php?image=hwak2.jpg

np0 caps.
http://img370.imageshack.us/my.php?image=capsnf8.jpg

Please see the US ARRL frequency chart he

http://www.arrl.org/FandES/field/reg...ands_color.pdf

7000 to 7050 MHz is RTTY and Morse code only. If you want voice,
probably SSB try 7125 to 7300 MHz.

On Mar 25, 7:29 am, JosephKK wrote:

Please see the US ARRL frequency chart he

http://www.arrl.org/FandES/field/reg...ands_color.pdf

7000 to 7050 MHz is RTTY and Morse code only. If you want voice,
probably SSB try 7125 to 7300 MHz.

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

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?