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