On Wed, 05 Jan 2005 12:23:44 GMT, "Merwin Dooley"
wrote:

Try this.
http://www.grove-ent.com/WR0130.html
I lokked at that and am amazed that a balun can give 5dB gain! What I
would expect is that it could help in reducing the noise floor and
thus sound like you have gain; or provide a better impedence match (at
some frequency(ies) to allow more signal to pass - perhaps. But gain,
nope - I just don't see it unless I have totally missed out on some
part of my radio education.
Howard



1) The DX-160 has an Antenna trim knob, so is a preselctor redundant?
2) The 9:1 matching impedance transformer is intriguing, but can they
be found/purchased already built?

Thanks in advance for any input!

SWS

Howard wrote:

On Wed, 05 Jan 2005 12:23:44 GMT, "Merwin Dooley"
wrote:

Try this.
http://www.grove-ent.com/WR0130.html
I lokked at that and am amazed that a balun can give 5dB gain! What I
would expect is that it could help in reducing the noise floor and
thus sound like you have gain; or provide a better impedence match (at
some frequency(ies) to allow more signal to pass - perhaps. But gain,
nope - I just don't see it unless I have totally missed out on some
part of my radio education.
Howard

You've missed a lot...

It ain't rocket science...

Damn.

dxAce
Michigan
USA




1) The DX-160 has an Antenna trim knob, so is a preselctor redundant?
2) The 9:1 matching impedance transformer is intriguing, but can they
be found/purchased already built?

Thanks in advance for any input!

SWS

On Wed, 05 Jan 2005 23:31:40 -0500, dxAce wrote:



Howard wrote:

On Wed, 05 Jan 2005 12:23:44 GMT, "Merwin Dooley"
wrote:

Try this.
http://www.grove-ent.com/WR0130.html
I lokked at that and am amazed that a balun can give 5dB gain! What I
would expect is that it could help in reducing the noise floor and
thus sound like you have gain; or provide a better impedence match (at
some frequency(ies) to allow more signal to pass - perhaps. But gain,
nope - I just don't see it unless I have totally missed out on some
part of my radio education.
Howard

You've missed a lot...

It ain't rocket science...

Damn.

dxAce
Michigan
USA


Huh? If I'm mistaken, which could be, at least give me a hint why I'm
wrong and I will follow up on it. I know this isn't rocket science
as I work with rocket scientists and many know little about radio.
Until shown otherwise I stand by my statement that the balun will not
add gain to the antenna - though it has other characteristics that
will improve the received signal.

Have a good one DX,
Howard
ps - I don't use a portable as my primary receiver 8-}

Howard wrote:

Huh? If I'm mistaken, which could be, at least give me a hint why I'm
wrong and I will follow up on it.

Oh, ignore our professional idiot.

You did miss something, however. The impedence mismatch makes the
energy transfer from the antenna to the receiver to be inefficient. 5
dB is just about right for any 9:1 matching transformer (from an
end-fed wire to a 50 ohm load).

I'm not going to attempt to explain the theory behind it since I will
certainly leave something out and the peanut gallery will come to life
again, but think about SWR and reflected power and how bad the
mismatch can be without the transformer vs. how bad it would be with
the transformer.

For a practiacal demonstration try (BRIEFLY) to feed a speaker from a
tube amp without using a matching transformer. (You'll want a
blocking capacitor, though.)

I know this isn't rocket science
as I work with rocket scientists and many know little about radio.

:-)

Until shown otherwise I stand by my statement that the balun will not
add gain to the antenna - though it has other characteristics that
will improve the received signal.

No, no *gain* added to the antenna, but better power transfer to the
radio from the antenna. 5 dB is what I've measured as well. I use
ICE prepackaged transformers and Mini-Circuits transformers.


Have a good one DX,
Howard
ps - I don't use a portable as my primary receiver 8-}

--
Eric F. Richards

"Nature abhors a vacuum tube." -- Myron Glass,
often attributed to J. R. Pierce, Bell Labs, c. 1940

"Eric F. Richards" wrote:

Howard wrote:

Huh? If I'm mistaken, which could be, at least give me a hint why I'm
wrong and I will follow up on it.

Oh, ignore our professional idiot.

You did miss something, however. The impedence mismatch makes the
energy transfer from the antenna to the receiver to be inefficient. 5
dB is just about right for any 9:1 matching transformer (from an
end-fed wire to a 50 ohm load).

I'm not going to attempt to explain the theory behind it since I will
certainly leave something out and the peanut gallery will come to life
again, but think about SWR and reflected power and how bad the
mismatch can be without the transformer vs. how bad it would be with
the transformer.

For a practiacal demonstration try (BRIEFLY) to feed a speaker from a
tube amp without using a matching transformer. (You'll want a
blocking capacitor, though.)

I know this isn't rocket science
as I work with rocket scientists and many know little about radio.

:-)

Until shown otherwise I stand by my statement that the balun will not
add gain to the antenna - though it has other characteristics that
will improve the received signal.

No, no *gain* added to the antenna, but better power transfer to the
radio from the antenna. 5 dB is what I've measured as well. I use
ICE prepackaged transformers and Mini-Circuits transformers.

OK, so it adds 'system' gain.

Call it what you want!

dxAce
Michigan
USA

"Eric F. Richards" wrote:

Howard wrote:

Huh? If I'm mistaken, which could be, at least give me a hint why I'm
wrong and I will follow up on it.

Oh, ignore our professional idiot.

If I'm a 'professional idiot' then I'm a damn good one!

LOL

dxAce
Michigan
USA