Try this.
http://www.grove-ent.com/WR0130.html

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 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

QUADRA,
..
Consider an "Around-the-Room" (Ceiling) Loop Antenna,
or an "On-the-Wall" Loop Antenna as an INDOOR Antenna
to use with your RadioShack "Realistic" DX-160 Receiver.
..
The Loops will generally be about Forty Feet plus
for an Around-the-Room (Ceiling) Loop Antenna, or
Thirth-Six Feet plus an On-the-Wall Loop Antenna.
..
1. Use Hook-Up Wire for the Antenna Wire Element.
RadioShack Catalog # 278-1225
Sixty Feet of Stranded #20 AWG Insulated Wire
..
2. Use a 'piece' of 300 Ohm TV Twin Lead as the
Feed-in-Line from the Loop Antenna to the Terminals
on the back of the DX-160.
RadioShack Catalog # 15-1174
Two 20 AWG Stranded Copper Conductors
Insulation consists of Inner Low-Loss Foam Insulation
and Outer Covering of Heavy-Duty Polyethylene
..
IMHO - Using the RadioShack DX-160 with a small size
(short length) "In-the-House" Loop Antenna; that using a
Matching Transformer and Pre-Selector are not required.
..
READ - Indoor Antenna & Lead-In = Hook-Up Wire / TV Twin Lead
http://groups.yahoo.com/group/Shortw...nna/message/75
..
READ - Try "In-Door" {Inside-the-House} Antennas First before . . .
http://groups.yahoo.com/group/Shortw...a/message/1036
..
READ - Looking for a "Silent Antenna"
Consider a {Shielded} Loop Antenna
http://groups.yahoo.com/group/Shortw...a/message/1008
..
READ - A 'look' at three MFL Antenna Turners / Pre-Selectors
http://groups.yahoo.com/group/Shortw...na/message/980
..
READ - Two InDoor "Hidden" SWL Antenna Ideas
http://groups.yahoo.com/group/Shortw...na/message/209
..
READ - The Carpet Loop Antenna
[ Sizing the Loop and Choosing the Cable ]
http://groups.yahoo.com/group/Shortw...na/message/292
..
..
iane ~ RHF
..
All are WELCOME at the Shortwave Listener (SWL) "Antenna Ashram"
http://groups.yahoo.com/group/Shortw...na/message/502
Some Say: On A Clear Day You Can See Forever.
I BELIEVE: On A Clear Night . . .
You Can Hear Forever and Beyond, The BEYOND !
[ With the an AM/MW - FM - SWL Antenna of your own making. ]
..
..

QUADRA,
..
READ - The RadioShack Realistic DX-160 Receivers
- - - - - USERS - ANTENNA - SURVEY - - - -
..
SOURCE - Newsgroups : Rec.Radio.Shortwave
From: *t (David Neece)
Date: 1998/05/20
Subject: RadioShack Realistic DX-160 Users: Antenna Survey
..
RadioShack Realistic DX-160 = http://tinyurl.com/4qzlc
http://groups-beta.google.com/group/...75e180bc56f5a4

..
..
RadioShack Realistic DX-160 and Eavesdropper Antenna Installation
SOURCE = Newsgroups: Rec.Radio.Shortwave
From: Charlie Meyer *t
Date: 1997/12/31
Subject: Advice: Realistic DX-160 and Eavesdropper Antenna Installation
http://groups-beta.google.com/group/...09bd848888d809

..
RadioShack Realistic DX-160 - Home Made Antenna Questions
SOURCE = Newsgroups: Rec.Radio.Shortwave
From: *m (Christopher A. King)
Date: 1999/09/10
Subject: Home Made Antenna Questions
http://groups-beta.google.com/group/...11f88ff0220628

..
..
iane ~ RHF
..
All are WELCOME at the Shortwave Listener (SWL) "Antenna Ashram"
http://groups.yahoo.com/group/Shortw...na/message/502
Some Say: On A Clear Day You Can See Forever.
I BELIEVE: On A Clear Night . . .
You Can Hear Forever and Beyond, The BEYOND !
[ With the an AM/MW - FM - SWL Antenna of your own making. ]
..
..

" wrote:

Hi--

I have a Realistic DX-160 in very nice conditiion I bought about 10
years ago (for $15!). My current living situation in Los Angeles no
longer affords me the luxury of an outdoor antenna, so I am using 40
ft. of 16 gauge copper speaker wire running along the ceiling moulding
as my antenna.

(ALSO: the DX-160 is in the same room with a lot of other electronic
equipment: computer, TV, stereo, audio recording equipment, mixer,
etc.)

I've read a lot in this newsgroup about modifying the DX-160, but as my
radio engineering skills are in their infancy, I've decided on
improving my antenna situation. It seems preselectors or the 9:1
matching transformer have favorable reviews here but I'd lke to know:

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

If it were me, I'd sell the DX-160 and use the money I got for it, along with the money I was planning to spend on a preselector or mlb to buy a better radio.

I suspect a $75 Kaito or Degen 1103 would be easier to tune, more stable, and at least as sensitive as your DX-160.

For about $150 you could get a Sony 7600GR - it's one of the better portables, and has a good sync detector.

If you're willing to spend a little more, you'll have other options.

The thing is even if you added $1,000 of accessories to your DX-160, the heart of your system is still going to be a "nothing special" radio.

Making your own MLB really is easy, but with a 300 ohm antenna input, you'd want something in the range of 1.5:1 for a random wire.

I normally prefer MLB's to preselectors because I'd just as soon have fewer things to tweak, but on the DX-160, a preselector might do more for you than a MLB.

But a decent modern portable with a simple loop around the ceiling will probably give you the most bang for the buck.

wrote:

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?


Some food for thought...

http://web.telia.com/~u85920178/


Which has this in it. It's hard to find, but it's there.

http://web.telia.com/~u85920178/antennas/balun0.htm

mike

MII - Thank You Very Much for this Link / URL ~ RHF
..
..
WHAT -?- "RF BALUNs" - by Harry Lythall [SM0VPO]
..
BALUN = http://web.telia.com/~u85920178/antennas/balun0.htm
..
WHY -?- Should "I" Read this WebPage / Check-Out this Link URL ?
..
READ = http://web.telia.com/~u85920178/antennas/balun0.htm
..
Elemination of Radiation from the Feeder Cable
..
Makes the Antenna Radiation Pattern Predictable.
..
Dramatically Reduces QRM, TVI to neighbours.
..
Helps to Keep RF Out of the Shack.
..
CHECK-OUT = http://web.telia.com/~u85920178/antennas/balun0.htm
..
..