In article . net,
"Sanjaya" wrote:

"Telamon" wrote in message
..
.
In article . net,
"Sanjaya" wrote:

I've read and heard both sides of the argument about antenna tuners
being great, or not helping at all and are a waste of money. I've
been told they are only for shortwave transmitting, and I've been
told they work well to improve shortwave reception on faint signals.
I've had it suggested to me that I get a pre-selector instead.

I can't find anyone who actually experimented with either a tuner or
pre-selector... at least none of what I've read and heard was stated
as "experience"... rather it seemed like theory or conjecture.

Does anyone here actually use a tuner or pre-selector for shortwave
listening, and if so, with what results? I'm looking at the MFJ-959C
antenna tuner at
http://www.universal-radio.com/catal...amps/2574.html Note that it
says "for receive only".

A tuner solves a specific problem. If you don't have that problem it's
not going to help much. The problem is selectivity. If your radio has
enough for your listening situation then the tuner will not do much for
you other than boost the signal a little that you are trying to hear.
The tuner will reduce the other signals above and below where it is
tuned to your radio.

There are various types of tuners that behave somewhat differently but
this is the GENERIC explanation for them.

You can the maximum benefit from a tuner if it is used to resonate an
ordinarily non-resonant antenna like a random wire Marconi type antenna.
For this to work well the wire is directly connected to the tuner and
then the tuner is connected by coax to the radio. The tuner changes the
ELECTRICAL LENGTH of the wire so it resonates at some frequency. The
boost from using the tuner to resonate the wire can make the difference
between hearing a very weak signal or helping to make it more legible if
it is next to a much stronger station on a nearby channel.

It is basically a DX'ing tool used to tweak the antenna situation in
order to get the weakest of stations.


Thanks Telamon.

Your welcome and I meant to say above "You can get the maximum benefit"
at the start of the second paragraph up.

--
Telamon
Ventura, California

Sanjaya wrote:

I've read and heard both sides of the argument about
antenna tuners being great, or not helping at all and are
a waste of money. I've been told they are only for shortwave
transmitting, and I've been told they work well to improve shortwave
reception on faint signals. I've had it suggested to me that I
get a pre-selector instead.

I can't find anyone who actually experimented with either a tuner or pre-selector... at least
none of what I've read and heard was stated as "experience"... rather
it seemed like theory or conjecture.

Does anyone here actually use a tuner or pre-selector for shortwave listening, and if so,
with what results? I'm looking at the MFJ-959C antenna tuner at
http://www.universal-radio.com/catal...amps/2574.html
Note that it says "for receive only".

If you're using a portable receiver with a fairly long external antenna,
a passive preselector would be the most useful device between the
antenna and receiver. It would help to eliminate the symptoms of signal
overloading caused by insufficient dynamic range in the receiver. I used
a preselector with the Sony-2010, connected to an inverted-L antenna. It
made a big difference with reducing intermod's.

Quality table-top receivers like the Drake-R8, Icom-R75, AOR-7030 and
many others, don't need a pre-selector or antenna tuner to enhance
reception. They work very well when connected directly to a well
designed external antenna. My R8B uses an inverted-L with a good 'RF'
grounding system to reduce the noise from domestic sources like
televisions and computers. Keeping the noise down is more important than
getting the last bit of energy from the antenna with a tuner.

BTW- The MFJ-959C is "for receive only" because it's componants can't
handle the power from a transmitter. Universal is not trying to give
their opinion on whether you should or should not use an antenna tuner
for receiving.


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"starman" wrote in message ...
Sanjaya wrote:

I've read and heard both sides of the argument about
antenna tuners being great, or not helping at all and are
a waste of money. I've been told they are only for shortwave
transmitting, and I've been told they work well to improve shortwave
reception on faint signals. I've had it suggested to me that I
get a pre-selector instead.

I can't find anyone who actually experimented with either a tuner or pre-selector... at least
none of what I've read and heard was stated as "experience"... rather
it seemed like theory or conjecture.

Does anyone here actually use a tuner or pre-selector for shortwave listening, and if so,
with what results? I'm looking at the MFJ-959C antenna tuner at
http://www.universal-radio.com/catal...amps/2574.html
Note that it says "for receive only".

If you're using a portable receiver with a fairly long external antenna,
a passive preselector would be the most useful device between the
antenna and receiver. It would help to eliminate the symptoms of signal
overloading caused by insufficient dynamic range in the receiver. I used
a preselector with the Sony-2010, connected to an inverted-L antenna. It
made a big difference with reducing intermod's.

Quality table-top receivers like the Drake-R8, Icom-R75, AOR-7030 and
many others, don't need a pre-selector or antenna tuner to enhance
reception. They work very well when connected directly to a well
designed external antenna. My R8B uses an inverted-L with a good 'RF'
grounding system to reduce the noise from domestic sources like
televisions and computers. Keeping the noise down is more important than
getting the last bit of energy from the antenna with a tuner.

BTW- The MFJ-959C is "for receive only" because it's componants can't
handle the power from a transmitter. Universal is not trying to give
their opinion on whether you should or should not use an antenna tuner
for receiving.


Thanks for clearing that up Starman.

= = = "Sanjaya" wrote in message
= = = link.net...
I've read and heard both sides of the argument about
antenna tuners being great, or not helping at all and are
a waste of money. I've been told they are only for shortwave
transmitting, and I've been told they work well to improve shortwave
reception on faint signals. I've had it suggested to me that I
get a pre-selector instead.

I can't find anyone who actually experimented with either a tuner or pre-selector... at least
none of what I've read and heard was stated as "experience"... rather
it seemed like theory or conjecture.

Does anyone here actually use a tuner or pre-selector for shortwave listening, and if so,
with what results? I'm looking at the MFJ-959C antenna tuner at
http://www.universal-radio.com/catal...amps/2574.html
Note that it says "for receive only".

SANJAYA,

The Age Old SWL'ers Question:
Do I Need a Antenna Tuner ? -or- a Pre-Selector ?

The MFJ-959 is OK for what it does. The one feature that would
interest me would be the ability to use it with Two (2) Radios
and Two (2) Antennas. Switch between the Radios and Antennas.
The built-in Amplifier can be helpful for hearing weak signals.

If you are using a simply Random Wire Antenna or any Antenna
with a 'direct' Coax Cable Feed-in-Line. The MFJ-959 should
help in 'matching' you Antenna to the Radio's Input and
improving your signal transfer.

HOWEVER - If you are using an Improved SWL Random Wire Antenna
that uses a 9:1 Matching Transformer (Balun / MLB) then you may
not see any real 'improvement' in your receive signal.

This is the so called "Low Noise" SWL Antenna.
[ Please READ These Three Links ]
http://www.anarc.org/naswa/badx/ante...e_antenna.html
http://www.anarc.org/naswa/badx/ante..._longwire.html
http://www.anarc.org/naswa/badx/antennas/grounding.html
ABOUT THE "LOW NOISE" ANTENNA 'DESIGN CONCEPTS':
A Random Wire Antenna Element coupled via a 9:1 Matching
Transformer at the Near-End of the Antenna with a Ground Rod
and Coax Cable Feed-in-Line to the Receiver. This is the basic
SWL Antenna that uses the "Low Noise Antenna" 'design concepts'
that were popularized by John Doty.

You may also wish to consider these two other MFJ Products:
* MFJ-1045C SWL Receiver Pre-Selector with built-in Amplifier
which covers the Shortwave Bands from 1.8 to 54 MHz.
http://www.universal-radio.com/catal...amps/0807.html
* MFJ-1020C Indoor Active Antenna which covers 300 kHz to
40 MHz (LW, AM/MW and SW Bands) in five bands; and when used
with an External (OutSide) Antenna, the MFJ-1020C functions
as a Pre-Selector.
http://www.universal-radio.com/catalog/sw_ant/1413.html


FWIW: I use a Low Noise SWL Antenna with a Grove Mini-Tuner
"TUN 3" which is very much like the MFJ-956 MFJ-956 Long Wave,
Medium Wave and Shortwave Pre-Selector Tuner.
http://www.universal-radio.com/catal...amps/2964.html
- Most times I simply use it in the ByPass Mode.
- Sometimes I will switch it over ti Fine-Tune a Signal.
- The major reason I use it is to Switch-Out "Ground-Out"
the Antenna when I am not using the Radio for Safety.

READ: John Wagner's Shortwave Tips & Tricks
http://www.dxing.com/tips.htm
- Section: Antennas for Portable Receivers
- Point # (7) The Wagner Active Preseletor Antenna

READ: Antenna Tuner, radio preselector, what is the difference?
http://groups.yahoo.com/group/Shortw...a/message/1119
- Five "Do-It-Yourself" Antenna Turners with Schematics
- Impedance Matching Unit VS. Pre-Selector/ATU
- Pre-Selectors = So Many Choices . . .
- Antenna Tuner / Pre-Selector = The 'little' Box that May Help !


iane ~ RHF
..
Some Say: On A Clear Day You Can See Forever.
http://groups.yahoo.com/group/Shortw...na/message/502
I BELIEVE: On A Clear Night...
You Can Hear Forever and Beyond, The Beyond !
..
..

"RHF" wrote in message
om...
= = = "Sanjaya" wrote in message
= = = link.net...
I've read and heard both sides of the argument about
antenna tuners being great, or not helping at all and are
a waste of money. I've been told they are only for shortwave
transmitting, and I've been told they work well to improve shortwave
reception on faint signals. I've had it suggested to me that I
get a pre-selector instead.

I can't find anyone who actually experimented with either a tuner or pre-selector... at least
none of what I've read and heard was stated as "experience"... rather
it seemed like theory or conjecture.

Does anyone here actually use a tuner or pre-selector for shortwave listening, and if so,
with what results? I'm looking at the MFJ-959C antenna tuner at
http://www.universal-radio.com/catal...amps/2574.html
Note that it says "for receive only".

SANJAYA,

The Age Old SWL'ers Question:
Do I Need a Antenna Tuner ? -or- a Pre-Selector ?

The MFJ-959 is OK for what it does. The one feature that would
interest me would be the ability to use it with Two (2) Radios
and Two (2) Antennas. Switch between the Radios and Antennas.
The built-in Amplifier can be helpful for hearing weak signals.

If you are using a simply Random Wire Antenna or any Antenna
with a 'direct' Coax Cable Feed-in-Line. The MFJ-959 should
help in 'matching' you Antenna to the Radio's Input and
improving your signal transfer.

HOWEVER - If you are using an Improved SWL Random Wire Antenna
that uses a 9:1 Matching Transformer (Balun / MLB) then you may
not see any real 'improvement' in your receive signal.

This is the so called "Low Noise" SWL Antenna.
[ Please READ These Three Links ]
http://www.anarc.org/naswa/badx/ante...e_antenna.html
http://www.anarc.org/naswa/badx/ante..._longwire.html
http://www.anarc.org/naswa/badx/antennas/grounding.html
ABOUT THE "LOW NOISE" ANTENNA 'DESIGN CONCEPTS':
A Random Wire Antenna Element coupled via a 9:1 Matching
Transformer at the Near-End of the Antenna with a Ground Rod
and Coax Cable Feed-in-Line to the Receiver. This is the basic
SWL Antenna that uses the "Low Noise Antenna" 'design concepts'
that were popularized by John Doty.

You may also wish to consider these two other MFJ Products:
* MFJ-1045C SWL Receiver Pre-Selector with built-in Amplifier
which covers the Shortwave Bands from 1.8 to 54 MHz.
http://www.universal-radio.com/catal...amps/0807.html
* MFJ-1020C Indoor Active Antenna which covers 300 kHz to
40 MHz (LW, AM/MW and SW Bands) in five bands; and when used
with an External (OutSide) Antenna, the MFJ-1020C functions
as a Pre-Selector.
http://www.universal-radio.com/catalog/sw_ant/1413.html


FWIW: I use a Low Noise SWL Antenna with a Grove Mini-Tuner
"TUN 3" which is very much like the MFJ-956 MFJ-956 Long Wave,
Medium Wave and Shortwave Pre-Selector Tuner.
http://www.universal-radio.com/catal...amps/2964.html
- Most times I simply use it in the ByPass Mode.
- Sometimes I will switch it over ti Fine-Tune a Signal.
- The major reason I use it is to Switch-Out "Ground-Out"
the Antenna when I am not using the Radio for Safety.

READ: John Wagner's Shortwave Tips & Tricks
http://www.dxing.com/tips.htm
- Section: Antennas for Portable Receivers
- Point # (7) The Wagner Active Preseletor Antenna

READ: Antenna Tuner, radio preselector, what is the difference?
http://groups.yahoo.com/group/Shortw...a/message/1119
- Five "Do-It-Yourself" Antenna Turners with Schematics
- Impedance Matching Unit VS. Pre-Selector/ATU
- Pre-Selectors = So Many Choices . . .
- Antenna Tuner / Pre-Selector = The 'little' Box that May Help !


iane ~ RHF
.
Some Say: On A Clear Day You Can See Forever.
http://groups.yahoo.com/group/Shortw...na/message/502
I BELIEVE: On A Clear Night...
You Can Hear Forever and Beyond, The Beyond !
.
.

Thanks RHF. Checking your links.

We use an antenna tuner to feed our W8JK antenna for use for shortwave
reception for two reasons:
1. The 8JK has a high impedence input so it is fed with 300 ohm ladder
line; thus the use of the tuner (in this case) acts as a balanced
transformer.
2. The 8JK was "cut" for 20 meters. For use on other frequencies, the
tuner acts (with adjustment) as a conjugate match that provides a 50 ohm
input to the receiver.

Results of the tuner appears to peak signal strength as the impedence of
the receiving antenna is transformed by the matching provided by the tuner.

Tuners are passive in nature; that is, they require no amplifier
electronics and associated power. They may be unbalanced input to
balanced output (or vice versa) or unbalanced to unbalanced
input/output. Preselectors on the other hand are active devices. They
vary in design and may provide matching as well as gain.

The selection of the device you choose will depend on the type on
antenna system you employ.

In any case, good luck!

John
Sanjaya wrote:
I've read and heard both sides of the argument about
antenna tuners being great, or not helping at all and are
a waste of money. I've been told they are only for shortwave
transmitting, and I've been told they work well to improve shortwave
reception on faint signals. I've had it suggested to me that I
get a pre-selector instead.

I can't find anyone who actually experimented with either a tuner or pre-selector... at least
none of what I've read and heard was stated as "experience"... rather
it seemed like theory or conjecture.

Does anyone here actually use a tuner or pre-selector for shortwave listening, and if so,
with what results? I'm looking at the MFJ-959C antenna tuner at
http://www.universal-radio.com/catal...amps/2574.html
Note that it says "for receive only".

On Tue, 21 Sep 2004 01:15:42 GMT, John Steffes
wrote:

We use an antenna tuner to feed our W8JK antenna for use for shortwave
reception for two reasons:
1. The 8JK has a high impedence input so it is fed with 300 ohm ladder
line; thus the use of the tuner (in this case) acts as a balanced
transformer.
2. The 8JK was "cut" for 20 meters. For use on other frequencies, the
tuner acts (with adjustment) as a conjugate match that provides a 50 ohm
input to the receiver.

Results of the tuner appears to peak signal strength as the impedence of
the receiving antenna is transformed by the matching provided by the tuner.

Tuners are passive in nature; that is, they require no amplifier
electronics and associated power. They may be unbalanced input to
balanced output (or vice versa) or unbalanced to unbalanced
input/output. Preselectors on the other hand are active devices. They
vary in design and may provide matching as well as gain.

The selection of the device you choose will depend on the type on
antenna system you employ.

In any case, good luck!

John

John,
I'm not sure I understand why you feel a preselector is an "active
device"? From everything I've learned, active devices are such things
as transistors, IC's, hybrids etc or a reference to a circuit that
requires power to operate. The preselectors I've seen are 'passive'
in that there are no semiconductors and no power required - excluding
models that also have a built in pre-amp. Rather they are basically a
'tank' circuit that with a combination of inductance and capacitance
create a 'bandpass' so only frequencies in a given range easily pass
through the preselector to the receiver.

Am I missing something in either your explanation or my understanding
of a preselector?

Howard

Howard,

The preselectors we have dealt with have been , in general, active. They
have used positive feedback to increase the "Q" of the resonant tank
circuit providing greater selectivity. It is reasonable to accomplish
this using no positive feedback (bandpass design) as you suggested.

John

Howard wrote:
On Tue, 21 Sep 2004 01:15:42 GMT, John Steffes
wrote:


We use an antenna tuner to feed our W8JK antenna for use for shortwave
reception for two reasons:
1. The 8JK has a high impedence input so it is fed with 300 ohm ladder
line; thus the use of the tuner (in this case) acts as a balanced
transformer.
2. The 8JK was "cut" for 20 meters. For use on other frequencies, the
tuner acts (with adjustment) as a conjugate match that provides a 50 ohm
input to the receiver.

Results of the tuner appears to peak signal strength as the impedence of
the receiving antenna is transformed by the matching provided by the tuner.

Tuners are passive in nature; that is, they require no amplifier
electronics and associated power. They may be unbalanced input to
balanced output (or vice versa) or unbalanced to unbalanced
input/output. Preselectors on the other hand are active devices. They
vary in design and may provide matching as well as gain.

The selection of the device you choose will depend on the type on
antenna system you employ.

In any case, good luck!

John


John,
I'm not sure I understand why you feel a preselector is an "active
device"? From everything I've learned, active devices are such things
as transistors, IC's, hybrids etc or a reference to a circuit that
requires power to operate. The preselectors I've seen are 'passive'
in that there are no semiconductors and no power required - excluding
models that also have a built in pre-amp. Rather they are basically a
'tank' circuit that with a combination of inductance and capacitance
create a 'bandpass' so only frequencies in a given range easily pass
through the preselector to the receiver.

Am I missing something in either your explanation or my understanding
of a preselector?

Howard

On Tue, 21 Sep 2004 09:22:41 GMT, John Steffes
wrote:

Howard,

The preselectors we have dealt with have been , in general, active. They
have used positive feedback to increase the "Q" of the resonant tank
circuit providing greater selectivity. It is reasonable to accomplish
this using no positive feedback (bandpass design) as you suggested.

John


John,
Thanks for the reply, nice to know I wasn't off-base in my thinking.

Howard

Howard wrote:

On Tue, 21 Sep 2004 09:22:41 GMT, John Steffes
wrote:

Howard,

The preselectors we have dealt with have been , in general, active. They
have used positive feedback to increase the "Q" of the resonant tank
circuit providing greater selectivity. It is reasonable to accomplish
this using no positive feedback (bandpass design) as you suggested.

John


John,
Thanks for the reply, nice to know I wasn't off-base in my thinking.

Howard

A shortwave preselector can be either active or passive. The former
usually has an amplification stage followed by an impedance matching
output circuit in addition to the tuned circuit(s). The passive type has
only the tuned circuits. Some preselectors can be both active or passive
if the amp' circuit can be turned off (lowered to unity gain) or
completely bypassed. The main advantage of any preselector is it's
bandpass filtering (tuned circuit) which provides a means of removing
signals outside the frequency range (band) that the user wants to hear.
This is particularly useful for receivers (usually portables) that don't
have a good antenna input circuit to accomplish this filtering process
internally.


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