Do-You-Need-One-? : SWL Antenna "Matcher" -versus- SWL Antenna "Pre-Selector"
RHF
- - On Jan 22, 8:34 pm, bpnjensen <bpnjen...@yahoo.com> wrote:>
- - MFJ makes two items that they describe specifically
- - as preselectors, the 1046 and 1048 - one "passive"
- - and one powered.
MFJ-1046 is a 'Passive' Pre-Selector for "SWL" Receivers
and Covers 1.6 MHz to 33 MHz
http://www.mfjenterprises.com/Product.php?productid=MFJ-1046
http://www.universal-radio.com/catalog/preamps/3736.html
-versus-
MFJ-1046 is a 'Passive' Pre-Selector for "HAM" Transceivers
and Covers 1.6 MHz to 33 MHz -has- Transmit Delay-Switch
http://www.mfjenterprises.com/Product.php?productid=MFJ-1048
http://www.universal-radio.com/catalog/preamps/3749.html
- - The passive has fewer parts, but the instructions at
- - the MFJ site blithely suggest that both do a great job.
- - They advertise the 956 as a tuner.
MFJ-956 LW/MW/SW is a basic "Pre-Selector" Tuner
http://www.universal-radio.com/catalog/preamps/2964.html
http://www.mfjenterprises.com/Product.php?productid=MFJ-956
.
- I always thought that the word ''tuner" referred to tunable
- circuitry designed to match a transmitter to an antenna
- whereas "preselector" is most often used with lower power
- levels as is typical with antennas for receivers. They both
- work as tunable bandpass circuits with the "tuners"
- generally having a lower Q.
-
- My old Grove TUN-3 (preselector) has much sharper
- (selective) tuning whereas the MFJ-949E (tuner) has
- a wider frequency range of bandpass.
MFJ-949s Amateur [HAM] Radio Antenna Tuner
http://www.mfjenterprises.com/pictures/MFJ-949E.jpg
Most of the SWL'ers who have the old Grove TUN-3's : Love Them :o)
http://cgi.ebay.com/220727917586
.
Some SWL'ers who are running a simple Longwire {Random
Wire} Antenna using a Bare Wire as the Antenna Element
with an Insulated Wire {No Coax} as the Feed-in-Line to the
Radio : Like the the old Mizuho Antenna Couplers {with the
Screw Terminals} for both "Matching" the Wire Antenna to
the Radio plus Pre-Selecting the Frequency Band Range and
Tuning with-in the Band.
http://www.mizuhoradio.com/kx.html
.
Speaking of Shortwave Radio Listening [SWL] Only :
.
Generally I have been my understanding that a so-called
modern day SWL type of Antenna "Tuner" with an SO-239
Jack is designed for 50 Ohm Coax Cable; is as you say has
a Tunable Circuit to Continuously 'Match' the Feed-in-Line
with the SWL Antenna at its End : Over a broad range of
SWL Frequencies from 1.8 MHz to 30 MHz.
-result- Optimize {Peaks} for a given Frequency the Amount
{Level as seen on the S-Meter} of RF Signal getting to the
SWL Radio from the SWL Antenna.
-example- MFJ-16010 Antenna "Matcher" Tuner
http://www.universal-radio.com/catalog/preamps/1329.html
http://www.mfjenterprises.com/Product.php?productid=MFJ-16010
.
IMHO : If you have a Matching Transformer [Balun/UnUn]
installed at the Far-End of the Feed-in-Line; between the
Antenna-&-Ground feeding into the Coax Cable these
Antenna L&C "Match" Tuners seem to have less effect.
http://www.universal-radio.com/catalog/preamps/1329.jpg
.
Where-As so-called modern day SWL type of Pre-Selector
with an SO-239 Jack is designed for 50 Ohm Coax Cable;
is as you say has a Tunable Circuit to Continuously 'Tune'
a Narrow Band of SW Frequencies and Attenuating all
out-of-band Frequencies with Sharp Attenuation of both the
AM/MW Band {1.8 MHz and below} and the FM/VHF Band
{50 MHz and above}. The SWL type of Pre-Selector "Tunes"
over a broad range of SWL Frequencies in 'Steps' from 1.8
MHz to 30 MHz.
-result- Optimize {Peaks} for a given Frequency the Amount
{Level as seen on the S-Meter} of RF Signal getting to the
SWL Radio from the SWL Antenna +Plus they Attenuates
Out-of-Band Signals.
-example- MFJ-956 LW/MW/SW "Pre-Selector" Tuner
http://www.universal-radio.com/catalog/preamps/2964.html
http://www.mfjenterprises.com/Product.php?productid=MFJ-956
NOTE : The 'features' that I like about the MFJ-956 is the
http://www.universal-radio.com/catalog/preamps/2964band.jpg
"BYP" B-Pass : Switched Out-of-Circuit : Direct-to-Antenna
"GND" Grounded : Shorted-the Antenna-to-Ground
when you are not using the SWL Radio
.
SWL Antenna "Matcher" -versus- SWL Antenna "Pre-Selector"
? DO YOU NEED ONE ?
-or- Simply follow the : Five Basic Steps to
a Better Shortwave Radio Listening [SWL]
http://groups.google.com/group/rec.radio.shortwave/msg/6c4c310e1afb921c
http://groups.google.com/group/rec.radio.shortwave/msg/057a022ab4331b71
http://groups.google.com/group/rec.radio.shortwave/msg/0a8fa281b0b839e4
.
do you need one -iane ~ RHF
Twain Harte, CA -USA- : http://tinyurl.com/2fn6xog
Grundig Satellit 800-M Receiver
.
Shortwave Listener QSL Reports : http://tinyurl.com/2d9qlq
http://www.google.com/group/shortwave-listener-qsl-reports
.
- = 2FN6XOG = - & - = 2D9QLQ = -
.
.
Why an Antenna Tuner May Be A Waste of Money
-by- Daniel A Grunberg
http://groups.google.com/group/rec.radio.shortwave/msg/9072488832ac9501
http://groups.google.com/group/rec.radio.shortwave/msg/dce9f77be434c796
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Shortwave Radio Listening [SWL] :
Keep It As Simple as Necessary
http://groups.google.com/group/rec.radio.shortwave/msg/9f36f251b9a4a60d
http://groups.google.com/group/rec.radio.shortwave/msg/dffae94f056b968b
.
SWL'ers that Ensuring You House's Electrical System
is Wired Correctly and Properly Grounded
http://groups.google.com/group/rec.radio.shortwave/msg/1062dc8426d197b8
.
RFI Silencing the Electrical Path from your
AC Mains to your SWL Radio Shack Room
http://groups.google.com/group/rec.radio.shortwave/msg/b437f90b2ce8dc76
* Clamp On RF Choke Stops Noise on AC Mains
http://groups.google.com/group/rec.radio.shortwave/msg/cdf26a8fff964246
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Using a 12 VDC Battery Power [1 AH] for a 'portable'
AM/FM Shortwave Radio a/o Solid-State HF Receiver
http://groups.google.com/group/rec.radio.shortwave/msg/7c122d57f21c667c
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SWL Antenna 'Matching Transformers' : MLB & UMB & LIM & LWA...
-the-acronym-name-game-
http://groups.google.com/group/rec.radio.shortwave/msg/89dc141d19e817df
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