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The Quantum Phaser is a device that combines the signals from two separate antennas and allows the manipulation of level and phase of the signals so that a single, steerable null results. It is optimized for use on the crowded MW band, can be used with antennas of virtually any type and is capable of snagging DX not usually obtainable with conventional antennas alone. Adding a phasing unit to your DX toolbox is one of the surest ways of adding new stations to your log.
After years of experimenting with literally almost two dozen phaser designs ranging from conventional LRC approaches to delay line designs to various JFET-as-bridge configurations, I finally settled on the current Quantum Phaser. The principal design criteria were: (1) effectiveness and (2) ease of use. While not the most flexible of phaser designs, it is effective and is very easy to use and it can also be used as an antenna switch.
When I began designing the Quantum Phaser, I noted the shortcomings of the only currently available commercial phaser and designed around them. That is, the currently available phaser requires irreversible (for the most part) modification to its circuitry for optimal use on the MW band; a lack of an antenna switch requires the constant full resetting of level controls as phasing is pursued; on my sample the phasing control was stiff/rough making fine adjustments frustrating; and the vertical orientation of the front panel resulted in hand pain after hours of use. In brief, the Quantum Phaser comes ready for use on the MW band, has an antenna switch to easily select antennas, has controls that were selected for smoothness (and are treated with an anti-scratchiness compound), and critical controls are mounted on an ergonomically correct sloped front panel. In addition, in contrast to other phaser designs, the Quantum Phaser is not festooned with arrays of knobs and switches but rather has three critical control knobs and two frequently used switches....about as easy as it gets.
The Quantum Phaser employs a broad-band phasing circuit that can create a steerable null that permits (in many instances) the nuling of a pest station to such a degree that weaker, previously masked signals become audible. Unlike a loop antenna with its figure-8 receiving pattern, the Quantum Phaser creates a single null thereby allowing stations in directly opposite directions to be nulled independently.
The Quantum Phaser utilizes a passive front-end , double-bridge phasing arrangement with a post-phasing 10-15 dB JFET/NPN amplifier. It is housed in the same size cabinet at the Quantum QX Loop with its sloping front panel and is painted a semi-gloss black. It accepts antennas with impedances of 50-600 Ohms and provides an output of 50 Ohms. It can be powered by a DC source of 9-15V (either by an AC adapter or Quantum Battery Pack). Like the Quantum QX Loops, the Quantum Phaser is made with high quality parts. For example, the antenna switch is a high-reliability model (MTBF = 100,000 operations), semiconductors are name brand, the potentiometers are treated with an anti-scratchiness compound, etc. And, of course, the Quantum Phaser is fully guaranteed for one year and warrantied for life.
-- OPTIMIZED FOR 500-2000 kHz
-- 10-15 dB JFET/NPN AMPLIFIER
-- UNTUNED, PASSIVE FRONT-END
-- SUPER SMOOTH CONTROLS
-- HI-REL ANTENNA SWITCH
-- SLOPING FRONT PANEL
-- CAN BE USED AS ANTENNA SWITCH
-- REQUIRES NO MODIFICATION
-- DESIGNED FOR EASE OF USE
POWER ON/OFF -- Self
explanatory; LED indicator.
LEVEL A -- Allows setting of signal level of Antenna A.
LEVEL B -- Allows setting of signal level of Antenna B.
PHASE -- Varies relative phases of Antennas A and B.
ANTENNA SWITCH -- Selects Antenna A, Antenna B, or both (A+B).
-- Reverses the relative phases of Antennas A and B.
REAR OF QUANTUM PHASER
obtain a deep null, the to-be-nulled station must be equal in level on both
antennas and the phase relationship on the two antennas must be 180-degrees
out of phase. Basically, the procedure is as follows:
1. Set LEVEL controls to MAX (i.e., CW); set PHASE to 12 o'clock.
2. Select Antenna A; note signal level on receiver S-meter.
3. Select Antenna B; note signal level on receiver S-meter.
4. Adjust LEVEL of stronger antenna to equal weaker antenna level.
5. Adjust PHASE for null.
6. Repeat Steps 4 and 5 for deepest null.
(If a "peak" was noted in Step 5; flip INVERT switch and repeat Step 6.)
SIZE: 7" x 5" x 2"
COLOR: Satin Black
WEIGHT: < 1.5 lbs.
AMPLIFIER: Two-stage JFET/NPN
GAIN: 10-15 dB
POWER REQUIREMENTS: 9-15 VDC (2.5mm miniplug; tip positive)
POWER CONSUMPTION: < 25mA
ANTENNA INPUT IMPEDANCE: ~50-600 Ohms; UHF (PL-259) or banana plug
OUTPUT IMPEDANCE: ~50 Ohms; UHF (SO-239)
OPTIMUM RANGE: 530 - 2000 kHz
NULL DEPTH: >60 dB (depends on site/signal conditions)
FREQUENTLY ASKED QUESTIONS
"Can I use the Quantum Phaser with a portable radio?"
Only if the external
antenna jack of the portable automatically disconnects the radio's internal
ferrite rod antenna.
Obviously, if the internal antenna is not disconnected, it will continue to pick up an undesired signal even after the phaser has nulled it. Therefore, if screw terminals are used on the portable (usually an indication that the internal ferrite rod remains active) or if a device such as the Quantum Coupler is used, phasing with the Quantum Phaser (or any other phaser) will not work.
If you use only a portable for DX, you might try the "poor man's" phasing technique described in the literature included with the instructions for the Quantum Stick+. It's not as easy as phasing with the Quantum Phaser but it is possible to experience the phasing phenomenon with a little practice.
"Will I be able to null my strong, local pest stations?"
A lot depends on the antennas you are using and the neatness of your shack.
In order to completely null a troublesome local, the Quantum Phaser (or any phaser, for that matter) must "see" only a single-phase signal from each of the two antennas. That is, for example, if your lead-in wire or patch cord is unshielded, the possibility exists that it too will pick up the signal (along with that of the antenna proper) and will present a signal with two different phases for that antenna to the phaser. The phaser can only manipulate a single set of phase relationships between the two main antennas. The "extra" phases presented by the lead-in wires cannot also be nulled so that some residual pest signal may remain.
At my location, my worst pest is WRNE-980, a 10 kW slopper directly across the bay from me that registers at least S-9 +40 dB on my Drake R-8. I am able to completely null WRNE into the noise and DX the frequency at almost any time of day or night. I have also received several reports from Quantum Phaser users reporting that the nulling of S-9 +55 dB signals is not unusual.
See another FAQ below regarding nulling strong locals.
can completely null my local but I don't hear any other stations.
This is a phenomenon that usually only occurs during the daytime when your antennas aren't receiving any other signals on that frequency.
It can also possibly occur during the signal-intense nighttime hours if both of your antennas are directional in the same direction. Generally, however, during darkness there are plenty of stations on each frequency and nulling your local pest will result in your hearing weaker stations underneath.
are the best antennas to use with the Quantum Phaser?"
Just about any two antennas can be used with the Quantum Phaser although super long antennas may result in overloading even with the Quantum Phaser's passive front end (the Quantum Phaser has a sensitivity pot located on the circuit board to allow for sensitivity adjustments; the stock setting is "wide open").
In theory, the best antennas to use with a phaser are a pair of whip antennas with their nondirecitional reception patterns. The potential problem with whip antennas is that they are particularly sensitive to the vertically polarized electrical noise that is present around most shacks. If your location is relatively electrically quiet, there is much to recommend the whips.
Two untuned random length wires oriented between about 45-60 degrees from each other also work very well. They possess similar directionalities (to pick up the pest station) but enough difference in directionality to produce stations from different directions. Note that directionality on the AM broadcast band doesn't generally appear until antennas reach 100+ feet, and only on the high end of the band. The longer the antenna, of course, the greater the directionality and the lower in frequency that it appears.
(Note that when using untuned antennas, because of the Quantum Phaser's broadband circuitry, complete nulling of a target station will also tend to null, to some extent, adjacent frequencies and in the same general direction as the target station. Tuned antennas are less likely to do this.)
A popular antenna combination is the loop and "longwire" combo. This is the combination I prefer because of the cardioid receiving pattern it produces. I can rotate the loop's head and steer the null through 360 degrees searching for new targets.
"Will the Quantum Phaser work on LW ?"
Yes and No. While the phasing action on the Quantum Phaser extends to well below the AM broadcast band, its untuned front-end can result in MW feedthrough on the LW band. Unless you are using tuned antennas, use of the Quantum Phaser on LW is not recommended.
"When I use the Quantum Phaser with my home-brew loop and a longwire to null out one of my strong locals, I can null most of the local but 'Donald Duck' talk remains."
happening is that the tuning sharpness, or "Q," of your loop is
too high to completely null your strong local. To null your local, a
very deep null is needed. As the null gets deeper (i.e., the carrier
is reduced), the skirts of the band-reject curve get narrower. This
narrowing of the band-reject curve gets so extreme that only the carrier is
nulled and not the sidebands of the signal. So you have remaining, in
essence, the sidebands without the carrier and this sounds like a
The remedy for this situation is to "spoil" the tuning sharpness (or "Q") of the loop (or preselector, if you are using one) so that the sidebands can also be nulled. Both the Quantum QX Loop and the Quantum QX Pro come with a Q-spoiling control to allow deep nulls of strong locals. That is, they are "phaser ready."
NOTE: If you presently own a Quantum Phaser and want to increase the post-phasing gain, drop me an email at firstname.lastname@example.org I have an instruction sheet for increasing the gain (requires some soldering ability).