Rf-clipper Mc1350

MFJ's new QRP SSB station for 20 meters.

MFJ Enterprises, Inc. P.O. Box 494 Mississippi State MS 39762 Telephone: (601) 323-5869 Orders: (800) 647-1800 Fax: (601) 323-6551 Price Class: $220

rhat good is a 20 meter SSB QRP transceiver? I kept mulling this over En my mind as I unwrapped the newly-arrived MFJ-9420. After allT all my previous experience on 20 meters was based on my activities as a serious DXer; I rarely ventured onto this band unless the trusty 2 kW linear was online and ready for battle.

Plays Right Out of the Box

Within several minutes the radio was up and running—the MFJ-9420 is ready to plug in and play right out of the box. Just connect an antenna, a 13.8-volt power source (I used the optional wall-plug power pack) and the optional hand mike, and the radio is ready to use. Tuning the usually crowded band yielded some surprises: The MFJ receiver is a real performer. Under the tiny hood a well-designed six-pole crystal filter gave good singlesignal performance that rivaled some of the full-sized multiband HF rigs I have owned, The rig covers the American phone band from 14,150 to Hh350 kHz. MFJ uses a custom-made 4 to 1 vernier drive capacitor, along with an analog dial scale calibrated in 10 kHz steps. Besides the tuning, only three other controls are provided—a volume control, power switch, and tune switch.

Internal Speaker, AGC and S-Meter

An internal speaker is mounted under the cabinet cover No skimping here, the speaker is 3,5" for good fidelity and volume, and faces upward where it will do the most good. The designers used a bridge-type audio IC for some real AF power.

Another surprise for a radio in this price class was the inclusion of an S-meter that is fairly accurate—a 50 jjV signal from my signal generator produced the desired S9 meter reading. Another nice touch was including backlighting for the meter. The AGC, which is derived from the audio, was also smooth acting, without Lthumps/S overload, or other glitches being noted. I parked the MFJ-9420 on several net frequencies for hours at a time, and no drifting was noted. 1 also found that 1 was able to quickly find and tune to the DX stations spotted on the local PacketCluster node,

Working DX

Working the DX stations spotted on the DX Cluster was another story,. Basically, this is a QRP radio, and even with 12 watts output, some discretion is needed in a pileup, \ tried the usual ploy of yelling my call, followed with a plaintive, "QRP J,. QRP . . . p" but, alas, this usually resulted in several competing stateside stations responding with catcalls of disbelief. Abandoning the DX Cluster with its self-generated piieups yielded much better results. By finding a clear frequency and calling CQ, or better yet, careful tuning and find* ir ig the DX first, I quickly filled two or three log pages with European, South American, and Caribbean stations. Almost all of the reports were 89 or better, and were given before I disclosed my transmitter power,

The Transmitter Has Punch

Used with the optional AC wal1 adaptor power supply, the transmitter will deliver about 9 watts output.

Going to a 13,8 VDC source, such as batteries, will produce 12 or more watts of power. The "tune" button locks the transmitter on, and gives about 5 watts of carrier for adjusting an external antenna tuner, when used. The Motorola final transistor used In the MFJ-9420 is rated for 40 watts, so it is unlikeEy that any sort of mismatch will damage it,

MFJ proudly advertises their new "constant carrier" RF speech processing system in the 9420. This is simply a transmitter ALC circuit with a very fast decay time that permits the transmitter to follow voice peaks and valleys so that the average transmitter power is always maintained at a fairly high and constant level. The transmitter ALC action is monitored on the S-meter during transmit. This probably yields results similar to what a good AF speech processor would do: in the order of a

3 or 4 dB improvement in my readability to another station. In any event, while a true RF clipper would give more talk power, it would also double the cost of producing a radio in this price class. And besides, an honest 3 or

4 dB improvement is nothing to sneeze at. DX stations commented favorably on the audio punch of my signal, and a few noted that their S-meters barely wavered while I was transmitting.

Technically Speaking

What's inside? In my opinion, the designers really did their homework on this American-made set. Many of the stages do double duty between receive and transmit, most notably the AGC/ALC and IF stages. The radio is a single conversion design, with a 10 MHz IF and the VFO running in the 4 MHz range. The front end is a NE6Q2 serving as the RF mixer and VFO. CAD-designed bandpass filters are used in the receiver front end and transmitter driver stages. NE602 mixers are used for the product detector and transmitter mixer stages as well. The IF stage is a single MC1350 IC, followed by the six-pole ladder filter. Most of the circuitry is IC; in a quick

Equivalent Mc1350

peek Inside I counted seven eight-pin ICs and a small handful of discrete active components. A miniature antenna relay is used—no antenna switching diodes to burn out here.

Whatl Didn't Like

It was hard to find any fault with the radio since, even though my set was from the first production run, no problems have been found. One thing 1 noticed was that the large amount of IF and RF gain during transmit, ail following the IF ladder filter, did produce a transmitter white noise floor that could be a problem when used in close conjunction with other 20 meter stations, such as during Field Day, But, please note that the transmitter does meet current FCC specs for spectral purity.

J also missed having a RIT control, my voice is slightly bassy^ and stations have a tendency to off-tune my signal so I sound better to them. Including an earphone or external speaker jack on the rear apron would be an useful addition.

What [ Did Like

Almost everything! The case is solid and well-made. The tuning is smooth, thanks to the vernier drive and hefty 1.25" tuning knob; and the dial is accurate and the VFO is stable. The speaker size and placement is ideal for good volume and audio clarity. I was impressed with the IF ladder filter performance, and with the AGC action and the inclusion of a backlighted analog meter. These are nice touches for a radio in this price class and for its intended QRP audience.

Twelve watts and the RF processing system used by MFJ wifl produce contacts, You don't have to be an experienced QRP milliwatt masochist to enjoy QRP! Yoy can see fine results without the usual frustration encountered by some beginning QRP enthusiasts. And the radio (it measures 2-1/2" x 61/2" x 6,0") battery supply, mike and a simple wire dipole can easily be toted in a small gym bag to exotic DX locations or on your next business or camping trip. To sum it up, MFJ's 9420 is a winner!

Order your subscription to 73 Amateur Radio Today. Call today at 1-800-274-7373.

BUY AMERICAN, BETTER PRICE AND QUALITY

The SG2000 HF transceiver Is type accepted for commercial antf marine service made wilh traditional U.S. commercial radio quality (ynd of course it can be used on [he ham bands atsn). While the Japanese radios have 2 final transistors lhal strain to put cut 100 watts on the low bands and only 75-flS watts on ren meters, the SG2O00 has 4 large Irgn&iajqrS that loaf along at ISO watts on ALL THE BANDS TNCLUDING ID METERS! Some of rhe SG2000 features are: 1) A control head remotawo (no special kit necessary) up lo 150' away from ihe rig, perfect for automobiles and boats, up to & heads can be utilized and used as Intercoms also. 2) The iarge$i display ot any hf iransceiver. 3) 644 pre* programmed memories and 100 user programmable memories. 4J operable from -50F (-45C) to iasF (+fi5C). You wani quality right? Here is what every SG2000 must endure before they're shipped tm^ (he factory. 1) They're factory aligned, 2) cVERY 5G2000 is keyed down at full power fCW 150 Walts) into an open antenna for ahoul 10 seconds, then connected to a shorted antenna and keyed down for an additional 10 seconds. 3) EVERY SG2000 is pui in the "BURM-JN" iack and keyed down for 24 hours non-slop at full power CW. Don't try tfcat with the foreign radios. 4) EVEHY SG2Q00 is than re-checked ior alignment and put in the torture RACK" wh&r4 they are keyed on and off every 10 seconds for 24 hours, 5) The SG^OOO is then re-evaluated and all control functions are verified to ensure thai the microprocessor is up to spec. THEN AND ONLY TH|N IS THE 5G20G0 ALLOWED TO LEAVE THE FACTORY.

The boltom line is price, you know how expensive commercial rigs are normally, we are selling trie SG2000 BELOW DEALER COST at only Si .5&5.G0 each!! That's a S400.00 savings! We guarantee the Lest pnee.

The SG230 SMART-TUNER is Ihe best HF aulotuner at any price, and lo promote a product that is made In trie USA, we're offenng it at the guaranteed best price of only S443.00!! WHY THE SG230? bECAuSE: When you tune an anienna at it's base you are resonaiing the antenna, instead of jusi matching the coax to the radio as with other tuners such as the ATE0. etc The result YOUR SIGNAL GETS OUT MUCH BETTER. The Kenwood ATM. AT450 and olher Simitar tuners can onfy match 3:1 mismatches (YES onty 3:1) so forget matching anyiriing but a fairly decen; anienna. The SG230 can match from 0.5 Ohm to 10 kilohm antennas (up to a 200:1 mismatch), so it Can easily match random wires, dipofesH rain-gutters, shopping carts, etc. The result MOFtE POWER.

To order, se^d check or money onler with $3.50 for shipping, along wiih your shipping address (sorry no U.S. Post Office BtJHea UPS will nat deliver} and T^Sc-pfiane number to:

Joe Brancato

+1 0

Post a comment