The 9420 is described as a 'Travel Rig' and is primarily an SSB transceiver, although a CW 'adapter' can be added as a plug-in module. 10 watts PEP is easily achieved from this little beauty which can result in many enjoyable contacts from the home station, car or holiday location. It operates from a nominal 13.8 volt supply, drawing 2 amps on transmit, so a small PSU or nicad stack can be used.
The microphone required is the usual 600 ohm dynamic type, the only other requirements to get on the air being some form of 20 metre antenna.
I have used mine to effect from the home station with dipoles and have had several DX contacts, including Brazil (PY), Ws and many chats into Europe. Being a compact little rig makes it ideal for holiday use and I enjoyed taking it to Tenerife and working as EA8/G3YCC using just 17 feet of wire on the hotel balcony. Using this very compromise set up, QSOs into Scandanavia, Germany, Ireland etc., were achieved.
When on holiday in Scotland, we parked up by the river at Kelso in the Borders, plugged the rig into the cigar lighter, put my home made pre-tuned 20 metre whip on a mag mount and worked SMs, PA0s etc., and even a UA station near Moscow - not bad for ten watts PEP to a four foot whip!
Audio quality on transmit is excellent, due no doubt to the in-built processor and I have had one report which preferred the MFJ 9420 to my Kenwood TS850SAT!
There are few controls on the front panel, VFO tuning, volume/DC, microphone connector, analogue meter, a couple of LEDs and a tune button.The latter produces RF at reduced level for tuning purposes. Receiver audio and selectivity is very acceptable.
On the back, just the DC input and antenna socket are used, however, there are holes for the optional CW add-on (not used) and a pre-set microphone gain and that's it! No bells and whistles, no memories or frequency readout, you just plug the thing together and operate, it's as simple and easy as that and it works very well. There is a bit of drift when switching on from cold, but after a couple of minutes the frequency is rock solid.
The PA is a rugged MRF477, but care must be taken of course to provide it with a 50 ohm load.
None are really required, but I did use one of the spare holes at the rear, intended for the CW adapter, to add a headphone socket.The only other addition, again using the back panel, was for a fuse holder. This requirement was forced on me when reversing the DC leads (OOPS!), blew the internal PCB fuse (a wiggly bit of track). Fortunately there is an 'idiot diode' fitted, for people like me, so no damage was done to the rig! You think you will never do it, don't you, but sure enough, one day you will - there speaks the voice of experience and owner ofmany blown fuses!
I readily recommend the MFJ 9420 as an efficient little sidebander for twenty metres, although the price is a bit high in UK (around 200 pounds). The main UK supplier is Waters and Stanton (tel: 01702 205843), with which I have no commercial connection, nor do I with MFJ.