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Reviews Categories | QRP Radios (5 watts or less) | MFJ 93X0 Cub QRP xcvr Help

Reviews Summary for MFJ 93X0 Cub QRP xcvr
MFJ 93X0 Cub QRP xcvr Reviews: 33 Average rating: 4.2/5 MSRP: $79.95
Description: Single band CW QRP tcvr.
Product is in production.
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You can write your own review of the MFJ 93X0 Cub QRP xcvr.

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WB0FDJ Rating: 4/5 Aug 14, 2010 17:58 Send this review to a friend
Simplicity....  Time owned: more than 12 months
I ordered this radio because I had decided to get into kit building and needed to log some hours with the soldering iron. This filled the bill. I apparently had better luck with mine than others: once assembled it worked without drama or surprise. As others have noted at first theres some drift, after 30 minutes it settles down. I get about 2 watts out. In retrospect this is a very simple kit to build and I would recommend it to the ham who hasn't done much building. I've made quite a few fun contacts with my 20 meter Cub and usually run it off a small 12 v battery pack that I ordered for my smaller QRP rigs. It's a real gas to build your own stuff and got me started in building.
KU4UV Rating: 0/5 Apr 12, 2010 20:54 Send this review to a friend
Be afraid, be very afraid  Time owned: 0 to 3 months
Gee, I really wanted to like this kit, but after seeing all of the tombstoned SMD components on the circuit board, I am very reluctant to even finish building and testing it. The circuit board of the kit has about 5 different SMD capacitors that are not even completely soldered to the circuit board. One end is soldered to the board, while the other end is standing on it's end! MFJ quality and QC rears it's ugly head once again. I have contacted MFJ and requested a return shipping label. I will be requesting a full refund of my money from MFJ, and wish me luck as to getting a refund. I just can't in good faith recommend this kit after seeing the poor quality of this circuit board. To those who have built and are enjoying this kit, God love ya. I know now why everyone knock's MFJ's quality, because they deserve their poor reputation. It is really a crap shoot whenever you purchase an MFJ product as to whether or not you will get a dud. This is in no way knocking Mr. Littlefield who designed the kit. I contacted Mr. Littlefield and he was very helpful. I just can't recommend this kit at all. I will purchase a kit from Oak Hills Research or Ten-Tec. I can trust Ten-Tec because I know they will help me out if I have a question or need a replacement part. I think I have purchased my last MFJ product.
WB6IYM Rating: 5/5 Jul 11, 2009 15:07 Send this review to a friend
Another great kit building experience.  Time owned: 0 to 3 months
I built the 40-meter version of this little radio last Christmas and was quite impressed with its performance. So, having nothing planned for the July 4th weekend, I bought the 20-meter version now available from ARRL and gave it whirl.

Everything went together nicely, except when I applied power and went through the testing and alignment procedure, I discovered there was no output whatsoever! The receiver worked great, and the radio keyed, but no power out - zero!

My 9340 draws about 240 ma on transmit and puts out about 2 watts on the meter. The 9320 drew only about 120 ma and no output power. I triple checked all components and their locations without finding any errors. Then off to Fry's Electronics for a new PA (2N5109). Still nothing. A digital multimeter revealed some significant voltage discrepencies (from what is published in the manual) on the pins at U5; so I think I had a PC board with some bad SMD's installed.

Monday morning I called MFJ and they shipped me a new kit forthwith. I had it by Friday via UPS and 2 hours later, I was happily transmitting on 20 meters. I certainly need to tip my hat to the MFJ customer service department for that one! The first one goes back via prepaid label from MFJ on Monday.

The rig is every bit as good on 20 as it is on 40. However, for about the same power out (2 watts +/-) it draws about 340 ma on 20 compared to the 240 ma on 40. Don't know what's going on there.

This morning I worked Alaska, Hawaii, and several stations in the mid-west in the IARU HF Competition. Antenna was a Butternut HF9V on the ground. So the thing works!
K8JD Rating: 4/5 Dec 26, 2008 12:19 Send this review to a friend
More thoughts on the 9380.  Time owned: 6 to 12 months
A few more things about my 80M cub, I like this rig enough that I just ordered a companion, 40M version of the CUB. I hope the grief I had with the shipping time is not repeated !
Makes a nice travel kit along with a roll of antenna wire,tuner/swr meter and my old 9030 rig and battery pack!
WA6L Rating: 4/5 Sep 2, 2008 13:53 Send this review to a friend
Best $99 radio kit around  Time owned: 0 to 3 months
I have completed many kits from Heathkit, Elecraft, and Ten-Tec, and the 9380 is by far the easiest kit I ever built. The majority of the components on the board are pre-mounted SMT, so you are left with just a couple of dozen "through the hole"" items to finish the radio. My total construction time was about 3 hours, including alignment.

You can say what you want about MFJ quality, but this kit was top-notch. All the parts were there, the instructions are clear and complete, and the alignment went without a hitch. The little cub worked the first time power was applied to it and has not had a single problem.

If I was going to pick a nit about the kit-building process, it would be that the instructions are not detailed enough concerning winding and installing toroids. This kit is geared toward the first-time builder, and they are probably going to need more help with toroids than anything else. The instructions were complete, but it would have been helpful to provide more information on stripping and tinning the coils.

Once the kit is complete and aligned, you have one nifty little $99 radio. You have to keep that figure in mind, and it is unfair to compare the cub with radios costing much more.

The receiver is impressive for a rig with this parts count. It appears to be very sensitive and the bandwidth is quite narrow. On transmit, my 9380 puts out a solid 2.5 watts and the signal is clear and clean.

The VFO is varactor-based and the drift is considerable when you first apply power. It takes a good 15 minutes for everything to stabilize; after which it is steady enough. This is just an operating hint and not a complaint.

The one complaint I do have concerns the tuning range of the cub. On my 9380, I have a range of approximately 70 kHz. The problem with that is the tuning control is a single-turn 10K potentiometer. With a large range and a single turn, it is difficult to accurately tune in signals. You can go right past a strong signal without hearing it, and once you find it, it takes a very, very sensitive touch to get it centered in the receiver bandwidth.

I don't see the need for that wide of a tuning range for a QRP rig. Half of that would be fine. I think that an easy mod would be to put a 10K resistor in parallel with the pot and reduce the tuning range in half. I will give that a try as time permits.

With that aside, the little cub is a fun project and well within the capabilities of the first-time kit builder. Once completed, you have a very serviceable QRP rig that can be a lot of fun to operate.


John, WA6L
K2PGB Rating: 4/5 Jun 9, 2008 14:53 Send this review to a friend
FUN RADIO  Time owned: more than 12 months

WD8DSB Rating: 4/5 Apr 15, 2008 06:29 Send this review to a friend
Great little QRP rig (almost perfect).  Time owned: 0 to 3 months
Yesterday I built the MFJ-9340, and so far very happy with the results. Using a 13.0 volt supply, power output was a hair under 2.0 watts using the stock 2N5190 output transistor. Then installed the MRF-237 in place of the stock output transistor and output power came up to around 2.75 watts, and adjusted it back down to 2.5 watts.

I like the QSK on this rig, and have had good reports on quality of signal (tone). Worked DX last night (YN4SU) from near Indianapolis using my 100 foot attic dipole.

Only major problem was a surface mount capacitor (C33) was standing on end (one end not connected to anything). Broke C33 trying to move it back into position, so replaced it with a standard through hole cap.

Wish the rig had a little more audio volume during the day with weak signals on 40 meters, but it's acceptable. Tried using a little Radio Shack external audio amp and this really helps crank the audio level up to ear banging levels.

You will need a good magnifying glass to read the capacitor values when building this rig, and good strong alignment tools.

My other QRP rig is an HW-8, but I can already tell that the MFJ-9340 has become my favorite 40 meter QRP rig due to its single signal reception (super het receiver), size, QSK, and power output.

KC4FKX Rating: 4/5 Apr 7, 2008 13:29 Send this review to a friend
If you are new to kit building, this is the one!  Time owned: 0 to 3 months
This kit went together without a hitch. There were no parts missing and the instructions were very clear and easy to follow. If you are new to kit building or if you are looking for a nice little qrp rig that is not "rock bound", give this one a serious look. I purchased mine along with the "Low Power Communications" book.
As mentioned by others, this is a hot little receiver. My 40M version ended up with slightly more than a 60khz spread along with about 4.5 watts out with the stock PA. I'm rating it a 4 because it comes without a built in keyer like some other rigs do. I used an external Picokeyer. It also has a slight key click but I plan to perform the modification for that found elsewhere on the internet and install a Small Wonder Labs Freq-mite to let me know my exact frequncy. This will be my "throw in the bag" rig for camping and trips to the beach along with a Norcal BLT and doublet antenna.
I've built a host of other rigs such as the OHR 100, NorCal 40, SST, SW+ , Rockmite, DC40, and many others. This was by far the easiest and quickest (due to SMD parts already installed for you) rig to build. I was receiving signals before the alignment process. I'm glad I purchased and built this little rig. It was and continues to be a great experience. It won't matter if this is your first kit or simply another addition to your collection (and this one should be in everyone's), I'm sure you will enjoy building, using, and modifying this little gem.
KD8BIL Rating: 5/5 Jan 12, 2008 15:38 Send this review to a friend
First Kit - I'm inspired  Time owned: 0 to 3 months
Received this kit as part of a QRP bundle through ARRL (included the book "Low Power Communication") for Christmas. It was a joy out of the box, there were no missing parts and I felt that MFJ really wanted me to enjoy this radio and learn in the process. There was a lot of extra info in the manual such as instructions on making a voltage regulator which I made and making an antenna as well as hints on how to operate QRP - and they suggested how to mod the thing to get a little more power out of it. 3 negatives were long time shipping, no tools included to align the radio, and a question I emailed to MFJ was unanswered. My cub had poly caps at c6 and c7 and it drifts down upon warmup but not much at all after the first 5 minutes. I finished the kit on Straight Key Night and was amazed at the flury of CW - I have since received respectible reports from NYC and Louisiana from my qth in Dayton Ohio at 2watts running on batteries and through a simple dipole. I have been inspired - Thanks to ARRL and MFJ - this rig sits next to my Heathkit SB-102 and I haven't used the Heathkit since.
K9EX Rating: 5/5 Dec 6, 2007 18:46 Send this review to a friend
Great Value with Hot Rcvr  Time owned: 0 to 3 months
I bought the 80 meter version of this kit about a year ago and I just got around to building it at the end of Nov, 2007 (it took me just a few hours to build).

I heeded W5ESE's and KD2DL's collective advice, below, and upgraded the caps and final output transistor to a MRF-237 (NTE341). My unit puts out a respectable 3.5 W and I have really been enjoying using the Cub on the air, making numerous, solid contacts with it in just a few days.

I think 3.5W is just about right to make the QRP experience downright enjoyable - any less than 3W or so and you're definitely in for more of a challenge so I strongly recommend upgrading the Cub's final output transistor to the MRF-237 (NTE341).

My unit does indeed drift, as noted by other reviews, but only when transmitting and only just slightly. Allow at least 30 minutes for "warm up" before you even consider using it and then expect some drift when you transmit.

The Cub's receiver section is extremely hot and outperfoms my trusty Icom IC-718. (Of course, selectivity/strong signal rejection is not nearly as good as the 718.)

Very strong signals overload the Cub and can blank-out the receiver temporarily - you'll get a hint when you start to hear clicks on strong receive signals - about all you can do is adjust the tuning slightly and/or back down the volume.

Despite these very minor issues, the Cub is an easy kit to build, a great QRP perfomer and a superb value at its price point - it's exceedingly simple to use and has an extremely hot receiver. It all adds up to a ton of fun with a "back to basics" sort of feel to it.

Highly Recommended.
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