- Amateur Radio (Ham Radio) Community

Call Search

New to Ham Radio?
My Profile

Friends Remembered
Survey Question

DX Cluster Spots

Ham Exams
Ham Links
List Archives
News Articles
Product Reviews
QSL Managers

Site Info
eHam Help (FAQ)
Support the site
The eHam Team
Advertising Info
Vision Statement

Reviews Categories | Filters, Audio: (DSP and others) | MFJ-721 Help

Reviews Summary for MFJ-721
MFJ-721 Reviews: 3 Average rating: 5.0/5 MSRP: $79.95
Description: SSB/CW Audio Filter
Product is in production.
More info:
Email Subscription
You are not subscribed to this review.

My Subscriptions
Subscriptions Help

You can write your own review of the MFJ-721.

KF7FOW Rating: 5/5 Jul 19, 2010 07:54 Send this review to a friend
great little gizmo!  Time owned: 3 to 6 months
I went to a local hamfest looking for a DSP to help clear the background static when I'm listening to distant stations on my gen coverage receiver (a Kenwood R-300 with 1 very ineffective "narrow" filter). I coulnd't find a DSP but a guy talked me into buying this MFJ-721 instead and now I couldn't be happier with my purchase.

It's so useful that I've taken to carrying it back and forth betweem my gen cov receiver and my ham shack receiver each day. With the gen coverage receiver I can lower the background static to manageable levels using the SSB selections, and with my ham receiver I can pick out a weak CW station in a crowd using the CW selections. I wish I had two of these things!

On the plus side the unit is sturdy with metal and heavy duty bakelite construction. There is plenty of room inside for fat fingers like mine. I rewired the front phone jack so I could get sound out of both ears of my stereo headphones.

On the negative side I'm going to replace the power jack on the back with a standard 2.1 mm jack for a 12v wall wart. The micro-phone jack doesn't fit anything I have for a power supply (and I didn't get one with it so I have it direct-wired right now). The RCA jacks on the back are a little too close together to plug both sides from my patch cable in at the same time. No problem really since only one side is used anyway. The rotary controls on the front are solid feeling, but stiff working. And I have to remember to keep my headphones off my head when I turn on the power so the loud POP doesn't hurt my ears.

But everything works just as it should and I'm having a great time playing with the options. I plan on using it with my TS-520S (once it gets fixed) to provide the CW filter that my TS-520S doesn't have. I'm keeping my eyes open for another one at hamfests now. Highly recommended for older (pre-digital) radios.
K0KES Rating: 5/5 Jan 29, 2006 14:03 Send this review to a friend
great!!!  Time owned: more than 12 months
I have had and used the MFJ721 for several years with several different radios and have allways noted much better selectivity with it switched in line many timess making the difference between copying or not.You also can tune the filter to peak up a signal this works very well.This filter makes an excellent addition to most radio rooms.I have never found a receiver it wont help.
KY4Z Rating: 5/5 Feb 1, 2005 07:14 Send this review to a friend
Adds new life to older gear  Time owned: 6 to 12 months
I picked up the MFJ-721 audio filter off eBay some months back. The price was right, and I was looking for a cost-effective (i.e., cheap) way to improve the filtering on an old favorite rig, my Heathkit HW-16.

In short, the MFJ-721 has exceeded all my expectations. It's nearly like operating a completely different rig!

The unit has four filter bandwidths for CW and three for SSB. I've tested it on SSB and was surprised how nicely it works. Most of my use has been on CW, and I can attest it's been a great addition to the shack. I can rub shoulders with other ops in a crowded band without fear!

The MFJ-721 is an older unit that was replaced by the updated MFJ-722. The 722 adds a notch filter to the existing filter capabilities of the MFJ-721. MFJ also moved the headphone jack to the BACK of the 722, which means you have to handle the unit every time you use. The 721's front-mounted headphone jack may be ugly, but it's certainly more functional.

While I didn't expect the MFJ-721 to transform my HW-16 into an ICOM IC-756 PROIII, I am very, very happy with the improvement in how it operates. I gave the MFJ-721 a 5 rating for the fact that it's added a great deal of enjoyment to my use of the HW-16.

If you have any questions, problems, or suggestions about Reviews, please email your Reviews Manager.