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Reviews Categories | Filters, Audio: (DSP and others) | MFJ-784B Help

Reviews Summary for MFJ-784B
MFJ-784B Reviews: 30 Average rating: 4.4/5 MSRP: $249.95
Description: DSP Noise Filter
Product is in production.
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PY2FWA Rating: 5/5 May 12, 2005 11:56 Send this review to a friend
FB Job  Time owned: 0 to 3 months
I bought the MFJ784B today and i very happy with it, With my TS-450S and FT-840 (both without any filter)the signal with this DSP filter was excellent, very station on 40Mts band i can't hear whitout the filter, fantastic.
K2PGB Rating: 5/5 Mar 27, 2005 14:53 Send this review to a friend
Near Perfect  Time owned: 3 to 6 months
Have 500 cycle filters in both a TS-680s and TS-140S and also use a TS-830S. The filter works great on CW and SSB. Could not be more satisfied.
K8AC Rating: 5/5 Feb 22, 2005 06:42 Send this review to a friend
Gets the job done  Time owned: more than 12 months
I've used the 784B for a couple of seasons now on 160 meter CW. My requirement was to be able to dig the weak ones out of the noise better. The secret is to use the filter with AGC ON, CW mode, and tunable filters knobs properly set. No need for a very sharp bandwidth as set by the B/W control. The filter often makes the difference between barely discerning the signal and 100% copy. I've used Timewave 599zx and DSP 9 filters and neither came close to the MFJ for weak signal CW. The auto notch also works well on SSB (better than Timewave) and you'll hear less artifacts in the resulting audio.

Note that this filter is large in comparison to the competition.
K2JF Rating: 5/5 Aug 26, 2004 18:18 Send this review to a friend
Where'd the noise go?  Time owned: 0 to 3 months
I live in the middle of Manhattan and have tried everything to deal with this S8 noise level. I thought it was power line noise, but now think it's ol' QRN - atmospheric noise. Anyway, I got this 784B only a week ago and really love this piece of equipment. It takes that noise right out to where I can listen now without thinking I'm sitting in the bottom of Niagra Falls anymore.
I find that setting the filter to SSB, even though I primarily operate CW helps in the quality of the audio. The noise reduction and AGC are incredible and with just a little experimentation it's easy to find the best combination of settings to make for good listening.
I've bought and sold all manner of gear lately but this one is staying right here.
KB3JLZ Rating: 5/5 Feb 26, 2004 11:32 Send this review to a friend
Pretty darn good!  Time owned: 0 to 3 months
Have had the unit for almost three months. Wow! I am also on of those that other than the setup, just puts the instruction manual in the file cabinet. Dont! Keep it handy to see what the knobs and buttons really do. I agree with other reviewers that a spectrum analyzer (software one will work!) is really usefull in setting/seeing what the filters do. A great example is the waterfall display in PSK31/other digital modes. WOW! I was working 15m PSK31 and used the unit to clean up/wipe out a bunch of QRO PSK people. Brick-walled everything except the weak signal I was hunting after. RTTY modes was impressive as well. SSB mode helps alot too. The auto notch just wipes out the on freq tuners dead! Mind you this box isnt going to solve all your noisy band problems but if you have an older rig that dosent have DSP (like my 757gx) this guy will work some lesser wonders for you.

Really like it!
AF4KK Rating: 4/5 Jan 28, 2004 14:46 Send this review to a friend
Great (not so little) unit!  Time owned: more than 12 months
I've been using my MFJ 784B since 1996 and it's been a fine unit. My favorite functions are the programmable filters (they can get quite NARROW!), the built-in SSTV filter and the very-adjustable noise-reduction function. The amp built into the unit also reduces stress on your radio's audio output section. My only gripe is its (sort of) large size but that's a minor issue. Well done, MFJ!!
XE1UFO Rating: 5/5 Sep 4, 2003 18:40 Send this review to a friend
Really great!!  Time owned: more than 12 months
I used this unit with the following rigs:
--Atlas 210X (with only 2.7 Khz built-in filter)
--Kenwood TS180S with double in-line 1.8 Khz filters
--Kenwood TS140S with single 2.4 Khz filter
--Alinco DX70, with 2.4 Khz filter.

I espescially enjoyed using it on 160, 80 and 40 meters for digging signals out of the noise. It DID take a little work to learn, but very well-worth the trouble. It of course does its greatest difference on radios with the widest built-in filtering. On 40 meters it is great for knocking out the broadcasters.
PY5CL Rating: 4/5 Jul 16, 2003 19:46 Send this review to a friend
It Works  Time owned: more than 12 months
I was not able to adjust filters until I started using it with an audio spectrum software, now I know how much filter to apply
W7TUT Rating: 5/5 Mar 4, 2003 13:52 Send this review to a friend
Works great, easy to use  Time owned: 0 to 3 months
Am using it on a Yaesu FT-840 which had little
or no filtering. Works great. Narrowed up
SSB signals, reduced background noise and
didn't reduce received signal. Also eliminated
some feedback I was getting during xmit into my
external Kenwood speaker.
K6LDX Rating: 4/5 Feb 21, 2003 10:59 Send this review to a friend
Good for QRM  Time owned: more than 12 months
I used the MFJ784B for two years with my (non-DSP) FT840 and found it did a good job (for an AF filter) on QRM - took a little learning but was basically easy to use. It was less effective on QRN or local RF noise (AC lines, etc.).

I sold it with the FT840 when I upgraded to an (IF) DSP-equipped rig. Now I wish I had kept it as it has some flexibilities that my new rig's DSP doesn't have!

If your rig has DSP, it probably isn't worth buying unless you find a used one cheap. If you're using a non-DSP rig and have limited filters available, its worth considering.
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