- 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) | Midnight Science CW Regen Filter (AKA The Scrubber) Help

Reviews Summary for Midnight Science CW Regen Filter (AKA The Scrubber)
Midnight Science CW Regen Filter (AKA The Scrubber) Reviews: 3 Average rating: 5.0/5 MSRP: $70
Description: This kit was inspired by the inhibiting galactic noise encountered when listening to HF CW. Many proficient CW operators turn the AF gain full on and manage the audio signal and noise with internal rig filters and the RF gain knob. Even with these techniques band-limited cosmic static is present along with some man-made noise. There isnít much one can do to copy CW notes that are simply too weak; but, one can scrub away a portion of the static that makes its way into our consciousness with an audio regenerative filter.
Product is in production.
More info: http://
Email Subscription
You are not subscribed to this review.

My Subscriptions
Subscriptions Help

You can write your own review of the Midnight Science CW Regen Filter (AKA The Scrubber).

K4SUE Rating: 5/5 Jul 2, 2015 16:50 Send this review to a friend
Great CW accessory  Time owned: 3 to 6 months
I want to echo the two previous reviews. I bought this kit on a whim after seeing a mention of it in QST. Didn't really know what to expect, but I have been pleasantly surprised at its performance. I aligned it by ear with the idea that I will borrow a friends test bench and align it properly per the instructions. But, even by ear, I'm blown away at the way I can pull CW signals literally out of the mud, peaking them with the clarifier on my FT301D and adjusting the regen control for razor sharp filtering. Reminds me of the performance of the old Drake 2BQ and the Heath QF1 only magnitudes better. With no CW filter in the 301, this thing really, really plays well.
The kit went together easily, with extra resistors in case you want to change the center frequency (choices are 500, 600, or 700hz) and voltage regulators for you choice of external 12VDC or internally 9 VDC battery power.
Hats off to Xtal Set Society for this product.
KM4IXK Rating: 5/5 Jun 28, 2015 21:03 Send this review to a friend
Kit was easy to build and works well.  Time owned: 0 to 3 months
This kit went together in a couple hours. It was easy to build and there is lots of room between components. I recommend getting the case.

There is room in the top of the case for another project.

They supply two voltage regulators so you can decide to run off of 12v-36v only or have the option to use a 9v battery AND a 12-36v power supply. I chose the 5v voltage regulator option so that it will run on the 9v battery when needed (I used it on field day)

Alignment can be a bit tricky if you don't have an oscilloscope. Initially I did it by ear but later I bought a bitscope micro and re-aligned using that. The trick seems to be not to over drive the regen chips. Bring the signal levels up just high enough for it to max out but no higher.

The filter is quite narrow and does a great job of blocking out nearby cw signals.

Keep in mind that the regen properties also regen the hiss you hear when you have a narrow filter. Because of this, there is a slight learning curve to using it. I found that reducing the RF gain on my radio and increasing the regen on the device produces the best results with the least HISS in the headphones. Certainly far better than can be achieved without the device present.

I almost gave this 4/5 because they do not include labels for the face but since I plan to also put Son Of ZeroBeat in the same case, labels might have gotten in the way of that modification. So... for me it's a 5 out of 5!
AE6RQ Rating: 5/5 Dec 5, 2013 22:17 Send this review to a friend
It gets better with practice!   Time owned: 6 to 12 months
Adding to my previous review:

Now that I've had some time to really learn how to use this filter, including the need to put the receive signal ::dead-center:: of the passband and regen circuit (I use RIT to drop it right in) and , this will really pull a CW signal from very close to the noise floor to fully copyable.

Even before I apply any regen to the signal, the more traditional bandpass filter makes a noisy band a pleasure to listen to.


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