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Reviews For: NEScaf Audio Filter

Category: Filters, Audio: (DSP and others)

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Review Summary For : NEScaf Audio Filter
Reviews: 33MSRP: 29.00
Description:
The NEScaf is a switched capacitive audio filter based on the MF10 chip. It is
designed to be simple to build and use.

It is more flexible than previous filters for QRP rigs. It has two panel- mounted
controls -- a single center-detent potentiometer that sets the center
frequency of the filter's bandpass (default value settable between ~415Hz and
~1kHz), and a dual-ganged potentiometer that provides a continuously
variable bandwidth control (from ~60Hz to ~1500Hz). This ability to smoothly
vary the bandwidth is very useful.

The NEScaf is designed to be driven with a phones or speaker level signal.
Product is in production
More Info: http://www.newenglandqrp.org/wordpress/nescaf/
# last 180 days Avg. Rating last 180 days Total reviews Avg. overall rating
00334.9
W2GW Rating: 2006-11-12
Easy build - works great! Time Owned: N.A.
These days of low sunspots numbers, when N dominates the S/N ratio, it is nice to be able to narrow the audio passband and eliminate some of the N, especially if you are a CW op. The NEScaf filter does a great job of this.

This is a fine kit. It goes together easily. I mounted the filter in a black TenTec box, and it looks beautiful. (if you don't have the tools or the time to fabricate the case, this may not be for you.)

73,

John, W2GW

W5USJ Rating: 2006-10-11
Excellent variable bandwidth audio filter. Time Owned: 0 to 3 months.
My NEScaf came in the mail recently so as quickly as I could get to it I fabricated the enclosure for the peripheral parts and built the board. The enclosure is an LMB CR-421.

It all went together quite nicely with no major glitches. I didn't do all the testing steps as I don't have the equipment to do it as described in the instructions.

Right now, I have it connected to my FT-817 mainly because it generates a 700 Hz sidetone. I peaked the center frequency by ear using this audio source.

The audio bypass circuit isn't connected now and for CW only you may not need to do that. The wide bandwidth setting is more than enough to hear the adjacent signals. For SSB and other wide audio, the bypass is probably needed.

Audio Volume -- enough to knock you ears off. I have the filter connected to the headphone output of the 817 and it is plenty loud. With the adjustments made as described in the manual, the rig does the volume control job. Be sure to set the filter volume pot as indicated for initial adjustment. Or don't put your headphones on until you do...[g]

With the filter adjusted for minimum bandwidth, you can tell the signal is getting squeezed. No ringing was noticed with various input volume levels.

Next testing will be with the Rock-Mites and HiMites. The NEScaf looks like the perfect companion for these little rigs.

My NEScaf is permanently in-line with my headphones now. Not only does it provide the neat adjustable bandwidth, it also improves the quality of the audio. The high frequency rolloff helps cut down the high frequency noise.
W2BPI Rating: 2006-10-09
Great Filter Time Owned: 0 to 3 months.
Received kit quickly. Goes together easy. Good instructions for assembly, setup, and use. I built mine in a BLT tuner case. This way I can use it with all my qrp and qro rigs. You could easily build it into your rig. I have used many audio filters, but like this one the best. Very good product for the price.