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News & Announcements

Roofing Filters

Latest news, data.


Filter Order Information

NS production increases mean a much faster delivery for new orders


Filter Installation - FT-2000

Step-by-step, how-to install the NS roofing filter.  Now - a fresh rewrite with more installer tips!


Filter Installation - FT-950

The filter has been fitted into the first FT-950 with excellent results.


VIDEO: NS filter + FT-950

WMV 640x480  - 21mb

Demonstrates the attenuation of IMD tones from a 2 Khz tone pair


VIDEO: NS filter + FT-2000

WMV 640x480 - 29 mb

Shows the FT-2000 before and after the NS filter using IMD tone levels


OCXO for the IF-2000

Tame the drift from the RFSPACE IF-2000 with this simple OCXO conversion


DMU Bandscope Repair

A cure for the bandscope blues here



FT-9000 Roofing Filters for the FT-2000 Sub Rx?

VNA plots of roofing filters found in the main RX of the FT-9000, and the sub RX of the FT-5000.  What does this mean for the FT-2000?  Now  with DR3 measurements!


FT-2000 Sub RX AF Mod

Quiet down the weak signal hiss from the second RX with this easy mod ...


FT-2000 Front End Protection

Yaesu has made some changes to the front end protection circuits.  See the details here.


FT-2000 DSP Filter Characteristics

Plots of the DSP filter. As well as an investigation into the magic behind APF.  And how about CONTOUR?  It's all here!


FT-2000 Sub Rx Mods?

Investigations into the sub RX including filter response, quiescent noise and more...


Add APF to the Sub Rx

Follow the progress on this new project here.  See the results of a basic single op-amp design - and check out this computer controlled 24-pole version under construction now.  


FT-5000 300 hz Roofing Filter Characterization

How does the advertising and the reality match up on this filter?  Take a look here for answers...

DDS Sidetone

MFK keyer mod makes sweet music of the CW variety


Larcan 1KW 6m SS Amp

Just in time for 6m DX!


RX Antenna Switching

Just part of what's behind door #1.


Tower for 6m/12m/17m 

Mixes WARC antennas, a tilt-up tower - and a basketball goal!


Clifton Labs Z10023B

Got BC IMD?  The latest HPF from K8ZOA is the answer


From Attic to Acres

New country QTH brings a new shack and antennas.  Follow the progress here.


Kenwood TS-820S

My 1977 dream rig - now joining the shack lineup.  Details on the rig and mods, of course, here.


Stealth Attic Array Beam Rebuilds

Featured in Sept 2011 QST and 

NCJ May/June 2012


AC0C 2.4 KHz Roofing Filter

by Network Sciences 
For the Yaesu FT-2000 and FT-950

Built-to-order under MIL-spec processing flows by the best filter maker on Earth - Network Sciences!


Click HERE for more details.

AC0C Roofing Filter by NS - IN THE NEWS

Product Review - QST, May 2012

Click here to view - thanks to the ARRL!


Featured CQ Ham Radio Magazine, Japanese language edition, April 2011, pp 88-91

Article by Mr. Toru Kato, JG1RVN


Comments about the NS filter...

"If one already owns a 2000, I would spend the $300 for the filter.  I have gotten some good feedback on its performance."     Rob Sherwood NC0B

"No doubt about it, I did notice a vastly superior ability dig out and work the weak ones in crowded band conditions during the CQWW phone contest from the USA. As an example of this I finally worked zones 23 and 24 (China & Mongolia) on 40 to complete my 40 WAZ. only about 5 mores zones to go on 80 for 5BWAZ and now with this new filter I have a shot at it."  John W2YR/HS0ZDJ

"Jeff - HOLY SMOKES!!  Its in, and it rocks!  Thank you for all your effort ! This is the best investment I've ever made on this rig. Its cheaper than a uTune unit and works fabulously...   The performance of the filter is truly impressive.  "   Colin VE3MSC

"I've tried all the gimmicks from SCAF filters to DSP to narrow dedicated SSB filters - the combination of this NS roofing filter and the YAESU DSP to provide NOTCH, NR, etc. is something special. If anyone is sitting on the fence for any reason other than availability of $300 bucks - I would suggest in the strongest terms that they get off the fence and take advantage of this rare and amazing accessory."  Don WB8YQI

"OM Jeff, THANK YOU for your outstanding effort. That's Ham Radio of its very best !  I'm completely sattisfied with the solution."  Thomas DL1AMQ  

"I highly recommend the [NS] filter now available from AC0C. With this filter I recommend the FT-2000 to anyone; I now have the radio I always wanted...."  Greg KG6YV

"I can now tell a sharp difference between the 6kHz and the NS filter. Tuning off frequency with the 15 or 6kHz filters and switching to 3kHz makes the signal disappear. That wasn’t the case before as I could hardly tell any difference between 3 and 6kHz roofing filters."  Gerry  W1ID


More eHam.net reviews - CLICK HERE


Clifton Labs Z10022A AM BC HPF Under Test

Jack Smith knows how to build a filter.  N2PK scans here 


SO2V and the Microham Microkeyer MKII

Homebrewing a new digital interface for SO2V leads to a suprising shack addition


160/80/40m RX Loop

Top band noise a problem?  Maybe a receiving loop is the answer.  It was here!


Hantek 100 MHz DSO

100 Mhz dual channel digital storage scope with 7" LCD.  A major step forward to high-tech for the shack bench!


Alpha 76PA Mods

Adding grid circuit protection spins out of control once a MCU is considered...


The Ultimate Audio Filter

Microprocessor controlled, variable everything, 30 pole SCF filtering with multiple LPF and BPF modules - overall performance rivaling  that of DSP!


Loud Enough?

Station speaker amp featuring 2 channels, 50W RMS per side, HPF/LPF integrated for communications use


SB-200 Sleeper

Possibly the most radical SB200 mod ever.  You be the judge!


CW Skimmer Array

160m-6m bands. 24x7 service. Based on the high performance, low cost Softrock SDR.  A great DX tool that you can build.


FT-2000 + NS Filter Equals Performance of the $11,000 Yaesu PEP FTDX-9000MP and $10,600 Icom IC7800!

According to a new lab test reported in the July issue of QST, the DR3 performance of the Yaesu flagship rig is 85db 2KHz spacing DR3 test and generally noise limited. That's nearly the same range as the FT-2000 with the NS filter!

Also, a look back at prior QST reviews for the IC-7800 Icom flagship rig shows an ARRL-reported 86 db 2 KHz spacing DR3 test.

ARRL members can access the lab results here:

IC-7800 QST 03-2007

FTDX-9000MP QST 07-2010


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