Yaesu FT-950 and FT-2000 Roofing Filter Optimization and Improvement Project

Making a Great Radio Better                                         




The Yaesu FT-2000 represents what I believe to be the best value in ham radio today.  Exceptional ergonomics combined with great performance and a super feature set; it is a pleasure to operate. And when it's not in use, it's still great - covering a desk in the way a rig "should" look. 

Unfortunately, some choices made in the 1st IF design of the rig left it with quite a poor performance score in one area - close-in high-strength signal handling capability, commonly measured as 3rd order dynamic range.

This specification is important to guys working pile ups and contests where the chance of a couple of high strength signals near your QSO can, under the right circumstances, result in IMD 'ghosts' appearing.The rig, as sold by Yaesu in it's stock form, has a IMDDR3 performance score at 2KHz spacing of about 63db.  Yet the general rule of thumb is that a rig with a performance score of over 80db is needed to prevent difficulties in most cases.

However, by using the NS roofing filter, typical IMDDR3 scores increase to as much as 85 db! 


Questions? Contact me at "jeff at AC0C dot com" 






The Yaesu 3 KHz filter measures about 7 KHz wide at -6db. 

The spectrum display at the left, is taken from the 2nd IF and shows what the filter shape of the original rig's filter looks like.











When fitted with the NS roofing filter, the front end is far more selective with a -6db bandwidth of about 2.4 KHz wide.













  • Tight 2.4 KHz -6db bandwidth

  • Up to +20 db increase in the tough 2 Khz spacing IMDDR3 benchmark




  • More DX

  • Higher contest scores

  • Less QRN

  • Less QRM

  • More amateur radio satisfaction





Joining me in the early work were Charlie Mazoch, W5VIN, originator of the famous "Charlie Mod" - and Daniel Sandu YO3GJC, author of "Mod 2."  Charlie and Daniel were among the first to attempt to characterize and then address the IMDDR3 score issue.

Unfortunately, what they were lacking is a filter with truly world class performance.  The single filter available at that time provided only slightly better in bandwidth than the stock filter - so the next step was finding someone who really could hit the 3KHz target.  The search for the filter proved much  harder  than I had anticipated.  



When searching for a manufacturing partner for the project, many where contacted - including the most recognized names in the filter business. Without exception, every company contacted told me "3 KHz at 70 MHz? Not possible." Every company, except one, that is - Network Sciences.

Providing excellence in the filter design and subsequent manufacturing is our partner Network Sciences who brings world-class capabilities to design and execution.  NS is primarily a builder of high end filter solutions for military applications.  And they bring that technology to bear on this project.  The performance of the filter is testimony to Network Sciences' world-class design and manufacturing capabilities.    

NS was ultimately able to take the extreme demands of this project and turn them into a real filter, with amazing performance.  The results of this work has resulted in the availability of a new tool for serious DX and contests alike.






In production now.  See orders page (below) for details.


Place your order today and start enjoying the benefits of this world-class selectivity and performance enhancement!   


















* Typical values listed.  Parameters subject to change without notice.  Actual performance improvement depends on many factors beyond the function of the filter alone.

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