Call Search
     

New to Ham Radio?
My Profile

Community
Articles
Forums
News
Reviews
Friends Remembered
Strays
Survey Question

Operating
Contesting
DX Cluster Spots
Propagation

Resources
Calendar
Classifieds
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
About eHam.net

   Home   Help Search  
Pages: [1]   Go Down
  Print  
Author Topic: MFJ 986 vs MFJ 989D  (Read 1514 times)
KJ6TSX
Member

Posts: 123




Ignore
« on: October 02, 2012, 09:39:32 PM »

What is the better tuner between the MFJ 986 and MFJ 989D?
The 986 is a differential "T" tuner the 989 is a "T" tuner what exactly does that mean?
Looking to buy a 1000 watt tuner these seem to be in my price range, any suggestions or comments?
Thanks
George
Logged
KJ6TSX
Member

Posts: 123




Ignore
« Reply #1 on: October 02, 2012, 09:54:00 PM »

I just re-read the specs on the two tuners and realized that the 986 has 1 adj capacitor the 989D has two. I assume that makes it more precise???
Logged
WB6BYU
Member

Posts: 13571




Ignore
« Reply #2 on: October 03, 2012, 09:06:25 AM »

The "differential" tuner still has two capacitors, but they are on a single shaft.
That is supposed to make it easier to adjust because there are fewer knobs.

The tradeoff is that the differential approach doesn't allow both capacitors to
be near maximum capacitance.  For the same capacitor size, the differential will
always use less capacitance than the standard "T" network, which means that
efficiency may be less.  Much of the time this won't matter much, but if you
are matching low impedance loads on the lower bands (80m and 160m) it can
be important.

In practice, with a conventional "T" network I try to leave one or the other
capacitor at maximum and just adjust the other (although some loads won't
match this way).  That means, most of the time, I'm only dealing with one knob
in addition to the inductor anyway.
Logged
KJ6TSX
Member

Posts: 123




Ignore
« Reply #3 on: October 03, 2012, 02:55:56 PM »

Thanks for the reply
Now I Know and it even made sense
Thanks
George
Logged
Pages: [1]   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.11 | SMF © 2006-2009, Simple Machines LLC Valid XHTML 1.0! Valid CSS!