Tom, W8JI, made some excellent points in his posting. What he failed to
mention is that MFJ is his employer. Consulting or otherwise; they pay
the freight and have for several years.
The Oren Elliott Products roller inductor started out as a fair copy of
the more expensive Cardwell/Johnson 229-203-1. Ceramic form, taper
pitch, ceramic end insulation. It did not have the far superior roller
positioning and tension mechanism of the 229 series.(something about
Patent law I believe). This version ended several years ago when OEP had
difficulty obtaining the ceramic form. The Delrin form was developed to
replace the ceramic one but it no longer had the taper pitch. It is
certainly not an industry standard inductor as Tom would like us to
believe. The Cardwell IS the ONLY STANDARD of COMPARISON and has been
for over 40 years. Early versions also had parasitic problems on 17M
although I do not understand why. By this time MFJ was OEP's biggest
customer and the quality continued to decrease; even the ceramic
insulators were replaced by some form of pressed paper. Up to this time
Radiokit (me) had continued to buy OEP parts for their 1500W T Match
kit. (Our kit was renowned as the only tuner that could handle the full
output of the real big amps on 80 and 160M). Never once did we have a
reported problem with the ceramic form inductor overheating at or beyond
the legal limit. I chose to discontinue that kit rather than stoop to
MFJ inspired quality.
Another interesting bit of trivia is that the MFJ 3KW tuner caught fire
in the ARRL lab. Not just once, but the replacement unit too. At under
1KW. It should come as no surprise that that small fact was missing from
the QST review.
Tom mentioned the Dentron tuner and again I believe his comments are
misleading. The original 600W tuner was developed around the time of
their 10-160L amp which originally used 4 811A's and later switched to
572B's (and smoked the load cap on a regular basis). It was rated at
1200W PEP, not 3KW. As Dentron progressed up the power curve with the
Clipperton L, MLA-2500 and DTL-2000 a larger tuner was needed. This
became the popular 3KW Super Tuner. I think they also had another tuner
rated in between .
The very nice Ameritron ATR-15 was an almost carbon copy of the big
Dentron. Same OEP capacitors, same B&W coil, same Centralab switch. I
cant say if the ATR used a Lexan (a higher priced B&W option) insulated
coil or the same polystyrene as the Dentron. BTW, is the ATR still
produced?? The Dentron coil did have a tendency to deform over the
years when pushed at high RF levels. Tom was also very intimately
involved at Dentron and Ameritron back in the Ohio days and is also known
as the Chief Engineer at MFJ/Ameritron today. He is a damn good engineer
and I am not trying to impugn his abilities. However Tom, I do feel that
you are spewing forth with the MFJ party line and are the designated
damage control spin doctor. I'll let you chase me around the MFJ booth
at Dayton!
Radiokit (me again) has worked with Cardwell to produce a higher power
version of their 229-203-1 28uh roller inductor. It uses #10 silver
plated wire in lieu of the original #12. We are also seriously
contemplating a new T Match tuner kit using that inductor, big
capacitors with Jackson Brothers drives/dials, and a Millen Turns
Counter (yes it is still produced) that will specifically be aimed at the
low band operator. It will not be cheap and there has to be sufficient
interest. Please private E-Mail me about prices, etc. I am not sure
about the administrators "advertising" policy and will keep any of those
discussions off-line.
Altho critical, I hope that Tom and others will not take this reply as a
personal attack. I have known Tom for many years and will always respect
his abilities. However, my criticism of MFJ has continued for many years
too. I was also watching the many replies to 4X1AD on another
reflector....WOW, talk about some irate customers!!
73 and a great '97 DX season to all.............Carl KM1H
--
FAQ on WWW: http://www.contesting.com/topband.html
Submissions: topband@contesting.com
Administrative requests: topband-REQUEST@contesting.com
Sponsored by Akorn Access, Inc & KM9P
|