[HCDX]: MFJ-1026 - Problems

["W.A. Merriman" <merriman@xxxxxxxxxxxxxxxxxx>]

On the evening of Oct 11 was doing some casual tuning around Medium
Wave and happened to tune down below the band.  Starting at 510 kHz
and every 10 kHz going down I noticed some mixing products.  On some
freqs, such as 490 kHz, these were fairly strong.  Started looking
for things wrong and discovered that I had inadvertantly turned on
the amplifier on the Aux Antenna of the 1026.  Immediately turned it
off hoping that the spurs would disappear but unfortunately they did
not.  Although the signals got weaker, they were still there.  When
the 1026 was turned completely off the spurs went away thus confirming
that it was the source of the problem.  Replaced the MFJ-1026 with my
DL-2 Delay Line Phasing Unit and with the DL-2, even when the broadband
amp was turned on there was absolutely no trace of any problems.

On Oct 12 checked out the 1026 during the day.  With the amp turned off
there was no trace of any mixing products but when the Aux Antenna amp
was turned on I had a very weak signal on 480 kHz.  This test was done
around 1030 local.  At 1200 I checked again and this time with the amp
on there were signals on several freqs from 490 kHz down and the one I
noted earlier on 480 was noticeably stronger.  Again with the amp off
all spurs disappeared.

My MFJ-1026 has been in use for over two months and this is the first
time I've noticed any problems - but they may have been there and I just
didn't notice.  Have not run into any spurs inside the MW band yet but
I suspect they are there and covered up by stronger signals.  Although
these problems, which may be limited to my unit do not mean that the
1026 cannot be used for MW phasing they do indicate that the Aux Ant
amp should not be used, at least with an external antenna and that 
great care should be used in identifying what is heard.

It will be very interesting to see if other DXers have these same problems
with the 1025/1026.  In Europe problems would probably start at 513 kHz
and go down every 9 kHz.  The receivers used were a Drake R8A and a AOR
AR7030 Plus.  Both gave the same results.

73/DX

Al-K4GLU

PS: The Aux Ant amp in my unit is set to position number 3, moderate
    gain on an external antenna as shown in the owners manual.
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