[Boatanchors] You never know what you'll find in a boatanchor manual

[Glen Zook]

Actually, there are like 3 resistor values that were
changed in the DX-100B which helped slightly with the
drive on 10 meters.  Those changes are outlined in a
Hints & Kinks column in QST around 1960.  It costs
well under $1 even if you had to get the resistors
from Radio Shack.

The changing of the antenna loading from the 50 pf
variable and switched fixed capacitors to a 3 section
variable was a Heath modification kit that came out
before the DX-100B.  Those transmitters that were
modified with the new antenna loading were generally
known as DX-100A models.  That was one of the reasons
that the next production version was called the
DX-100B instead of the DX-100A.

Frankly, except for the antenna loading circuit the
DX-100B was a cheapened version of the DX-100.  The
cabinet was cheaper to make (and was the same as on
the TX-1 Apache, RX-1 Mohawk, HA-10 Warrior, and the
HX-10 Marauder except for the paint color).  The front
panel switch that controlled the VFO and 4 crystal
positions was changed to a slide switch inside and a
single crystal.  The only other change was that the
DX-100B had the holes already drilled for the SB-10
conversion kit.  You had to drill the chassis if you
added the SB-10 to a DX-100.

There also was a Heath modification kit that was for
both the DX-100 and DX-100B that added a spotting push
button to the front panel to turn on the VFO without
putting the transmitter in transmit.  The kit also
included a change to the VFO to improve keying
characteristics.  The instructions for that kit can be
found on BAMA.  Adding the spotting switch is
definitely a worthwhile project.  The keying
modification is "iffy".  It does help slightly with
the possibility of "chirp" but also runs the VFO
constantly when in transmit and thus can be a problem
if you monitor the signal on your receiver when
sending CW.

In general, at least in my opinion, the DX-100 is a
slightly better transmitter than the DX-100B.

I grew up about 35 miles from the Heath plant in St.
Joseph, Michigan (their mailing address was in Benton
Harbor but the actual plant was in St. Joseph).  When
I was in high school I used to drive up to the plant
just to see the new kits (there was a showroom in the
front of the plant).  Sometimes I would have a
question about some Heath item that I owned and the
receptionist would telephone back into the engineering
department.  One of the engineers, often the person
who had designed the kit (or was a member of the team
that designed the kit) would come out.  Usually I left
with a bag of parts and a hand drawn schematic for
some modification that would improve the performance
of the unit.  No charge for either the parts or the
advice!

Glen, K9STH


--- Bob Young <youngbob53 at msn.com> wrote:

I found an original letter dated 6-8-63 to the Heath
Co. stapled in the manual along with the response from
Heath dated 6-10-63 (like to see that happen today),
from Ed Borezo Jr. K1SHH asking for info on mods for
this transmitter to change it to a B. They wrote back
and advised against changing it as I guess it would
involve extensive modifications (or they just wanted
to sell another transmitter)









Glen, K9STH

Website:  http://k9sth.com


 
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