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Author Topic: SW+ 40 Modifications  (Read 3081 times)
NS2X
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Posts: 16




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« on: April 26, 2010, 07:50:13 PM »

Any suggestions on "Good Modifications" for the Small Wonder Labs SW+ 40?  It seems like a very good prospect for QRP and wanted to check with the experts before building...thanks... Greg NS2X
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VE3WMB
Member

Posts: 286




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« Reply #1 on: April 27, 2010, 08:23:55 AM »

I would guess that the most common mod is RIT. SWL used to sell an RIT kit but it is now discontinued.
If you Google "SW40 RIT" I believe that there are still some schematics floating around. 

Adding a Freq-Mite is also a good idea. There are also a number of small keyer kits (I have a K1EL K12
in my SW40+ along with a Freq-Mite) available. It is also worth purchasing the enclosure / controls
as it gives the end result a more professional look. Others may prefer to package the rig in their own
enclosure.

The SW40+ has evolved since the early days when it was known as the NE-4040 and
it works surprisingly well for a $55 radio, there are really no problems that require "fixing".

This little rig is still one of the best deals in Amateur Radio IMHO.

Michael VE3WMB 
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WB6BYU
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Posts: 13142




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« Reply #2 on: April 27, 2010, 09:13:37 AM »

One of the ARRL QRP books had a whole chapter on modifications to the original 40-40 rig
that is the basis of the SW40+.  I don't know how many of the mods were made in the
newer version.  They included RIT, fixed frequency operation, reduced current draw,
improved TR switching, etc.

A friend and I got several of the bare boards and built them up ourselves (both of use
having very well stocked junk boxes.)  Mods included replacing the op amps for lower
current draw, reducing power dissipation in the driver stage, using a 3-watt CB transistor
for the final, and perhaps a couple of others that I forgot.  I used a 10-turn "Knob Pot"
for the tuning control, which gives excellent resolution across the lower end of 40m,
though the glass cover over the indicator is rather fragile and has broken.  A standard
10-turn pot and knob is somewhat heavy compared to the rest of the rig, but gives
very good control on the tuning.
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W5FYI
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Posts: 1044




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« Reply #3 on: April 27, 2010, 05:22:33 PM »

The article "Revisiting the 40-40" is in the ARRL book QRP Power. AE6C and KB6FPW gave their impressions of the 40-40 (also referred to as a NorCal 40, or SW-40). It's a pretty comprehensive article, but it was written before the SW-40+ came on the market. Some mods are probably worthwhile, and some not likely so. Nonetheless, it is a good read, even if you don't have a '40 to modify. GL
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