SITE MAP
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MODS
An Archive of Useful Modifications to SGC Equipment
Modification of radios has been a tradition
in the HF community.
In many cases, modifications can provide desired
functionaliy for uses unforeseen or not intended to be addressed by the
original manufacturer.
Some of the mods shown on this page are not approved
by the manufacturer.
Information provided for educational use only. No
liability assumed.
In some cases, modifications of internal circuitry
may void a manufacturer warranty.
Some of these modifications have been designed by
Amateur Radio or radio experimenters.
SG-2020 Mods
A.
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General Coverage "Export" Frequency Mod |
B.
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Heil Microphone Element Mod |
C.
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CW Thump Filter (external) |
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A. SG-2020 General Coverage Transmit Frequency Mod
Enables transmit from 1.6 through 30MHz
Photo shows front panel circuit board and 4 pin cable connector unplugged
for access to "Export" jumper. |
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1. |
Disconnect power, remove 3 screws from bottom, and remove enclosure
by sliding chassis out. |
2. |
Unplug 4 pin connector from front panel PC Board behind knob. |
3. |
Using a very small diagonal wire cutter, cut the wire jumper between
the black encoder and the 4 pin connector on the front panel PC Board.. |
4. |
Plug in 4 pin connector and re-assemble chassis in enclosure. |
5. |
Observe authorized frequency liimits. |
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B. SG-2020 Heil Microphone Element Mod
Changes the stock dynamic microphone element and modifies the
internal microphone circuit to operate with the Heil crystal element for
more audio "punch".
Photo shows R25 changed from 100k to 220k for more gain and R28 changed
from 2.7k to 5.6k
to match Heil crystal microphone element. |
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1. |
Disconnect power, remove 3 screws from bottom, and remove enclosure
by sliding chassis out. |
2. |
Unscrew 3 screws with 2 spacers, and carefully remove sheild plate
at position B shown in 1st photo of bottom of PC Board. |
3. |
Using a soldering iron and tweezers, carefully remove R25 (100k) and
solder in its place a 220k type 0805 resistor. |
4. |
Remove R28 (2.7k) and replace with 5.6k type 0805 resistor. |
5. |
Re-install sheild plate, spacers, 3 screws. |
6. |
Re-assemble chassis in enclosure. |
7. |
Dis-assemble microphone case, de-solder leads from microphone element,
and remove element. |
8. |
Install the Heil microphone element using supplied foam spacers to
hold it in place. |
9. |
Carefully solder the microphone leads to the Heil element contacts. |
10. |
Re-assemble microphone case. |
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C. SG-2020 External CW Thump Filter for Headphones
Alleviates Audio Thumping in CW Mode
Drawing shows series LC filter of 330uH inductor,
10uF capacitor, with stereo mini input and output. |
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1. |
Procure parts:
Stereo mini jack and plug. 330uH inductor. 10uF capacitor. Wire and
enclosure for mounting parts and stereo jack. 2 conductor cord for plug. |
2. |
Mount stereo jack, run cord through hole in enclosure, solder plug
and parts inside enclosure according to schematic. |
3. |
Plug into speaker jack of 2020. |
4. |
Plug headphones into Thump Filter jack. |
5. |
Use of filter in SSB mode not suggested. |
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Do you know of a useful modification for SG equipment?
Your comments and contributions are welcome on the SGCgear
email list.
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