Jeff, I did this mod on my IC-735 some time back. There was no earth
ground. The entire circuit is self-contained in a small RS enclosure
with the ALC jack and the adjustment pot being the only two connections
to the outside (of the enclosure). The ground is strictly a connection
back to the battery. However...the rig is earth grounded and if the
circuit requires an earth ground then maybe that would suffice. I pulled
out the schematic but it doesn't say anything about being earth grounded.
73,
Mike Kopacki, KF2EW
On Thu, 01 Jan 1998 10:10:51 -0500 Jeff & Bea Hahn
<jhahn@bellatlantic.net> writes:
>ICOm sent me the following project to make ICOM rigs operate at QRP
>levels. I would appreciate it if someone would tell me how to do an
>earth ground with the battery, R2 and the cable (my shack is on the
>second floor). I have tried to find the answer in books from the
>library but can find no discussion. One reference seemed to suggest
>that they should just be taped so there will not be a short and
>forgotten.
>
>
>
> *********
>
> QRP MOD FOR ICOM HF TRANSCEIVERS
> (from ICOM, dated 6/1/94)
>
>
> /
> |-------------/ *----/\/\/\/\----|
> (-) | S1 R1 | to
> *-----| | ALC
> < jack
>9 volt alkaline battery R2 > <--O
>---------O----->
> < | shielded |
> *-----| > | cable |
> | < | |
>
> | | | |
> | *----| |
> | | |
> ----|---- ----|---- ----|----
> ----- ----- -----
> --- --- ---
>
>
>With this circuit connected to the radio, the power output is
>adjustable between 0 to 100 watts. For best results, leave the RF
>power at maximum and adjust for desired power using R2.
>
>S1 is used to turn off circuit when radio is not in use or QRP
>operation is not desired.
>
>
>Radio Model: R1 Value R2 Value
>
>IC-761, 765 47K Ohms 20K Ohms
>
>IC-720(A), 735, 740, 2M Ohms 1M Ohms
>745, 751(A), 275A/H
>
>IC-725, 726, 728, 729, 220K Ohms 100K Ohms
>736, 737(A)
>
> *********
>
>
>Thanks,
>
>Jeff Hahn, KR4YS
>
>
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