Known Gasoline GENSETS for the AN/GRC-109 system:
First photo: The UGP-12. 125 Watts, 115 VAC, 400 cps, 2-stroke (manufacturer unknown) as described in the GRC-109 manual as an alternate field power source. At the 2014 MRCG event at San Luis Obispo, Chuck demonstrated his UGP-12 (pictured). It was remarkably quiet and produced little smoke.
Second photo: The 125 Watt, 115 VAC, 400 cps 2-stroke Homelite Model XLA115/1/400/1P as used by the Army’s 10th Special Forces Group. Photo of a layout for a unit communications team equipment inspection, mid 1970’s.
It is presumed these generators would be powering GRC-109’s from a safe house, bunker or as a backup in an HQ someplace – rather than tactical “mudborne” operations.
Also note the GRA-71 Code Burst Keyers, the PRC-74 HF sets and the PRC-25/77’s etc. It seems reasonable that the Homelite generator replaced the UGP-12 later on in time. The Homelite Tech Manual (TM5-6115-405-15) is dated July 1967.
Special Forces comm gear inspection layout photo courtesy of W1OC, 10th Special Forces Group (E).