[MRCA] Grounding SP-600 JX-17

[mr3hi8st8or5y at cox.net]

Belated New Years to all,
There is no ground connector that I can find on the back of this red knob Hammarlund. Grounding does improve reception. I had been using the Allen wrench No. 6 clip to connect to ground. HOWEVER, I felt current under my shoe when steping on the solid wire to the grounding rods. The photo of the back in my manual shows nothing labled ground. 
So, if you have one of these, is it grounded and if so how?
73,
Roger