Replacing 4 x D cell with 2 x 18650 rechargeable cells
finally I ended up making something myself.
Thread rod, with bolts ans washers, 18650 protected cell so cuts of after volt drops at cutoff inserted in PVC pipe.
All I need now is just a bit of foam to keep the 18650 battery centered in PVC pipe.
Measure voltage is 8 volts, I am 2 volts above original original D cell voltage. Side of radio has DC power plug that read 7 Volts I guess I am only 1 volt above operating spec will this damage the radio long term ? time will tell, its running fine now. and I don't have to reorder D cells.