Topband: cutting coax stubs for 80 meter 4-square

[terry burge]

Hi guys and gals,


I have got DX Engineering 75 ohm foam coax to make the stubs/feeders for my Comtek 80 meter 4-Square and am finding some difficulty. Neither my MFJ-259B nor my Rig Experts AA-170 seem to indicate a 1/2 WL at 7500 KHz or a 1/4 WL at 3750 KHz? Or any frequency up or down from there. Seems to me the last time I did this a few years ago I didn't have a problem getting a 1/2 WL dip indicating a resonance location. But now I just don't get any indication of a resonance.


DX Engineering said they had got some 75 ohm foam coax that instead of 0.84 VF was more like 0.80 down to 0.76 VF. But checking all the way down to 6000 KHz on 40 meters or 2500 KHz on 80 meters fails. 


 My test is to use either antenna analyzer with a PL-259 installed at one end and an open or a short at the other. I started with 57'7" of coax. Tried both with the coax in a roll and strung out. What am I doing wrong?


Terry

KI7M

😞