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Thinking out loud again.

For MFJ to claim that it is good up to UHF with a resistor the length of a UHF antenna, I would think that the shield has to be working along with the resistor to form something of a transmission line.

If the dielectric in a coax cable is changed from air to oil (1 to 2.4), the characteristic impedance is cut roughly in half.

If you have a center conductor in a square shield, the characteristic impedance is approximately Zo = 59.96 * ln(1.079*D/d).

I am wondering if making the inner shield bigger would help with it being in oil. The MFJ-264 manual specifically states not to run it in any liquid, and the only reason I can figure is the dielectric change. IDK.

[QUOTE="brandon7861, post: 855176, member: 53724"] Thinking out loud again. For MFJ to claim that it is good up to UHF with a resistor the length of a UHF antenna, I would think that the shield has to be working along with the resistor to form something of a transmission line. If the dielectric in a coax cable is changed from air to oil (1 to 2.4), the characteristic impedance is cut roughly in half. If you have a center conductor in a square shield, the characteristic impedance is approximately Zo = 59.96 * ln(1.079*D/d). I am wondering if making the inner shield bigger would help with it being in oil. The MFJ-264 manual specifically states not to run it in any liquid, and the only reason I can figure is the dielectric change. IDK. [/QUOTE]

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