Larsen NMO 150/450/758 length

[kb3isq]

I have both the Larsen tri-band antennas (one with and one without the spring) both are 16 inches from the whip base to the tip. The spec shows they are 16.5 inches. Question should I extend them to 16.5 or leave them at 16?

 

[mmckenna]

If you are using them for transmitting, you should use an SWR meter to adjust.
If you are using them for receiving, leave them as is unless you have the test equipment to properly tune it.

Anything else would be guessing.

 

[kb3isq]

Thanks, was just wondering why Larsen states a 16.5 inch whip and then ships them with a 16 inch whip.

 

[mmckenna]

Thanks, was just wondering why Larsen states a 16.5 inch whip and then ships them with a 16 inch whip.

They are primarily intended as antennas for multiband transceivers. That would mean anyone installing them for transmitting use would put them on an antenna analyzer and properly tune them before use.

While they are used as a scanner antenna, that isn't their primary market.