Tim Boyd said :

I have installed a inverted V wire antenna. I have it connected with a
1:1 balun at 30 feet from the ground. The center wire is 66 ft 6 long
snip
Right now the antenna works from 40 meters to 6 meters
snip
I am getting started in MARS and need to transmit around 3.350 MHZ

You just said it above...your antenna is ~66 feet in length, about
right for 40 metres. If you need to transmit around 3.5 MHz, you will
need to double the size of the antenna at the very least. You will
probably need somewhere around 128 feet of antenna, though it varies a
little depending on numerous factors specific to your installation.

However...

The end is 8 feet from ground.

That's another problem entirely. The idea is to keep your antenna
roughly 1/4 wavelength above terra-firma. Easy to do at 20 metres,
harder at 40 and very hard to do at 80. My own 80M dipole is only
about 45 feet above ground level and even with 600W, getting a signal
out is a chore at times on that band. If you can, you would do very
well to get the entire thing up as high as you can.

You may also face space problems with an antenna of that length. If
your property size won't allow you to put up a high 128'-foot-long
antenna, there are electrically shortened antennae out there that
might work acceptably for you, but will offer you greatly reduced
bandwidth. If you're also a licensed amateur in addition to MARS
operator, and you want to use that antenna for 75M phone, you'd have a
problem with one of these shortened dipoles.

Good luck.

73 de Peter, W2IRT
(ex-AB2NZ, VE3THX)

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