Unless the receiver's NF is >3dB, "sun" and other atmospheric noise is the limiting factor in most cases so all kinds of preamps generally don't help much...if the receiver is any good to begin with. I was pretty active on 2m e.m.e. back in the late 70s/early 80s and never used a preamp, even for that. 7/8" Heliax for feedline, less than 75' long, contributed <<1 dB to my NF and I had no problem copying anyone who could also hear me. Kill the preamp.