If you have a recommendation, I'd be open to it. It's a new subject for me... added the 7 db antenna and it came with a 3 (I think those were the numbers). In OR/WA, we will be dealing with mountains, valleys, and trees (3 db), but on longer trips to the SW, it will be more open desert (7db). It was my understanding that they work better in those respective environments. That's why I went with what I did, but it's easy enough to swap them out though.
That micro antenna you have has negative gain, and if it's NOT made by a well known brand like Maxrad, Antennex, Comtelco, etc then it's probably even worse, and doing damage to your radio.
Higher gain = lower angle of radiation. That box blocks most of the signal behind you.
A 1/4 wave antenna is a unity gain antenna. Its radiation pattern is more like a bubble, so while it doesn't go out as far as say, a 5/8 or a 1/2 wave, its radiation pattern is more even. The higher the gain, the more the pattern gets squished from the top, until it's more like a donut, with almost no radiation to the top, and squeezed out more to the horizon. So, the 'small antenna in mountains, long antenna in desert' actually is a good way of doing things.
A 1/4 wave antenna on UHF is only 6".... and it's a whip. Very thin, compared to that thick, wide dummy load that leaves much more surface area to hit/snag on something.
BUT, 1/4, 5/8, 5/8 over 1/4, 5/8 over 5/8 etc all require groundplanes. A flat plane that's a reference to ground, to 'push' the signal off of. Think of it as a trampoline of sorts. Without a groundplane, not only will the radiation pattern be absolute garbage, but more energy will be reflected BACK into the radio - too much, and it damages the radio. So, if you have a 50W radio, and a 2:1 SWR (which is probably MUCH worse, with lack of groundplane and poor antenna) ~11W is going back into the radio and dissipated as heat.
A 1/2 wave doesn't really require a groundplane, as it's half of the antenna, working much like a dipole. A 1/2 wave without a groundplane is unity gain and works much like a 1/4 wave, but with much better SWR. A 1/2 wave WITH a groundplane will have ~3db gain and will have a radiation pattern in between a 1/2 and 5/8 wave, which is the best of both worlds, IMO.
Also, not only are Chinese antennas known for false marketing, but even well known manufacturers engage in some tomfoolery with stuff like '3db MEG' - "mean effective gain", which is BS. You'll also see dbi and dbd.
Dbi = gain over a magic isotropic radiator that radiates equally in every direction.
Dbd = gain over a dipole.
If you have some friends that are hams - ask them to borrow an SWR meter or find out if one of them has a nano-vna..
As far as suggestions.
I'd run a 1/2 wave 99% of the time, and only switch out the 5/8 when absolutely necessary. I think a 5/8 over 5/8 might be a bit much, though, and you won't see the benefits you think you will, but you have it, so it won't hurt anything. The half wave will actually have more gain than the 1/4 wave due to the 1/4 wave requiring a groundplane and the halfwave doesn't require one. The difference in gain between a 1/2 and 5/8 wave will be virtually null due to the fact that the 5/8 requires a groundplane. The 5/8 over 5/8 realistically might be 5db, at absolute best. Vs a little over 2db for the 1/2 wave... While a 1/4 wave will most definitely work better if you're in a valley in the mountains, the difference at shorter ranges is going to be neglible.
The bigger issue is, the proximity of the box is gonna lead to bad SWR regardless.
1/4 wave
1/2 wave
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