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sirio mobile ntennas
- Thread starter hotrod
- Start date
nice install. not sure about the ground plane tho. i have one that i tried out with the wilsons, found the results margional, i haven't tried it out yet with the sirio....what were your before and after results with it?
I would say that it would depend on a lot of factors. On my truck it works great because the antenna is not mounted on the cab. It makes a very noticeable difference. On my car it makes even more difference. I may be wrong but ive read that you talk off the frame and the body is just a big capacitor. Well since my car has no frame and its all one solid body with no frame rails the ground plane seems to make a difference. I have spent quiet some time trying different antennas and different mounts and well a lot of different everything and these set ups work in my particular situations.... Results may vary LOL... The wilson 5000 didnt cut it. There was an over whelming improvement when i ditched it for the sirio.^^ ab v c^^
I think if the antenna is grounded to the UHF connector and the sheet metal below; then that sheet metal surface should act as a ground plane. If a mag mount is used; then the magnet will have capacitive coupling to the sheet metal for the ground plane - IIRC. Never tried it the way you have it set up - with that ground plane. But my Sirio antenna works quite outstanding w/o it. Of course, YMMV. So long as it matches out OK and you've checked it with an analyzer and everything looks as it should; then I would stay that course too.
Bonding
Odds & Ends
There is one more aspect of bonding that merits mentioning. As stated above, even seasoned amateurs confuse DC and RF grounds with ground planes. As a result, too many amateurs believe a DC ground strap from the mount to a hard point on the body or chassis is a substitute for a ground plane. It is not.
Lastly, a 1/4 wave vertical antenna (loaded or not) is one half of a dipole. When used as a base station antenna, a vertical must have a number of radials under it. These radials act as the missing half of the dipole. In the case of a mobile antenna, the missing half is supplied by the vehicle, and its apparent capacitance to the ground underneath the vehicle. Since ground loss is the single biggest factor with respect to efficiency for any vertical (especially a mobile one), maximizing what ground plane a vehicle represent, is essential. As with the number of radials, the more you have, the better. This is true of bonding as well.
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A vehicle is not a ground plane, but rather acts like a capacitor between the antenna and the surface under the vehicle which acts as the ground plane. Since the surface in question is a poor conductor of RF, ground losses occur. If we wish to maximize the system efficiency (the mobile station as a whole), we need to maximize the RF continuity of the vehicle; hence proper bonding. Obviously, proper antenna mounting, and placement are important too. k0bg
Odds & Ends
There is one more aspect of bonding that merits mentioning. As stated above, even seasoned amateurs confuse DC and RF grounds with ground planes. As a result, too many amateurs believe a DC ground strap from the mount to a hard point on the body or chassis is a substitute for a ground plane. It is not.
Lastly, a 1/4 wave vertical antenna (loaded or not) is one half of a dipole. When used as a base station antenna, a vertical must have a number of radials under it. These radials act as the missing half of the dipole. In the case of a mobile antenna, the missing half is supplied by the vehicle, and its apparent capacitance to the ground underneath the vehicle. Since ground loss is the single biggest factor with respect to efficiency for any vertical (especially a mobile one), maximizing what ground plane a vehicle represent, is essential. As with the number of radials, the more you have, the better. This is true of bonding as well.
.
A vehicle is not a ground plane, but rather acts like a capacitor between the antenna and the surface under the vehicle which acts as the ground plane. Since the surface in question is a poor conductor of RF, ground losses occur. If we wish to maximize the system efficiency (the mobile station as a whole), we need to maximize the RF continuity of the vehicle; hence proper bonding. Obviously, proper antenna mounting, and placement are important too. k0bg
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i agree that it makes a big difference...way back when before i did the install on my vehicle i went through and did extensive bonding work on it..from what i remember it took three days to complete at a relaxed pace.
by the time i was done i used almost 50' of tinned 5/8' ground braid. and with the understanding that hard mounting the antenna is always better, the thought of messing around with a headliner of a 10+ year old full sized vehicle has me sticking to mag mounts for the time being..and i don't really see or have a problem using the sirio magmount, by the time that the rust that the heat causes ever becomes an issue...... the vehicle will be sitting in a junkyard.
by the time i was done i used almost 50' of tinned 5/8' ground braid. and with the understanding that hard mounting the antenna is always better, the thought of messing around with a headliner of a 10+ year old full sized vehicle has me sticking to mag mounts for the time being..and i don't really see or have a problem using the sirio magmount, by the time that the rust that the heat causes ever becomes an issue...... the vehicle will be sitting in a junkyard.
Well my Sirio 5000pl is in the mail from H&Y. It shipped Thursday so after Custums Canadian thinkings about it, it should be here next friday. I also ordered another hardmount wilson 5000. My plan is to tune the wilson for 11 metres and use the Sirio for 10. (or maybe viseversa).
uh,oh, your not planning on mounting both of them on the same vehicle are you? if so,
it won't work. i tied it, can't get the antennas far enough apart to keep them from interfering with one another.
it won't work. i tied it, can't get the antennas far enough apart to keep them from interfering with one another.
Well I suppose if I worked real hard the 11 metre antenna could be a reflector for the 10 metre, but that would be like too much work. I just plan to unscrew one and screw of the other.
i would have to say that would be the only way. played around with that setup for about a week and couldn't get it to work.
so it's back to changing out the whip again for running both bands.
so it's back to changing out the whip again for running both bands.
If you had two 5000's you could just unscrew the lever for the break over pull it off and switch them out??
^^ ab v c^^
why?? my sirio z180 will tune 10 and 11 with 10 meters around a 1.7 .thats without any tuning