Cascadia Antenna Solutions

It's even closer when you run the antenna straight up no tilt... which is what I'm gonna do tomorrow when I put my key down antenna back on !!!!!!

 

I'm not sure how any of this relates to Craig's feed point being elevated 40 inches away from the body of the truck.
The feed point is where the coaxial cable attaches to the antenna stud. If the antenna bracket is grounded to the body of the truck then it is necessary to put that bracket as close to the body of the truck as possible.
If the antenna bracket is not grounded to the body of the truck it gives you the luxury of elevating it as high as you want assuming you have a ground element bolted directly to that bracket.
It's almost as bad as the guys that well the metal tab to their headache rack and mount a single antenna to that metal tab on top of their headache rack on the rear of the cab 6 feet away from the counterpoise which would be the frame of the truck. I wouldn't expect much performance out of that scenario either

 

Read carefully..
Many amateurs harbor the notion that DC grounding an antenna mount will magically act as, or replace, a ground Plane. It will not! It may DC ground the antenna's base, and it just might RF ground it too depending on the straps length and width versus the frequency of operation. However, it is by no means a replacement for an adequateground plane under the antenna! Incidentally, the term ground plane is a bit of a misnomer (see next section).

The body of the vehicle and the capacitive coupling to the surface under the vehicle, is acting as a ground plane, and a lossy one at that! Typical ground plane losses vary between 2 and 10 ohms, 10 through 80 meters respectively, but in the real world they may be as high as 20Ω on 80 meters. It is also possible to have higher ground losses on 40 meters, than on 80 meters. The primary cause are standing waves between the body of the vehicle, and the surface under it. This fact should not be confused with the term SWR!

Since ground losses dominate theefficiency equation, decreasing them byjust one ohm, can make a significant increase in ERP (effective radiated power). And be advised, ground loss cannot be measured with a common ohmmeter or determined by measuring the input impedance of your antenna!

Further, excessive ground losses directly relate to the level of common mode currents. Common mode current causes all sorts of RFI issues, both ingress and egress, and a can drasticallyreduce the receiver's SNR. Put another way, excessive ground losses can turn an otherwise efficient antenna system into an also-ran.

In a mobile scenario, there is one other ground we need to concern ourselves with, and that's a proper RF groundreturn for the coax shield. Remember, RF must flow back to its source. It will do so in the shortest path it can find (the one with the least resistance). Ideally that's within the coax cable. However, improper mounting (atop long posts, extended brackets, magnet mounts, clamps, and luggage racks) causes an inordinate amount of RF to flow on theoutside of the coax (common mode current), or down inadequately-chokedmotor control leads if so equipped. Incidentally, common mode current flow is the main cause for both egressed and ingressed RFI.

 

that's all fine and good bottom line is the 40" pole mount works better on the truck.. I've used both options you want the coil above the roofline you do not want to be able to see that coil !!! The pole is a much more stable option.... that 27" shaft is a cheap aluminum stick plain and simple ...... funny thing is I came on this site in July of last year until I came on this thread there's not one word or even mention of grounding let alone a ground strap ???? Hmmmmmm I run double straps on both my doors and showed that.....doesn't make a difference too me what's in a book or some know it all video or videos. And no I'm absolutely not talking about you....i know what works best on my truck !!! Everybody else has to figure out what works best on theirs.....

 

All fine and good who's the one on this thread who complaining about having receive issues. Me or you.

 

Wayward rf off that coil is a much bigger issue than the grounding on these trucks...everyone is in trouble relying on that 27" predator by the quality of that antenna.... as I've stated and wished for a much much better antenna is out there and it desperately needs to be built..... hell my key down antenna has 2 to 3 times better receive range than that great almighty predator stick...

 

How exactly can anyone comment or have ideas knowledge of that 40" pole mount when there are extremely very very few of them out here? ??? Even the cb shop men who set antennas for a living cannot do that..............................

 

With the pole, ground losses shoot through the roof.
Best option is using a longer shaft mounted directly to the door.

 

Exactly how could the antenna and coil being farther away from the trk. Aka 27" predator help pull the receiving incoming signal into the truck and radio..

 

Had to have a 30k back when it very first came out.... hooked it up in orlando almost immediately heard mark when he was still in Amarillo. It was like he was sitting in my truck or a truck right next to me. Crystal clear !!! Dont think I heard or picked up much of anything on that thing for well over a month using it.... it had to get the hell off my truck by then.... talk about poo poo on a stick that thing was a poo poo stick.... coulda wiped my butt with that $150 including uncle Sam's tax