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Cascadia Antenna Solutions

Discussion in 'CB Radio Forum' started by mike5511, Apr 30, 2014.

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craig_sez Road Train Member

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bored silly said: ↑

You sure positive that's a stainless steel mount/bracket almost positive it's made outta aluminum num num
Click to expand...

Well its not buffed alum num num num...

craig_sez, Jan 22, 2017

#1041
craig_sez Road Train Member

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bored silly said: ↑

You sure positive that's a stainless steel mount/bracket almost positive it's made outta aluminum num num
Click to expand...

Go to cb world and look for cascadia cb adjustable mount..

craig_sez, Jan 22, 2017

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bored silly Road Train Member

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craig_sez said: ↑

Go to cb world and look for cascadia cb adjustable mount..
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I got one of the friggin things although I have no idea why ???

bored silly, Jan 22, 2017

#1043
bored silly Road Train Member

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rabbiporkchop said: ↑

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 adequate ground 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 the efficiency equation, decreasing them by just 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 drastically reduce the receiver's SNR.
(Noisy awful receive)
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 ground return 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 the outside of the coax (common mode current), or down inadequately-choked motor control leads if so equipped. Incidentally, common mode current flow is the main cause for both egressed and ingressed RFI.

Notice:
However, improper mounting (atop long posts, extended brackets, magnet mounts, clamps, and luggage racks) causes an inordinate amount of RF to flow on the outside of the coax (common mode current)
Click to expand...

ferrite's --- phar rites

bored silly, Jan 22, 2017

#1044
craig_sez Road Train Member

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Ment to look those up when i was home last..

craig_sez, Jan 22, 2017

#1045

bored silly Thanks this.
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craig_sez said: ↑

Ment to look those up when i was home last..
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Pull up dx engineering they sell them ...ham radio outlet their good people there. .....

bored silly, Jan 22, 2017

#1046
craig_sez Road Train Member

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Yeah ill have to when i home..

craig_sez, Jan 22, 2017

#1047

bored silly Thanks this.
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craig_sez said: ↑

Well its not buffed alum num num num...
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But it's still aluminum num num num that's the problem

bored silly, Jan 24, 2017

#1048
craig_sez Road Train Member

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NO its ss..Tastes like it is..Needs salt though..

craig_sez, Jan 24, 2017

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Keith Petrella Bobtail Member

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mike5511 said: ↑

I promised pictures so here they are. 7ft SkipShooter fiberglass antenna. (a top loaded antenna) My SWR is pretty much flat across 120 channels (export radio). I wanted to stand it straight up but the closer the antenna got to the cab, the higher the SWR got. The antenna is flimsy, thus the brace. The brace is made out of Lexan, which is what they make motorcycle windshield's out of. They won't shatter. I got a piece from the local glass shop to make this non-conductive bracket. The wind blows the antenna back at highway speed to about vertical. It also leans away from the truck some so that helps keep the reflection (swr) down as well. I slip seat so the coax is just run thru the door. You can run the coax into the engine compartment and there is grommet to pass thru the firewall under the steering wheel area. This works about as good as any mobile set up I've ever had. Just takes a few minutes to install. Overall hight is just under 13'6".
Click to expand...

I tried the setup like this with and without step grounding the door. antanna leaned at multiple different locations. but the moment the door is closed all the way I end up with swr between 2 and 3 accrossed the board.

Keith Petrella, Jan 28, 2017

#1050

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