new antenna coily whip Ch-1= 3.0 swr ch-40=2.5 swr

[hotrod]

Thanks also for clarifying swr long short 1-40 Sometimes I wish I was like others "Hey it works great!" I have replaced the nut bolt antenna mount. The coax the antenna and even the radio all for poor trancieve LOL

yw. now that ya told us ya replaced all this im sure its location. moving it
to the back may not help much id go straight for the roof. also i wouldnt have
got a dual coil .i would,ve got a single coil.more coil = more loss . 102 whip no loss.

 

[hammer0630]

In the first picture, I see another antenna just a few feet from the one that's giving you the trouble. Entertainment radio? It represents another piece of vertically-polarized metal in the near field; that can play hob with any adjusting you try to make.

Now if this one works then my luck in general has changed!

 

[hammer0630]

yw. now that ya told us ya replaced all this im sure its location. moving it
to the back may not help much id go straight for the roof. also i wouldnt have
got a dual coil .i would,ve got a single coil.more coil = more loss . 102 whip no los

 

[dx31353]

Measure the length of coil and times by two ..say the coil is nine inches long ...you would want a minimum of 18 inch from the cab via a straight line .

Thanks for the info.

Sent from my SCH-I545 using Tapatalk

 

[hammer0630]

Now if this one works then my luck in general has changed!

Unfortunately it didn't change anything.

 

[The DB]

102 whip no los

I wouldn't go that far, especially in a mobile environment. The losses present from the inadequate ground that is the vehicle chassis will always be present, and be far greater than the difference between a 5 foot antenna and your 102...

The DB

 

[Shockwave]

Inadequate ground plane under the antenna is the problem. This will always cause the resonant frequency of the antenna to be higher than desired. The antenna appears electrically shorter because it does not see a full reflection of itself underneath it. Adding ground straps to other metal not located under the antenna does not provide the needed reflection either. Any help seen here is a result of the wire or strap itself in most cases.

I would move the antenna to the center of the roof for performance. If that's not an option you could try to lengthen the whip. Compressing the coils will also drop the resonant frequency if they are not too rigid to bend a little. Even if these tricks provide a good SWR in that location, it still will not work as efficient as it would on the roof. If you have an amp, try disconnecting it in a process of elimination because they can cause this problem too.