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Upgrade radio antennas


turbogrill
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Hi

 

I am looking to upgrade our antennas hoping to get better reception. 

We have buafeng 4watt radios. I don't think they are the issue. 

 

1. We already have a roof antenna but it has a very long cable to the radio, is this an issue? 

 

2. Could the cable to the roof antenna be of low quality? It looks much thinner then the typical TV coax cables. 

 

3. The pit radio antenna came with the radio and its pretty short and I assume it was made for both VHF and Uhf. Would a dedicated Uhf antenna help? Is 5/8 better than 1/4? What should I get? 

 

4. Does power matter? 

 

I tired understanding the theory about antennas, seems complicated. Smith charts do look cool...

 

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Hi Turbogrill

 

Here are a few links that will help in the set up.

 

Yes the length is a issue but more than that it depends on VHF vs UHF freq and the install.

 

See videos at the bottom of the page-

http://www.sampsonracing.com/Shark-Fin-Phantom-Elite-Antenna-Coax-for-Racing-p/phantom-standard-system.htm

 

hope this helps Cheers, Shawn

 

 

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That shark fin antenna Shawn posted is awesome.  Whip antennas are great when you're mostly stationary, but at 100mph they get a bit bendy, and their emission pattern goes to poop.  Best reception we ever got was with a 5/8 over 5/8 whip antenna, but only at a standstill.  Once the car is moving at any kind of speed, the shark fin is unquestionably better. 

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1 hour ago, Shawn Sampson said:

Hi Turbogrill

 

Here are a few links that will help in the set up.

 

Yes the length is a issue but more than that it depends on VHF vs UHF freq and the install.

 

See videos at the bottom of the page-

http://www.sampsonracing.com/Shark-Fin-Phantom-Elite-Antenna-Coax-for-Racing-p/phantom-standard-system.htm

 

hope this helps Cheers, Shawn

 

 

 

Thanks! So you would recommend the shark fin?

For the 1/4 wave whip I can pick the exact frequency that is a 1/4" wave length. But what about the shark fin?

 

1 hour ago, Hi_Im_Will said:

That shark fin antenna Shawn posted is awesome.  Whip antennas are great when you're mostly stationary, but at 100mph they get a bit bendy, and their emission pattern goes to poop.  Best reception we ever got was with a 5/8 over 5/8 whip antenna, but only at a standstill.  Once the car is moving at any kind of speed, the shark fin is unquestionably better. 

 

Aha! That makes sense! I was curious to why Shawn recomended a shark fin antenna, seemed odd.

Our antenna is not rigid at all.

 

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We also use baofeng radios, with good result...   we use a quarter wave, its about 6" rigid metal (like you would see on a cop car)

 

So without getting too complicated...  this type of antenna is a ground plane, it requires a nice flat "ground" or earth below the antenna...  what this means is it does its best work when mounted in the center of a sheet of metal, like your roof or trunk...  you start to compromise its effectiveness when you move it to an edge, or worse, mount it to a tab or something...

 

Second, tuning antennas is critical...  you need an SWR meter to properly tune an antenna...  you cant really expect to just open the package and stick it up...  you need to be able to hook up the SWR meter, and adjust the length (trim and set screw) to get the proper antenna length, getting that dialed in makes a big gain..

 

Of course just having any external antenna is generally better than an internal one, but you will see big gains from proper installation and tuning..   SWR meters are not that expensive and are a must have in my opinion...   

 

I like something like the Surecom SW-33

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Please understand UHF antennas are not tunable only VHF antennas. They make different UHF antennas depending on what bandwidth you run but road racing is mostly run in the 450 to 470 bandwidth and those antennas are not tunable.

 

A SWR meter can tell you Kickback information due to poor grounding or a bad antenna coax. It can also tell you your total output wattage. On a VHF system it will also tell you if your antenns is tuned properly. But those types of antennas are trimmed to the proper frequency and normally come with a card telling you how it is to be trimmed.

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Is there the option to just replace the whip antenna with the shark fin and leave the existing coax and even screw on base?  I have the standard whip antenna you guys sell at the moment.

 

Would a much larger remote antenna at the pits make a difference?  Larger or smaller difference than swapping the car antenna to a shark fin?

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