Ok, so I just installed a 110W Astro Spectra UHF in my truck, it's run to a 1/4 wave spike...the issue was posed to me that a 1/4 wave spike would not be sufficient to handle the output. If that were true then my VHF high power deck would be having the same problem. So before I go transmitting more I want to make sure that this setup is not going to fry anything.
That being said on a slightly off topic question, how far apart should said antennas be to prevent any problems?
Thanks.
High power decks and proper antenna?
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George
- Posts: 266
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- What radios do you own?: X9000, HT1550XLS, MTS2000, etc
Re: High power decks and proper antenna?
The 1/4 wave antenna is the best antenna for handling the power you could get. There is nothing to go wrong. Generally, no spring and not much way to damage it. You can dump as much power as you want into this antenna.
As for spacing antennas...Try to go a little greater than a 1/4 wave of the lowest frequency between that antenna and the next antenna.
What I have done on my trunk lid is spread my antennas to the furthest distance that keeps the antenna mounts in the support channels in the trunk lid while keeping them in the mid middle. The reason for not body mounting is due to the curves of the metal not allowing an NMO mount to be installed.
My antennas are a dual band larsen 2/70 and a NMO54. Total seperation is about 28 inches.
On my other car I have flat surfaces all the way around. Due to its size I have no problems with separation and have a 5/8 VHF on the right, UHF gain in the middle and a low band on the left. All antennas are Motorola Spectrum antennas.
In short, get as much separation as you can, try to follow the 1/4 wave rule and ultimately do the best you can while working around ladder racks and whatever else may be on your truck.
Again, about that 1/4 wave...you will have no problem with that antenna with as much power as you want to dump into it.
George
As for spacing antennas...Try to go a little greater than a 1/4 wave of the lowest frequency between that antenna and the next antenna.
What I have done on my trunk lid is spread my antennas to the furthest distance that keeps the antenna mounts in the support channels in the trunk lid while keeping them in the mid middle. The reason for not body mounting is due to the curves of the metal not allowing an NMO mount to be installed.
My antennas are a dual band larsen 2/70 and a NMO54. Total seperation is about 28 inches.
On my other car I have flat surfaces all the way around. Due to its size I have no problems with separation and have a 5/8 VHF on the right, UHF gain in the middle and a low band on the left. All antennas are Motorola Spectrum antennas.
In short, get as much separation as you can, try to follow the 1/4 wave rule and ultimately do the best you can while working around ladder racks and whatever else may be on your truck.
Again, about that 1/4 wave...you will have no problem with that antenna with as much power as you want to dump into it.
George
Re: High power decks and proper antenna?
First of all, who told you the 1/4 wave antenna would not handle the 100 watt transmitter?
If it was a radio tech, I would request that he no longer work on any of my radios. If it
was the manager or owner of a radio shop, I would look for another radio shop. I smell
the interest in selling you another antenna as the motivation for the comment.
As for the spacing, you have already had that answered. Space them accordingly.
Jim
If it was a radio tech, I would request that he no longer work on any of my radios. If it
was the manager or owner of a radio shop, I would look for another radio shop. I smell
the interest in selling you another antenna as the motivation for the comment.
As for the spacing, you have already had that answered. Space them accordingly.
Jim
kcan146 wrote:Ok, so I just installed a 110W Astro Spectra UHF in my truck, it's run to a 1/4 wave spike...the issue was posed to me that a 1/4 wave spike would not be sufficient to handle the output. If that were true then my VHF high power deck would be having the same problem. So before I go transmitting more I want to make sure that this setup is not going to fry anything.
That being said on a slightly off topic question, how far apart should said antennas be to prevent any problems?
Thanks.
Re: High power decks and proper antenna?
I've pretty much always run my 110w drawers on 1/4 waves, never had a problem. Best damned antenna as far as I'm concerned, and a heck of a lot cheaper. I agree with the above, whoever told you it wouldn't work was smoking something good.
Re: High power decks and proper antenna?
The only limiting factor would be the size of the feedline between the transmitter and the antenna(higher losses=more heating), and RG58/U should be able to handle 110W, even at UHF.
The 1/4 wave offers more bandwidth than either base-matched 1/2 or 5/8 wave antennas(10 Mhz vs. 6 Mhz or less at the 1.5:1 VSWR points). It's still wise to check the match between the antenna and feedline no matter which design you're using to verify a good match across the portion of any band that you're using.
The 1/4 wave offers more bandwidth than either base-matched 1/2 or 5/8 wave antennas(10 Mhz vs. 6 Mhz or less at the 1.5:1 VSWR points). It's still wise to check the match between the antenna and feedline no matter which design you're using to verify a good match across the portion of any band that you're using.