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Checking swr on a radio,would power lines affect it?
- Thread starter AmericanEagle575
- Start date
Yep. Another thing I chased my tail on. I never messed with the tvi trap on my radios but had amplifiers oscillating. The harmonics they produced made the swr go up with the amp on. I could sometimes retune the antenna for a lower swr with the amp on but when I turned it off it was unacceptable.
Not sure of the vehicle you're putting this on, but if you've got 1.5 SWR from a previous install using this antenna - verify that the antenna is still capable of giving you that 1.5 SWR - can you put it back on that other vehicle to verify?
Because we may be missing something...you said Trunk Lip, or Lid?
Oldtymer put it best...
Usually there is a "Seam" that the finish metal is epoxied onto the frame underneath onto that trunk lid frame. The way this is done, gives this finish metal the strength it does. And at the same time, seals it from the elements to prevent perforation rust thru. But it's thin finish metal for the exterior and tears like tin foil if you try to do anything more than look at it. And with the Epoxy there is little conduction - unfortunately most cars are now produced with as little spot welding as needed and the rest is all seamed and then stamped or epoxied. So you have little choice to "apply more ground" except to maybe relocate the mount closer to a trunk lid hinge area that you may be able to "pigtail" some braided wire or even a simple bonding strap so you can then apply the grounding the trunk lip mount has (it's setscrew(s)- onto the frame of the vehicle where that hinge assembly mounts to. (one of it's mounting bolts). This way may help enlarge the region it grounds to; in helping provide enough "Counterpoise" with small area SWR issues.
How much of a change are we talking about. A significant amount or splitting hairs like 1.2 with the doors closed and 1.3 them open?
At a couple of kw I haven't noticed a change in swr with doors open vs closed. I have a fwd and reflect meter inline at all times. If were trying to split hairs theres probably a difference but I'm not looking that hard.
Before I installed the puck mount I had an antenna mounted to the bed. All kinds of things made the swr fluctuate. Especially with the power on.
It's a 2012 Hyundai Elantra and it's a a mag mount Wilson 1000 antenna if that info helps on the trunk lid!
Splitting hairs for sure plus I only run mag mounts. The mag mounts are more touchy with incidental reactance of the surrounding area.
Oh, mag mount - trunk LID - got it, not lip...ok - well, do you have a rear defroster "Grid" that can affect SWR if the coil is close to it.
Else usually when they are on a truck bed or other "square pieces" that's is used, is/provides too small of surface run for waveshape (work with me here I'm talking about counterpoise and it's length in symmetry) and seems only to lower SWR in one edge or another - that is because as the antenna works the image in a counterpoise, remember it's attempting to make an image - so if there are location and length issues, well - you have what you're having now...
Care for a relocation effort or are we stuck with that spot?
Else usually when they are on a truck bed or other "square pieces" that's is used, is/provides too small of surface run for waveshape (work with me here I'm talking about counterpoise and it's length in symmetry) and seems only to lower SWR in one edge or another - that is because as the antenna works the image in a counterpoise, remember it's attempting to make an image - so if there are location and length issues, well - you have what you're having now...
Care for a relocation effort or are we stuck with that spot?
That's why it's best on the roof, there is no rear defroster on a Pickmeup - just a thing they call a "cab"
This is the center of the roof and the PVC pipe is carrying the Ham Stik antennas. Go look in my album to see the camper top and roof rack.
Ok...
I don't know if you've seen it, but the OP has got a Elantra:
That's the problem...
Not what's in your wallet.
Or the Album...
I don't know if you've seen it, but the OP has got a Elantra:
That's the problem...
Not what's in your wallet.
Or the Album...
I don't know about anyone else but I usually try to find a nice quiet place with no chance of low flying objects interfering with my measurements and I will park right in the middle of all those beautiful wires that shield me from flying saucers and such like the one in the image below. And when I'm done and I get about 3 miles away from here the radio starts working much better so it must work to use this spot to set my radio up .
Be sure to bring a fluorescent tube along - to help light the way to see the SWR meter if you ever have to re-tune it in the middle of the night...
My last car a 2008 Chevrolet cobalt had a rear defroster and I had it in the same spot,no problem, I think I'll have to trim the whip a little bit.