High SWR caused by adjacent antenna?

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Beakster
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High SWR caused by adjacent antenna?

Post by Beakster »

Hi,

I've got 2 home made antennas on my roof. A copper pipe j-pole for 2metres and an inverted V dipole for 10m. Both of these have their RG6 feedlines running together down and into my room, about 50ft of coax each.

It seems that after putting the 10m dipole on the roof the SWR was higher than I measured on the ground. I have the hypothsis that when I transmit on 10m the RF is being picked up by the 2m j-pole and then radiated from it's feedline into the 10m feedline increasing the SWR.

I removed the feedline from the 2m dipole and than seemed to decrease the SWR by about 0.8 across the band. Does that sound like a likely scenario? If so is there any way to reduce this other than moving the 2 antennas and/or their feedlines further apart?

Thanks
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ch25
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Re: High SWR caused by adjacent antenna?

Post by ch25 »

It's not RF but antenna surroundings. That's all.
Chris
You can't have too many antennas...
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Beakster
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Re: High SWR caused by adjacent antenna?

Post by Beakster »

ch25 wrote: 02 Apr 2020, 14:34 It's not RF but antenna surroundings. That's all.
Chris
Ok that sounds reasonable. I'm thinking of using a long horizontal wooden dowl to tie the ends of the dipole and mouting the top of it higher. That should lift it clear of everything else whilst still keeping the angle at 90 degrees.
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