Dual antenna connection

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I run a new coax from 6el 5m antenna and connected it to Ant2.
Ant1 is a 2el Steppir connected through Microham Power meter.
I was suprised to see that when I TX on Ant2 50mhz antenna, my power meter (that connected to Ant1) shows 0.011w and SWR 8.47. 
Any idea why I would see SWR reading from Ant 1 when I transmitting to Ant 2?
No other panadapters/slices active at that time, only slice A.
Thanks
Sergey, KN7K
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Sergey Abrikosov

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Posted 4 months ago

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Paul

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If the antennas are close enough to eachother you will easily have enough received power to give a reading on the second antenna. If you cannot increase the separation, a band pass filter will give more attenuation if it is a problem.
(Edited)
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Sergey Abrikosov

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It seems like the case. Antennas about 3ft apart on small tower. It is not a problem yet as I am running 100w for now. Interesting to see what will be the reading when I will have an amp.
Sergey, KN7K
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Bill -VA3WTB

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The antenna inputs have 70db isolation. but in some cases when antennas are to close as said by Paul it is common to use a band pass filter for even more isolation when using an amp.
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Rick - W5FCX

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Sounds like you have reflected power coming back from Ant1 and it’s feedline into the SWR meter and there’s no output power on Ant2; hence, high SWR ratio of reflected vs forward power.
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Sergey Abrikosov

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Any recommendation for a band pass filters?
Thanks
Sergey, KN7K
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Paul

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Depending on which transceiver you have, this may not actually be a problem since the filters in the rig will already be attenuating out-of-band RF to some degree.

However, a high pass filter in line with the 50MHz antenna should give further isolation if you need it.

You could also add a low pass filter in line with the Steppir for even greater isolation. Those filters must be capable of withstanding full transmit power. You choose suitable cut-off frequencies to suit the max and min frequencies that you will operate on. You could home-brew. If not, try the Array Solutions or Dunestar websites.

Finally, if you only operate on a limited bandwidth within 6m, you could make a coaxial stub to notch out 50MHz and place it accross the line feeding your Steppir.

If you are not trying to receive on The Steppir and transmit on the yagi simultaneously, these methods may be overkill.
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Sergey Abrikosov

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Paul,
Thanks you for suggestion.
Will have to check how does it look at higher power.
Currently I just tested on 50mhz antenna with 100w from flex 6600.
Next thing to try to TX on 1.8-28mhz with Acom 2000a and see how it will impact the 50mhz.
If it will be an issue than will consider the filters.
Sergey, KN7K