This is a VERY complex question and a simple
"minimum distance" between antennas will not suffice.
A more complete answer is:
IT DEPENDS - It depends on:
Frequency
Antenna Gain (size)
Antenna Orientation
Antenna Height
and probably several other factors.
KENWOOD receivers (TS180, TS830, others?)
are VERY sensitive to strong signal levels. There
is a specific WARNING in the instruction manual
not to exceed 7 VOLTS at the antenna input (if I
remember right). My old Collins 75A3 has a similar
warning for 50 volts!
I have built Protection Boxes for all 3 of my TS830's
consisting of a series 2 Watt 22 Ohm resistor followed
by 4 high diode stacks of each polarity at the receiver
input end. This is inserted in the Receiver Antenna input
line through the TRANSVERTER plug where a remote
antenna switch is used to select between the transmit
antenna (also from the Transverter plug) and Beverage
receiving antennas.
To determine the power transferred from one antenna
to another, aim the antennas toward each other, transmit
full power into one antenna and measure the power delivered
through the other to a dummy load with a wattmeter. Convert
this to voltage to compare with the maximum voltage rating
of your receivers.
73 / GL, Tom N4KG
>>>>>>>>>>>>>>>>
On Tue, 20 Feb 2001 (PST) <aa6eg@bob.tmx.com> writes:
>
> From: aa6eg@bob.tmx.com
> To: towertalk@contesting.com
> Subject: Antenna Separation Distances
>
>
> Hello Towertalkians...
>
>
> I would like to know what the minimum separation
> requirements are
> for antennas on a site with respect to preventing damage to receiver
> front
> ends by multiple users of the site. We have an existing antenna
> farm at
> the old Ft Ord, which occupies about 5 acres of an open hillside and
> hilltop containing mostly 70 ft wooden poles. Many of the poles are
> clustered quite close together, sometimes 25 ft from each
> other..Since
> ours is a city owned facility that primarily will be used for HF
> contesting, but will sometimes
> have other ham activities shared, I am formulating rules for
> separation of
> antennas when operating. Worst case of course, will be unprotected
> radios on the same band, with Kilowatt power outputs. How close
> would you
> think antennas could be without inflicting damage to each other's
> receiver? How about unprotected radios with closely spaced antennas
> but
> different bands, KW level outputs? Any hazards between VHF or UHF,
> and HF
> radios at high power levels? We had a front end of an old Kenwood
> TS180
> fried due to uncoordinated use of radios/antennas at the site. The
> two
> yagis involved were about 20 ft apart, at a KW level, and on the
> same
> band, with predictable results.
> What say, guys?
>
> Thanks....
> Pat, AA6EG/N6IJ....
>
>
> --
> 73, DX, de
> Pat, AA6EG/N6IJ;
> aa6eg@tmx.com;n6ij@hotmail.com
> 599 DX Drive, Marina CA 93933
> See us on the web: www.polkinghorn.org/n6ij,
> or: http://communities.msn.com/N6IJWRTC2000
> "The Contest Station from MARS"
>
>
>
>
> --
> FAQ on WWW: http://www.contesting.com/FAQ/towertalk
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> Administrative requests: towertalk-REQUEST@contesting.com
> Problems: owner-towertalk@contesting.com
>
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