[Elecraft] Re: Question re K3 diversity reception

[Jay Bromley]

http://www.pvrc.org/~n4zr/Articles/simple_protection_for_the_fledgl.htm

Here is a link that may help?  It has been posted here before.

73 de jay/w5jay..




>I have been using SO2R in some of the RTTY contests for several years now. 
>When I first set it up I was concerned about blowing the front end 
>transistors in my (then) paired ICOM 756PRO radios. It occurred to me that 
>I could simply measure RF voltage coming back in from the "other" antenna 
>when under full power and verify that I was below the voltage that might 
>damage the input devices. I made up a simple 50 ohm loaded diode probe for 
>the measurements with my DVM.
>
> The usual techniques of stubs and filters, along with antenna separation 
> of apprx a hundred feet, yielded worst-case voltages of around 300 mv with 
> 1000 watts tx'ed on the "other" antenna. I assumed this could easily be 
> tolerated by the radios and so far this has proven correct through 3 
> generations of different pairs of radios.
>
> I would recommend this technique of actually measuring the incoming 
> voltage, then use common sense as to what levels are tolerable.  Yesterday 
> Wayne gave some guidance on tolerable levels with the K3, removing some of 
> the guesswork.
>
> Jerry W4UK
>
>
>>"Subject: RE: [Elecraft] Re: Question re K3 diversity reception
>>
>>Wayne,
>>To carry this one step more, what about when I am running multiple K3's on
>>different bands at the same time? Do you recommend to use external receive
>>bandpass filters on the receive lines if I am using receive antennas on 
>>the
>>Receive Antenna and/or Aux input?
>>And also use transmit bandpass filters on the transmit antenna input when 
>>I
>>am using the transmit antenna for both receive and transmit?"
>>
>>
>>Julius Fazekas
>>N2WN
>>
>>Tennessee Contest Group
>
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