[TowerTalk] Any filter?

[ec1cwg@dxhunters.com]

Hello,
A friend of mine EA1BXN is looking for a filter or something similar that allow him to work with two hf radios on different frecuencies without problems...let say one in 20 and the other one in 40 or so. He has the yagi and the wire antennas pretty close (at 4 or 5 ft) and he´s scared about the possibility of damaging one of the radios while he´s transmitting with the other one. He use to switch off one of them although he leaves the antenna connected. Both rigs are on the same desk side by side.
He sometimes runs 1kw and he hasn´t got a problem...yet. Not sure if it´s important but his main radio is an Icom 756ProII with a Dentron Clipperton amp and the second one (the one connected to the dipoles) is a FT1000MP Mark V field (without amplifier). 
I´ve thought on a 2 position antenna switch. One position for the dipoles and the other connector attached directly to an independent ground rod. That way BXN could switch his Mark V directly to ground while not in use although this would depend on my friend´s memory wich is still in good shape (I guess)...Any better idea outta there?...Thanks in advance. 73s
EC1CT Fernando
E-mail: ec1cwg at dxhunters.com
URE & ARRL member