[Elecraft] Transverter Question

[SpecRisk at aol.com]

I have a K2 and added the Elecraft transverter interface using split rx/tx.  
I am using 28 MHZ as an If and use only TRansverter 1 on the menu. I am using  
50/144/222/432 DEM transverters  with split lines out using an external  
switch. The K2 drives the transverters fine but on RX I can hear strong 144 MHZ  
signals even thought I am on 222. For switching I built a DEM IF switch(no  
longer sold). It uses a switch and an IF amp on TX &RX plus pots to balance  out 
the power/gain. At first I thought the problem was in the DEM switching box  
because of the IF amplification and the use of a switch as opposed to a relay.  
I  Then built up a switching box using good isolation relays made by Dow  Key 
microwave. (2) SP4T are used and controlled by a 2P4T switch which also  
switches the contoll/PTT line but the problem still exists. Has anyone else  
experienced this problem while using the Elecraft transverter interface? 
George, W1JHR