It's been long debated as to whether or not the Beligerents were homing in on each other's receiver emissions or not, but it is technically feasable. That's how some US police depts. and the RCMP find out you have a "Fuzzbuster" ( I always called mine the "Metox") in your vehicle. Then they cite you.
If I remember, the Metox was a basic Regenerative detector, which if improperly operated can put out a fairly strong signal. They re-radiated the received signal even when properly operated.. The first oscillator in a Super-Hetrodyne receiver will radiate, also. The frequency radiated will be the received frequency plus or minus (depending on the mixing scheme used) the Intermediate Frequency.
The Navy was concerned enough about this that they contracted RCA to build them the ultimate receiver, cost no object. RCA gathered the best and brightest, and what resulted was the RBA-RBB-RBC series of receivers. First Local Oscillator emission on these was in the order of -90 Db, in an era when the noise floor of of the best receivers was maybe -80 to -100 Db. (the 1950's R-390 and R-390A approach -130 Db)
This was acheived at considerable expense, though, between $2700 and $3200 for each rig, and this in 1942 Dollars! I have an RBB, it's a very good BCB to Lo-HF rig.( frequency range 500 Kcs. to 4 Mcs.) If I ever find the other 2 receivers at a reasonable price, I want them, but not if they have to be shipped...They weigh almost 100 Lbs. each!
Hope this has been at least interesting,
John R.