Go figure this one out.
I have a GWS 8 channel dual conversion RX. I plugged in a Futaba d/c xtal and range checked it using a JR TX on ppm, setting the RX on positive shift. Good range. Plugged in a Hi Tec d/c xtal on same frequency and range check again...same range. Plugged in a JR single convesion xtal(grey cover) on same frequency....not only did it work but still range checked out fine.

GWS says to use their xtal or either a Futaba or JR and I assumed they meant the d/c JR but didn't realize that most JR is single convesion at that time. I use Hi-tec xtals in Futaba and vice versa and have never had a problem so not surprised that the Hi-tec worked well in the GWS.
PilotFrog

That's bizarre. And I believe technically impossible. Are you SURE that the JR crystal is an SC crystal?

Bizzare as it may seem the JR xtal (grey cap) was pulled right out of my JRPR 549 ppm receiver which is supposed to be single conversion... right? Perhaps it is operating on a harmonic of the xtal????
I am not too familiar with where the 2nd IF oscillator gets its refrence signal. I believe the first IF is around 10.2 Mhz and the 2nd is 455 Khz. I have my old First Class FCC Ticket but never messed around with bonning up on RC repair....maybe I should!
PilotFrog

How do you suppose your crystals would know if you are using two IF's or one? I don't think they really care. Good flying!

Well, because in either the SC or DC Rx design the first stage's xtal for the given R/C channel is displaced by the IF frequency. For SC, it would typically be native frequency minus 455Khz. For DC, it is typically freq minus 10.7Mhz. Of course there is a second stage in a DC Rx to baseband the signal.

Frankly, I am blown away that someone was able to get a SC Xtal to work in a DC Rx. This was such a oddity that I had to try it myself.

I took a Hitec RCD3600 DC Rx and a JR R600 SC Rx. Swapped the xtals. Both Rx's were dead as a door nail after the swap. Not a peep from either, even when I was next to them.

Pilot Frog, does your SC JR Rx work when you plug a DC xtal in it? Can you repeat the original experiment again too?

Thomas,
The DC xtals DO NOT WORK in the JR rx. I was a bit leery trying it but it was ok after I plugged the SC xtal back in. As you know the currents go up in a oscillator circuit if it is not oscillating. Also the SC xtal NO LONGER WORKS in the GWS RX, Both are "dead as a doornail" just like yours.
If the IF for single conversion is 455 Khz and the first IF is 10.7Mhz for dual conversion then it should not work and now it doesn't! This really throws me now and it all occurred because of a mistake I made by assuming the JR xtal was DC and the grey cap JR xtals are definitely SC.
Well, everything is doing what it is supposed to so now we may never know. I've lost enough sleep on this one.
PilotFrog

It appears the universe is in balance once again. Looks like your earlier experience will remain a mystery for now.