Futaba 9CHP on Different crystal.

[Super-Hornet]

Hi all

On weekend, I tried changing my 9CHP to different frequency (E.g. 40.880MHz to 40.840MHz) with Futaba's TX Crystal clock. The RX side, my RX claim can accept various brand of crystal (I use Hitec 40.840MHz) but it doesn't work.

May I know why?

Super-Hornet

[9VDXN]

Is your crystal a single conversion crystal that's being used on a dual conversion receiver?

[Super-Hornet]

My RX is a single conversion. I use single conversion crystal.

If I can't make it work, I might want to sell those crystal.

Super-Hornet

[BonJour Brat]

A rule of thumb is to use the rx brand's crystal for rx and tx brand's crystal for tx.. I've learnt it the hard way

[Super-Hornet]

Hi Bon

The interesting thing is that in the following scenerio:
Situation #1
TX - 9CHP using Futaba Crystal of 40.880MHz (e.g. that is the default frequency when I bought 9CHP).
RX - Sky and Tech RX using Futaba or Hitec 40.880MHz, single conversion
Result: It works. That proove my RX can accept Hitec Crystal.

Situation #2
TX - 9CHP using Futaba Crystal of 40.840MHz.
RX - Sky and Tech RX using Hitec 40.840MHz, single conversion
Result: Cannot work.

Situation #3
TX - 9CHP using Hitec Crystal of 40.800MHz.
RX - Sky and Tech RX using Hitec 40.800MHz, single conversion
Result: Cannot work.

Conclusion:
Could it be that 9CHP can only accept crystal of frequency higher than whatever that come with it? Like if stock is 40.880MHz, it can only accept higher than 40.880MHz

Super-Hornet

[9VDXN]

That is very strange.... hmmm......let us know when you figured it out...

[ammo]

According to my experiences, S&T Rx need to be synchronised via the method shown in the instructions whenever u change freq.
can be quite frustrating to get the thing right, the rx sometimes just doesn't accept, but it'll work when u get it right.

[Super-Hornet]

Hi ammo

I suspect it is not the RX side because if I use stock frequency on TX, and if I just change around my RX clock (Anyhow plug also can) and it work.

I even tried using Feigao and same thing as above scenerio.

Either I go and waste my money to purchase a higher frequency to try to proove it really have to go higher frequency or someone has higher frequency with to test the theory.

Super-Hornet

[ammo]

erm.... shake your crystals, if there is even a slight "click", it's a goner