ORIGINAL: Dave McDonald While it's true that a single conversion crystal can't replace a dual conversion cyrstal, the original post clearly stated he was dealing with dual conversion receivers and crystals.
I have about 7 Hitec crystals all on Ch 40, but few Futaba crystals. All are dual conversion as well as all of my Futaba/Hitec receivers.
Since the original post dealt only with Futaba and Hitec dual conversion crystals, my answer was based on my experience with Futaba and Hitec dual conversion crystals. For me they have proven to be completely interchangable.
Whilst some USA residents have reported Futaba and Hitec DC RX Xtals have been interchanged on 72 MHz, for clarification of those who did not notice originators query related to USA Ch40 (72.590), Xtals on 35, 36 & 40 MHz are not interchangeable. Hitec DC RX crystals on 35.36 & 40MHz have a frequency 10.7MHz ABOVE the nominal frequency whereas Futaba DC RX crystals are 10.7MHz BELOW nominal frequency. Hitec FM TX xtals are cut at half nominal frequency whereas the Futaba FM TX xtals are cut at 1/3 nominal frequency.
FWIW a local xtal manufacturer, who supplies USA military, has confirmed the specifications between the two brands are different. There is also a difference in physical sizes, Futaba RX crystals are slightly larger and do not fit correctly into Hitec RX with either the correct vibration damping rubber boot or bands, as applicable and provided with each Hitec RX, in place. Futaba TX xtals do not fit into Hitec TX Xtal holders.
If you are quite relaxed about risking an expensive model, and possibly hours of work, against a few pennies worth of the correct crystal for optimum performance, so be it.
Regards
Alan T.
Alan's Hobby, Model & RC FAQ Web Links