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*Spitball* · 08-09-2009, 08:49 PM

If you can point me to a statement by other manufacturers that they too have a 'HI<>LO' separation, I would appreciate it.
Someone with a modicum of RF knowledge has chimed in - me - a lifetime of work with transmitters of all sizes, frequencies and power, and receivers of most configurations and with radio control systems from 1948/49 or thereabouts to the present, gives me the confidence to make the statements I have.
As far as I'm concerned it is only Futaba that I know of, that has this HI-LO thing and that I'm sure it is because they feel that the span of Channel 11 to Channel 60 (virtually one whole megahertz and twice the IF of a single conversion receiver) is a mite too broad to guarantee good selectivity and so tune up their things around the center of the LO band and also the center of the HI band.
I'm not going to confound the issue by going into Image Rejection, Band-width and Selectivity or even Adjacent Channel Interference about which you seem concerned, but can only say that it would be down-right irresponsible of me to make the statement I did if I did not know better.
I hope that helps??

08-09-2009, 08:49 PM	#7
Spitball !!! CONFIRM YOUR ACCOUNT !!! I am: Cedric V. Join Date: Oct 2004 Location: St. Marys, Ontario N4X 1C1 Feedback: 11 / 100% Posts: 1,244 Total Props: 1	Re: Hitec focus 4 question If you can point me to a statement by other manufacturers that they too have a 'HI<>LO' separation, I would appreciate it. Someone with a modicum of RF knowledge has chimed in - me - a lifetime of work with transmitters of all sizes, frequencies and power, and receivers of most configurations and with radio control systems from 1948/49 or thereabouts to the present, gives me the confidence to make the statements I have. As far as I'm concerned it is only Futaba that I know of, that has this HI-LO thing and that I'm sure it is because they feel that the span of Channel 11 to Channel 60 (virtually one whole megahertz and twice the IF of a single conversion receiver) is a mite too broad to guarantee good selectivity and so tune up their things around the center of the LO band and also the center of the HI band. I'm not going to confound the issue by going into Image Rejection, Band-width and Selectivity or even Adjacent Channel Interference about which you seem concerned, but can only say that it would be down-right irresponsible of me to make the statement I did if I did not know better. I hope that helps??