High band vs. Low band Rx

On Sun, 5 Mar 2006 12:16:10 -0600, " snipped-for-privacy@wowway.com" wrote in :

So far as I know, it's an outmoded concept.

Futaba (I think) used to tell people not to change crystals without having the RX retuned if the change in frequency was more than plus or minus ten channels.

All of the Hitec RXs I've purchased come without a crystal. You just buy the crystal you want and put it in.

It is different, of course, if we're talking about HAM band receivers and 72 MHz. You can't change a receiver from HAM to 72 MHz, so far as I know.

Marty

High Band versus Low Band is most commonly a distinction made while discussing Futaba aircraft radio equipment. Futaba dual conversion receivers are either rated as low band (channels 11 through 35) or high band (channels 36 through 60). For whatever reason, Futaba doesn't design their receivers to work with just any channel, they're specifically engineered for the lower or upper half of 72mhz frequencies.

Basically, if your transmitter is on channel 11 through 35, you need to pair it with a low band Futaba receiver along with your specific frequency crystal. If your transmitter is on channel 36 through 60, you need to pair it with a high band Futaba receiver along with your specific frequency crystal.

JR, Airtronics, and Hitec all make receivers that can accept any crystal between channel 11 to 60 on the 72Mhz frequency band.

| High Band versus Low Band is most commonly a distinction made while | discussing Futaba aircraft radio equipment. Futaba dual conversion | receivers are either rated as low band (channels 11 through 35) or high band | (channels 36 through 60). For whatever reason, Futaba doesn't design their | receivers to work with just any channel, they're specifically engineered for | the lower or upper half of 72mhz frequencies. ... | JR, Airtronics, and Hitec all make receivers that can accept any crystal | between channel 11 to 60 on the 72Mhz frequency band.

Close, but not quite.

Basically, you take your RX and tune it to a specific channel. It'll work best at that channel, and as you get further from that channel, performance will decrease.

JR/Airtronics/Hitec gear is tuned to channel 35 or so by default. So it'll work best on channel 35, a little less good at 34 or 36, etc. But even channels 11 and 60 will work reasonably well, even though we're 25 channels away.

Futaba gear is tuned to channel 23 (low band) or channel 48 (high band) give or take a channel or two. The advantage of doing it this way is that as long as you keep in the correct band, you're at *most*

With the right skills and tools, a RX can generally be tuned to any specific channel, whether it's high band, low band or `middle' band. (As long as you stick to the same band. You cannot simply tune a 72 MHz RX to 27 MHz, for example.) Tuning your RX to your specific channel will give the best performance, but the gain usually isn't that signifigant unless it was way off before.

If you buy a brand new RX, it's probably tuned to approximately channel 23 (Futaba low band), 48 (Futaba high band) or 35 (JR/Airtronics/Hitec), no matter what crystal is actually in it.

However, if you then send it in to the factory for repair or retuning, they'll probably tune it directly to the channel of the crystal in it, which will give you the best performance.

Though really it rarely matters. You may get 2 miles range with a perfectly tuned RX, or 1 mile range if it's a low band RX on channel

1. You probably can't see your plane at over 1/2 mile, so ...

(To be fair, my figures are guesses. Do your own testing.)

Thanks, guys! I appreciate the comments. Most of my equipment is Futaba, so I guess I'd better be "Heads up" about the subject.

Thanks, Harlan

Please pardon the one-time test

On Sun, 5 Mar 2006 19:46:54 -0600, "hed" wrote in :

Ego te absolve ...

Marty

Thanks, Doug! I knew somebody out there would be happy to expand upon my reply.