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Hobbico Freq. Checker

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Old 11-14-2005, 04:52 PM
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TimC
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Default Hobbico Freq. Checker

I've been pondering the cause of a mystery crash last Saturday. I have a little Hobbico scanner that lights up if a channel receives a signal. I fly on channel 24. I the past I have noticed hits on ch. 23. Today I found hits on 22 and 25. This area only has three of us who fly and none of us were flying this morning. Is it possible there could be some broad band interference in this area of 72 MHz? The instructions say the range with antenna is 300'. I assume this means another RC transmitter. It seems a much stronger signal from far away could register as a channel in use also. Would any signal strong enough to light up the LED be strong enough to shoot down a model?
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Old 11-14-2005, 05:29 PM
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Default RE: Hobbico Freq. Checker

There are a LOT of signals that can interfere with R/C models....pagers, fleet communications, radio-controlled cranes, and so on. The 72 MHz band is designated for commercial use, and the R/C channels are intereleaved between the commercial channels. They are allowed up to 1,000 Watts of power, R/C tranmsitters are allowed up to 0.750 Watt of power.

A high-power user as many as 3-4 channels away, so to speak, from your channel could cause interference and loss of your model. If one of those users can be shown to affect R/C channels, then the only alternative is to find R/C channels that are not affected. FCC regulations give R/C users lower priority than the commercial users.
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Old 11-18-2005, 02:53 PM
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Default RE: Hobbico Freq. Checker

BAX...you did not answer his question......will any signal that lights up the LED be strong enough to shoot down a model? That is my question ALSO. Thanks Capt,n
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Old 11-18-2005, 03:52 PM
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Default RE: Hobbico Freq. Checker

Yes, if the LED's are lighting up like a Christmas tree, and you know for a fact that nobody is flying for 60 miles, is there some bad ju ju happening?
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Old 11-18-2005, 04:34 PM
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Default RE: Hobbico Freq. Checker

If the Hobbico frequency checker has a light on that you're sure is not an in-use R/C channel, then the unit is receiving something. That may be "bleed" from a too-close R/C transmitter that has its antenna fully extended, or it could be outside interference. Random signals are always happening, so a light could come on during one scan, and not be on the next. If a particular light is staying on, then it may be that someone's left a transmitter on, or you have a channel that's being swamped by some non-R/C source. For example, we have several companies in our area that use the 72 MHz commercial channels, and they ruin about 8 R/C channels here. Those channels are banned at the local field--guaranteed interference and crash!

That's why there are 50 R/C airplane channels: so that we can have plenty of channels to use if some are blanked by other users.
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Old 11-28-2005, 11:45 AM
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Default RE: Hobbico Freq. Checker

After my experiences with the Hobbico Frequency Checker, I would not put too much faith in it. See the following review:

[link=http://www.rcuniverse.com/magazine/article_display.cfm?article_id=565]http://www.rcuniverse.com/magazine/article_display.cfm?article_id=565[/link]

I had a similar problem as the reviewer. I get an active channel indication almost constantly, usually in the 26-28 range, but higher or lower depending on the temperature. I'm sure it is a problem with the unit, since I get the indication even inside a sheilded RF chamber. I'm planning on taking mine back for replacement.

Bob R.
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