frequency change for TX and RX

My radios are on a busy channel at my club and I'm considering changing the frequencies of both the TX and RX. I'd have to only go one or two channels away like going from 40 to 38 or 42 on both the TX and RX. Is this a safe move? I've heard disagreements about changing to too many channels away for the TX and then having the TX retuned by the manufacturer.

Any help?

Swede ========================================

There was a month long argument that finally ended the other day on this subject.

It just doesn't seem possible that you could have missed the thread.

FCC regs were quoted to prove it is illegal to change TX crystals in the US. The exact same regs were quoted to prove it is not illegal.

AMA and many radio manufacturers lean toward the opinion that it is illegal. They may or may not be right. Radio mfrs want the money for retuning so it's easy to understand their position.

Some radio manufacturers sell TX crystals to the public and some do not. If your manufacturer does not sell crystals, you need to send it in; if they do sell them, just make your own decision and be prepared to deal with negative consequences IF they happen. If you shoot down someone's plane you'll probably spend a lot more than it would cost to have the radio retuned.

Why not get the new crystals and then get your TX and RX re-certified? The tests will quickly tell you if you are at risk of shooting anyone down on adjacent frequencies, or if you RX is going to misbehave.

Russ.

This has been stated in this forum so many times one would think it must be chiseled on a stone tablet, but where exactly does AMA say that (in written terms that form a part of a member's insurance contract with AMA)? Here is the relevant part of the AMA Safety Code:

"4) I will operate my model using only radio control frequencies currently allowed by the Federal Communications Commission. (Only properly licensed Amateurs are authorized to operate equipment on Amateur Band frequencies.)"

Doesn't say anything about changing crystals, nor anything about compliance with FCC regs, other using the allocated frequencies.

Abel

unless the FCC has changed their rules, and its been along time since I was involved with Transmitters, it is against the law to change xtals unless you have a FCC license, generally a 2nd class ticket and under the supervision of a 1st class ticket. based on how much wattage is being transmitted. All Tx/Rx have to be re-tuned to the frequency that the new xtal has. It doesn't matter if its SSB, VHF, RADAR, FM, or AM.

Now there have been great improvements in radio gear and maybe its no longer a necessity to re-tune, but I sure don't want to crash another's plane. If the cost of re-tuning is out of your price range, maybe you should find another hobby.

All

Not so, the point being *have* to be.

You don't HAVE to retune - either legally, or in practice, in the UK for example.

One accepts that output power and sideband emission will not be absolutely optimum, but they are within tolerance.

Nonetheless, its done as routine, with no ill effects provided the correct brand of Xtal is used. Non or other brand Xtals have shown to give frequency offsets from what is marked on the can, with other transmitters than intended, significant enough to cause concern.

About a year ago, this issue was addressed in Model Aviation. I believe it was Steve Kaluf's column. The official word was that if you voilated the AMA's interpretation of FCC regulations, you violated the Safety Code, and your insurance coverage was compromised. The specific issue was using Hitec Spectra modules in Futaba systems, but the statement made was general, and therefore applied to ALL FCC regulations. You can't just pick and choose the ones you want to follow, and expect the AMA to cover your ass when you choose to not follow the wrong regulation at the wrong time...

It's just like the FCC regulations themselves. Maybe Part 95 doesn't explicitly say, "Thou shalt not change crystals," but it does say, "crystals must not be accessible to the user," and there are regulations elsewhere in the FCC regulations that spell out who can work on what.

But AMA can make any 'official" interpretation they please and that's the rule that applys re exclusions from coverage, regardless of what is written into the insurance contract? Don't think so, but then with what the lawyers have done to fubar civil law in this country, maybe it so. Sure glad I have umbrella coverage from a real insurance company.

So I'm in violation of the law if the manufacturer of the Tx I bought made the crystal accessible to me. It figures.....

Abel