League Requests Rule Change to Ease Spread Spectrum Operation

NEWINGTON, CT, March 20, 2006--The ARRL has asked the FCC to modify one of its rules governing spread spectrum (SS) operation on Amateur Radio frequencies. The League this month petitioned the Commission to drop all but the first sentence of §97.311(d), which now requires the use of automatic power control (APC) for SS stations running more than 1 W. The ARRL request would retain the 100 W overall power limitation for SS.

"The effect of the rule change would be to eliminate an automatic power control provision that has proven over time to be impractical" in terms of compliance, the League said in its Petition for Rule Making filed March 13. It also argued that the provision--one the League had proposed and supported more than 10 years ago--was unnecessary to protect the operations of other licensees and had "unfortunately served as an unintended but effective deterrent to spread spectrum experimentation" on ham radio.

Since the FCC first approved the use of spread spectrum techniques for Amateur Radio in 1985 on bands above 225 MHz and at power levels up to 100 W, there's been limited--but never widespread--experimental amateur operation. Over the years, the FCC also authorized Special Temporary Authority (STA) in some instances to allow broader SS experimentation. More recently, the FCC has made the SS rules less restrictive in response to League showings that the rules were hampering SS experimentation and that interference has not proven to be an issue.

The ARRL says it now agrees with those who opposed the automatic power control provision in WT Docket 97-12, which the Commission concluded in 1999. Those changes not only relaxed rules governing the use of spread spectrum techniques by radio amateurs but opened the door to the possibility of international spread spectrum communication.

"Now seven years later, it is apparent to ARRL that the rules requiring APC indeed have proven to be difficult to implement, unnecessary and something of a barrier to SS experimentation," the ARRL said in its latest rule making petition. "Section 97.311(d) can be greatly simplified without increasing the risk of intra-service or inter-service harmful interference."

The ARRL said it has no problem with the 100 W power limit because there's no evidence it "contributes to the current regulatory disincentive to experiment with SS." The 100 W power level also limits the power spectral density of an SS emission, contributing to compatibility between Amateur Radio SS and narrowband modes in the same allocations, the League said.

The rules already in place make spread spectrum "essentially secondary to any amateur narrowband emission modes," the League pointed out. "Given these existing rules, the APC requirement is not necessary to avoid interference to any other user of the same spectrum as the amateur SS emission."

In any event, the League concluded, radio amateurs employing SS modes would remain obliged to comply with the rule requiring use of "the minimum transmitter power necessary to carry out the desired communication." That was a primary reason the ARRL asked for the APC provision in the first place.

The FCC has not yet assigned a rule making (RM) petition number to the ARRL's petition nor invited comments.

In its Notice of Proposed Rule Making (NPRM) WT Docket 04-140, the FCC, in response to another ARRL petition, proposed extending the bands available for spread spectrum to include 222-225 MHz. On its own initiative, the Commission also recommended permitting SS operation on 6 and 2 meters, a move the ARRL opposed. In its comments, the League cited concerns about raising the noise floor on 6 meters and the fact that both bands already support substantial narrowband and weak-signal work, meaning "fewer opportunities for frequency reuse in those allocations."

The Commission is expected to conclude WT Docket 04-140 this year. The FCC suggested that restrictions on spread spectrum already in place should be sufficient to prevent any adverse impact of SS operation to other users of 6 and 2 meters.

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