ARLA/CLUSTER: ARRL avisa empresa americana para que evite interferencias nas bandas de amador em Onda Curta

[João Costa > CT1FBF]

ARRL warns experimental licensee to avoid interference to HF ham activity

The ARRL has asked a Massachusetts company that plans to conduct
experimental transmissions over wide portions of the HF spectrum
either to avoid Amateur Radio allocations or to announce the times and
frequencies of their transmissions in advance.

The FCC last fall granted MITRE Corporation of Bedford, Massachusetts,
a 2-year Part 5 Experimental License, WH2XCI, to operate 21
transmitters at 10 fixed New York and Massachusetts sites. MITRE plans
to test wideband HF communication techniques on a variety of bands
between 2.5 MHz and 16 MHz.

"[I]t will not be possible for MITRE to operate these transmitters
within the Amateur Radio Service allocations...without causing harmful
interference to a large number of Amateur Radio operators on an
ongoing basis," ARRL Chief Counsel Chris Imlay, W3KD, said in a
February 12 letter to MITRE.

Imlay said that if MITRE does not agree to avoid ham radio bands or to
announce times and frequencies of transmissions ahead of time, it will
ask the FCC to rescind the company's Experimental License or to impose
a prior notification requirement "in real time for each and every use
of the transmitters authorized at each site."

The WH2XCI Experimental License authorizes maximum bandwidths of 5
kHz, 500 kHz, and 1 MHz at effective radiated power levels of 6 W, 24
W, or 122 W. MITRE has indicated that most bandwidths would be between
100 and 300 kHz.

"At these power levels with the operating parameters proposed, it will
be impossible to conduct your tests at any time within the Amateur
Radio allocations and, at the same time, avoid harmful interference,"
Imlay said. He noted that MITRE already conceded this point in a
technical exhibit submitted to the FCC with respect to its 1 MHz
bandwidth mode.

Imlay said that when interference from MITRE's wide-bandwidth
transmitters "inevitably occurs in the narrow-bandwidth, sensitive
receivers" hams use, amateur licensees will have no way to determine
the source of the interference or know to whom they might complain.

"Thus, your assurance of operation on a 'non-interference basis' is
meaningless under the circumstances, and yet that is both a special
condition of operation" of the WH2XCI license and under FCC Part 5
regulations, Imlay told MITRE.

"It is ARRL's intention to ensure that this experimental
authorization, improvidently granted to the extent that it includes
heavily used Amateur Radio allocations, is not permitted to cause
interference to ongoing Amateur Radio HF communications," Imlay
concluded.

MITRE obtained the Experimental License to investigate high data rate
wideband HF communication systems that exploit polarization diversity
multiple input, multiple output concepts to expand the bandwidth of
the communication channel.

Fonte: ARRL