Page 7 - Combined_28_OCR

2--October 16, 1968

4. Approximately 120 db noise level inside the race car.

5. The lack of acoustical insulation in the Bell helmet.

6. Insufficient noise cancellation of the crystal microphone.

7. The possible necessity of the driver to make radio control adjustment.

8. Complete lack of security and assurance that spurious signals would
not interfere.

An analysis of the problems encountered and the partial success of the
operational tests, indicate that with the proper selection of equipment and
frequency spectrum, problem Nos. 1, 2, 3, 7, and 8 would be adequately
corrected. Problem Nos. 4, 5, and 6 are all caused by the environment of
high acoustical noise. To resolve these problems, a special helmet would
need to be designed with good acoustical features and built in earphones and
microphone. Considering the present state of the art, only the microphone
would present a moderate challenge.

Recommendations for the selection of communication equipment are that
the transceivers be of commercial construction fo Hi uggedness, FM modulated
(5 kHz deviation) for freedom from RFI and audio clarity, 3 to 20 watts
output power, and operate in the 150 mHz or 450 mHz band (450 mHz
preferred). The additional feature of a tone squelch circuit would enhanc D C
Security, Safety, and make possible the use of the base station for other
communication links without interference with the race driver.

The selection of a suitably designed, NASCAR approved, crach helmet
containing earphones and microphone would be the only additional noteworthy
items of equipment necessary for an operational system. Other items such
as equipment assignments, FCC license, operating procedures and discipline
would be managerial in nature and as such are not included in this report.

L. H. Scott
LHS/eh

cc: H. H. Miller
A. B. Orth