Part 15 use of 1710 kHz has been discussed. But what is this frequency reserved for otherwise? What kind of licensed service takes place on 1710 ?
Part 15 use of 1710 kHz has been discussed. But what is this frequency reserved for otherwise? What kind of licensed service takes place on 1710 ?
47cfr2.106
Carl,
According to 47cfr2.106, (table of allocations), the band from 1705-1800 kHz is allocated for fixed, mobile, and radiolocation services under FCC parts 80 (Maritime) and 90 (Private Land Mobile). Just how active those allocations are I am not sure. You could do an FCC ULS search to see what licenses are held for that band.
Here is the link to the description of the US Table of Frequency Allocations (47cfr2.105): http://edocket.access.gpo.gov/cfr_2008/octqtr/pdf/47cfr2.105.pdf
And here is the link to the table itself (47cfr2.106):
http://edocket.access.gpo.gov/cfr_2008/octqtr/pdf/47cfr2.106.pdf
You’re probably going to be interested in page 470.
TIS stations
The band of frequencies available for TIS stations formerly included 1710 kHz. The latest version of Section 90.242, which governs TIS stations, no longer includes 1710 kHz.
R. Fry has convinced me that
R. Fry has convinced me that my operation on 1710 is an error.
Technically correct
Mr. Fry is technically correct in his assertion that 1710 is not covered under the provisions of 15.219, but the fact remains that the Grant of Certification for the Rangemaster transmitter includes 1710. You can view the grant on his web site or you can download it from the FCC Equipment Authorization Division. Furthermore, the transmitter is not designed to be compliant with 15.209 and there is no practical way that a user could adjust it to comply with that section.
If I had more “skin in the game” I’d give 1710 a try and see what happened! But I am not a gambling man!
Be Afraid
Be very afraid…
RE: Be Afraid
FWIW, I just emailed with a fellow who has been broadcasting all day every day on 1710 for the past 6 years with no problems.
530 kHz
Just outside the AM broadcast band at the lower end is 530 kHz, which, like 1710 kHz, can also be tuned by most AM radios. This frequency is legal to use under Section 15.219. TIS stations can also be assigned this frequency.
Attenuation
F.C.C. Quote:
Sec. 15.219 Operation in the band 510-1705 kHz.
(a) The total input power to the final radio frequency stage
(exclusive of filament or heater power) shall not exceed 100 milliwatts.
(b) The total length of the transmission line, antenna and ground
lead (if used) shall not exceed 3 meters.
(c) All emissions below 510 kHz or above 1705 kHz shall be
attenuated at least 20 dB below the level of the unmodulated carrier.
Determination of compliance with the 20 dB attenuation specification may
be based on measurements at the intentional radiator’s antenna output
terminal unless the intentional radiator uses a permanently attached
antenna, in which case compliance shall be deomonstrated by measuring
the radiated emissions.
————————————————————————————-
So does this section refer to attenuating spurious signals outside of the band, below 510 and above 1705?
Or does it mean that if you operate, say on 1710 khz that you should apply 20 Db attenuation to your carrier to stay compliant?
I’m sorry if I missed the point here but to me this sounds like this is a countermeasure to prevent any unwanted spurs from showing up above or below the 510 to 1705 BCB.
Although there is another side to the coin, if i transmit on 1710 khz or anywhere else on the AM BCB i should always be sure my signal does not cause spurious emissions on any band .
Rule for 1710 Operation
Hello Rock95seven
Intentional Radiation on 1710 kHz is not a spurious emission, but is referenced in this section from Part 15:
15.223 Operation in the band 1.705-10 MHz.
(a) The field strength of any emission within the band 1.705-10.0 MHz
shall not exceed 100 microvolts/meter at a distance of 30 meters.
However, if the bandwidth of the emission is less than 10% of the
center frequency, the field strength shall not exceed 15
microvolts/meter or (the bandwidth of the device in kHz) divided by
(the center frequency of the device in MHz) microvolts/meter at a
distance of 30 meters, whichever is the higher level. For the purposes
of this section, bandwidth is determined at the points 6 dB down from
the modulated carrier. The emission limits in this paragraph are based
on measurement instrumentation employing an average detector. The
provisions in § 15.35(b) for limiting peak emissions apply.
(b) The field strength of emissions outside of the band 1.705-10.0 MHz
shall not exceed the general radiated emission limits in § 15.209.
Rule for 1710 Operation
The 1710 to 1800 band was originally used for Police radio and the original LORAN navigation system. The Police radio usage goes way back to the ’30s and ’40s and the LORAN usage stopped sometime in the ’60s or’70s (I think). Police moved to VHF and LORAN moved to 50 kHz, or so, and then stopped service altogether recently. GPS superceded it.
I wonder if 1710-1800 kHz is actually used by anyone? The 160 meter ham band includes 1800-2000 kHz. There may be an on line database that can be searched by frequency. If anyone finds one, a post would be helpful.
Drug Deals and All!
In 1975 I had a Cobra cordless telephone. The handset transmitted to the base on 49 mHz. The base transmitted to the handset around 1730 kHz.
I started monitoring the range from 1700 kHz to 1800 kHz and was amazed to hear telephone conversations as far away as 5 to 10 miles.
I don’t know when they quit using that range of frequencies but there’s probably one still out there somewhere.
I found these frequency pairs listed on a scanner website:
46.6300 Ch 2 Cordless Phone, input 49.845, old out 1710 kHz
46.6700 Ch 3 Cordless Phone, input 49.86, old out 1730 kHz
46.7300 Ch 5 Cordless Phone, input 49.875, old out 1750 kHz
46.8300 Ch 7 Cordless Phone, input 49.89, old out 1770 kHz
46.8700 Ch 8 Cordless Phone, input 49.93, old out 1690 kHz