Odd close call hit-trooper 3

[IQ_imbalance]

So I had a close call hit on ~419MHz (have to check the scanner to see if it stored it) when the MSP Trooper 3 chopper flew by the house. I’d like to think it was a data stream but honestly it sounded more like the whine from an electric motor. Anyone experience something similar w/helo traffic?

 

[maus92]

So I had a close call hit on ~419MHz (have to check the scanner to see if it stored it) when the MSP Trooper 3 chopper flew by the house. I’d like to think it was a data stream but honestly it sounded more like the whine from an electric motor. Anyone experience something similar w/helo traffic?

ADSB data is 1090 MHz and is bursty; MSP VHF comm is ~ 47 MHz and *maybe* they can send data and would be continuous. 419 MHz is in the Federal band, so not sure why MSP would be using that spectrum. Maybe they are working with a fed agency and you heard AC whine in the intercom circuit (common with helos.)

 

[IQ_imbalance]

aaaaand i didn't store it before turning the scanner off. I'll leave it in close call auto store for awhile and see if i get another crack at it.

 

[iMONITOR]

417 MHz to 419 MHz
FCC ID Applications By Frequency.
- MHz
ITU # 9 - UHF Ultra high frequency – TV broadcasts, microwave ovens, mobile phones, wireless LAN, Bluetooth, GPS, and Two-Way Radios (300-3000 MHz)

Lower	Upper	Details
410	420	This band is used in the Industrial/Business Radio Service. This band is allocated for both Federal and Non-Federal use. Operation of unlicensed Part 15 Devices is permitted between 410 and 420 MHz.

 

[maus92]

There is a radio service called MedRadio that operates in 410-420 MHz band, but it's usually low power patient networks. The left box are Federal users; the middle box is non-Federal. The right box is FCC Part rules.

 

[boatbod]

Could have been a strong signal causing intermod or a harmonic?

 

[KevinC]

Could have been a strong signal causing intermod or a harmonic?

If the OP was using a SDS-series radio I'd suspect this was a false hit.

 

[IQ_imbalance]

It was received on the bct-15x, and was definitely correlated w the proximity of the helo. Can’t rule out it being a harmonic of another signal though.

 

[wtp]

back in the 90's, when i had just moved to Florida, someone told me that the sheriff's helo had camera on it and they used a cable TV frequency to transmit. what they meant was it was not a regular over the air frequency that anyone could receive on their TV.
i never picked up anything on any frequency.
at the time i had a cable ready TV that would receive cable channels by rotary tune and i had a TV antenna on it, lots of static and nothing else.
just passing it along, you never know.
i lived less than 4 miles from the airport, so i thought i had a chance.