Dish Remote Antenna...

[scannerbum]

Does anybody know what frequency that the remote antenna, on the back of the unit operates on? Seems to work great for 800mhz...

 

[trooperdude]

345Mhz license free band.

Same as garage door openers.

 

[rankin39]

The frequency I was given by the serviceman was "around 390 MHz." I'm not in a position to say that 345 is wrong though, and different DVRs may have different channels for the remote. My antenna measures between 6-7 inches, which would be about right for 390 and would also be approximately a half-wave vertical at 800 MHz., which would account for your reception in that range.

Bob, w0nxn

 

[wannabescannist]

trooperdude or rankin39, is there a name for this band? What FCC Part do these devices operate under? I've looked up Part 15, 18, and 27 and couldn't find these frequencies mentioned.

 

[rankin39]

I don't know a name for the band per-se, but a number of different switching devices operate in this part of the spectrum (which is shared with the military, which is the primary user). Garage door openers, automobile door lock openers, satellite TV remotes, home security systems, etc. all use the 300 MHz. range. Each device is generally encrypted so that other people's similar devices won't open your particular system and vice-versa. One of the problems with this range is that some of the new military trunking systems operating between 380 and 400 MHz. interfere with the civilian devices. Air Force One has been known to raise and lower garage doors when it's in the vicinity too. I still don't know the precise frequencies, and my BCD996T "close call" does not pick them up. Maybe "trooper dude" has more info than I do.
Bob, w0nxn

 

[wannabescannist]

Thanks for the info...I'm curious as to how these remote control devices utilize RF bandwidth. Seems in Europe they might operate under the LPD(433MHz) or SRD(860MHz) bands but don't know what it's called here in the US.

 

[N_Jay]

Thanks for the info...I'm curious as to how these remote control devices utilize RF bandwidth. Seems in Europe they might operate under the LPD(433MHz) or SRD(860MHz) bands but don't know what it's called here in the US.

It is usually considered ISM (Industrial Scientific, Medical) service or under Part 15 "Unlicensed Transmitters"

 

[trooperdude]

In my copius free time I'll stick one in front of the service monitor and see what the remote operates on.

Figure around Valentine's day. LOL

 

[wannabescannist]

It is usually considered ISM (Industrial Scientific, Medical) service or under Part 15 "Unlicensed Transmitters"

I thought it might've been ISM as well but didn't locate any ISM band that encapsulated 345 or 390MHz.

But it looks like they do operate under 15.231 (Periodic operation in the band 40.66-40.70 MHz and above 70 MHz):

[...] the intentional radiator is restricted to the transmission of a control signal such as those used with alarm systems, door openers, remote switches, etc. Continuous transmissions, voice, video and the radio control of toys are not permitted.

So it looks like anything over 70MHz....(minus those listed in 15.205).

There has to be a common "recommended" band to use, and based on the past responses, seems to be somewhere in the 300-400MHz range. Might have to take some stuff apart and measure the (hopefully soldered-in single-wire) antennas. Based on 15.205 (prohibited frequencies), the range might be 335.4MHz-399.9MHz.

 

[rankin39]

I googled "frequency garage door openers" and got a number of interesting sources. The one that had the most specific info said:

"The range of different types of frequencies depends on a variety of factors: geographic location, manufacturer preference, etc. We stock and sell radio sets with the following frequencies (in MHz): 288, 300, 310, 312, 318, 340, 390, 434, and more; we commonly get inquiries from Canada & other countries that use other frequencies."

There were many articles mentioning the interference from the new military LMR band, 380-399.9 MHz. including an FCC notice on the subject. So there is no one single frequency band in use for remote signaling to DVRs, garage doors, security systems, car locks, etc.

Bob, w0nxn

 

[steve_k]

One of the problems with this range is that some of the new military trunking systems operating between 380 and 400 MHz. interfere with the civilian devices. Air Force One has been known to raise and lower garage doors when it's in the vicinity too.
Bob, w0nxn

Not sure if this is fully correct but I remember awhile back there was a rumor some cadillac owners were having problems with their car's alarm going off and the vehicle shut down. I think they (GM) concluded it might be a frequency test conducted by the navy or DOD but could not confirm.....
Imagine somebody who did not know better going down a back road and this happened to them? Probably their first thought would be they have about ten seconds to make peace with themselves before the wind force from a nuclear blast (that did not actually occur) hit them.

 

[wannabescannist]

As far as car alarms/remote entry systems are concerned, looks like the most common frequencies I could find were 302MHz, 315MHz, and 433/434MHz (European LPD band).

My alarm (DEI) works off of 433.92MHz and was able to hear it through my scanner (transmitter's probably now unsynchronized with the receiver or my door or trunk is probably open while I sit here typing...lol). Even left the scanner on that frequency with squelch open and was able to hear a pretty good amount of data bursts.

Doing some FCC searches (don't know why I was about to take stuff apart!) on some alarms listed in the above link, found some info:

The code is carried by 315 MHz carrier with AM OOK (on-off keying) modulation and radiated by a printed circuit board antenna. The data code is of a pulse width modulation format to express bits "0" and "1". The data code period is controlled by the encoder clock, which is an RC oscillator type that is integrated into the encoder. [...] The 315 MHz. transmit frequency is generated by a SAWR (Surface Acoustic Wave Resonator) stabilized, Colpits oscillator. Frequency tolerance is better than 315 MHz +/- 150 kHz.

Not that you can do much with that info but sometimes I find my remote-entry sometimes doesn't work when I'm at school and practically right in front of my car, leading me to believe my battery's dead...yet when I get home or am at work, I'm able to unlock the doors from half-a-block to a block away. I think some 70cm ham is jamming the frequency...lol.