HFU HF Underground

Loggings => Satellite, Radiosondes and Other VHF/UHF Signals => Topic started by: flexoman61 on April 13, 2017, 1917 UTC

Title: 49.847 mHz Baby monitor?
Post by: flexoman61 on April 13, 2017, 1917 UTC
Picking up a signal on 49.847 MHz, sounds like someone's baby monitor.
I tuned past it, don't want to spy on people, but do these monitors operate around this frequency?
Title: Re: 49.847 mHz Baby monitor?
Post by: ChrisSmolinski on April 13, 2017, 2025 UTC
Yes, the older ones used that range as did cordless phones, the newer models are around 900 MHz I think.  I don't know if newer models are still analog or digital.
Title: Re: 49.847 mHz Baby monitor?
Post by: fpeconsultant on April 14, 2017, 0029 UTC
Yes I used to hear nearby baby monitors in the same 49mhz range - quick to turn the dial too. 
Title: Re: 49.847 mHz Baby monitor?
Post by: flexoman61 on April 14, 2017, 0058 UTC
Thanks for the info. We used those things for years when our kids were small.

Title: Re: 49.847 mHz Baby monitor? Yep...
Post by: ThaDood on April 17, 2017, 0944 UTC
        They still sell 49MHz FM baby monitors, and with two channels. CH1 = 49.870MHz, and CH2 = 49.850MHz. Ya got a good 6M, or a decent scanner, antenna and you can hear those sucka's a couple of miles easily.
Title: Re: 49.847 mHz Baby monitor?
Post by: R4002 on April 21, 2017, 0447 UTC
I used to have a neighbor with an older-generation 10-channel 46/49 MHz cordless phone with the base station (which had a telescopic whip antenna) located on the top floor of their 3-story home.  The cordless phone base station in question got out several miles and the neighbor talked on the phone a lot.  

The 49 MHz band is still used even though most baby monitors have moved up to the various ISM bands 900MHz/2.4GHz/5.8GHz (and various combinations of digital/video/spread spectrum).  The same can be said for cordless phones (plus the 1.9GHz DECT band).  However, cheaper cordless phones still use analog 900 MHz band (902-928 MHz) for base-to-handset link transmissions, often using random frequency steps (there appears to be no standardization in regards to this, with some companies using 12.5 kHz channel steps, others using 40 kHz channel steps, etc).  

RadioShack used to sell 49MHz walkie-talkies (the TRC-512 model among others) before they switched to selling FRS radios.  The 5 channels used by these radios were also the channels used by baby monitors (and cordless phone handsets!).  Made for interesting situations when a neighborhood had baby monitors, cordless phones, and kids with 49MHz FM walkie talkies all on the same frequency.  Further complicating things is the fact that 49.600-50.000 MHz is technically a US military band, and US Army helicopters have been monitored on 49.700 MHz, 49.750 MHz and 49.950 MHz.  

49.830 MHz
49.845 MHz (some companies use/used 49.850 MHz instead)
49.860 MHz
49.875 MHz (some companies use/used 49.870 MHz instead)
49.890 MHz