Help needed in monitor solution

[jdbob]

I am a caregiver for an extremely disabled person living in a relatively rural area. I have been using baby monitors to keep track of her as I do work around the house and yard with limited success over about 30 years. Lately, the monitors don't have the range that they used to and I'm really getting pinched in my activities. I've tried many different brands and prices and they're all pretty much the same--crappy. Does anybody have any suggestions for improvement to either the monitors, or perhaps a different approach?

My client listens to her computer reading aloud all day and cannot push buttons or in any way activate a transmitter so it has to be always on, so walkie talkies probably wont work. I would really like to just boost the transmitting power of her unit, there's nobody close enough for it to interfere with other wireless devices. I'm not learned in electronics but I can solder a connection and pretty much do everything myself around here that needs doing or fixing.

Any ideas?

 

[(*steve*)]

The range on those things is probably at least partially determined by:

1) transmit power
2) receiver sensitivity
3) noise
4) antenna(s)
5) frequency

You seek to improve (1), however looking at the others may be simpler (and on that basis let's also discount (2)).

If the same units have been behaving worse, it is possible that the amount of electrical noise has been increasing (have there been more residences popping up over the last 30 years? or perhaps power lines?). It is possible that the computer itself is the cause of some significant noise, however a noise source somewhat closer to the receiver wrt the transmitter is more likely. If you can't reduce the noise you're generating (or if you are not in control of the stuff that is noisy, this is not much help)

The 4th option is the antenna. If noise is a problem, then increasing the size of the receiver's antenna is unlikely to help (unless you want to carry around a directional antenna with you -- and keep it pointing the right way). However it may be possible to improve the antenna on the transmitter. This may be as simple as connecting a longer piece of wire to it, or as complex as getting an appropriate antenna for the operating frequency.

Another option (also tied to noise) is the frequency that the units operate at. It is possible that the band they use is quite noisy and finding units operating on a quieter band may help substantially. The problem with devices like this is that they operate on "unlicensed" bands, which all tend to be noisy and occupied.

 

[davelectronic]

Monitor trouble

Hi there, ive read your post, looking in to better distance there are a couple of models of PMR radio available with settings on them to be used as a permanent talk both ways essentially a baby monitor, yet a much greater range, and as there frequency is UHF the signal is good for not meters, but miles, certainly around a rural area, once set they talk both ways, no button pushing on this setting, yes they look and are hand held sets, yet they use a system known as VOX voice operated transmission, the person talks and the other receives, this is one mode the other mode is the same radios, but its set to receive both ways as a baby monitor does, and UHF is excellent in all conditions, in the US they sell the same radios but its called another name, not PMR but something else.

In the UK there 0.5 watts, this does not sound much yet they will outpace a baby monitor by 10 or more times in distance, worth looking in to. Dave. these come with a standing desk top pod.

http://www.maplin.co.uk/twin-pack-mt800-pmr-two-way-radios-217931

These are at an electronics store over here in the UK, there very good quality and would last a very long time. ( PMR ) public mobile radio.

 

[daddles]

What Dave is referring to is probably the FRS (family radio service) in the US. If the current offerings do have the VOX or continuous transmitting (baby monitor), you might strongly annoy other people trying to use the frequency you're transmitting on. You may also find that there is significant traffic on the channel you choose to use (the frequencies are public, after all).

I looked briefly at the Cobra website and had to laugh a bit at the ranges they give for their radios: 15, 30, 35 miles, etc. They might behave that way in a flat desert or at sea, but I've never seen those kinds of ranges. I'd at least divide their numbers by 2 and probably by 4 or 5 to be conservative. I've been cycling on a large lake in the mountains near where I live and talking to my wife in camp across the lake, a distance of a mile at best. The signal was fair, but when I went deeper into the forest, I lost contact. As always, beware of marketing-speak.

 

[jdbob]

I have tried doubling the receiver antenna wire with no noticeable effect, and in the past I tried an much larger antenna for the transmitter and that didn't work - maybe it didn't match the frequency right.
Would noise actually lessen the signal or just muddy the reception? I get the out-of-range beeping from the unit all the time.

 

[jdbob]

PMR radio sounds like exactly what I need. I will look into it (maybe as FRS?). I do live in a forested, hilly area but not too much around the house.

Thanks everyone for the input, and any more ideas are welcome.

 

[(*steve*)]

I think a key question is: What has changed in the last 30 years to make the existing solution fail? If you don't get some handle on this, you may fall into the same hole again.

 

[jdbob]

I'm guessing that with all of the wireless devices in use now the FCC may have lowered the ceiling for transmitting power to the bare minimum for just in-house use. Another possibility is wimpy batteries. I've noticed that the batteries that come with a unit are far better than what you replace them with, even when you buy from the manufacturer.

 

[poor mystic]

I have heard that some of the microcontroller boards come with Zigbee, which could easily answer the OP's needs, even over quite great distances if desired. I'm sorry I don't have enough knowledge to fill in much more but Google Is Your Friend.

 

[(*steve*)]

Quite possible. What happened to the baby monitors from years ago?

 

[poor mystic]

No-one seems to know. (what happened to the baby monitors of yore)
Maybe there was too much information getting spilled all round the place about private lives, and The People went "urrk".

 

[davelectronic]

monitors

Hi again, baby monitors at best manage a few hundred meters or so, PMR in the UK is quiet, not alot of users i scan a great deal of frequecies with my scanner, the spec was for a rural area, so i was thinking not to built up. the sets of PMR have CTSS control over frequecy alocation in the radio set up, ie you can add sub frequencys on both radios, not sure how Busy the channels are in the US. Rural should be ok. And the US name mentioned sounds like the UK equivelent if i remember. 5K on a baby monitor !

 

[davelectronic]

Monitors

On my rubbish phone, only get 512 charecters. PMR should be ok, most sets like the link i left give over 300 frequecy combinations, interferance in arural area is unlikley, i have used them, there easy enough. i use CB to keep contact with me mum. but the PMR sets have the monitor setting, 0.5 watts rural will be good performance. a little expensive, but worth it, and again UHF offers very good performance.

 

[poor mystic]

If you could find a portable phone with a decent radius you'd be off to a good start. Then all you'd need would be a speakerphone to complete a simple 2-party telephone ciruit.
The speakerphone would provide hands-free bothway communications for that person for whom you care, while you would carry the portable.

 

[davelectronic]

Monitors

what a good idea apart from the possible call charges involved, if its normal phones on a network or supplier to pay the cost, what phons dont involve charges for call ? i want a couple. Dave.

 

[poor mystic]

no network charges on a telephone line that goes only between 2 points without involving the network

 

[davelectronic]

Monitors

Nothing i know of uses telephone with out charges being involved, maybe iam missing something, more detail and enlightenment would be good, if available, such a phone would be useful to me. Dave.

 

[poor mystic]

Enlightenment comes in some unique form to us all, Dave. See attachment - PSU can be anything from 5V - 50V, polarity not sensitive but should be high impedance supply.

In the application I suggest for the OP, one of the phones would be replaced with a speakerphone and the other with a portable.

 

[davelectronic]

monitors

Yes i know that idea, but your tied down by wire/cable, i had a feeling the radio operative was on the move in a rural area, might be wrong, in which case a fixed, or semi fixed installation would be fine. Dave.

 

[KJ6EAD]

The older baby monitors used 49.830 MHz. For a while there were some at 900MHz but the newer ones all seem to be 2.4GHz.

I don't think the FCC allows continuous transmission on either FRS or GMRS.