Portable Phone Frequencies

April 18, 2005 10:28 AM

What's the difference between the various frequency bands for portable phones? I wish to buy a portable phone / digital answering machine for my home (not a cellular phone), and have noticed they come in 900Mhz, 2.4Ghz and 5.8Ghz versions. Is there a difference between these that I should know about before buying a phone?
posted by jacquilynne to technology (18 comments total)

I tried googling this, but can't find an explanation amidst the advertisements and all the cellular stuff.
posted by jacquilynne at 10:29 AM on April 18, 2005

Higher number is longer range.
posted by duck at 10:38 AM on April 18, 2005

As I understand it, the basic difference between them is the range you get with them. I have one 900 Mhz and a couple 2.4 Ghz phones at home and the range difference between them is so big, I'm thinking of switching all of them to 5.8 Ghz.

On preview: duck beat me to it.
posted by Penks at 10:40 AM on April 18, 2005

These are the radio frequencies at which the cordless phones operate.

You would select the highest cordless phone frequency possible for better sound quality, and eliminate phones with frequencies that would interfere with other signals you might have in your home.

For example, 802.11b and 802.11g wireless networking operate on 2.4 GHz, while 802.11a wireless networking operates at 5.8 GHz.

If you have wireless networking, or plan to set up wireless networking in the future, to avoid interference you would purchase a phone with a different frequency.
posted by AlexReynolds at 10:40 AM on April 18, 2005

The range I'm looking for is basically something that'll cover the 4 and a half feet between my desk and my couch, and maybe occasionally make the leap about 8 feet to my kitchen, so I'm not sure range is a huge problem. But call quality and limiting static is important to me, and it sounds like the higher range phones are better for that, as well?
posted by jacquilynne at 10:57 AM on April 18, 2005

Yes...higher number means less interference from any cause (distance being the big one). It also means less intererence from walls, other devices and anything else.

Also, you may end up carrying the phone around more than you think. I take my phone down the basement of my building (to the laundry) or even outside on occassion. Also, you may at some point move somewhere where the distance from the couch to the kitchen is greater than the current distance. I would go for the 2.4 at least.
posted by duck at 11:00 AM on April 18, 2005

The higher the number, the higher the brain cancer risk. Or so some would have you believe.

Don't do 2.4GHz if you want wireless. There's just too much interference.

I read that 5.8GHz phones don't penetrate walls very well, which is exactly opposite what I expected.

I own 900MHz phones. They're cheap. I can place units around the house to cover all the range I need.
posted by five fresh fish at 11:14 AM on April 18, 2005

Don't do 2.4 GHz if any of your neighbors are going to want a wireless network. I've been on the receiving end of this and it stinks.
posted by alms at 11:26 AM on April 18, 2005

I am under the impression that the 5.8GHz phones do not penetrate walls with any reliability. My parents lucked out and got a 2.4GHz phone that does not interfere with their wi-fi, but I understand that's lucky, and is not something that should be counted on.

If I had to get a cordless phone, I would choose a 900MHz for the above reasons, plus, they're cheaper.
posted by schustafa at 11:42 AM on April 18, 2005

Yup, apparently, there's nothing special about 5.8 ghz phones. Mark @ BB has a favorite
posted by rschroed at 12:25 PM on April 18, 2005

To echo the others here: I would go with 900MHz for the phone, definitely - I'm cursing my 2.4GHz phone because I can only use the 54MBps mode of my 108MBps 802.11g WAP, and 5.8GHz isn't good because of wall penetration issues.

I've had plenty of 900MHz and 2.4GHz phones and have never noticed a significant difference.
posted by Ryvar at 1:33 PM on April 18, 2005

We have a wireless network at home and just purchased a Panasonic 5.8 ghz two line cordless (not from this store). We really like it. I'm surprised at the clarity and I can go a great distance outside (much beyond my property line) and it still works.

I am finding no problem with the connection going through walls (and we have a 50 year old house with lathe and plaster). The only down side to this system is you can only add 3 additional handsets.
posted by Taken Outtacontext at 2:45 PM on April 18, 2005

Don't do 2.4GHz if you want wireless. There's just too much interference.

Poppycock. Didn't affect my wireless network and the phone base and the wireless router are right next to each other. They can operate on different channels; the interference claim is just one more myth. Get spread spectrum technology for the longest range and least interference. I had a 2.4 GHz phone with this that took me a block away from home.
The replacement for that phone, a 5.8 GHz without spread spectrum but otherwise same manufacturer etc., seems a bit shy of that performance, but it was cheaper.
posted by caddis at 4:05 PM on April 18, 2005

So, the conclusion I draw from this thread is that I should buy 900Mhz, 2.4Ghz or 5.8 Ghz.
posted by jacquilynne at 7:00 PM on April 18, 2005

I think the 2.4 and 5.8 phones tend to have better range than 900 MHz. If that doesn't matter then the 900 MHz phones are definitely cheaper. Digital is better than analog and more secure, if that matters. Given that your range seems very short you may prefer to focus on price and features rather than frequency.
posted by caddis at 7:08 PM on April 18, 2005

Poppycock. Didn't affect my wireless network and the phone base and the wireless router are right next to each other. They can operate on different channels; the interference claim is just one more myth.

This is wrong. The further away one sideband is from the another, the less interference there will be. So, as in my case, if your 2.4GHz phone uses channel 1 (as is default for 2.4GHz phones), you get the least interference by using channel 11. My particular model of phone renders channels 1-6 completely unusable.

The reason I cannot use the 108Mbps feature on my WAP is because such WAPs use double the spectrum space, or basically the entire 802.11 frequency range. The phone takes up the entire lower half of available channels, and thus I am confined to using a standard single 54Mbps connection.
posted by Ryvar at 8:27 PM on April 18, 2005 [1 favorite]

I found that the 2.4 was much better than the 900. The only problem with the 2.4 was that I couldn't use it when running my microwave. I have a 5.8 now and it has worked flawlessly. Just as good or better than the 2.4 with no microwave interference and I haven't noticed any "wall penetration problems". I used both the 2.4 and the 5.8 with a wireless network and noticed no issues.

My vote is for the 5.8
posted by Carbolic at 8:39 PM on April 18, 2005

(1) Higher frequencies may go farther through free space than lower frequencies, but they are more easily stopped by dense objects. They are easily stopped by metalic or wet objects. 900MHz seems to go through just about everything. Cell phonse outside the US often run at 900 MHz, ATT/Cingular now support 800 MHz for their digital cell phones. Previously, it was reserved for analog cell phones (the analog network designers chose the frequency with the best penetrating capability)

(2) 802.11B and 802.11G operate at 2.4GHz, so that band is best to avoid for phones. It may not impact *your* 802.11 network, but if you are running 802.11 and a phone your neighbor will probably have trouble. Stay away from teh 2.4 GHz phones.

(3) 5.7-5.9 GHz phones seem to have the most features and work decently well in many situations. 900MHz phones are probably the best, but the marketing dudes seem to want to push 5.x GHz devices.
posted by b1tr0t at 12:42 AM on April 19, 2005