walkie-talkie use within city limits

It depends on so many factor, like how many other people are using the same channel.

Is it reliable? In the open countryside, maybe, in the city, no, in the Antartic, probably yes

martin

Do you mean handie-talkies, like you get a pair of at Radio Shack? Then, probably not.

But if you're talking about those newfangled cell phone thingamabobs with a simulated walkie-talkie feature, then probably yes. (at least, according to the TeeVee ad.) ;-)

Good Luck! Rich

So when are we going to get WiFi enabled mobile phones that can use Skype when they latch onto an open network?

Walkie-talkies vary in quality. Some of them are no better than toys. To get 1-2 miles in the city with obstructions you need a quality device like one of the handie-talkies marketed to ham radio enthusiasts, but for that you would need a license. For unlicensed use, there are handie talkies like the ones you find in motorcycle accessory catalogs for communicating on rides. I've never used them, but a quarter mile sounds do-able, at least out in the open. Going inside buildings makes it more difficult of course. It depends on the power and sensitivity of the devices, and the frequency. And you get what you pay for.

Aren't cell phones a lot cheaper than walkie talkies these days?

Not here (UK) I've seen them as low as $8 a pair.

But the walkie talkies can be used where there is no cellular coverage.

I use the Motorola Walkabout and get at least two miles with when there aren't any significant obstacles. These were over $100 each several years ago. I gave the grandchildren each a Uniden (I think about $40 for a pair) and they seem to work almost as well, but aren't as hardy and they use dry batteries.

City coverage is mixed, sometimes very good, sometimes very poor.

Don

You can already do that with Windows Mobile phones and, I would guess, Palm OS-powered phones.

That being said, Skype is a great example of where a drop in quality is acceptable when the price is right (free).

This is not a design issue unless you are griping about the workings of the walkie talkies.

Michael

Or unless you wish to talk about politics, war, wine, sex, food, etc.

Don

Drop in quality?! Surely you are joking? Listen to this test recording I made.

That recording is of a one-ended (broadcast?) conversation, not of a conversation of two people, each on one end of a circuit. As such, what is missing is the time delay between the time a sound is uttered and the time it would be coded, sent, and then received at the other end of the circuit.

Your recording does not contain the echo that exists on low bit-rate encoded systems. If you have ever experienced a Network echo-canceller failure on a cellphone call you will know how badly the call is degraded.

The free part of Skype is good; the quality is fair, but not as good as the Public network 56/64 kbit/s coded calls.

Don

The combo FRS/GMRS are pretty cheap these days. You are supposed to buy the $75 FCC license to use GMRS. There is a real big foul up by the FCC and companies selling these things. GMRS will let it opperate on the GMRS channels at the maximum power. Some of these have 4-5 watts which is pretty good for getting through some buildings. At 460 mHz the penetration is fair. Cell phones at the higher freqs will penetrate further. Walkie-talkie cell phones are simly simplex rather than duplex saving channel space.

greg

That was a recording of me in Bedford, talking to Russell in Norwich in real time, both of us on Skype.

I should add that at my end I use a 3 yr old AMD XP2400+ processor with

Nice, but my main point was that Skype doesn't provide any guarantee level of service, whereas a regular POTS connection very much does (and a cell phone connection is maybe somewhere inbetween... hard to say...). If it works for you (and it certainly does work for many people), great, but it's not the kind of thing I'd want to run a business off of -- every now and again the conversation does "stutter," drop-out, etc.

For free I'm certainly not complaining, though.

There is no low bit-rate coding in that conversation.

I recorded to wave and encoded at 128kb MP3

Ok, but that isn't relevant to the issue of the effects of low bit-rate coding in telecommunications. The recorded end-to-end conversation was not low bit-rate coded (common voip).