INTERNET PHONE - Ham Radio on the Leading edge
By Ben Gelb and Bill Meara
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This article originally appeared in 1997 in "The Leading Edge," the annual technical journal of the
Vienna Wireless Society
On the morning of Saturday, October 25, 1997 Vienna Wireless Society member Ben Gelb, KF4KJQ, was sitting in his Vienna, Virginia living room with his trusty 2 meter HT. Suddenly, the squelch crackled and a call came in from fellow club member Bill Meara, N2CQR. This might seem like a very routine 2 meter contact, but there was something very different about it. Armed with only a feeble HT, N2CQR is normally out of simplex range for Vienna and can't even key the VWS club repeater. On this particular morning, these two stations were communicating with the help of a new, "leading edge" communications technology: Internet Phone.
I-Phone came onto the scene in 1995. An Israeli company called VOCALTEC developed a software package that would allow users to send their voices down the internet's fiber-optic pipelines. While the Internet had until recently been limited to carrying packets made up of text, the ever-expanding speed and bandwith available on the net opened up the possibility of sending audio and video down the pipeline.
While the cicuitry is complex almost beyond comprehension, the principles are easy to understand. When one I-phone user speaks into a microphone connected to his home computer, the I-phone program takes the audio signal, digitizes it (converts it into a series of numbers in digital form), organizes these numbers into packets (similar to those of packet radio) and sends these packets to the receiving computer via the internet. At the other end, the receiving computer assembles the packets, and converts the digital numbers back into an analog AF signal that drives the computer speakers. And this all happens so fast that it appears to be instantaneous.
Hams have carved out a place for themselves in the cyberspace world of I-phone. The I-Phone world is divided up into topic groups. When you log on, you can specify that you are only interested in the ham radio groups. In the ham radio topic groups the user is greated by a form of electronic bulletin board showing the callsigns of users who are currently on the system. Two clicks on the mouse and your computer will be calling the other station. The I-phone software then establishes a cyberspace pathway to the other station and you can begin to QSO. Old Timers will be pleased to learn that our ham radio traditions have been carried into the new world of cyberspace. Even though there is absolutely no need to do so, hams in this system very frequently use their callsigns when turning the conversation over to the other fellow. There is the same kind of friendly "rag chew" culture that you find on the "real" ham bands. And our beloved "73" prosign is definitely in use on the new I- Phone "band."
The opportunities for DX rag-chewing are just mind blowing. Imagine shooting the breeze with the VK's and the JA's to your heart's content. No QSB. No QRM.
I know that some will argue that this "isn't really radio" and in a sense they are correct. Its not really quite the same as bouncing signals off the ionosphere. But the Internet and Internet phone provide us with exciting new options that will greatly enhance our enjoyment of the radio hobby. Ben's Saturday morning QSO from his living room provides one example of what can be done.
Here's how that QSO worked. (See diagram). In order to connect I-Phone to his 2 meter base station gear, Ben needed a circuit that would allow the audio from his computer's Soundblaster card to trigger the Push to talk on his transceiver. We built a little VOX circuit around a six dollar kit from Ramsey electronics. Audio out from the computer went to this little "VOX BOX". Ouput from this VOX consisted of one line carrying the audio signal and a PTT line to key the transmitter. Ben also connected the audio out from his transciever directly into the mike input of his computer's Soundblster card. I-phone has its own internal VOX circuit so we didn't have to worry about VOX for the audio signal going from Ben's base station 2 meter rig to the computer.
Before leaving his shack and going to his living room, Ben logged onto the I-phone system. In essence, he put his callsign up on the bulletin board (along with a note saying that callers would be transmitting on 14X.XXX). His Base station transceiver and his HT were placed on the same simplex frequency. Sitting in front of my computer in Falls Church, I saw Ben's call appear on the I-Phone bulletin board. When I clicked my mouse on his callsign, a packet pathway was established between our two computers. When I said "KF4KJQ this is N2CQR" my words were digitized and pecketized and sent via the internet to Ben's computer, where they tripped the VOX box and modulated his base station transceiver. Ben heard my call on his HT and replied. Thus we established the historic "First I-phone - two meter link" between Vienna and Falls Church! Marconi - eat your heart out!
Now of course Falls Church to Vienna is not exactly great DX, but distance is largely irrelevant on the internet. We knew the system would work for calls coming in from anywhere on the globe. After that first QSO, Bill decided to see if he could get some DX stations to call Ben. Sitting at the computer and consulting the bulletin board, he notice that Brian, VK3EO was on the system. Bill gave him a call and explained that Ben was standing by in his living room with HT in hand. Brian agreed to give him a shout. Within minutes, the squelch on Ben's HT crackled again, this time with a call from the other side of the world! As they say in the computer world: "Cool!"
As Ben's QSO with Australia demonstrate, connections to the Intenet open up a world of fantastic opportunity for our VHF and UHF bands. For example, repeater's around the world are being linked to the I-phone system. Sitting in the comfort of your own home, you can now easily participate in the afternoon drive-time two meter net in Johannesburg or Sydney. Using the system described above, Ben could have put the Vienna Wireless Society two meter repeater into the I-phone system simply by putting his base station rig on the repeater frequencies.
I-Phone has some applications that should be of special interest to our club. In part because of our Washington area QTH, we have members whose work responsibilities have carried (or will carry) them far from Vienna. I-Phone can help them keep in touch. We have some members who've retired to Florida. There is no reason why we couldn't set up a system through which they could access our club repeaters from sunny Florida. Nick and Krishna could key the repeaters from the U.K. and India! And this link to the outside world would be of obvious benefit to our Vienna Emergency net...
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