VE3NCQ

Chatham now has its very first EchoLink node available over the air. Sponsored by VE3NCQ, this node, number 309497 is available for use by any amateur operator within range. Local hams are encouraged to scan and monitor this node – you never know when a QSO will connect, so let’s make sure the world finds some activity in Chatham-Kent.

When using the 2 meter access on 147.420, you do NOT have to be registered with EchoLink to use this service! You do NOT need an internet connection. It does not cost anything. All you need is the node number of the user you want to connect with (which is of course available online at www.echolink.org ), or simply reply to anybody that opens the link remotely. There are some shortcuts listed below, and frequently used nodes can be programmed into the system with shortcut access. Up to 10 different nodes can be connected at the same time for a mini-conference – this can be expanded by using one of the over 200 conference nodes (similar to IRLP reflectors).

Currently, the radio is set to 147.420 simplex, but this is subject to change. (The antenna works better 1 MHz lower.) If required for special circumstances, this could be temporarily retuned to the VE3KCR repeater on 147.120+ to create a wide-area link. All access codes are DTMF (touch tone).

EchoLink Etiquette

• LISTEN before keying up or entering DTMF commands
• IDENTIFY your station before invoking commands
• enter 08 to find out if link is connected to someone already
• don’t disconnect a connected link unless the other parties are finished
• remember this is a Simplex Node, not a repeater. There could be a distant station using the link that you can’t hear.
• keep transmissions short. There is a 200 second timeout.
• allow a slight delay after keying up before speaking
• leave extra space between transmissions to account for packet delays
• Don’t key up rapid-fire after an internet transmission (like I do), the RX won’t trigger for 1 second and you’ll be talking to yourself
• close the link when finished (using #, or ##), and identify your station as clear
• RESPECT the system. All connections will display my callsign to the remote system.

The station consists of an ICOM IC-230 which I modified to provide a carrier operated squelch signal along with all the other interface signals required. I built the radio interface board using spare parts, including relays and transformers salvaged from a pair of modems which were blown up by lightning. The whole thing is connected to my webserver (which hosts about 50 domains including this one) where the EchoLink software is running. The connection uses 2 of the USB ports – one controls the radio interface though a USB to Serial converter, and the other provides +5 volts to the interface board to drive the transmit relay transistor. (The same lightning strike which blew up the modems wiped out two DSL modems, three routers, the parallel port and both serial ports on the webserver, which is why the USB converter is needed.)

The sound card is a Sound Blaster AWE32 which uses the line in and out jacks. Audio is connected to the radio through the pair of phone modem transformers for isolation. The computer receives audio directly from the radio discriminator, and the line-out feeds the radio accessory audio input.

The antenna is the home-brew one detailed on the home page. The SWR curve was steeper than NEC4WIN95 predicted, but the resonance was bang on. Predicted gain is over 7 dB, and preliminary tests, using 10 watts feeding 50 feet of RG-213 with the antenna 10 feet off the ground confirm a nice low angle of radiation. Once the antenna is raised to its final position at 30 feet, with full 60 watts, most of Chatham-Kent should have mobile coverage, including the 401 from Tilbury to Ridgetown. It already covers the city of Chatham for those using an HT, and any type of base station or beam should gain access across Chatham-Kent.

I would welcome all feedback about this link. Where does it work from, or where is it inaccessible? Does the frequency cause interference to other users or services? Would another frequency be better? Were any problems encountered? (On occasion, the computer has failed to respond to an incoming signal, but changing to the CTS pin seems to have solved that. Also, the intermod problem seems to be cleared up since I tightened up the front end, which also boosted the received signals.)

Watch for new features and functions to be added to the system. I have obtained the SDK (Software Developer’s Kit) with API, so I intend to do some of my own programming and add custom functions over the coming weeks. I have already programmed a courtesy tone at the end of local transmissions, and am working on some DTMF shortcuts and atomic clock time beacon. There are also plans to mirror the output to a transmitter on the 902 MHz band which will repeat both local and remote signals from 147.420, and allow full duplex to take advantage of some of the exciting HF nodes that are available.

Please enjoy using this link!

Echolink Mobile Coverage Map (approximate, using 20 watts into external whip)