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Desktop Computer 12vdc Conversion for Telpac and a Portable Airmail Station in a Box

By: Edward R. Breneiser, WA3WSJ

Berks County, PA ARES/RACES AEC

Don’t throw those older desktop computers away! Yes those old Pentium-M, Celeron or full power P4 systems can still be used in your ARES/RACES Group. I’m an AEC for the Berks County, PA ARES/RACES Group and we recently have been trying to build some WL2K infrastructure here in Berks County, Pennsylvania. I started reading all about WL2K and then decided that I would like to try to put a WL2K Telpac Gateway Station on the air 24/7 here in Berks County, Pennsylvania. The first thing I did was to ask our ARRL EPA ASEC what frequency I should use as to coordinate with the rest of the ARRL EPA Section. I was informed that I should use 145.770mhz and try to put my Telpac Gateway on the air 24/7 with battery backup. Maybe you’re now asking yourself, “ what the heck is a telpac station?” A telpac gateway is used by the WL2K Network to pass Emcomm email. It does this by using 2M packet and Emcomm software to take information and distribute it to the internet. To read more about WL2K, please look at http://www.winlink.org. Now I need to figure out all the pieces to make a telpac gateway work. Let’s see I need a 2M rig, antenna, TNC, computer, 12vdc power supply, battery , DSL service and some software. All this “stuff” has to work together and then I’ll have my telpac on the air for Emcomm. First thing I did was to send out a few emails to different internet reflectors asking if anyone had any of these items. Well, I was given a nice Hustler 2m Base station antenna, and an Astron RS-20A Power Supply. I purchased a Kantronics KPC-3+ TNC for around $190 and a used Yaesu FT-2600M Radio for $100.

Next I purchased a West Mountain Radio Super PWRgate PG40S for around $120. This nifty device automatically switches from my 12vdc power supply to a 12V/35AH Battery and provides a safe charge to the battery

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I later needed way to connect all these devices so I bought a bunch of 15A Anderson Power Pole Connectors to wire up everything and a West Mountain RIGrunner 4005 DC Power Panel with five outlets and 40A capability for around $65.00 I now need a computer. To eBay I go and find a Dell Desktop GX150. It has two com ports and a bunch of USB ports. It also has Windows XP and some internet software on it and 1G of RAM. Not to bad for $50.00! Let’s see I need some WL2K Software to run the telpac so I download Telpac from the WL2K Website for free! Please note, the Telpac Software now in use will be replaced by RMS Packet. RMS Packet is now in the beta-testing phase, but will probably be released before this article goes to print. The WL2K Network is also changing as I write this piece. The PMBOs or Post Office Mail Box will be taken out of the system soon. Instead of connecting to a PMBO and then a CMS or common message server, the user soon will go directly to a CMS. This eliminates the PBMO and speeds things up. To make a long story short, I wire everything up and it actually works! Here’s the kicker – I only know it works by others sending emails through it as I don’t have a portable Airmail station etc. So now I decide it’s time to build a WL2K VHF Portable Airmail Station. Again I make a list of what components I need to make this station. I need a 2m radio, laptop, TNC and a case to house all these parts. Again I send out a message on a few internet reflectors and snag another Yaesu FT-2600M for $40.00! I like this rig because of its solid construction, 60W capability and it has a connector on the back to connect a TNC. The external TNC port really is a nice feature. As for the TNC, I buy another Kantronics KPC-3+ as they easily work with all my WL2K gear setups etc.

Home Depot has cases that look like they will fit the bill so I buy one and start mounting the 2M radio and KPC-3+ to the lid. I also buy a white Formica-covered wooden board from Home Depot and cut it to fit inside the case. This acts as a self to put the laptop on when in use and I can still store gear beneath it on the bottom of the case. All looks good, but will it work? Not yet because I now need some software to run the Airmail station. I go to the WL2K Website and then to the Airmail Website and download the needed Airmail

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Software. Airmail is a wonderful program, works great and has an easy learning curve. I now need to power my portable Airmail station so I install a chassis-mounted Anderson Power Pole Connector on the rear of the case. This way I can just plug in my power source be it battery, AC power supply etc. I usually take an Astron 40A switching supply with me to drills, but also use a 12V battery when needed in the field. The rear plug feature allows me to use any 12v power source. I just unplug one and plug the other source into the case. Once the portable Airmail station is operating, I test it using my WA3WSJ-10 Telpac. After a short learning curve with the Airmail Software – it works. I’m actually sending emails to my EC and to myself using one of my email accounts. Now it's time for the acid test. I install the portable Airmail station in my truck and go mobile. I can’t believe it- I’m sending and receiving emails from my truck through my WA3WSJ-10 Telpac Gateway! Once I had WA3WSJ-10 Telpac on the air, I left it run to see what would happen after a few weeks. It worked fine, but every time my home lost power the computer just died. I had two choices concerning the computer. I could plug it into a large UPS unit or convert it to a 12VDC input computer. This is where the Brits come to the rescue. Peter, G8HAV, saw one of my emails and emailed me on how he had converted a Dell desktop computer to 12VDC input and included pictures. His pictures and story seem great so I follow his lead. No need to reinvent the wheel here –hi! This is just what I need so we exchange a few emails and I find myself buying a nifty little DC –DC converter for my desktop computer. I purchase a M2-ATX 160W Automotive PSU from Short-Circuit.com for around $90.00. Yes it costs more than the desktop! This board runs the entire desktop and connects to the same plug on the motherboard where the 110v power supply DC output had made connection. Yes you disconnect the original 20-pin Molex plug and plug in the supplied cable attached to the new DC-DC Converter Supply. I also just bolted the new supply to the rear of the desktop with two bolts and nuts. I then needed to connect my hard drive and the DVD drive. The supplied power cable only has one plug so I go to Radio Shack and buy a Y-Adapter power cable. This does the trick and all is now wired and looks great. The entire conversion took me around an hour – very easy!

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Again I connect all and it works! I’m now a happy camper. I then let the telpac gateway just run to see what will happen for a few weeks. I now have the 2m radio, TNC and computer on my battery backup system. Now when I lose house power my DSL modem and wireless router go belly up! I decide to just buy a small APC UPS Unit ( $50) to backup both of them as they draw a small amount power. Problem solved as both the DSL modem and the wireless router just “keep on

ticking” when I unplug the power cord to the UPS unit. Let’s see what I have invested in my WA3WSJ-10 Telpac to date. So far I have spent close to $700 on my telpac station, but I did manage to grab a few items for free. If I had to purchase all the items new, count on spending around $1,000 or more for a nice telpac station that will run 24/7 with a battery backup system. This project as been a real learning experience. When I started this project, I knew nothing about WL2K. The first thing anyone should do is to educate yourself about WL2K. Read what it is all about, read about the software, read, read and read! Most importantly, ask questions and get help when you’re racking your brain about an issue. Oh yes, you probably will be straining that brain as things don’t always go as planned, but help is usually close at hand even if it’s “across the pond” – hi! Also subscribe to the various internet-related WL2K reflectors as these really helped me out with my software problems, equipment and general guidance.

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WA3WSJ-10 Telpac Power and Battery Back-Up System

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WA3WSJ’s 2M Portable Airmal Setup Here are a few great internet WL2K-related reflectors to subscribe to: http://groups.yahoo.com/group/wl2kemcomm/ http://groups.yahoo.com/group/airmail2000/ http://groups.yahoo.com/group/PaclinkMP/ http://groups.yahoo.com/group/RMSBeta/ http://groups.yahoo.com/group/LOADING_WL2K_USER_PROGRAMS/ http://groups.yahoo.com/group/mars_wl2k/ http://groups.yahoo.com/group/CanadianWinlink/