Ham Comms

I envision a ham radio network. Many to one, one to many, many to many and one to one. Voice, text, video. The ultimate communications medium. And it’s entirely possible.

Hams have a great deal in Canada. We are un-encumbered with restrictions that choke hams in other countries. This gives us a unique edge on ham technology compared to many other countries around the world. And we should take advantage.

Thoughts?

 

Echolink and APRS – EchoAPRS

Well. I’ve been looking at several ways to make a linked radio system without anyone spending a lot of money. Echolink seems to be ideal. APRS would be very useful for finding active NODEs. Some changes – or rather conventions – need to be in place.

  • All DTMF access codes must be identical.
  • Each repeater or link must beacon its position on APRS
    • OUTfrequency ( O:147.120)
    • INfreq (I:147.720) (IN and OUT will be the same for a simplex NODE)
    • PL tone (T:100 {“0” if no PL})
    • Prefix (P** {“0” if no prefix})
    • Current NODE connection (N:217613 {“0” if not connected})
    • A typical status would be: VE3KCR-1>WIDE1-1,WIDE2-1:=4200.0N/08300.0W ECAP O:147.120 I:147.720 T:100 P:0 N:0
  • Repeaters should mention their NODE number (and optionally the prefix) when IDing.

These 3 things need to be done to make the system viable and popular. And these things are easily done.

DTMF

The DTMF codes all need to have the same prefix and structure. And let’s trim the common commands down to this:

  • Connect – # node
  • Disconnect Last – 73
  • Disconnect All – ##
  • Reconnect – 69
  • Status – 411
  • Play Info – 611

As long as these commands are the same on EVERY repeater, Echolink is usable anywhere there is a NODE. Many systems are EchoIRLP and should use prefix “A” for Echolink and “B” for IRLP. Others use “*” or “**” due to various hardware configurations. The prefix can be squawked in the APRS beacon and announced in the ID.

APRS

Since an Echolink station needs to have internet to be a NODE, the station can also run APRSIS32 (or similar) software to act as an APRS beacon for the Echolink station. This way, approaching stations can determine their range to the NODE.

ID

It should be very simple for a NODE radio to ID the NODE# and any other information an approaching user may need to make a connection. Easily done with EchoStation software. This way, even a user without APRS can get the information.

Notes

These simple constructs would allow Echolink use the the most usability and flexibility possible. Currently, it’s nearly impossible to use someone else’s -L or -R (when travelling) due to the many connection variables. If these were made known in real time when a user is in the area, it would be a huge boon for Echolink.

 

EchoIRLP

To those that don’t know what IRLP and Echolink are, here’s a brief(ish) explanation. They are both ways to link repeaters but they have significant differences.

IRLP (Internet Radio Linking Project)

Remote IRLP nodes (generally repeaters) are accessed from your local node (generally a repeater) by entering a 4 digit DTMF code. Some nodes require a “prefix” often an asterisk ‘*’ or pound ‘#’ although some use ABC or D and some don’t use ANY prefix. Our local node requires TWO asterisks due to technical issues mostly.

Other connection options include “reflectors” which allow several nodes to be connected together – like a party line 🙂 Some reflectors have 50 or more connected repeaters and some only have two or three.

Echolink

Echolink is a bit more flexible. Echolink nodes can be accessed through RF nodes (either a repeater or a simplex channel) like IRLP but also via a computer or smart device – cell phone or tablet. You can also start up your own Echolink node by downloading the software for free and using a link radio pointed to either a simplex channel or a repeater. Nodes can also be connected to “conferences” (like an IRLP reflector).

To use an RF node you enter a 5 or 6 digit DTMF code exactly like IRLP – often with a prefix as well. To access a node through a computer (or smart device), you’re given a list of available active nodes to choose from (this list is very big). The nice thing about using Echolink via a smart device/computer is you can access your local Echolink node from anywhere in the world where there is internet access!

EchoIRLP

Some repeaters have both IRLP AND Echolink available. To initiate an IRLP call, one enters a prefix and the node number and to initiate an Echolink call, one enters a different prefix before the node number. This is so the node computer can distinguish between the two.

Summary

  • IRLP can be accessed by RF (radio) only.
  • IRLP uses special hardware/software (proprietary)
  • Echolink can be accessed through RF links or computers/smartphones using free software.
  • Echolink uses free Windows® software for both user and sysop nodes.
  • For the most part, IRLP nodes can only be accessed by other IRLP nodes and Echolink nodes can only be accessed by other Echolink nodes. There are some “gateway” reflectors/conferences that accept connections from both.
  • Both systems use DTMF codes to link. IRLP generally uses “73” to unlink. Echolink nodes often use “73” although they often use something else.

Hope that helps 🙂

EchoStation

I was looking for announcement software for the 146.680 repeater. I currently have EchoLink running on my desktop and connected to my radio. This seems to work quite well but, there is no way to make EchoLink do announcements. So, after looking up EchoStation, and actually trying it out, I paid the big dollars ($19) because it is one of the few pieces of HAM software that actually WORKS! Yep, easy to set up, easy to use, etc.

Then I discovered that it’s a bit limited in to what it can announce – only static announcements! Jeez, I need it to announce the time and stuff and there was no way it would do this. I discovered that it uses separate .txt files to hold the announcements in. SO, I fired up VB6 and made a form and some timers and PRESTO. It now does: current time, weather, weather alerts, club announcements, random stuff at 1/4 hours and more. And, it’s only “slightly” cumbersome.

Since EchoStation is $19, I figure I can charge $5 for my add-on and maybe make a little cash. I do use EchoStation as a DTMF decoder (that beats the module I was going to buy for $127) so that’s a savings of over $100. And EchoStation also includes an “auto patch” (make phone calls over the repeater) feature so that’s a nice bonus. All in all, a pretty good deal.

DB9 to USB

It turns out there is such a thing as a DB9 (male) to USB serial adapter. And, I have a couple DB9 female connectors that I bought at a yard sale for 50 cents each that will work out quite well. The adapters work out to about $6 each on the eBay which isn’t bad I suppose. Also, I’ve decided to use RG59 coax (cheap stuff) as audio cables. That should provide enough shielding against all the stray RF in the shack to not add much noise to the audio signals from radio to computer. Hopefully. As well, I’ll make a small circuit to handle audio (600:600 transformers) and PTT (either a relay or 2N25 opto-coupler). As well as being more reliable and better sounding, I don’t want to blow up any more USB adapters.

Good thing this is all coming out of my “experimenting budget”. Lol. The first EchoLink/V71a cable didn’t work out as planned really (the audio sounded “strange” and “echo-ie” although it would have been ok for digital stuff) but, it also cost nearly anything as I had most parts just lying around anyway. Once I do get it all sorted out, the next cables/cost will be finalized.

Having said that, I’m just going to hook up the Azden PCS-3000 as the EchoLink radio anyway so its basically a moot point at this stage. I’m also placing its antenna where it won’t interfere so much with my main radio setup. That is, fairly close to the ground with my TV tower sort of shielding it from the main setup.

To summarize:

  • build a PTT circuit
  • build a 600:600 transformer board
  • use RG59 coax as audio cables
  • use a DB9 to USB adapter (or possibly the UART boards alone)
  • hook up the Azden PCS-3000
  • move the antenna

Now, if I only had a robot cable-to-connector solderer/assembler….

 

Kenwood V71a to Computer Cable

After seeing how much Kenwood wants for their EchoLink cable SET (that’s right, two cables), I did some investigation. Are you kidding me Kenwood? Anywhere from $50 to $80! It does come with two cables (one for audio IN/OUT, and one for the RST, PTT and all the other data – which I don’t need). Since I’m using EchoLink in VOX mode, I have no reason to use the RST. OK, down to ONE cable? Can I purchase this one cable separately? No, I can not. Is the audio IN/OUT/PTT available at the 6-pin (essentially a PS/2) back-of-radio connector? Yes it is! So, now down to ONE cable. Does the Kenwood cable containing the audio have a PTT line? NO! It’s in the other cable! Oh Kenwood. Now I’m back to TWO cables. Confused? So was I.

Then I came across this website: http://planetkris.com/2009/05/setting-up-a-kenwood-tm-v71a-for-aprs/ Finally, I now know which pin is which. Kenwood doesn’t make this crystal clear do they? Just buy the cables! HAH!

Oh ya. THAT’S what I need alright. Audio IN/OUT and a PTT line – all with one cable. Also, there’s a COS line (SQC – pretty sure – I’ll bring it out anyway) that could also be utilized. So, off to the eBay. I bought some of these parts in quantity (like, 5 or 10 of each) so your mileage may vary but, here is the price breakdown:

  • $4.17 UART (serial to USB) (btw, you’d need something like this for the Kenwood cables anyway as they use a standard DB9 serial connection and unless you’re using a 10 year old computer, you probably only have USB ports – yet another Kenwood oversight)
  • $2.12 for two 1/8″ stereo plugs (only if you don’t have adapters and stuff for the audio cables – I didn’t)
  • $2.60 PS/2 plug (you can hack a PS/2 keyboard connector apart but for $2.60, phhtt, new ones)
  • $2.00 audio cable (from Goodwill)

Total, $10.89 (and a month of waiting for China). Now that’s more like it. I also had a couple of USB audio cards that I bought on eBay earlier for $2 each. I got a 4-port USB hub at the Dollarama for $3. This way, I can use just one USB port on my computer for the whole shooting match. Pretty slick eh? You can use 2 USB ports if you desire though to reduce costs.

Hopefully I can get the soldering iron out today and wire this up. I might even take pictures!

 


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