Author Topic: Packet Radio Q&A  (Read 849 times)

Offline SCWolverine

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Packet Radio Q&A
« on: February 20, 2018, 08:03:12 AM »
I (and other local hams) have some Packet Radio Questions. There are some that are more pressing than others and I'll ask them first:

1. Nodes vs. Digipeaters:

I understand the difference between the two.

I do not understand how to set up my TNC's (Kantronics KPC3 and /or TNC-x) to specifically act as either of the two.

My preference (for both units) is to establish them as Nodes to help build-out the local Packet Network.

In my searching, I cannot locate a clear path of direction for the settings needed to activate the above listed TNC's as a "Node".

2. SoundCard Packet

I'm having success with Sound Modem and EZ Term from UZ7HO for simple point to point packet operations (with my Signalink USB).

Again, I have a 'Node' question. I keep "hearing", but can't find, that a SoundCard Packet Modem cannot be used as a 'Node' in the Network. Any ideas if that's right or wrong-or how to make it happen?

I'm open to any and all additional Packet Radio Discussion too. Thanks!

Offline Smurf Hunter

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Re: Packet Radio Q&A
« Reply #1 on: February 20, 2018, 02:33:07 PM »
I have more experience with #2 so I'll start there.

In that context, you are using a KISS TNC (keep it simple silly).  There's not any brains beyond translating the RX audio into ASCII text and vice versa sending text over air as audio.
For applications like APRS and VHF Packet winlink, KISS is perfect.

In the olden days of packet, a TNC did much more.  They were almost mini-servers in a way. If you are familiar with dial-up modem BBS (bulletin board system) TNCs could actually store basic mail messages locally on the hardware. Think of it as a public bulletin board where people left notes for others. Additionally a full featured hardware TNC understood who it could talk to, and you could configure "routes".  e.g. Station A seeks contact with station D, and the TNC knows to forward A->B->C->D

In the above context, a "node" and "digipeater" attempted to solve the same problem of bridging the distance of out of range stations, but with many stations, digipeaters were inefficient. 3 people repeating everything is a little annoying, but 300 is chaos.

I recently got this AEA PK-232 TNC, and there's a decent explanation in the manual about how this came to be:
http://www.repeater-builder.com/aea/pk232/pk232mbx-operating-manual.pdf

See section 4.3.3.3

I hope others join in with more comments.

Offline SCWolverine

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Re: Packet Radio Q&A
« Reply #2 on: February 23, 2018, 05:56:45 AM »
Thanks!  (I just swapped a PK232 for a back-up repeater)

This Site and PDF/PP really helped it make even more sense! http://w9tca.com/w9tca/Files/Doc/Events/Meeting%20Presentations/Packet_Workshop_2012-02-18_with_notes.pdf

I just  realized yesterday, while going through the set-up notes linked above that a TNC could be both a Digi and a Node (as well as the other stuff) at the same time-or depending on how the other stations connected to it! That was quite freeing to get a hold of.

The Signalink question persist (can it be a node/digi) if anyone has info that direction (or maybe it's just the same as above).

FYIW: My current set-up is the Alinco 135 and a KPC3 (not plus). I also have a selection of Signalinks and Kenwood TM281's for soundcard packet.

Still Learning!

Offline Smurf Hunter

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Re: Packet Radio Q&A
« Reply #3 on: February 26, 2018, 03:07:58 PM »
I'm currently fabricating and testing out a home brew interface cable for my mono-band FT-2900.  There's not DIN jack, so I bought a 6 wire RJ-9 (like a phone cord but with more wires inside), cut that in half for the mic jack, and used a 1/8" audio cable (like aux in from smart phone to car stereo).  While the form factor is pretty large, and the power requirement a little high (it'll partially light up, but not function properly with < 1 amp), the AEA PK-323 is a full function TNC.  I got mine for free, and there's another free one at our EOC.  Hamfest have them < $50.

If I'm really ambitious I may integrate with a Raspi and run some old fashioned BBS online games like Red Dragon or maybe Zork.  There's enough packet (and nerds) in the great Seattle area for this to at least be a novelty for a short while.  I'll send updates if they happen :)


Offline Carl

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Re: Packet Radio Q&A
« Reply #4 on: February 26, 2018, 05:36:54 PM »
The PK232MBX has a built in mail box and while they need a bit of power,they are well built .