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Recently I was at one of the local fire stations doing some antenna system repairs and used one of our group's Kenwood TM-V71A based portable voice/packet stations for some tests. Our local packet group has a few of these portable voice and packet setups and they come in handy for a variety of uses.
As planned, once the repairs were done I fired the V71 up and ran some tests to several area repeaters via a spare dual-band VHF/UHF "ham radio" antenna we have up on the department's radio tower. Once that was done, I figured why not test some 9600 baud packet using this setup. This portable setup is preconfigured for voice and 9.6k packet, so just add a terminal or your favorite client software (Outpost, etc) and away you go.
The antenna is a Comet GP-3 dual-band antenna. It has about 3 dBd gain on VHF and about 5 dBd of gain on UHF. Not a high gain antenna by any means, but it offers low SWR over a wide bandwidth and is well suited for this usage. The Astron SS-30M power supply would normally be overkill for just the TM-V71 dual-band radio, but the extra amp capacity allows for adding a HF rig to the mix if needed.
In the video you will see the terminal pulling down a SATERN news bulletin that is about 9.2k in size and prints out as a 2.5 page document. The TM-V71 and PK-96 combo make quick work of it. The transfer took about 33 seconds and the AX.25 protocol ensures 100% accurate delivery. I was using a Windows 7 laptop running the WinPack terminal program for this test.
This particular BBS user port is set up with fairly conservative 9600 baud settings. This is done for channel sharing reasons and to accommodate some other end user radios in use that are not as fast as the Kenwood TM-V71 and TM-D710 radios. The port can run faster if needed.
This packet BBS is operated "RF only" 24x7 without depending upon the public internet or any IP based network for message transport. In today's EMCOMM world, the value of such a independent "backup" messaging system should be increasingly obvious.
Yeah in our multimegabit IP connected world, 9600 baud may sound too slow. That is till those nice high speed networks fail, overload, suffer physical infrastructure damage, come under cyberattack, etc etc. Plus practice has shown than most real world EMCOMM messaging needs will involve message sizes easily handled by a 9600 baud packet link.
For the ham radio EMCOMM folks, allow me to leave you with some food for thought...
How long would it take you to send that message over a "voice" net and with 100% accuracy?
What if those pages are chock full of complex words like medical terms/names?
What if you needed to send dozens of these messages? Hour after hour? Day after day?
A 9600 baud digital system sounds a lot better now eh?
