Friday, October 31, 2014

FLDIGI/Digital Modes Introduction and Training on November 22nd

Mark your calendars for November 22nd.  From 12:00 noon until 4:30 PM at the Hardesty Regional Library, the TDRC will be conducting an in-depth training session of the FLDIGI software package with a general review of digital modes including:

PSK (including BPSK, QPSK, PSKR)
Feld Hell

Recent tests with PSK on 40m have confirmed 80 mile NVIS contacts with power budgets of as little as 5 watts, making it an excellent narrow-band mode for messages of all types.

There will be hands-on training on the FLDIGI software, along with some demonstrations of its capabilities for messaging and file transfer.  We will cover from hardware setup, initial software setup, all the way through good operating practices.

To provide the best learning experience for participants, we have limited the training session to no more than 25 attendees.  Please RSVP ASAP to to reserve your spot.

Halloween + APRS

Decided to take my Yaesu VX-8GR for a walk tonight for Halloween with my daughter.  Here's what the path looked like.  All of the packets were transferred to the internet via my Igate at the house, which was convenient for making sure they were received!  The VX-8GR is a good little APRS HT that doesn't have all the bells and whistles of the Kenwood TH-D72, but also is not nearly as expensive.

Thursday, October 23, 2014

What is KISS? What software uses KISS?


Here's some quick info straight from Wikipedia:

KISS is a protocol for communicating with a serial terminal node controller (TNC) device used for amateur radio. This allows the TNC to combine more features into a single device and standardizes communications. KISS was developed by Mike Chepponis and Phil Karn to allow transmission of AX.25 packet radio frames containing IP packets over an asynchronous serial link, for use with the KA9Q NOS program.[1]

Basically KISS eliminates the old "CMD:" prompt that we all grew fond of in the 1980s and 1990s on packet radio.

An article from 1987 by Phil Karn and Mike Chepponis introduces it by stating:

Standard TNC software was written with human users in mind; unfortunately, commands and responses well suited for human use are ill-adapted for host computer use, and vice versa. This is especially true for multi-user servers such as bulletin boards which must multiplex data from several network connections across a single host/TNC link. In addition, experimentation with new link level protocols is greatly hampered because there may very well be no way at all to generate or receive frames in the desired format without reprogramming the TNC.
The KISS TNC solves these problems by eliminating as much as possible from the TNC software, giving the attached host complete control over and access to the contents of the HDLC frames transmitted and received over the air. This is central to the KISS philosophy: the host software should have control over all TNC functions at the lowest possible level.
The AX.25 protocol is removed entirely from the TNC, as are all command interpreters and the like. The TNC simply converts between synchronous HDLC, spoken on the full- or half-duplex radio channel, and a special asynchronous, full duplex frame format spoken on the host/TNC link. Every frame received on the HDLC link is passed intact to the host once it has been translated to the asynchronous format; likewise, asynchronous frames from the host are transmitted on the radio channel once they have been converted to HDLC format.
Of course, this means that the bulk of AX.25 (or another protocol) must now be implemented on the host system. This is acceptable, however, considering the greatly increased flexibility and reduced overall complexity that comes from allowing the protocol to reside on the same machine with the applications to which it is closely coupled.


KISS quickly became the standard, and even was used by soundcard and other software to simulate a TNC.


AGWPE (Packet)
D-RATS (D-STAR "super" messaging and file transfer)
BPQ32 (Packet switch, messaging, chat, and APRS)
Winlink2000/RMS Express (message handling)

WINAPRS (Old APRS program)
UiView (Old APRS program)

So, as you can see, literally a whole new world of functionality has been opened by providing the "KISS" Port in FLDIGI.

Results of Wednesday evening Testing of PSK31

The good news was that our Claremore station (KC5SHE) was able to get his soundcard interface to work with his radio.  The bad news is our 0.5 watt operator (KD5NJR) was unable to participate because of commitments to his church that evening.

We proceeded with testing at the higher 5 watt power level.  PSK-250 was easy to copy.  Both signal strengths were reading S9 at the end points (28 miles apart).  S/N ratio according to the FLDIGI software was 28-30 db.  I have been able to decode below 5 db on S/N ratio, but that usually with somewhere between 20-30% bad characters.  From 10 db on upwards, copy is very good and only the occasional character may get lost.  So the testing indicates we are a good 18 db above a reasonable cutoff point.

It is worth noting that the testing was conducted the evening after a fairly significant solar storm, so band conditions were fairly unfavorable.

Hopefully we will have additional lower power test data to share over the next few days from KD5NJR for comparison purposes.

All in all, this continues to validate the concept of using groundwave/NVIS on 30m or 40m to establish a network of PSK nodes, with minimal power required at each.

Monday, October 20, 2014

FLDIGI now supports KISS

The TDRC was extensively involved in the testing of the beta version of FLDIGI from May of this year until now.  One of the neat features that we tested was a KISS port on the FLDIGI software.  KISS is the protocol typically used by TNCs and soundmodem software to interface with packages such as UIVIEW, WINAPRS, etc.  Even the D-RATS software that is normally used on D-star has the ability to interface with KISS modems (either through a COM port or telnet port).

This is an incredible breakthrough for FLDIGI, as it opens up its use for APRS, conventional keyboard to keyboard packet, and even the advanced messaging technologies in the D-RATS software package.

In the case of the TDRC, we were able to successfully interface FLDIGI to our BPQ32 packet bulletin board system.  Instead of using the 30 year old technology of 1200 bps packet, we now have the ability to move data using the latest modulation schemes in PSK, FSK, and many, many others.

We have now placed a second HF rig at the TDRC BPQ32 BBS site and will be interfacing it to the FLDIGI software in the next few weeks.  An announcement will be made once the system is online.  Our plan is to select a band that is easily worked on HF (perhaps 40m or 30m) so that the system will have coverage over NVIS distances (typically 300-500 miles).

If enough of you have interest, we might even put a D-RATS port up for fun.  Drop me a line at if you would like to see D-RATS on FLDIGI.

Update on PSK testing

Wow, it is amazing how 19 days can pass before you know it.

For those of you that were interested, there was another test performed on 30m and 40m to establish additional supporting data.  The good news is that we confirmed groundwave/NVIS distance of 28 miles with no problems on either 0.5 watts or 5 watts.  The bad news was that the receiving station near Claremore (KC5SHE) was operating using a hand microphone, instead of the traditional rigblaster setup.  That posed some challenges with the background noise from the room, so none of the measurements will be posted at this time, as the variances were pretty high.

We are looking to do another test this Wednesday, October 22nd.  Looks like KC5SHE will have his Rigblaster running at that time.  That should give us results that will be repeatable and worthy of being published.

For those of you that would like to participate, here are the specifics:

6 PM         (7036 khz, 1500 hz center frequency)
6:30 PM   (10140 khz, 1500 hz center frequency)

PSK-125 will be the starting mode, with a switch to PSK-250.  All transmissions will start with an identifier, so make sure to set your FLDIGI software to translate that appropriately.  If you have questions regarding setup of FLDIGI, contact me at

Wednesday, October 1, 2014

Results of Club Experiment on September 28th

Preliminary conclusions:

Lack of line-of-sight caused VHF to be unusable at the 28 mile distance, especially with the ridge line between Jeff AE5ME and Scott KC5SHE, which is approximately 20 feet taller than either antenna.  Attenuation on the order of 100 db is probably occurring.  Situation did not change whether station was running 0.5 watts, 5 watts, or 75 watts.  Guessing that usable distance will probably be on the order of 5-10 miles tops at 20 foot antenna elevations.  This is common on 2m simplex, so it confirms what we originally believed.

Normally that would lead us to say we need ball tall antennas on high sites. However.....

The real magic occurred on ground wave on both 30m and 40m.  It one word it was excellent.  30m was a more quiet band, but also a very narrow band to operate within.  Easily can obtain good copy of the signal out to 28 miles.  The 1.75 mile signal was essentially "full quieting".  Ridgeline essentially had very little impact on the signal strength.  Similar results on 40m, but also a lot more noisy from other sources, such as DX and shortwave radio stations adjacent to the band.

Between 30m and 40m, I think we are finding a band with decent propagation characteristics, that will keep us from having to use the traditional 250 foot or above tower to build a digital network.  That has been the traditional issue that kept traditional 2m packet from being continuous coverage.

All tests were conducted with some version of PSK, whether it be 125, 250, or 500.  Did some -1000 in short bursts, as well.

Further investigation with Scott KC5SHE next weekend will help establish values for comparison to the closer range transmissions.  Probably looking at doing something Sunday evening, October 5th.