Issue #26: Guest Article - The RFBitBanger Transceiver and SCAMP Digital Mode

Stay tuned!

https://github.com/profdc9/fldigi

 

Thank you for your time to post this.

 

Hi Alex, great post -- sure adds some value to the article. Much appreciated, Dave W7DGJ for "Trials and Errors -- Ham Life with an Amateur"

 

Thanks very much for your feedback and the praise. It really does mean a lot. I put a lot of hard work into this and I hope that it meets expectations. I know it's not perfect but I wanted something that would simultaneously be very usable and buildable from simple parts, not an easy combination to achieve.

You can use the RFBitBanger to send CW, just by typing in your message into the keyboard. It also supports a paddle if that is your preference (set the mode and WPM first in the configuration).

BTW, there is an indicator bar for signal strength. For example, there are instructions in the manual on how to use WWV and CW mode to calibrate the crystal frequency. To do this, the signal strength bar is maximized on the tone. I usually use the 10 MHz frequency for this, and I find that I can get it within +/- 20 Hz this way fairly readily. The signal strength indicator is important if you use SCAMP because it's what you use to line up the internal filters with the two SCAMP FSK tones.

Also, I did make a version of fldigi that includes SCAMP, so that all of you who don't have an RFBitBanger can try SCAMP. You can clone the repository at https://github.com/profdc9/fldigi . I hope to get this into the official fldigi distribution. I have tested it back-and-forth with the RFBitBanger and it works well. It's probably even a good more for ordinary use, as it is low bandwidth and uses FEC. It includes all six modes (both OOK and FSK) that are implemented in the RFBitBanger.

Again thanks for your feedback and I hope you enjoy your RFBitBanger and make many QSOs with it!

73,
Dan
KW4TI

 

Thanks Don for the courtesy you show when you are here. A valued part of our community! Dave

 

This is a very interesting and promising project, having a small off the grid essentially powered standalone QRP trx that can do not only Voice (SSB), CW, RTTY but use a keyboard for sending text messages under Prof. Marks SCAMP Protocol and not only!
A number of fellow Hams from AthensQRPNet, have decided to make a group build of the RFBitBanger and have also tested the SCAMP protocol under an alpha version of FLDigi.

 

Konstantinos, please let us know how it goes and what impressions the group has of Dan's transceiver! Dave, W7DGJ

 

Here is a nicely done demo of the bitbanger rig and all modes supported.
I can see where this mode would work with the QMX...

RFBitBanger Demo - YouTube

 

Don, thanks. I think this is an exceptional introduction to the radio and the experience of owning an RFBitBanger. Good link, appreciate it. Dave W7DGJ

 

I offer to help QRP Labs implement SCAMP on their radio. I allow the source code to be used for commercial purposes so it might be better be adopted. However, the QRP Labs radios generally do not support a keyboard unlike the RFBitBanger, so entry would have to be using a code key or serial port, or perhaps a keyboard plugged in with USB-on-the-go if the QMX supported that in the future. I think fldigi with SCAMP would work with the QMX, however, this would require a PC which adds a lot of extra hardware.

73,
Dan
KW4TI

 

Thanks Dan, you are always generous with your IP! Dave, W7DGJ

 

With my current KX2 I am able to 'do' RTTY/PSK31 messaging via a paddle attached to the radio.
In a practical sense - I load the memories with canned messages (CQ etc) and fill in the other station with the paddle. A - to me - good work around. I had thought the on/off nature of the SCAMP mode would be the key for use on the QMX so no need for a PC/tablet in the field.

The QMX memories can work in the same fashion as outlined above - tho RX might be problematic...

Thanks for the reply

Don//KL7KN