In the April 27-28 VOA Radiogram, a VOA news story was transmitted using Flamp, a program that accompanies Fldigi. Flamp divides text or any type of file into a certain number of blocks, each with a certain number of characters. Then it transmits the file more than once, with subsequent transmissions filling in any blocks that did not have the correct number of characters during the first pass.

To test Flamp, I used the MFSK128 mode. This mode is very fast, thus prone to errors, hence useful for experimentation with Flamp. My own reception of VOA Radiogram on April 28 at 1300 UTC on 6095 kHz provided a textbook example of how Flamp works. After the first of two transmissions, three blocks were missing, i.e. rejected because they had the wrong number of characters :

Then all of the text was transmitted again. Flamp filled in the blocks that were missing:

The result was a perfect html file that could be saved, or pasted to a text editor, and opened in a web browser. The result looked like this:

Many listeners reported reception of a high percentage of the blocks after the second pass, but without 100% of the blocks received, the file could not be opened. This suggests that, next weekend, I should set Flamp to transmit three times. A 3X transmission of Flamp will take more time, so the question for us is whether the slower but more robust MFSK64 transmitted once is a better solution than MFSK128 transmitted multiple times.

For some listeners, Flamp did not work at all. One cause for this is that the beginning code was not not received correctly (“header corruption”). It should look like this:

Any actual use of the Flamp concept in international broadcasting would require a software application that simplifies the process and places it in the background.