Long-Distance Radio-Telegraphy

The use of diversity for voice-frequency telegraphy on HF radio circuits

Radio labelings of distance graphs

for any two distinct vertices x and y, where d(x, y) is the distance between x and y in G. The radio k-labeling number rlk(G) of G is the minimum of maxx,y∈V (G) |f(x)− f(y)| over all radio k-labelings f of G. The study of radio k-labelings was initiated by Chartrand et al. [1], motivated by radio channel assignment problems with interference constraints. Except for paths [1, 3] and cycles [5],...

Distance Is Dead , Long Live Distance

For many educators, the phrase ‘from distance education to e-learning’ conjures up the view of an ‘evolutionary’ progression beginning with correspondence study and developed through more sophisticated technologies to its current identification with computers, the Internet, and the World Wide Web. For others, particularly those with little knowledge or experience of (and often equally little in...

Direct Distance Measurements to Superluminal Radio Sources

We present a new technique for directly measuring the distances to superluminal radio sources. By comparing the observed proper motions of components in a parsec scale radio jet to their measured Doppler factors, we can deduce the distance to the radio source independent of the standard rungs in the cosmological distance ladder. This technique requires that the jet angle to the line of sight an...

Long distance transport.

A few years ago, I attended a 1-day symposium on long distance transport at a national meeting in a country abroad. Towards the end of the day, as the participants became tired and no general agreement was in sight, one observer from an allied discipline remarked, "Why can't you translocation workers make any progress, you still discuss the same miserable old models that were proposed 40 years ...