Questions tagged [ionosphere]

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Is transmitting digital data just like transmitting voice signals?

I would like to find a free shortwave frequency and start transmitting digital data ( from 1 to 10 Mhz ) . I will be just transmitting binary data for couple of hours , and i won't use it for voice-...
13 votes
1 answer

How do Radio Regulations and Frequency Allocations Apply to an Ionosonde?

An ionosonde is a special HF radio transmitter that periodically transmits a signal that sweeps across a large portion or the entire HF spectrum to identify the propagation of radio signal in the ...
4 votes
5 answers

How does one know when band conditions are optimal and what factors to consider?

On many of the DX sites, one will find many variables for solar weather to include flux, A, K, sunspots, etc… I’d like to know how to read those and know what to look for. As I understand it, the sun’...
3 votes
2 answers

What is really happening during RF ionospheric refraction?

We all know that the ionosphere — when charged — refracts RF energy, but why? In other words, what is actually occurring at a molecular level to cause radio waves to bend back to earth because of ...
16 votes
7 answers

What is the cause of this unusually long period of terrible HF band conditions?

I've been a ham for over 40 years, but never has there been such a prolonged period of such poor propagation. This has been especially the case over the past six months or so, and they continue to ...
5 votes
2 answers

How is it possible for an HF signal to go around the world when part of it must be in sunlight?

I believe most of us know about the ionosphere, and skywave propagation, but I'm kind of tripping up on the D-layer. If the ionospheric D-layer absorbs HF signals (40 meters, for example) during the ...
5 votes
2 answers

Incoming angle of radio signal reflected off of ionosphere

I am about 870 miles and 16 degrees due west of WWVB at Ft. Collins, CO. WWVB transmits at a frequency of 60 KHz. At this distance I should be getting the signal reflected from the ionosphere. If I ...
1 vote
1 answer

What is the best solution to transmit data by the ionosphere over at least 7500 km? [closed]

I know that some amateur radio are using some frequencies that are reflecting on the ionosphere to transmit data over super long distances. I am wondering if it is possible, without an insane lot of ...
8 votes
1 answer

Are ionospheric predictions useful in practice for ham radio operators?

A number of government agencies around the world provide ionospheric predictions, such as vertical foF2 or oblique path useable frequency range advice. Examples include IPS, SWPC and DIAS. Typically, ...