Hello there.

My name is Kelly Lindman, Licensed Ham Radio operator 5B4AIT.

Before HamSphere I ran a big remotely controlled receiver network called JavaRadio and later DXTuners. DxTuners then turned into GlobalTuners by Ivo Smits in Holland. Some parts of DxTuners and its spirit are still in operation in the GlobalTuners network.

I operated that network for 10 years (1998-2008).

In late 2007 / early 2008 I launched a totally new concept - HamSphere!

HamSphere is a virtual shortwave tranceiver client that works in Windows, Linux or Mac or any other Java driven system.

It communicates over a simulated Ionosphere called "HamSphere". It covers 6m to 160m Ham band including 11m. It uses double side band modulation and each band is 100 kHz wide.

The system does not emit any RF and it is 100% safe to operate in any country.
Everything you hear on the system is part of a big shortwave simulation called "HamSphere".

You will find the system very similar to the shortwave band as it has noises and scratches called QRN as well as unwanted signals called QRM. The propagation is very much like real shortwave. Sometimes the conditions are bad and sometimes they improved quite a bit.

HamSphere can be used by both licensed and unlicensed DX:ers.


Technical description:

I use real radio principles with local oscillators, balanced mixers, filters etc. The modulation is true Double Sideband Modulation with carrier suppression hence the "donald duck" sound when you swirl the knob. The receiver is a direct LO-mixer detector where I just add the carrier (Beat oscillator) to detect the audio. Filters are made from 17-pole FIR filters producing effective 3.8, 2.8 and 0.7 kHz filters.

CW Keyer and CW operation is true Contineous wave operation. I simply inject a carrier wave in the Sphere and key that. You will notice that the built in keyer has a clean Sine wave on both side bands whereas if you modulate CW with a side tone oscillator it will produce two interfering tones.
In future releases operators will be able to key the transmitter on/off with a CW key producing a 100% clean sine wave.

There are however limitations in the HamSphere sampling process. Operation from 90 kHz offset and up (such as 50.190) might produce distorted audio. Due to the Sphere sampling frequency of 192 kHz the following frequency offsets should be avoided:

90-96 kHz (Some audio sampling artifacts)
96 kHz (Dead lock = Sample rate / 2, will not produce any audio)
96-100 kHz (Out of band operation, audio will be distorted by bit quantization noise)
0-1 kHz (Near Local Oscillator Deadlock. Out of band operation, audio will be distorted by bit quantization noise)

Tuning HamSphere outside the specs is not prohibited, but please observe the audio limitations.

Operating HamSphere within 20-30 kHz (such as 7020 kHz) offset would theoretically produce the best audio.

73
Kelly
5B4AIT