My comment certainly generated some replies! COFDM seems to be one of the 'flavours of the month'. It does have a lot to offer where multipath is a problem, viz. digital broadcasting over HF through
An LF 'RTTY type waveform' already exists - Jason ! 'Normal' RTTY, even at the narrowest shift / baud rate for any of the standard software, would be far to wide to be sociable on LF. Andy G4JNT As s
On Thursday, December 02, 2004 5:21 PM, Johan Bodin [SMTP:[email protected]] wrote: I agree. CW is clearly the best choice for word processing and it is ideal for writing computer programs. Who needs a
As PSK31 uses differential coding, it is the phase change over the 32ms signalling period due to freqeuncy error that is important. If for BPSK, we need to maintain the phase to less than 90 degrees
I don't know - and guess it is very dependent on the quality of the demodulation software. For example, what is the loop bandwidth of the bit recovery clock? Some PSK31 demodulators seem to do a bett
Four ways, I've already started negotiations. Also wating for a $3M lottery win to come through , and $45 million from the estate of another businessman lost on Concorde. Andy G4JNT Oh Boy... Now I'v
Think I was referring to the 74HC3257 devices - bus switches Seem to remember I measured in the region of +40dBm TOI at HF using one in a DBM design with a pair of ferrite transformers in a DBM arran
A research organisation that shall remain nameless has just made the decision that soldering irons have to have warning notices attached as they may be HOT. Perhaps this would be a suitable sign. Att
Many receivers probably have a high pass filter to reduce strong broadcast signals below 1.6MHz Andy G4JNT 73 Jan-Martin, LA8AK --Opprinnelig melding-- Fra: [email protected] [mailto
These days you might have a custom 24 bit A/D converter at the front end of an HF receiver for [the modern day equivalent equivalent of WW2 monitoring stations] that digitises the entire HF spectrum
Off the shelf A/D converters (mostly single chip) have come on in leaps and bounds in recent years, thanks to (dictated by ?) the mobile phone industry. I think most cell phone base stations just dow
For a normal A/D sampling at a rate approaching the Nyquist bandwidth (Fsample / 2) , Signal to Quantisation noise ratio is approximately 6.N - 1.7 - (peak to mean ratio). Where N is the number of bi
Can anyone recall this equation, I know it was mentioned on this reflector before... What is the output voltage for an untuned small loop into an arbitrarily high impedance? It is proportional to H,
Thanks to all respondees - I knew it was a simple formula and was (theroretically) an exact way of determining field strength. Just need to make sure the input impedance of the voltmeter is significa
Based on reading several works of (pseudo) fiction by authors who claim to have have 'talked to those in the know' and looking at some relevant web sites... That list of sensitive words almost certai
For a sinusoidal waveform, the minimum number of turns on a core is given by V(rms) = 4.44. F . N . A . B where V is the voltage across the winding F is the frequency in Hz A is the core cross sectio
I think you can go a bit further with that Alan. If you have a really long, low, wire then the current is returned via the ground, penetrating down to skin depths. The result is a big loop, with the
I wasn't suggesting actually going as high as 0.3Tesla as a working value for B, this is too close to saturation, but did say that a figure of 0.2T seems Ok for many applications. Furthermore, what I
Hopefully, if this gets posted my email problems are now resolved (Server name had to be changed, and hadn't kept the bulk email giving instructions sent 6 months ago) SNAP - we've done much the same
