All noise is reduced in proportion to the bandwidth, both external and equipment (thermal) noise. The power of thermal noise is given by kTB, where k is Boltzmans constant, 1.38E-23, and B in degrees
An alternative to the SD interface is my PIC based one, which is directly compatible and uses just two ICs one of them an op-amp. Andy G4JNT Rik's idea of bypassing the card is another good solution.
May recall a discussion about using Loran for propagation monitoringon this reflector a couple of months ago which I then forwarded to G3PLX. He seems to have started looking at this method of propag
The military ARE very concerned. That is one of the main reasons (along with the BBC and RSGB pressure) that the UK limit has been set much lower, and even that was 10 - 20dB up on what we really wan
The normal mode helix was covered in some detail in a 1974 (!!) edition of Radio Communication with a set of empirically determined equations for calculating resonance and winding dimensions. Seem to
The LF forum that was to have been held at the Crawley ARC and unfortunately had to be cancelled due to foot in mouth, will now take place at the Flight Refuelling Amateur Radio Society a week later
See you on the Microwave Committee stand ? 73 & 137kHz are microwave bands. Andy G4JNT Hi All. The RSGB 'VHF' rally at Bletchley is this weekend. Is anyone from the reflector going? Perhaps we could
There may be a possibility of an LF Roundtable / Forum at the Flight Refuelling Radio Club (G4RFR) HQ at Merley near Wimborne, Dorset. The original date of 13 May coincides with a 70MHz CW contest so
That centre tapped coil in the Decca transmitters is there to 'soak up' high current pulses generated in the short switching interval when both FETs may be on together - a few ns duration. This comes
The circuit diagram of my 700 Watt Switch Mode Tx design as presented at Wimborne has now been posted at : www.lwca.org/miscimg/swmlftx.pcx There is noa ccompanying documentation, so if anyone wants
As the one who originally suggested the contest idea at Wimborne suppose I ought to say something.... On the microwave bands, we have eaxctly the same problem of lack of activity and complaints from
Could you give me info on the little pot-core you use for your driver transformer in your PA? Material, turns? I used a Farnell 559-570 ferrite sleeve, intended for EMC suppression, no info on materi
Replying to Stuart's comments re Wolf signalling . This is quite a long EMail so if you have no interest in real radio comms engineering switch off now :-( I was thinking some more about James' talk
Seem to remember reading that LUF is a calculation based on D layer absorbtion. Propagation predictions software giving LUF uses sunspot number / solar flux and time plus lat / long, but unlike MUF,
A tesla coil eh....... That's a really high voltage Andy 'JNT I have now secured the keys to the Clubhouse and alarm for Sunday. I will bring along some Tea/Coffee/Milk. I also bumped into Chuck Hobs
Three said they were coming from the Crawley club, with the rest of the old Decca hardware. G3HEJ contacted me for directions, and so did a callsign I can't remember so it looks like we're into the t
I've often thought that a listening test amongst amateur radio operators under precisely controlled conditions would throw up some interesting results. Especially amongst the expert contest operators
Hi John, It should be a 0.5dB (about 1/10 of an S-point) improvement. Doesn't look impessive at the first sight, but all bits will help. Also, note that at the critical point on the error rate vs. S
Slight correction to details to getting the the Flight Refuelling Club HQ for the LF Forum / Roundtable. (Shows how long it is since I last went there) Andy G4JNT Just back from holiday and read this
The local Non Directional Beacon here, EAS at Southampton Airport on 391.5kHz, puts out strong odd order harmonics. The fifth harmonic on 1957.5 actually caused QRM once. The third harmonic is masked
