Not true on HF Rx. The UK Navy have used active whips on their ships for many years for HF Receiving - the AVK is a long tried and tested unit. A two-metre long piece of scaffold pole forming the E-F
Just yet-another case of a poor soul being taken over by the Health and Safety Police. Andy www.g4jnt.com This email has been scanned for damaging side-effects by the health and safety police, has be
We recently installed a commercial, (Procomm) E-field Whip at work for HF monitoring/listening. Its on the roof of the building, about 25m high bolted to a metal rail connected to the building steel
In which case, mounting it on top of a 20m high steel framed building is like having a 20m whip???? Or does the size of the plane under the active element matter. Our works one has an antenna platfor
You might like to try the JT4A mode available within the WSJT suite. The latest Ver 7.4 has improved JT4 decoding, and we've been using the wide shift JT4G version on the microwave bands over the las
Anyone finding my beacon a bit on the QRP side... Just got home from work (4 hours on a coach to do 50 miles, then 9 miles walk back home coz everything is stationary) Found the LF antenna sagging un
Sync = 21 That's more like it ! Andy www.g4jnt.com 2010/1/22 Gary - G4WGT <[email protected]> Jim, LF, Is it a 1st for UK 500 kHz WSJT JT4A 2 way contact ?? Thanks Jim, looks like my change of so
Re ERPs. I think mine is mostly right-ish. The antenna is a 7m high Tee with a large top-hat, so its effective height is pretty much the same. At a wavelength of 600m, that gives a radiation re
For the narrow range of frequencies needed for WSPR, a 90 degree phase shift network at audio need consist of no more than a pair of CR's; although a pair of op-amp allpass networks does a better job
I've made some minor tweaks to tthe WSPR transmission on the beacon signal: 1) Frequency moved up to 503875.0Hz after a request from DK land to avoid QRM over there. Sri, forgotton who asked for the
Making comparisons between WSPR and QRSS should take into account the signalling rate, and it is only fair to compare like with like. A WSPR transmission carries a callsign, a locator and a power l
RF Link Budget Calculator Results That spreadsheet is for calculating the free space path loss between two stations - given by L = 32.4 + 20.LOG(F.d) F in MHz, d in km Totally inappropriate for L
Those transmitters consist of a full bridge output, where the connection to the series LC is hard switched to alternately +V or -V. The result is a low impedance voltage source driving the tank.
Congratulations, "water pistol" 1200km - a very comfortable margin too. Andy www.g4jnt.com 2010/1/20 Lubos OK2BVG <[email protected]> Hello Roger, LF! This moment is just now: 2136 -7 0.2 0.5
That's how submarine communications antennas work on ELF (81Hz or whatever). A very long wire is grounded at the far end. the skin depth of poor conductivity ground results in a loop antenna with t
So go on: argue against the Rrad (an exact figure derived from basic electromag theory) and Rloss (easily measurable, called Ohms law) way of getting antenna efficiency. Or ERP = I^2 . Rrad
A serious appeal to all the CW and QRS(S) ops on this reflector. I'm interested in what can really be achieved in terms of readability of weak CW . For the calculations mentioned earlier I made
Yes, I did :-) The FT817 block diagram shows two oscillators in the chain a master at 22.625 and 'another' at 22.7785 - so that idea gets knocked out straightaway. They done it on the cheap :-(
Well, yes it is I suppose if you lump antenna directivity into the equation. I^2.R is the actual power radiated. Which direction it then goes is a different issue. Anyway, what is the true directi
