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Hi Tom, The amplifier itself plays an important role and we are basically trying to make its input impedance track that of the loop. The input filter forms a resonant peak in the amplifier response

Martin your website has a lot of very good information, and thank you for that. I see that your site shows a graph with the Wellgood having a peak response around 29MHz with the two series 82pF

Again: If you experience a rise in background noise with the antenna connected over a matched resistor, you're fine. If that condition exists, no need for more gain or lower noise figure. Then

The problem with modern devices seems to be the junction width, and it's very easy to punch holes through the very thin layers used in modern construction. I bought a load of low noise 3v 45GHz ft

Dave, the 2SC5551 is a bit faster than 300MHz!? A spectrum analyser is a very useful tool but not necessary to detect spurious oscillation. Measure the current consumption on an old analogue

Good morning Alan, I have a question about the design of wire loops. There are those with manufactured multi wires in one harness and the ribbon cable and the capacitance issues. You mentioned a

Using multicore cable of any kind seems to be a neat way of making a loop BUT the capacitance between turns is very high for flat ribbon cable and multiconductor bundled cables so you end up with a

And you can buy them even cheaper direct from NTE, though I don't know if that's only for US orders. That's where I got mine. https://www.ntepartsdirect.com/?????? Enter "NTE278" in the

I recently bought 10 of the NTE278 to test and compare to my old Motorola 2N5109's and Central Semi newer 2N5109's--it's the same transistor die and performs the same as the 2N5109. Steve AA7U

Does anonone have experience with an NTE278? It looks like a one-to-one equivalent of the good old 2N5109. Digikey price for a single Transistor is $0.91. NTE278 Datasheet (pdf) (

Martin, I concur 100%. With our many years of experience in this area we continue to utilize BJT technology. In those electrically hostile environments, our testing has confirmed the vulnerability of

Although an interesting design, although I note that it has no input low pass filter network. This has two implications. It makes it (and any receiver that may be connected) susceptible to

I would agree. However the problem we face, is that as wireless devices are increasingly moving up in frequency, and although excellent devices with high gain, low noise and unbelievable values of ft

I believe, there ist no ultimate choice transistor. Depending on specific requirements, there are serveral suitable transistors that are available and not obsolete. Some slightly better than others

[email protected]> wrote:

Fred, What would you consider the ultimate choice? The "best" transistor for HF antenna amps has been a moving target as transistors go obsolete. The 2SC5551 looks like it may be on the way to

Sorry, I am getting into this thread a bit late, but I have wondered about a similar approach for some time and how to work within the L/C ratio boundary for a resonant loop for any given band of

I once built a loop of a meter in diameter (square) using ribbon cable connected as you describe. You end up with a coil on the support structure with the number of turns that the ribbon coil has.

Is this loop good for vlf as well as the BCB? Fred N4CLA wrote:

I just uploaded my paper which is the basis for the design under