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40m is more useful, so personally I'd choose that option. You can build a wire dipole(s) or use a retuned CB antenna on the upper HF bands (including 10m) and it will be more efficient than a small

I have decided on either the MFJ-1786 (10 to 30 meters) or the MFJ-1788 (15 to 40 meters) mag loop for my sole HF antenna. I'm trying to decide which one might be best considering: * As meters

Quite agree with Dave. Here in London they are good, ie best i can do, but I can’t put up full size antennas and the noise floor here is at best bad. However hopefully moving to a much quieter

I believe some of the dissatisfaction of the loop antennas is that the buyer / user expects too much. I live in an RF quiet area of the county here in Northern Colorado. There is no way a loop can

Hi Simon, I am not in Consumer Test Business testing all amplifiers designed for active antennae. However, I have by training and schooling an acknowledge by looking at schematic diagram and having

Tom, Thanks for your correction finding a gross error in my calculations. Yes, it shall be 1.04 ohms. Also, I found another source by John VE6E4 that published his plot comparing three apmlifiers

BTW, my calculations for the common base input of the LZ1AQ are 26mV/25mA = 1.04 ohms (not 0.01 ohms), 2X because there are 2 inputs (P-P) so 2.08 ohms. This is of course very approximate. The input

Hi Rapheal I see you are interested in theory, but have you actually tried out these amps?? Easy to make, and thus try and evaluate, compare and see which works in the real world.. Just

Martin, 1. Thanks for the clarification of LPF circutry used in LZ1AQ amplifier design, I followed the frequency response showing an improvement at higher frequencies by using this circuit. 2.

This is to provide Low Pass Filtering of signals on frequencies higher than 30MHz, it also provides additional matching to the loop antenna on the upper HF frequencies where the loop is approaching

All, My take is on that, anyone can use SimSmith for modeling the antenna matching to RF amplifier input providing that realistic data is entered in the model. I noticed an unrealistic radiation

I read Mr. Duffy’s blog and while I appreciate his graphs I wish he would justify why he thought the equivalent circuit which he modeled in SimSmith had anything to do with the YouLoop. Dave

All, AirSpy Youloop with 2 turns and radius about 1/2 meter constructed of two RG402 cable limbs with a copper? shield in diameter 3 mm has following parameters: total calculated inductance that

One paper on this subject here : https://elektrotanya.com/sites/default/files/comment/2018/04/crvco.pdf Xtian

The paper "Resonant Power Conversion through a Saturable Reactor" is very interesting. If you find anything else on the subject I would be very grateful. Tthank you very much to all. Fernando

The article compares the distortion of a saturable inductor with a single varactor. This is the proverbial "straw man" comparison, since anyone who cares about distortion uses a pair of varactors in

Try this link. https://hal.inria.fr/hal-01274809/document Fred - N4CLA

It's the two turns and coax capacitance that contributes to it. I have an impedance plot that was sent to me privately by the designer Youssef Touil, and it is practically the same. I raised a

Martin, As you know antennae are used not only for SDR but for any designed receivers, thus practically would be better to specify sensitivity not as MDS. By the way, it makes sense to use MDS when

That loop must be fairly large to have a self resonance at 3.386MHz. Chris When the going gets weird, the weird turn pro - Hunter S. Thompson