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A tour de force by Chris Trask!! Re my previous suggestion of using constant current sources replacing R1 and R2 in Everett's great circuit, I leave the following quote by Chris.... lower (Q1). This

Hi Hisami, This is the paper the design was taken from. http://www.kiwisdr.com/docs/Complementary%20Push-Pull%20Amplifiers.pdf Regards, Martin

Hi Bill, I suggest you model your exact antenna and radial dimensions in eznec and check f/b at 2 degrees. Try optimising the f/b with a resistor 100-600 ohms in series with insulated radials on their

Hi Martin, Thanks for the infomation and advices. Thanks also for the recommend on "Chris Trask (fig.5)". I will look for the FETs. I have several pairs, but they all seem to have large Ciss. tnx &

I have just installed an Aziloop and I do not get good nulls - 10 -15 dB on 50 -100-mile ground wave signals, Loop is 13' on long side, 8' on short side and PVC mast is 15 feet. Radials are on the

Hi ?Mikek, The better IMD performance of the Trask circuit, means that it can be used with a larger antenna (one having greater self capacitance) such as a 1m whip. The coax transmission line forms

I have a question about the Trask push-pull amplifier. Doesn't it have a rather low input impedance to be connected to a probe antenna? Mikek

Hi Hisami, The PA0RDT https://owenduffy.net/antenna/PA0RDT-MiniWhip/ PA3FWM http://www.pa3fwm.nl/projects/miniwhip/ PA0NHC dual fet https://www.pa0nhc.nl/Miniwhip_20180416/index.htm Are probably the

Hi I have uploaded some pictures to my blog. https://www.7l4iou.com/2025/03/kp901b.html I will add circuits and descriptions. If I get enough results to introduce them. 73, Hisami 7L4IOU

The AMRAD active antenna is based on Burhan's circuit. https://www.arrl.org/files/file/Technology/tis/info/pdf/0109031.pdf W1VD also has a version using a common J310 jfet.

Two pictures are attached.

Hi Dave, Yes, You are right! There is no need to invest for old devices. tnx & 73, Hisami 7L4IOU

Hi Fred, Thanks for the advice. I had gotten a Soviet KP901B about 20 years ago. I remembered it and tried to improvise. The radiater is a Jpanese brass coin with a hole. Indeed, it worked as an

Hi Martin, Thanks for the advice. I have some low noise audio FETs (2SK170 etc) that I got a long time ago. I thought could not use them for RF because of large Ciss. However, LTSPICE simulation to

;-) That reminds me of the note in the AziLoop manual, “To be clear, the antenna does not move” Thanks for your explanation and assessment. Especially the reference to the earthing, which I will

Thanks Guy, I know your and Walt's ambitions for AM-DX, your solution is already very perfect. I can see that the size (one meter up or down) will be a very good option, also the self-supporting

The J-310 would be a much better choice. Dave - W?LEV [email protected]> wrote: -- *Dave - W?LEV*

Hi Christoph, I use 16m (50ft) circumference (W=20ft, top H=15ft, bottom H=4ft) .? I decided on this size for 9dB or 10dB noise over-ride from the antenna on 160m. using only 4 x 3.5m elevated

Most interesting!

With todays knowledge, the usage of a MOSFETs in the front stage of an active e-field impedance converter is not really a good idea. Even if some professional active-monopoles like the Eastern German