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Graham, Thanks, I picked up a box of the red ones at a hamfest and always wondered what they were called.They work well on my QRP EFHW antennas to add/subtract a 1/2 section of wire. 73 - Dave, N4ELM

Hi Vojtech, Good Question, and SimSmith to the rescue! Evaluating 4T FT114A 61 and 43 material for critical low frequency inductance and core loss: https://www.kn5l.net/kn5lEfhwUnun/FerrEval/ The

I wonder what would be the optimum UNUN (lowest losses) for 40m-20m end fed? That is the frequency range for a trail antenna nowadays due to solar minimum.

The comment on the critical frequency at the current solar minimum was quite enlightening to me. When I was simulating various in the field antenna typologies, I was taking into account the total far

Thanks Mike, The critical frequency is also effectively the frequency where near straight up the Ionosphere is for the most part transparent and non reflecting when at lower angles like less than 20

NVIS (Near Vertical Incidence Skywave) depends on the ionosphere reflecting near vertical signals back to earth. However this happens primarily at low frequencies and at a certain critical frequency

Dear all, My newest CWModem as partial kit available.... Please look at https://sites.google.com/view/pd0lew/projects/mrsc-ultimade-cwmodem for more information.

Graham, Thank you, I had to go back to my aircraft maintenace logs to find the part name and source I used. I are a pilot and aircraft owner. And Aircraft Spruce has acquired many of my AMUs (aircraft

Hi Allison, Very correct. The design I've suggested is using two FT114-43 cores, not 2.4" cores. The Selection was a compromise between size and loss, attempting to keep core loss below 0.3 dB for a

Allison: I think you are referring to "KNIFE DISCONNECTS" used in aviation. They take a heavy pull load without disconnecting. Quick and easy disconnect with a 90 degree rotation of the terminal. If

Allison, can you explain what you mean by "critical frequency" ? N8WQ

Low antennas for 60M and down to 160 are useful for short range. Unfortunately NVIS on 40M is way oversold as the critical frequency hasn't been near 7mhz in years except on rare days. I know as i

Shirley. I know Steve being a SB1/II builder and just about every one of his test gear and digital dial bits over the last 15 or more years. He designs really slick radios. I have two of the PAR

Different operators have different goals. An operator who is trying to minimize equipment weight, like KD1JV during his walks of the Appalachian Trail, might prefer to carry just one antenna. (Steve

John, I was aware of that. I have such an antenna, of good utility but for trying to get an specific area on a given band I go to mono-band antenna as the pattern is predictable even if the peak gain

Hi Allison, The quest was an 80 to 10 Meter Unun. Correct, for 20M and higher frequency, 61 material can be used with reduced loss. Similar stack of two FT114-61 with four turn primary, about 2.4uH,

John, For the 14mhz model, try using mu 125 material (FT240-61) as you getting near the point with hard ferrites (31 and 43) where their absorption properties are becoming significant. An image

In line with the end fed theme, but done differently... Mono band 10M EFHW about 16.3ft long (4.98m) fed with a L network. L network 2uh air wound for power handling and the cap is a roughly 6" of

Hi Vojtech, An EFHW antenna with high impedance, fixed ratio, Ferrite transformer Unun is but one antenna solution. As you mentioned, deploying portable antennas may result with varying antenna

I wonder what are the losses of such EFHW UNUN if faced with real world conditions. Let's say, I cut the end fed wire to length at my back yard, where the center of the wire is fixed to the top of a