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- Thread starter Omega-TI
- Start date

Trying my best, but what does this have to do with SDR?

Oh, it's "advertised" in the title of the link for SDR's. Yeah, a radio is a radio is a radio, but I had to put this someplace.

Well, I don't think you necessarily "had" to put it anywhere, but if you felt compelled, was the Antennas and Associated Hardware forum closed at the time you posted this thread?but I had to put this someplace.

It's possible it was closed. We sometimes do that to clean the background, change the bulbs that light up the forum and other general housekeeping chores. We try to do it at not so busy times.Well, I don't think you necessarily "had" to put it anywhere, but if you felt compelled, was the Antennas and Associated Hardware forum closed at the time you posted this thread?

DISCLAIMER: My brain does not function well due to my Encephalopathy caused by MELAS so this may or may not be correct.

According to the drawing in Post #1, the two closest radials form a triangle. The angles should be 120, 30, and 30 degrees (I think). The radials are the same length and the third side is 19 inches. Throwing those numbers into the triangle calculator at:

Online calculator for quick calculations, along with a large collection of calculators on math, finance, fitness, and more, each with in-depth information.

calculator.net

The radials should be 10.96966 inches each.

Knowing that, the radials should be tuned (theoretically) to 255.9894 MHz.

Am I correct with all of that? TIA!

Says it packs up at 12 inches, so assuming that's the length of the radials , so I'd say you're pretty darn closeDISCLAIMER: My brain does not function well due to my Encephalopathy caused by MELAS so this may or may not be correct.

According to the drawing in Post #1, the two closest radials form a triangle. The angles should be 120, 30, and 30 degrees (I think). The radials are the same length and the third side is 19 inches. Throwing those numbers into the triangle calculator at:

## Calculator.net: Free Online Calculators - Math, Fitness, Finance, Science

Online calculator for quick calculations, along with a large collection of calculators on math, finance, fitness, and more, each with in-depth information.calculator.net

The radials should be 10.96966 inches each.

View attachment 169748

View attachment 169749

Knowing that, the radials should be tuned (theoretically) to 255.9894 MHz.

Am I correct with all of that? TIA!

Ground radial resonance has nothing to due with the shape they all make together like a triangle, square, hexagon, etc, its their physical length that is important. If they are fixed at one length then they are best used near their 1/4 wave resonance and also their 3/4 wave resonance where a 1/4 wavelength radial will incur a 1/2 wave round trip for RF flowing from the antenna feed point to the radial tip then reflecting back, closely mimicking the feed point impedance. At 3/4 wavelength there will be a 1 1/2 wavelength round trip which will also mimic the feed point impedance.DISCLAIMER: My brain does not function well due to my Encephalopathy caused by MELAS so this may or may not be correct.

According to the drawing in Post #1, the two closest radials form a triangle. The angles should be 120, 30, and 30 degrees (I think). The radials are the same length and the third side is 19 inches. Throwing those numbers into the triangle calculator at:

## Calculator.net: Free Online Calculators - Math, Fitness, Finance, Science

Online calculator for quick calculations, along with a large collection of calculators on math, finance, fitness, and more, each with in-depth information.calculator.net

The radials should be 10.96966 inches each.

View attachment 169748

View attachment 169749

Knowing that, the radials should be tuned (theoretically) to 255.9894 MHz.

Am I correct with all of that? TIA!

With ground radials in the 10-12" range you won't be able to get a good match on any amateur band or public service band by tuning the top whip.

You may have not understood the triangle. It is the Obtuse Isosceles Triangle equation that was used to calculate the radial length to subsequently calculate the resonance quarter wave frequency of the radial.Ground radial resonance has nothing to due with the shape they all make together like a triangle, square, hexagon, etc, its their physical length that is important. <snip>

For $65, no F'n way. One would be better served with a telescoping monoband antenna, or even the old RS telescoping 20-006A scanner antenna and adjusting the length as needed. I'm figuring one could be creative enough to figure out a BNC mount for outdoor temporary use. I think these were going for $5 or $10 during the last days. I purchased one decades ago and nabbed a few more during the Radio Shack funeral march.

If your not familiar with Super Antenna, its all real expensive. The scanner ground plane is one of their cheaper items. Check out the price on one of their other products.

For $65, no F'n way. One would be better served with a telescoping monoband antenna, or even the old RS telescoping 20-006A scanner antenna and adjusting the length as needed. I'm figuring one could be creative enough to figure out a BNC mount for outdoor temporary use. I think these were going for $5 or $10 during the last days. I purchased one decades ago and nabbed a few more during the Radio Shack funeral march.

HF SuperWhip Tripod All Band 80m MP1 Antenna with Clamp Mount and Go Bag. Perfect for Vacation. The TM1 Low Profile Tripod sets up on any flat surface. The #1 HF Portable Vertical Antenna worldwide.

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Still, for VHF/UHF scanner stuff my Comet CA-2XRSR or NMO version mobile antenna works quite well. Still, I have not tried it without a ground plane. Time to test.

I have made many small ground planes and varied their length from around 13-19 with their telescopic height remaining about 18 for vhf, uhf and frankly unscientifically in the real world for

I was trying to see if I missed something, apparently I didn’t.

Speaking of, check out these speakers…

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