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sky wave are those reflected by the upper layers of atmosphere called ionosphere, and usually apply to frequencies around 3 to 30MHz. For line-of[-sight, think of sound waves: bass frequencies penetrate walls, yet high frequencies reflect off walls. Radio wave are same, the shorter the...

First of all, 25 watts is about 44dBm (not 40). 2nd, if you put 25 watts into a 12dB loss, then something is going to go up in smoke. To tune those correctly you need to view swept insertion loss and return loss at the same time. The only way to optimize insertion loss is by seeing the...

What you are asking concerns modulation index and bessel functions. You can google around for fm bessel sideband and whatnot. You will find that FM actually has an infinite number of sidebands, but only a limited number of them are significant. Precisely what the bandwidth is depends on the...

its there when your parked with the engine off? I mean parked away from power lines, houses, buildings, etc.

I would clarify that. Some people like to twiddle knobs instead of point-and-click. It has nothing to do with whats going on underneath the hood. Makes no difference if its implemented analog or digital. People care about the user interface as much as technical performance.

The days of older designs should be numbered anyways. Because many of the ICs and transistors in the 2950 radio are obsolete. They can only build them from stock on hand purchased many years ago. This also holds true for S-9 radio. But newer designs like magnum 257 have parts that are now...

Generating a precise and stable RF signal is so cheap these days, especially below 30MHz, such as this: DDS-60 Kit from the AmQRP They call it a VFO, but its output frequency is exactly locked to the divide ratio from a crystal. With something as cheap as a DDS, you can concentrate your...

Proper alignment is one thing. But if you think its the PLL causing the noise, it certainly can be. For any superhet receiver, any noise on the local oscillator will be heard, perhaps even with no received signal. The only way to be sure is put a good spectrum analyzer on TP3 to see how...

The rack mount is tired and redundant. Nobody rack mounts a base CB. I long for the days of wood veneer. Seriously though, my thoughts are with repackaging the SoftRock v6.3 design for 11 meters with a good power amplifier. Because we are in the "computer age".

Rarely is receiver sensitivity an issue below 30MHz. When man-made noise (powerline etc) is not a problem, then the I.F. bandwidth and dynamic range of the receiver become the limitations. I.F. bandwith is often wider than it needs to be, which allows more noise to come in. This is why DSP...

This GE Buck Rogers article might have a few issues. First is the statements about ladder-line/twin lead is a bit misleading. This type of line will not radiate if its balanced, and will handle a wider range of impedances with less loss compared to coax. Second is ignoring the...

Computer Aided Transceiver (CAT) may have been intended for more than just a computer controlling a radio. It may have also been meant for a radio to control an external device such as antenna tuner or something else from the radio. Or even cloning one radio to another. This could explain...

Trust your vehicle chassis to carry the current to run your radio? Why not run the black(-) directly to the battery as well. The various metal parts of the vehicle frame could have corrosion on the joints and maybe drops some voltage. Probably not an issue at a few amps, but is it at 8amps...

The quick way to compare antennas is by their power rating. The better antenna will have the higher power rating. Power rating is lower because something in the antenna is converting radio energy into heat, and will eventually melt something. Have you ever seen a power rating on a 102"...

A kw really from 5 tubes? NJ7P Tube Database Search The 6lf6 was rated at 40w plate dissipation. So 200 watts total plate area gives you 1000w peak. I suppose so if you count harmonic power.

The MAX3232 is not a USB chip, its an RS232 +/-9v chip. Would be alot more simple to use a direct USB->3.3v UART converter. One such device is the FTDI FT232, no charge pump shenanigans for +/-9v. FTDI has drivers for your computer to appear as a serial port to your PC software.

Even if not, this radio is not price competitive with the yaesu 857d. But I am eager to find out about the new DX-SR8T/E Detail information I think it might be $600 or less because it is HF only.

I dont know where that comes from. But take the Cannabis example. US federal law outlaws all cannabis use, but some states permit medical marijuana. Then 10th amendment assures states rights. So considering that example, an individual state in the USA could permit an activity than the...

I live north of los angeles and can say that channel 12 is used in the san fernando valley. But the level of activity is not like that on 17 in south-east LA and OC. 28 is only used further east. There are also tons of mexicans on 5, 7 and who knows where else.

Does your swr meter require calibration step before reading swr? If so, you should again do the calibration step after changing tx power.