Glenn W9IQ
  • Member for 4 years, 9 months
  • Last seen more than a month ago
Is this transmission line peak voltage formula published in CQ Magazine more accurate?
2 votes

Equation 1 as proposed in the article has two primary shortcomings: It does not address losses in the line. As a result, the formula may overstate the maximum peak voltage. It requires that ZG (the ...

View answer
Is this a broadcasting antenna?
13 votes

It appears to be a "vertical" CB ground plane antenna that had been mounted or stored in a horizontal orientation. It is not suitable for effective TV or FM reception. It is also noteworthy that one ...

View answer
Improving coverage of AIS receiving station
Accepted answer
1 votes

Your line of sight to the ship transmitting the AIS signal is one of the more limiting factors. Usable AIS VHF signals will travel just slightly further than line of sight conditions. This is known as ...

View answer
Reflection Coefficient to Impedance transformation on the Smith Chart
2 votes

Since you know the complex reflection coefficient, you can simply use this formula to calculate the complex impedance: $$Z=Z_O\frac{1+\rho}{1-\rho} \tag 1$$ Assuming the characteristic impedance is ...

View answer
BFO locked synchronous AM detection
Accepted answer
2 votes

AM synchronous detection will certainly reduce or eliminate selective fading. It generally isn't implemented simply due to the increased cost and complexity. But you will certainly be pleased with its ...

View answer
Can I build a radio telescope out of a parabolic TV satellite dish?
Accepted answer
16 votes

The primary factor to consider is the directivity of the parabolic antenna. It is given as: $$d=\frac{(\pi D)^2}{\lambda^2} \tag 1$$ where D is the diameter of the dish and $\lambda$ is the ...

View answer
Mounting a J-Pole and Yagi on the same mast
2 votes

Near and Far Fields To mount the two antennas in close proximity to one another, you should minimally ensure that neither reactive (near) field interferes with the reactive field of the other in ...

View answer
Why does not a bigger antenna receive more power?
1 votes

Let us say that I want to stick with a non directive antenna, because I do not know in advance the direction I will be receiving from. With this as the starting point, consider that there is no real ...

View answer
What is the equation relating maximum data transfer rates for a given EM bandwidth
Accepted answer
2 votes

The formula you are seeking comes from the Shannon-Hartley theorem: $$C=B\log_2\left(1+\frac{S}{N}\right)\tag 1$$ where C is the channel capacity in bits per second, B is the bandwidth in hertz, S ...

View answer
Can I monitor a refrigerator using ham radio?
3 votes

If you wish to transmit a measured parameter under US FCC Part 97 regulations, you would be operating under the telemetry rules. This is defined as "A one-way transmission of measurements at a ...

View answer
Peak envelope power should be 2:1 or 4:1 on meter?
3 votes

It depends... With a 100% steady modulated carrier, the PEP will be 4 times the unmodulated carrier power. The average power under this condition will be 1.5 times the unmodulated carrier power with ...

View answer
Suspected Damage in Coax Cable
Accepted answer
6 votes

It appears to be typical moisture ingress. The joint between the coax and the connector is not inherently waterproof. A damaged jacket can also be the source of moisture ingress. Normally the ...

View answer
Receiving audio output from IC-9100 through USB port
Accepted answer
1 votes

You need to install the Icom USB drivers on your PC. You mentioned that your PC is running Linux but I am not aware of any Linux drivers from Icom - I only see Windows support on their website. Once ...

View answer
Signal path to maximize RFI rejection in an urban environment
3 votes

As a new ham, you may have more success answering a CQ since you will then know that you can at least hear the other station over your local noise. Answering a CQ also requires less finesse so you are ...

View answer
How do active loop vs. passive loop differ in terms of noise rejection?
4 votes

Poor Loop Gain The small (<0.1 wavelength in circumference) loop antenna has very low gain. While the size somewhat lowers the directivity, the primary reduction in gain is due to inefficiency as ...

View answer
Impedance matching using Smith Chart and relationship to reflection
4 votes

You are correct that there is a clear correlation. Perhaps your Smith chart does not have the following scales along the bottom?: The technique is to use your compass to measure from the center of ...

View answer
Do FCC regulations limit digital data rate?
Accepted answer
11 votes

The Current FCC Regulations (as of July 2018) Parts 97.305(c) and 97.307(f) regulate digital modes primarily by symbol rate. The table in 97.305(c) maps bands/frequencies to specific symbol rate ...

View answer
where to look for (live or recorded) air traffic conversations for a specific area?
Accepted answer
1 votes

126.3 MHz is the Talkeetna CTAF (Common Traffic Advisory Frequency). You may have heard some traffic on this frequency while in-flight. Pilots use this to advise other pilots that they are in the area ...

View answer
Antenna design - Ground plane in simulation and in practice
Accepted answer
3 votes

The antenna is matched to be 50 ohm at A (Fig. a). So, to measure it in practice, the author designed a 50-ohm transmission line which connects A to B. Am I right? The antenna by itself is not a 50 ...

View answer
Can someone help record a specific radio signal at a specific time to help solve a radio based puzzle?
4 votes

The transmissions quoted most likely are not occurring. The quantity of frequencies is suspicious for any broadcasting service and some of the frequencies themselves are not suitable for broadcasting ...

View answer
Why do we have to hand wind toroids?
12 votes

I suspect the primary reason that the kit supplier does not ship the kit with prewound toroids is that there is insufficient volume to make it economical to have them commercially wound. A second ...

View answer
What should I put in a "Go box", "Go bag", or "go kit" for emergency communications?
6 votes

If I wanted to build a mostly-portable-but-still-comprehensive kit to use in emergencies, either my own, or simulated ones through ARES or RACES, what should I put in the kit? If you are active in ...

View answer
Is it possible to get a set of radios that will work 10 Miles in suburbs?
Accepted answer
1 votes

This depends largely on the elevation and clear line-of-sight conditions. You will find your answer under this question Could I expect 12 mile range with the GXT1000VP4 radios? included a simple ...

View answer
Could I expect 12 mile range with the GXT1000VP4 radios?
3 votes

These radios will operate largely on a line of sight basis with a slight boost from refraction. This is known as the radio line of sight. It is given as: $$D\approx1.41\sqrt{H} \tag 1$$ where D is ...

View answer
Can the Q of a loop antenna be changed?
Accepted answer
1 votes

An RF tag system is designed to function in the near field of the antennas. The frequencies involved are in the 13 MHz range and the antennas used in these applications are defined as electrically ...

View answer
Why is the insertion loss of my coax cable higher than expected?
Accepted answer
5 votes

Based on your description, I would suspect moisture damage. Moisture ingress in coax cables typically results in the corrosion of the copper braided wires in the shield. The oxide that forms ...

View answer
Two way ham radio to communicate between two stations
Accepted answer
6 votes

The answer to your question involves both technical and regulatory issues. Technical Considerations Radio signals can travel between two locations on earth either by line of sight or by propagation ...

View answer
Understanding of NFC Reader Antenna matching
4 votes

It is very difficult to help you with analyzing a circuit when clearly, and as you stated, your measurements were in error. The electrically fractional wavelength loop will have a very low feedpoint ...

View answer
NFC coil matching - Q factor improvement
1 votes

To begin with, your Q is too high. Your passband shape will cause too much sideband attenuation. NFC requires a 2 MHz passband so your Q should be no larger than 7. That is to say that your should not ...

View answer
Can WSJT-X's timing account for delay from RCForb?
Accepted answer
2 votes

When you suspect timing problems with FT8 decodes, simply manually adjust your computer clock to see if the situation improves. This is also the standard recommendation when you suspect the ...

View answer
1
3 4
5
6 7
14