Glenn W9IQ
  • Member for 4 years, 9 months
  • Last seen more than a month ago
What is an antenna tuner? Why bother with resonant antennas in the first place?
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12 votes

And if it is possible to use a tuner to make a transmitter feed power into a coat hanger then why do we worry about making resonant antennas in the first place? In a word - efficiency. Consider that ...

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Need a ferrite suppression material for choking 15 kHz to 60 kHz
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5 votes

I don't think it will work to add suppression to the fence. The fence charger is designed to support heavily reactive loads by generating pulses every second or two. The pulses are formed by dumping ...

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Efficiency of short dipole receiving antenna
8 votes

The efficiency of any antenna has a direct impact on the gain of the antenna. The gain of the antenna equally effects transmit and receive - a characteristic known as reciprocity. The highest gain ...

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Why can't I hear myself from a second radio when bouncing off a repeater?
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12 votes

You are experiencing what is commonly called desense (short for desensitization). The strong signal of your transmitter overloads your receiver making it unable to demodulate the much weaker, on-...

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Digital networks -- operator at control point, or automatic relay?
1 votes

I decided to redo my original answer as I didn't formulate my response to what the question specifically asks and I neglected to consider the intent of the "message forwarding system" ...

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If I receive an SOS signal, what is the proper response?
6 votes

Since this is all for a bit of fun, you could respond with the typical Morse Code response to indicate that the last transmission was successfully received: R: •-• Some operators stylize this as ...

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Sending a downloaded file on digital: third party communication?
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7 votes

From a Part 97 perspective, the definition of third party communications is: Third party communications. A message from the control operator (first party) of an amateur station to another amateur ...

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Ham operators often tell me that comparing gain to an isotropic radiator isn't much use because it's only a theoretical antenna, is this true?
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9 votes

Ham operators often tell me that comparing gain to an isotropic radiator isn't much use because it's only a theoretical antenna, is this true? No, that is not true. I generally find that hams that ...

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Is compression "encryption" under FCC regs?
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6 votes

For governments around the world to continue to trust that amateur radio has no nefarious purpose, it is essential that everyone that wishes to, can "listen in" to any amateur radio communications. ...

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Coax or bifilar windings for a choke?
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7 votes

In most multi-band balun applications, there is rarely a need to maintain a perfect 50 ohm impedance within the balun. The feedpoint or input impedance is varying widely so another impedance bump in ...

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Signing of messages transmitted over ham radio
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3 votes

Even though signing of a digest uses cryptographic techniques, this is permitted. The Part 97 regulations regarding obscuring clearly speaks of purpose/intent. The regulation you quoted is the only ...

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What is the equation for the arm lengths of a half wavelength dipole antenna?
5 votes

There are several factors that come into play in determining the length of a center fed 1/2 wavelength dipole - all of which center on the notion of a near resonant feedpoint impedance. To begin with,...

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Doublet with ladder line vs coax w.r.t. noise
3 votes

There are a few things to think about. Coaxial cable will likely not have a positive impact on your RFI. Unfortunately, urban locations are loaded with RFI. Antenna direction and distance are the ...

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Unidentified signals on FT8 frequencies
3 votes

Both marked signals follow an 8 tone MFSK pattern. The one on the left is about 125 hertz wide while the one on the right is about 100 hertz wide. The signal on the left appears to follow the ...

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What are Radio-location Services in the 1.9-2.0 MHz range?
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6 votes

I wish you well with the general test! The radiolocation services in question are defined in CFR 47 §2.106: NG92 The band 1900-2000 kHz is also allocated on a primary basis to the maritime ...

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Estimating the efficiency of a shortened (loaded) antenna
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6 votes

I applaud you for diving into this topic. The notion of trap efficiency has been driven largely by antenna marketing FUD (Fear, Uncertainty, and Doubt) with implicative phrases such as "no lossy traps"...

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What equipment and software do I need to read raw civilian GPS signals on my Mac?
4 votes

Start with a GPS receiver that outputs NMEA data. This data will be made available through a serial connection such as RS-232, USB, or Bluetooth. Pick a serial connection that you can use with your ...

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Cabling question between two devices
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5 votes

RG-174 cable does not offer very good shielding. This can be a significant problem when you are attempting relatively high levels of attenuation as the cable leakage may provide more signal than the ...

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From where do repeaters get their power supply?
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9 votes

You are correct that most repeaters that are on buildings or typical towers get their energy from the commercial grid. The repeaters that I own are all commercially powered. Repeaters that are ...

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Raspberry Pi with TNC-Pi - How to Connect to BBS
3 votes

Assuming that you have: correctly connected your Baofeng to the TNC installed the AX25-tools and AX25-apps configured /etc/ax25/axports with your call and the baud rate attached the serial port to ...

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How can a vertical Yagi for 10 m be mounted on on a vertical metal mast and be made to work properly?
1 votes

A very common approach that is used for satellite antennas is a solid, fiberglass mast. These are readily available from amateur radio distributors. The fiberglass mast has sufficient rigidity that I ...

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Suitable acoustic foam rubber for headphones?
3 votes

Audiophiles like to replace those plastic and foam earpads with a velour product such as this: If red doesn't suit you, there are other choices. There are several vendors for this type of product, ...

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Should I add call signs with /R suffix to the logbook?
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4 votes

FT8 decoding can use a technique called a priori (AP) whereby it uses naturally accumulating information for the purposes of increasing apparent sensitivity by about 4 dB. There is an increased chance ...

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Proper magnetic mount placement on roof
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3 votes

When dealing with UHF and VHF communications, height is often the determining factor of range for line of sight conditions. If there are obstructions that height cannot overcome, then more effective ...

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RTL-SDR: command or script to obtain power and deviation of an FM radio station
1 votes

You may wish to look into GNU Radio as the basic platform from which to develop your specific application. GNU Radio is based on the Python and C programming languages using SWIG for the interface ...

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Toroid Coupling Issue in Common-base Amplifier
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5 votes

The problem is most likely the type 43 core material. It is quite lossy at 21 MHz and is a poor choice for the auto-transformer. Unlike a transmission line transformer, the auto-transformer relies on ...

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What EXACTLY does front to back ratio mean?
2 votes

Antenna gain generally refers to the maximum gain of the antenna unless the context makes it clear that some specific elevation or azimuth angle is being considered. For a directional antenna such as ...

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Baofeng DM-1801 DMR: Language switched to Chinese
4 votes

According to the manual: This radio supports both Chinese and English language. The menu functions as follows: Press [MENU] to enter menu mode. Press [ ]/ [ ] to set, then press [MENU] to select. ...

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Why do some of the amateur radio license names imply something different than what it actually is?
3 votes

If your friend likes the "old" license classes, then he or she should like the Amateur Extra class because it has its origins in the earliest years of amateur radio. In the early 1920s, there were ...

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Can radio waves be made to travel as or along a particle beam?
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3 votes

Light waves and RF waves are both electromagnetic radiation. The only difference is that we can see the narrow band of frequencies that we call light. There is a common misconception that laser ...

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