# All Questions

3,392 questions
Filter by
Sorted by
Tagged with
40 views

### Detect multiple broadcast on same channel

I have a number of ear guards with two way radio communication. They can only be set to send and receive on the same channel, and they have the option of dividing themselves according to the ctcss ...
70 views

### Loop on ground for transmit?

If a large horizontal loop antenna, insulated but laying at ground level, works as an MF and low HF receive antenna, why (even though it has very high ground losses) can't it be used for transmit (to ...
219 views

### What is the radiation pattern of an ~60 foot end fed wire antenna used for 40 meters?

I live in a retirement center. The rule here is “Never do anything anywhere at anytime.” That translates to “No Antennas” which I have been told means I can put out an antenna as long as it is ...
70 views

### Is the time code a way to reduce paper work when it comes to logs?

So a clock can listen to a station WWVB to update time. My question is: Could you use the time code to mark your logs in conjunction with a recorder thus doing away with paper logs all together.
179 views

### Magnetic loop antenna: vertical vs horizontal

I have a magnetic loop antenna for T/R with remote tuning. I would like to mount this in the attic horizontally. Will I loose much performance between mounting it horizontally verses vertical?
90 views

### Why does capacitive loose coupling increase selectivity?

There are mutliple ways to couple antennas. It is said that an antenna is capacitive loose coupled if a small capacitor is used between the antenna and the parallel resonant circuit (like C2 in the ...
91 views

### Lost all pre-programmed channels in BaoFeng UV-5R V2+ after reset. What were they and how do I restore?

I purchased my first radio, and of course I reset it to factory defaults soon after I received it. (I think that wasn't the best thing to do) What options do I have to restore the radio to as-shipped ...
923 views

### What are the regulation requirements for running a repeater?

When I try to find information on the requirements to run a repeater, I just see a lot of results related to building one. But I'm wondering about USA regulations. Does one need a particular license?...
51 views

### 2 meter coax cable balun dimensions for use with a ground plane?

I have a commercially manufactured ground plane antenna for 2 meters. It will be fed with about 150 feet of RG 8/U . I've seen pictures of a coil of the feed line going to a 2 meter ground plane; this ...
125 views

### Baofeng UV-5R transmitting to Baofeng BF888s - 888s will not receive transmission unless holding “mon”

so i have just received today a baofeng uv-5r that i had ordered, i already had the 888s after programming the uv-5r to the same frequency as the 888s, i am able to recieve transmission all LEDs ...
560 views

### Calling a friend on simplex

Can someone please help clarify. I have tried searching all over, but almost all of the examples you find online and in books are for calling CQ on HF. I am new to ham radio, and recently got a few of ...
47 views

### APRS: What's the n in WIDEn-N?

In every description I've found of WIDEn-N, the capital N is described as the "hop count" / "ttl" (comparable to internet ...
41 views

### What's the difference between an APRS “item” and an APRS “object”?

What's the difference between an APRS "item" and an APRS "object"? A kenwood manual says Objects have timestamps, items do not. What does that mean, and how should it be used? Also in general: What ...
81 views

### GMRS Call Sign for Technician

I have a GMRS License and currently studying for my Technician’s License. Once I pass the exam, can I use my GMRS “Call Sign?”
34 views

### Combining two CFU455IT +/-2kHz (4kHz) ceramic filters to get a +/-1.25kHz (2.5kHz) filter for SSB

Can I put two of these cheap (less than 3USD) and common CFU455IT +/-2kHz (4kHz bandwith -6dB ) ceramic filters in series to get a lower bandwidth good for SSB TX? If I'm correct I will get -12dB at +/...
68 views

### Recommended Books For AM/FM (especially AM) Radio Design

I am trying to gain a better grasp of how to build an AM radio receiver. Can you direct me to some books (or other information) that will help?
35 views

### Is it possible to show frequency and channel name at the same time on AnyTone 878UV?

On the AnyTone 878UV I can choose to display the frequency or the channel name or frequency (Settings->Radio Set->4 Ch.Name). But seems to me like there's enough screen real estate to be able to show ...
79 views

### How to model my rooftop vertical on 4NEC2?

A few months ago I built a coil loaded vertical, and put it on my rooftop. My roof is made of corrugated metal, so I connected GND to it, to act as a ground plane (or is it a counterpoise?). With some ...
51 views

### I configured FlDIGI to dislay letters before my PSK31 signal and then I forgot how I did it

Several months ago, before I had a Transceiver that worked, I configured FLDIGI to graphically display the letters QC 13P in the waterfall as a preamble to my PSK31 transmission. I remember I was ...
70 views

### coax switches for HF

Like many hams I have several radios and several antennas. instead of constantly connecting and disconnecting coax cables I would like to feed several antennas in to some type of switch so I can ...
53 views

### What determines the bandwidth of an FM signal?

With an FM signal, it takes up more room in the radio spectrum presumedly because the carrier frequency is changed. On average what's the width of the FM sidebands? Does the deviation from the center ...
73 views

### How do I use a signal generator + oscilloscope to measure feeder length?

I could relatively easily take the feeder down and use a tape measure but it’s more of a challenge to learn how to measure the length using my oscilloscope -Red Pitaya - but I have to admit I have no ...
170 views

### How to make an RF probe for accurate power measurement at QRP power levels?

Typical SWR meters don't measure forward power very accurately at the lower end of the scale, which can be a real problem at QRP power levels. Better power meters like the Bird model 43 are expensive,...
137 views

I am making an AM radio with the specifications of: Part 1. Design a circuit with an antenna for tuning your receiver to a signal of a specific carrier radio frequency so that you can select a certain ...
135 views

### Signal power measurement

I have a radio with a nominal output of 1-30mW (frequency dependent) and amplify this with a 21.8dB capable amplifier (frequency dependent, but should be ~150mW). The signal output then passes through ...
111 views

### Optimal length of HT antenna for VHF UHF and diminishing return

I see folding antennas of various lengths that people are using for for their HT. My question is about the optimal length. I know it may "depend" on many factors so let me know if I need to provide ...
1k views

### How does FM station have fixed frequency when FM modulation changes the frequency?

I am not sure if this question fits better in physics.stackexchange or ham.stackexchange, feel free to correct me. I am new to studying RF and SDR in general, I was looking up how modulation works and ...
89 views

### Why does damping between two antennas increase with frequency?

While studying for a HAM license exam I ran into a question that I am having trouble with answering. There are two aspects that I cannot explain, given my current admittedly little understanding of ...
62 views

### Baofang uv-5rA/ repeater trouble

I programmed my Baofang UV-5RA radio to my local repeater about less than a 1/4 mile away. When I cue the mic and release, I get a signal from the repeater. However, I can only hear people if I have ...
19 views

### Ten Tec Argo IV wont connect to Fldigi on R Pi

Cannot connect to Raspberry Pi with Fldigi, ttyusb0 does not show up in any cat control functions. I can connect my TS590S to the Pi and I can connect the Ten Tec to any window machine. But I cannot ...
57 views

### FT450D no cw tx unless ppt is held

FT450D in cw mode does not transmit unless PTT is actuated. "BK-IN" not in display despite pressing function followed by vox/store button.
111 views

### What frequencies in 118–173 MHz can I transmit on without a license in Canada?

I have a Kenwood TM-261. It has the frequencies from 118 to 173 MHz. What frequencies can I transmit on without a licence?
39 views

### LA1185 FM downconverter shows weird behavior

I've built FM CCIR/OIRT downconverter based on Sanyo LA1185 IC. I've used most famous schematics for it with slight modification (added DC blocking capacitor 1 nF rated on the output) Coils L1 and L2 ...
86 views

I got my HAM Radio License (Grade-One) License issued on 2005 year (New Delhi, India). Unfortunately Date of Termination of the license is missing. Tried reaching Helpdesk via E-Mail but not much help....
88 views

### GNURADIO: What does the complex output of an osmosdr source translate to?

Warning: Noob question. I'm new to Software Defined Radio. My aim is to write a program that tells me the signal strength of a radio emitting source (I'll use three such sources and then try to ...
436 views

### Do FCC obscenity regulations apply to ham radio transmissions?

In particular when ham-sters are using the VHF or UHF bands and talking to each other through repeaters(as well as local radio nets). But also what about DXing? Do FCC obscenity regulations apply ...
72 views

### HAM Radio Exam in English in West Europe

Is the HAM Radio License exam conducted in English in any of the western European Countries?
53 views

### What Are Some of the Most Important Characteristics Applying to the Radiation of Monopole Antenna Systems?

Such characteristics are described in Answer 1 below, as sourced in a study of antenna engineering textbooks, and by generating NEC4.2 studies.
156 views

### Maximum legal QRQ CW speed?

Computer generated and decoded Morse Code seems to be a not-uncommon operating practice in the HF bands. Given this, and that there's no reason why Morse/CW signals can't be synthesized and decoded ...
57 views

### How can a ham from a non-CEPT country operate in Canada?

Long time maritime operator now semi-retired and messin' about with radios. Family in NL and want to bring my little QRP 40-meter rig this summer. I'd like to operate in Canada, specifically VO1 while ...
867 views

### Is “low loss” cable required for HF?

I use RG-58 for all my HF antennas, since it's light, flexible, convenient, and cheap. And super easy to choke. Whenever I have a problem I just loop a few turns of it on a ferrite core and the ...
98 views

### Extremely strong QRM on VHF?

I don't usually operate in 2 m, save for FM satellites. I usually go to a nearby park when I do this, for better view of the horizon. But I tried working them from home for the past couple of days, ...
141 views

### Why do we talk about common mode current from an antenna, but not from a transmitter?

There's a lot of information available about how to block common mode current originating at the antenna end of a coax cable. But, I haven't seen any reference to common mode current originating at ...
161 views

### Not participating in contests

I have only a small amount of time each week when I can get on the air. Frequently I turn on the radio and hear numerous operators participating in one contest or another. Is there some way to ...
85 views

### What is happening in a gutter “antenna”?

can you explain me what is happening with RF in a iron gutter? I've tried to simulate with nec2, but I'm just a beginner and doesn't really know all the parameters to come close to reality. This is ...
200 views

### Are there any “parrot” repeater software projects out there?

I happened across a discussion on building repeaters for Amateur radio, which lead to looking at GMRS repeaters (because apparently this is a potential source for inexpensive 70 cm Amateur repeaters), ...
76 views

### 144/430 MHz antenna on 155 MHz?

We have a local radio shop that started selling us Relm P150s with a high gain 9 inch antenna, and those are ok. He also has thrown in longer 15 to 14 inch dual band antennas saying use those in ...
89 views

I have set myself a challenge to write a Matlab script as proof of concept to send an FT8 CQ call (not necessarily for live transmissions yet, but I may extend the project). So far I have: Generated ...