# All Questions

2,626 questions
59 views

### What are Smart Antennas?

What are Smart antennas. Are them used in amateur radios and their significance in amateur radio communication over the conventional antennas?
556 views

### Is a 5 watt UHF/VHF handheld considered QRP?

QRP doesn't have a strict definition, though 5W or less seems to be a common threshold. So would "QRP operation" usually be considered to include UHF/VHF handhelds?
18 views

### Troubleshooting ICOM PS15 Power Supply

I got a power-supply gifted by my friend. When I powered ON, the main (120V) FUSE blows up. I started by disconnecting the transformer and the control circuit and powered ON. This time the fuse is NOT ...
33 views

### To which part of the band should I tune my Hi-Q wire antenna if my transceiver has an automatic antenna tuner?

I'm attempting to tune my DX-EE Alpha Delta multi-band wire antenna. The instructions state: The 40 meter sections can be shortened to the SSB section of the band by pulling the wires through the ...
204 views

### Are QRP transceivers only meant for CW communication?

I was just thinking about making a QRP transceiver, but are they only used for CW (Morse code) communication? If it is so, can I modify a QRP for two way audio communication?
32 views

### How to interpret VSWR results for an attic antenna

I have an Alpha Delta DX-EE antenna in my attic. The antenna is 40 ft long and my attic is about 5ft high by 55 ft long. There's a lot of other stuff up there--a chimney, Romex, Cat 6 cable, RG-6 ...
39 views

### Can ferrite beads lower coax cable velocity factor?

For VHF and UHF, it seems reasonable to slip ferrite beads over a coaxial cable to act as a transmission line common mode choke. It also seems reasonable to use beads with the smallest diameter ...
52 views

### How to convert a crystal controlled tranceiver to VFO (aka Unbinding from the Rock)?

If you look at the circuit diagram for a Colpitts crystal oscillator, it's pretty simple -- a crystal, load resistor, and capacitive voltage divider, with the positive supply feeding the control ...
44 views

### GnuRadio alternative for Selector Block

Hi I want to switch between tx and rx in a flow graph with my HackRF. I found this video that shows how it could be done. The key component is the Selector block which is now deprecated. Is there a ...
86 views

### NMO bicycle mount antenna has unexpected SWR

I built a bicycle antenna mount featuring an NMO connector to allow quick changes. With a 2m 1/4 wave monopole it gives reasonable SWR results (1.4 or so in the band of interest), with a particular ...
36 views

### did static fry my uv5r?

I was hit with a big arc of static from a metal door frame. I was a little over a foot away. It stung pretty good, then my coworker told me I was transmitting. My baofeng uv5r will not stop ...
3k views

### Why are vacuum tubes still used in amateur radios?

I wonder, even in this modern generation why the outdated vacuum tubes are used. In other electronic circuits they have been replaced by more efficient (and small) transistors years ago. Why they are ...
81 views

### How long can a transceiver be unused before I have to use a variac?

I have an old TenTec Argosy II that hasn’t been powered up for 20 years. How long can electronics go unpowered before I have to worry about the electrolytic needed a slow power up with a Variac?
23 views

### Using Satnogs' *.ogg files in GnuRadio flowgraphs

I want to use the *.ogg files available in Satnogs' database to test demodulation software for several satellites (using gnuradio). Can i use the ogg file source (available in gr-satnogs module) and ...
56 views

### How to measure wire for antenna leg | 40m inverted V

I am building the antenna for the first time and I have choosen to start with 40m inverted-v. I am almost done with the center insulator made of PVC piping elements, three eye hooks and SO 239 ...
70 views

I am in the United States. The title pretty much says it all. I am really into to building transmitters. It's even more fun for me than using them. I really have a lot of skills and would like to ...
1k views

### What is homebrew?

My question is the title itself: what is homebrew (or home brewing)? And how do homebrews differ from ordinary ham radios?
51 views

### Raspberry Pi rpitx for SSB with filter?

Using rpitx, we can transmit SSB using a single GPIO port from the Raspberry Pi. This of course uses square waves so creates a lot of harmonics. If I were to use a ...
75 views

### Is it legal to operate Ham Radios for educational purposes

I'm a student and new to amateur radios. Is it legal to operate ham radios for educational purposes without any license?
123 views

### What is a simple kind of amateur radio transceiver I could try to build, as a beginner?

I am new to amateur radio, and I'm trying to learn the basics of the hobby. I would like to build a simple radio transceiver from scratch (i.e. not from a kit). I have searched the Internet for ...
63 views

### What is the main source of error for SWR meters?

A swr meter is designed to work with a specific impedance transmission line, that usually being 50 ohms. The meter is calibrated to be correct for 50 ohms and it won't read correctly if the ...
27 views

### Can I store the DCS in an audio file and merge it into my audio stream?

Can I store the "digital coded squelch" in an audio file? I would like to repeatedly add a second DCS to an audio stream on a high-end Linux router. (running OpenWrt) I'm using two OpenWrt routers (...
58 views

### Is PC to Digital Radio possible, is there an existing solution?

Is it possible to setup up an interface from a PC to a digital radio that is able to communicate with a Hytera PD702 handheld (450-520MHz) or like type radio? Or are there off the shelf radios that ...
54 views

### Effective Area of Dipole Array

I'm trying to design a low frequency dipole interferometer antenna array. I am realizing how little I know about radio antennae. I'm confused by the concept of effective area $A_e$ and how it applies ...
63 views

### distance between shack and antenna

I am putting a 40m antenna in my attic and I was wondering would it be safe to have a shack in the room right below the attic (10ft of coax or less) or should I have my shack in the basement/ground ...
157 views
+50

### Loop antenna layout and radiation?

I've got, for the near term, limited resources to put up an HF antenna at my home. One of the options I can manage without excessive cost is a loop, which would enclose the house. I need to transmit ...
158 views

### Can I have a signal generator on while it's not connected?

The unit in question is an Elecraft XG3 test signal generator. It puts out anywhere from -107 dBm to 0 dBm. Is it safe to have these signal generators on and transmitting while not connected to ...
20 views

### Noise Floor when receiving Es'hail 2

I'm currently trying to receive the Es'hail 2 satellite using a standard TV LNB, 60cm dish and RTL-SDR. My dish is slightly offset by 2 degrees, and my SNR is only about 15dB unfortunately. My main ...
129 views

### Given the classical top down view, what does a bottom up view of RF waves look like?

Quote from Wikipedia, Photons: "Nevertheless, all semiclassical theories were refuted definitively in the 1970s and 1980s by photon-correlation experiments. Hence, Einstein's hypothesis that ...
49 views

### Why do receiver sensitivities vary so much with frequency?

I was looking for a 2.4 GHz WiFi antenna to catch a weak free WiFi signal, and amplify it so I can use it. I found Ruckus Metroflex NG, which can receive signals down to -108 dBm. Which is amazingly ...
917 views

### What did it mean to “align” a radio?

I've heard older hams talk about "aligning" their equipment. E.g. "I sent it to a guy for alignment" or "that rig probably needs to be completely aligned before you use it". As a kid, sometimes I ...
69 views

### Is double amplitude modulation useful?

If i amplitude modulate an AM carrier with an audio signal, can i then feed that resultant AM waveform into another modulator and amplitude modulate the AM signal to give a signal which is amplitude ...
69 views

### Does a loop antenna have less susceptibility to atmospheric noise than an open ended antenna?

I always get the feeling that an antenna which has a loop for the driven element such as a folded dipole or quad will pick up less static or 'high impedance' noise than an antenna that has free ends ...
92 views

### Are standing waves on a transmission line RF or DC?

I am very confused about Standing Waves on transmission lines. Wikipedia says "a standing wave, also known as a stationary wave, is a wave which oscillates in time but whose peak amplitude profile ...
95 views

### Is there a way to explain antenna radiation patterns on receive without reciprocity?

I don't consider myself an expert, but I have a fairly decent understanding of radio. I belong to a club that includes a number of people who have less theoretical background. I understand that ...
38 views

### How old do you have to be to be a ARES volunteer?

Look at the title for the body because my question is short.
37 views

PAT1220-C-10DB-T5 is a 10dB attenuator. (This chip is just an example, it could be any other component as well). Can I simply connect 3 of them in series in a PCB design to make my cheap 30dB ...
70 views

### Real world performance of magnetic loop antennas?

I was investigating about magnetic loop antennas. In a paper about them I found some bold claims: and This almost sounds too good to be true, considering a lot of us hams are surronded by city noise ...
49 views

### Noise reduction

I live close to an AM transmitter broadcasting in the kW of power. My RTL SDR dongle gets very overloaded. Using 2 AM broadcast filters, I have mostly managed to stop the overloading, at least from ...
61 views

### What to do when accidental emission can't be given a call sign ID?

Yes, obviously, it would be best if there's not an emission that doesn't include a call sign ID. Part 97 seems to say this should never, ever occur (the law is often written in that kind of black-and-...
100 views

### How can I get started with Amateur Radio?

I would love to get involved with amateur radio, but I'm not sure how. My community recreation center hosts a class to get a Technicians license for a reasonable price (\$10), and I know a little bit ...
44 views

### Ufer ground and ground rods

I am about to build a new house with a ham shack incorporated in it. I am considering installing number 4 copper wire in the foundation around the perimeter as my ground ring. Is it necessary to ...
59 views

### Selecting Directional Coupler for VSWR Measurement

Assume directional coupler is coupling with 16dB attenuation when signal is traveling from input to output. And directivity is let's say 20dB. If I understand correctly, when the RF signal is ...
49 views

### JS8: does a QSO over a relay counts as a valid QSO?

I'm playing with the new JS8 mode. One feature I find particularly interesting is an ability to relay messages using rigs of other OP's. Though I'm not sure whether such QSOs should count as valid ...
71 views

A set of utility lines, and above them some high voltage power lines, run almost directly over the backyard fence. Some radio antennas are situated so that they can't fall onto the utility or power ...
63 views

### What does CI-V stand for?

In the context of controlling a radio from a computer, what does CI-V stand for? I've noticed in relationship to a jack as well as USB. For example, from the Icom IC-7300 manual:
97 views

### Antenna options for a 10x20m property with a large metal roof?

I live in a house that sits in the middle of the city, in a lot 10x20m in size. The first 6x10m are covered by a metal roof with a rather low angle (IIRC only 50cm difference between the highest and ...
49 views

### How can I improve my Es'Hail 2 reception?

I'm using an RTL-SDR to receive Es'Hail 2. My chain is as follows in order: 60 cm TV Satellite dish pointing 2 degrees off Es'Hail 2 Universal LNB (from TV company, not really a stable frequency). ...