All Questions

-1
votes
2answers
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?
5
votes
5answers
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?
0
votes
0answers
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 ...
1
vote
2answers
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 ...
4
votes
4answers
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?
0
votes
1answer
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 ...
4
votes
2answers
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 ...
1
vote
2answers
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 ...
2
votes
0answers
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 ...
3
votes
2answers
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 ...
1
vote
1answer
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 ...
14
votes
5answers
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 ...
5
votes
1answer
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?
0
votes
1answer
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 ...
4
votes
3answers
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 ...
2
votes
4answers
70 views

How can I get a license to build broadcast transmitters?

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 ...
5
votes
1answer
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?
0
votes
1answer
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 ...
0
votes
3answers
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?
1
vote
4answers
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 ...
3
votes
1answer
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 ...
-2
votes
0answers
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 (...
0
votes
0answers
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 ...
5
votes
2answers
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 ...
4
votes
2answers
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 ...
4
votes
1answer
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 ...
3
votes
2answers
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 ...
2
votes
0answers
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 ...
4
votes
3answers
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 ...
4
votes
2answers
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 ...
9
votes
4answers
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 ...
1
vote
2answers
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 ...
5
votes
2answers
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 ...
2
votes
3answers
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 ...
3
votes
4answers
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 ...
0
votes
2answers
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.
2
votes
1answer
37 views

Attenuator Cascaded Connection

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 ...
3
votes
3answers
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 ...
1
vote
2answers
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 ...
1
vote
2answers
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-...
2
votes
3answers
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 ...
2
votes
1answer
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 ...
3
votes
1answer
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 ...
3
votes
1answer
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 ...
7
votes
1answer
71 views

overhead power-line safety

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 ...
3
votes
2answers
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:
7
votes
3answers
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 ...
1
vote
1answer
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). ...
2
votes
2answers
98 views

How does keying a CW transmitter work?

In my handbook it talks about keying the transmitter to produce the dots and dashes. Does this mean that the operator is turning the transmitter on and off, or does this mean that the key is turning ...
0
votes
1answer
41 views

Really Low SWR Reading On PMR

I spoke to a friend about what antennas I was using for PMR and the frequency range on them was only set to 170-430Mhz he said it could lead to a high SWR, So I decided to test it out for safety ...

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