All Questions

Lots of explanations i've read on the internet written by ham radio operators and in some text books state that a half wave dipole is resonant when the inductive and capacitive reactances cancel out. ...

I am an extreme beginner with SDR. I am trying to use the 820T2 & SDR device to capture uplink gsm packets sent by my phone to the nearest Base Station. I have an Rx Monitor App installed on my ...

Trying to lengthen my 10mtr. end fed to 39 metres in length. To do this I need the first leg (10mtr.) to run at a lower height approx (5mtr)turning back on a dog leg, and the final 29 meters then ...

Situation: You want to know when a satellite will pass in order to receive an image transmission or to work an amateur satellite. However, you cannot access internet for whatever reason, and ...

I am relatively new to HAM Radio so I’m still learning. I bought a Boafeng and of course feel like I need an upgrade. What would be the best choice?

I'm working on a project in microfluidics and it has become apparent that a significant challenge to overcome is a lack of consensus in connector design. I have been thinking about my time working ...

My brother and I are considering designing and building a remotely controlled submarine. As far as experience, I have some knowledge on RC systems, and I am almost done with my General license. My ...

I found this old log periodic antenna that I assume was from a TV. Could I, or how would I, use this on the amateur radio bands? My main focus would be VHF, with UHF being secondary and HF would also ...

I have a Baofeng UV-5R with stock and a Nagoya 701 (maybe fake?) antennas and wonder how I can receive voice from ISS astronauts? Do they have a schedule for going on air? I live in Romania so ...

I want to adapt the DVB-T AverMedia TV Pilot" tuner as a software defined radio, but it is not built on a RTL chip, so the question arises, is there some kind of driver to use my tuner as a radio?...

I'm brainstorming methods of mounting an EFHW. Unfortunately, I have no trees, so I'm considering a horizontal gutter mount which would afford me about 70 feet. Is this workable or should I consider a ...

I am working on a project designing a 40 MHz radio transmitter, but I need some clarifications. I need to know how to calculate its output impedance. I know how to calculate common collector's output ...

Just moved from SoCal and there were sites out there for exchanging code plugs for the Anytone 878uv. I was wondering if there are similar sites for the northeast of the US. I would love to get a ...

I'm in the process of planning a UHF CB radio repeater. And I've heard there are ones around that transmit a voice message/warning on their input frequency (as well as standard output channel ident) ...

I can no longer change modes in my Baofeng since I cleared all the existing parameters. Did I erase something I shouldn't have?

I have a Kenwood TH-F7E handheld transceiver, bought second-hand a bit less than a year ago. Until about 3 weeks ago, it worked perfectly, then I put it in a drawer and didn't touch it until yesterday,...

Contemplating a big magnetic loop antenna. Would a wide copper strip be better than a tube with the same conducting surface? Where will all the current be due to the skin effect? Would a flat ring be ...

I have 2 Baofeng bt-888 radios coming out of the box. The problem is that the radios still growl on all channels and the light stays green. Le Griche stops when we send a communication or when we ...

I just got all the parts to make a simple AM transmitter from Scitoys. I followed the instructions from different websites and they still don't work. I don't know why it's not working. On my ...

I've got a question and any clarification on that would be greatly appreciated. For calculating the pathloss in wireless communication we usually use the following formula: PL = pathloss (in dB) + ...

We are currently deciding between a dipole and a monopole for uplink (435MHz) , while the monopole is easier to feed, we are unsure of how effectively we'll be able to implement the ground plane, ...

This site gets many questions about people trying to track down RFI, or interesting signals picked up on radios. Often the exact location of the transmitter or the antenna would be a valuable clue to ...

I am attempting to hunt down many sources of RFI in and near the UHF amateur bands at my home, but I stumbled across a very specific one that I have definitely never heard before. This one sounds less ...

I have vague memories from the early 1990:s of some sort of service that broadcast something related to sunspot numbers, in CW, probably shortwave. I think the world "BOULDER" was in there ...

Baofeng radio's have two menu options for squelch tail elimination (STE). Item 35 is for general simplex STE, and item 36 is for repeater STE. My question is how would the radio know if a transmission ...

Can I use 2 identical rubber ducky antennas with a splitter on my CB HT radio to improve range?

Like the question says, can you feed a dipole with coax with no ill effects? Nothing else in the system, just the antenna and the cable.

Do FT8 operators typically respond to very late replies for an entire QSO? (for instance, transmitting in the 3rd slot or 5th slot after a CQ, to maintain even/odd alternation, instead of the time ...

For Yagi antennas where the driven element is electrically connected to the boom like the parasitic elements, how can this function without diminished performance outside of the design frequency? In ...

How does a ham Internet gateway work? Is it possible for someone to use that to listen for my transmissions (over the Internet without needing a ham radio)? Wouldn't the Internet gateway need to be ...

I am wondering if using a VHF/UHF ham radio for emergency (I get injured, become ill, run out of water/food, etc.) communication while hiking the Continental Divide Trail would be possible. I see that ...

When a cellphone is near an electronic device with speakers and someone's calling, we may hear a sound like this due to interference: Cell Phone Interference Sound Can we obtain any useful information ...

I connected USRP (together with antenna) to my computer to receive some signals. For this purpose, I used the built-in module "Spectral Monitoring (Interactive)". Unfortunately I noticed ...

I am planning on utilising a ferrite choke on a J Pole antenna for CMC. Placement directly on the feedpoint poses possible mechanical restraints. Is it okay to place it a quarter wave down the coaxial ...

Are there lengths of feed line to avoid or ones that may cause problems with an antenna system? For single band use. Appendix: The run of coaxial will be for the 10 metre band. I would imagine this ...

I have all the space in the world and wish to errect a single random longwire to use on the one band only. I understand that once such a wire is very long, losses associated with the wire itself (a ...

I have installed a grounding system just outside my radio shack and was careful to avoid a quarter wavelength or multiples thereof (for single band use), or anything in total length that is close to ...

What are the real losses associated with a typical gamma match at a set frequency? Furthermore, are there good designs or dimensions to minimise these losses?

Is it possible to obtain the S-parameters of a circuit with only S11 measurements (S11 measurement with a VNA)? My gut tells me that it should be possible by connecting open, short and characteristic ...

My understanding is the earbuds that connect to the aux port act as the antenna. It's a long wire. The problem is that the same wire is being used to power your earbuds so you can hear the radio ...

I have an EFHW 40-10 in inverted L configuration on a fiberglass mast. I'd like to put an aluminum push-up mast nearby for a 6 meter antenna. How close can I get to the EFHW with the push-up mast? ...

Why are notch filters used on the transmit side of a repeater duplexer? The primary purpose of a duplexer is to keep the transmitter output out of the receiver input, since they both operate at the ...

The point I'm confused about is the antenna. Depending on the environment, there are tons of different frequencies passing through you (FM, AM, 4G, SAT, etc). The electrons in the wire will move as ...

This is my first time ever asking a question on stack exchange or any stack site, so please be gentle if I missed something here. I am currently working on building a UHF (GMRS) repeater, and while ...

What are currently the (5 or 10) biggest amateur radio contests in terms of Worldwide participation (total number of stations or operators on the air during the contest)? Are they the ones with "...

ORIGINAL QUESTION I am trying to increase the range of communication between two SDRs to simulate near space communication. The output power of TX is 10dBm but I would need 37dBm for near space ...

I'm looking at a simple FM transmitter output (see picture). It is from the collector of a transistor and it goes through a DC blocking capacitor before the antenna would be connected. The entire ...

I just bought a Diamond CP-5NMO hatch/lip mount and intend to put it on the hatchback lip of our 2018 Subaru Forester and, if it will fit, another one on our 2019 Kia Niro EV. I understand that hatch ...

Are there any requirements to post, carry, or have available an official paper copy of one's radio license in order to operate in the U.S.? Do any states require physical possession of a printed ...

I have studied for and am ready to take my amateur radio license test but there are currently no licensed instructors available in my region to administer the test. Can I start acquiring ham radio ...