All Questions

I'm 99.9% certain that this will be OK, but independent verification would be reassuring. I am an "Intermediate" licence holder in the UK. This means that I am authorised to design and build my own ...

I would like to understand how to calculate receive wattage given the following (excluding feeder loss and SWR): Transmit 50 dBm (100W) => 24 dBi directional antenna => 30 dB path loss => 24 dBi ...

There is no difference between the High and Low power settings. Both being around 25 watts. Is there an internal adjustment or do I have to re-program the radio?

The well-known repeater listings/apps don't provide a database that you can download and use freely for any use in building your own app. Is there a such a freely accessible repeater listing database ...

Recently I've been reading about EME and there was one thing that surprised me. Many sources claim that EME has path loss for 2m band about 252 dB. In the same time they claim (one, two): Recent ...

In my working design, I have a transceiver TX on low power; Then boost it in a preamp phase in the back. The way I'm sending the signals (RX and TX) through the radio is by a network of 1/8 to 1/4 ...

When designing a waveform for packet radio usage, it'd be helpful to know a few things, mainly distribution of coherency bandwidths distribution of coherency times Whilst such statistics are ...

I have a baofeng DMR radio with SMS feature, and since there is not much DMR radio owners in my area I want to do something myself. The easiest thing I can do I thought is to send myself some SMS as ...

I'm having the following problem with my FT-817: 1) Receives fine on all bands 2) Transmits fine on 2m and 70cm 3) Doesn't transmit at all on 160m through to 6m 4) Keying the MIC on 160m to 6m, ...

I have Kenwood TH-D72 2m/70cm HT. According to the manufacturer the sensitivity is "Less than 0.18 uV". I would like to check this, since the radio is not new and I'm not it's first owner. To do this ...

Some time ago, I set up my Hytera PD785G. Unfortunately, I can't remember whether I have only requested my digital ID (I can look it up on ham-digital.org) or whether I have also entered it into the ...

I bought a FE-5650A rubidium standard reference from eBay in the hope I can readily use it: https://www.ebay.com/itm/142361240786 Unfortunately this is far from "reasily useable". First and ...

As I am settling on a design for a radio I need to figure out one thing: Should I modulate on low power and boost it up with a post amp, or should I go on full power right out of the gate?

So I have the misfortune of being an apartment dweller. I know that 50 watts is pretty safe as it is what first responders use on 2 meters. Am I really going to have to run around with an analyzer ...

I need a directional antenna for 10 m that is less than half the size of a yagi or quad with more than about 7 dBi of gain, does anyone know if such a thing exists ?

TL/DR: How does someone make a good horn antenna system without using expensively made parts? Welding thin steel for this is not something even pro welders can do (it's a specialty app.) What are DIY ...

Our local repeater is severely sabotaged by unknown parties. For example, broadcast radio transmissions are repeated. Other times someone will send a transmission, when a qso is in progress. Local ...

I want to share the same antenna for VHF (TX/RX 144-148 MHz) and for Airband RX-only (116-136 MHz). I live on a very congested area where filter is a must, so I'm looking for the best solution for my ...

I'm looking for an amateur radio license class in central Iowa, near Des Moines. I've been unable to locate anything through web searches.

Why does this band have special operating characteristics and what do they mean.

Ferrite beaded cords, and especially double-sided ferrite beaded cords, seem especially uncommon. Are there other, perhaps more effective ways, which I should be minimizing the EMI of my overcrowded ...

It's my understanding that FM is used for UHF, VHF, and SSB is generally reserved for other bands. From my understanding, FM better audio quality when reception is good SSB: more efficient (can ...

What if I wanted to run a radio broadcast station on a commercial SW band? Say, I am on a boat in international waters. Or say I am in a free country. I monitor the frequency for months and I check ...

My use case is intercontinental HF radio, and I am frequently traveling. Lugging a big rig is inconvenient and expensive ones get you into customs trouble all the time. So, I'm looking for a low cost ...

Anyone out there know of or developed s/w to predict HF conditions using ML?

Which currently popular digital/SDR modes do not require a pre-compiled library or pre-written source code? (e.g. has actually been used for QSOs as implemented from specification or sufficiently ...

In an effort to "up my game" attempting to build a VFO for my DIY transceiver, I've been looking at PLL theory and circuits. Many of my research references are quite old and I understand that many of ...

What is the best way to get an amateur radio license in different countries? This question is a community wiki, which means that it's sort of a placeholder, an index of answers. More info Answers are ...

I'm new to CW and one thing I couldn't figure out is when I supposed to send "E E". Let's say I'm calling CQ and somebody answers me. The QSO is almost over. Should it be ended like this: ...

I am making a superhet SSB CW receiver with a crystal filter on the input after the mixer. Do I have to use IF transformers as the coupling method? Or can I use capacitor coupling with resistors as ...

If something bad goes down (state-wide or nationwide), what frequencies should I be tuning into? I did see this answer, but I have a BaoFeng UV-82HP which cannot do HF at all, so what are my options? ...

I am buying a house in the UK and the property next door has two poles for antennas. The next door lady seems to be very nice person and said her husband is an RF engineer and he used these on ...

I am in rural Alaska and I am very far from anywhere that gives Ham Exams. I got a Ham Radio and I want to operate it and talk to people. However, I read that frequencies are not allowed to be ...

How is the signal-to-noise ratio for received CW and QRSS CW (and/or other ultra narrow-band DSP digital modes) typically computed? e.g. What noise bandwidth should be used to measure the spectrum ...

I have an analog 27 MHz transceiver which i am planning to convert to 10 m. The radio is an AM / SSB unit with a single conversion superhet receiver with an IF of 7.8 MHz using a crystal filter. This ...

What's causing these horizontal bands of noise? It's the middle of the day here in a low density city neighborhood. They were not present about 20 minutes ago; now they are even stronger and filling ...

When my father - who became a ham years after I did - passed away, I found an unstarted project (board + components), which I only re-discovered again years later. The board is marked DK0TV-001, and ...

In A Century of WWV, I found this mention of an unusual sounding instrument that may have once been commonplace: Calibration work was mainly focused on decremeters, instruments designed for ...

My gas burning heating unit takes its temperature readings from a 433 MHz thermostat, which is emitting precisely the same data packets in a packet train at some ~100 ms interval like this: 2 x OOK ...

When my university encouraged me to apply for an amateur radio license, they never mentioned the fact that my address would be listed on the public FCC database, for anyone who Googles my name to ...

I am DIYing a class-AB HF Linear Power amplifier. How to quantify the non-linearity of this amplifier. What are the common measures of non-linearity as applicable to RF power amplifiers? How to ...

I'm trying to listen in to the telemetry frequency for Wallops Island which is 411.325 MHz. When I punch this into my radio (Baofeng UV-5R), the closest I can get is 411.320 MHz. Will I still be ...

I'm using a commonly available imbedded firmware implementation of FreeDV with an SSB HF transceiver. It seems that FreeDV encodes the input audio signal in both the frequency and time domains, ...

What is so special about a low noise amplifier? If I were to design an amplifier, I would always design an amplifier with low noise anyway. Why is it emphasised as being “Low Noise”? What are the ...

I am looking for a output filter to use with a HF linear amplifier called miniPA70 which is available through several online auction sites. The circuit is available here : http://iu3idf.blogspot.com/...

If I understand things right if you go "down" to "lower bands" you eventually get to "top band", which is 160 meter band. Since this doesn't make any sense to me, is there something I'm missing? You ...

I am building the T/R switching circuit for an HF linear amplifier covering 80m band to 20m band. The current circuit takes a potential-free contact from the exciter and use this contact to turn on/...

What does this mean: CQ de KYHP QTC? K My father-in-law was a radio operator in the merchant marines during WWII — this was his last writing.

I'm trying to get a ham radio listener working with RTLSDR on an old Pentium 4. Unfortunately it is playing for a few seconds, then not playing for a split second, very split up. Is there a way I can ...

Linux Mint MATE 64 (system is up to date) I installed qsstv first it runs normally but no CAT .. then I installed hamlib and put in the same string for the USB Device like in FlDigi which runs now ...