All Questions

I do apologize if this has been answer previously, but the term "VFO" seems to have become overloaded over the years. I think I have a handle on the notion of multiple VFOs on device for the ...

Is it something to do with electrolysis?

A colleague was winding an air coil himself. It's a 110µH coil with 200 windings for an 80m antenna, intended to be used on a 600 W transceiver. He used a copper lacquer wire with 0.6mm diameter. ...

I've built the M0AYF active loop antenna for my RTL-SDR, using BC847C for the amplifier transistors. There are a couple very strong AM stations here, usually playing music. What I'm noticing is that ...

I've read that the commonly used 49:1 (7t:2t) auto transformer for Multi-band End-fed Half-wave (EFHW) antennas has criticisms as not being very efficient. I haven't found any other designs that ...

Does this look familiar to anyone ?

This is a question about power dissipated due to radiation and ohmic heating caused by common mode current in the coaxial shielding, specifically at VHF frequencies. When a balanced antenna (such as a ...

I built my first 1:1 CMC transformer recently using 100 ohm CAT5e pairs in parallel. I used an FT-114-43 with 9 turns on each side and squeezed it into a small box with female coax connectors. I plan ...

I am trying to eliminate RFI coming from a raspberry pi 4. The Rtlsdr(enclosed in a metal case) is directly plugged into the pi without any USB extension cable. The frequency of interest is at 1420....

Would it be possible to receive the transmissions from JWST (James Webb Space Telescope) as an amateur, building your own antena? Would the transmissions be encrypted? One source cites it using: S-...

I recently decided to conceive a 10W class 446MHz amplifier. I want to be able to amplify a 100mW signal into a 10W, for that i'm going for a two stages amplifier : SKY65162 to amplify the signal to ...

I am running a barefoot 100 watt radio for my HF operations now. Also using a MFJ tuner that's limit is 300 watts. I am putting on my wish list a 800 watt amp. So I know I will have to upgrade my ...

I just noticed the clock on my Yaesu VX-7R is running very fast. I noticed this a few days ago, where it would be days ahead. I would reset the time to the second and then, again, hours or days ahead. ...

My friend just got a 2006 Chevy Calorado and it came installed with an 3.5mm SMA cable running from the roof to under the dash. It was a park ranger vehicle so it would make sense that they needed a ...

By turning of CTCSS/DCS can there be an increase in performance*? *Performance: Battery life Latency Range Voice quality From what I understand CTCSS/DCS is extra work for the IC inside the radio. ...

There is a region of the lower 43 meter band designated for ISM use in the United States by the FCC starting at 6.765 MHz and ending at 6.975 MHz. Both "FIXED" and "MOBILE" usage ...

My name is Roger, I live in Sweden, have bought some old motorola synths x9000 transceivers that I need to reprogram, but have great difficulty finding the Rvn 4007E software as it should be. Have ...

Suppose that several licensed amateurs are part of a volunteer search and rescue team. The team is normally licensed and carries equipment to communicate on a variety of public safety bands in VHF/UHF ...

If you have an DC/AC Inverter with a AC Transfer switch (so it also connects to grid power AC/110V to pull power from the grid when/if the 12V battery source drains down), and the inverter ...

My radio is an mcHF kit that I just finished soldering up. It receives fine, but when I went to transmit it's giving off the scale SWR. I rechecked my antenna with my NanoVNA, and it shows 1.2 SWR at ...

I've been learning how to make 49:1 auto transformers to run end fed half wave antennas. As I understand it, the twisted lead forms a zero voltage point which acts like a ground. Assume I'm using ...

I just got off the phone with my town's electrical inspector (in Massachusetts), and he informed me that you are not allowed to hang anything electrical from "vegetation". He said if I did ...

I have a pair of hearing aids which can be toggled between listening modes (telephone, noisy room, outdoors, etc.) using a key fob-like device. The control fob was lost before I got the aids, so I ...

I'm seeing this strange signal on the CB band around 27 MHz, at a glance it looks similar to NFM modulation, but it's just noise when tuned to. It's transmitted about every minute. My setup is RTL-SDR ...

I have CHIRP daily-20220103 It works great on my Baofeng BF-F8HP. When I load the Baofeng UV-9R I cannot go to the settings tab. I can get to the memories tab just fine. I decided to load the software ...

Does anybody still hear phantom Morse code in your brain after ending a session? I'm hearing random beeps that definitely don't come from an external source. I tried to search Google but couldn't find ...

Has anyone been successful getting chirp to run on a Linux system that's primarily set up for Python3? I find it's complaining about not finding the serial module, but when I install it with pip (...

I recently decided to conceive a 10W class 446MHz amplifier. I want to be able to amplify a 100mW signal into a 10W, for that i'm going for a two stages amplifier : SKY65162 to amplify the signal to ...

I've had an interest in amateur packet radio for a long time, specifically working amateur packet radio satellites, and specifically the ISS digipeater. In my journey through to the infinitely ...

I would like to choose a feedline that is safe for the wattage at a given VSWR to avoid coax arcing. How do you calculate peak voltage given a peak power in watts and maximum expected VSWR from ...

I'm trying to understand the use of GS cards in NEC2 decks. The documentation is rather vague! Consider a basic stack: ...

I'm currently trying to broadcast my computer's audio output to a wireless microphone system receiver so that I can accompany my school's coming presentation with music. The frequency range is 480-598 ...

I'm working on some research for a project of mine. The project requires the use of millimeter wave radar. I am having a very hard time figuring out what the FCC's regulations on frequencies and ...

On the Baofeng F8HP display, which bottom or top is the RX and TX?

I'm used to simple RX/TX bandwidth configurations, on my VHF FM rig it's either narrow, normal, or wide. It seems to be much more complex on my new HF SDR rig, and the instructions don't say anything ...

I'm thinking about trying a coil in my collinear 5/8λ antenna, instead of the 3/8λ phasing delay line between the lower and upper elements pictured below. I figure that a coil with a certain ...

We are looking at the Qorvo QPL9547 LNA and the datasheet notes: For TDD Applications: R1 = 0Ω & R2 = 100K For FDD Applications: R2 = 100K ‘OR’ Pin 6 tied to ground. R1 = DNP/Omitted This will ...

I'm designing a 300W power amplifier using the MRF300AN from NXP targeting a center frequency of 146 MHz. Obviously I need to keep my fingers out of it and test into a dummy load, but generally ...

I have an assortment of whip antennas for various RX & HT devices such as a 2M/70cm FT740, a Uniden race scanner 29-54Mhz/108-174Mhz/406-470Mhz/806-956Mhz, a similar Realistic Pro-32 scanner and ...

Previously, I used the "Osmocom sink" and "Osmocom Source" blocks, but after updating the GNU radio to version 3.9.4, these blocks were gone. As far as I understand, now it has ...

I am just beginning to learn about SDR. I purchased a "NooElec NESDR Mini 2 SDR & DVB-T USB Stick (RTL2832 + R820T2) with Antenna and Remote Control" I plugged it into my Mac, downloaded ...

I'm trying to figure out how to properly connect new ground rods for an antenna to my main panel. Any advice from those who have done this + have great electrical knowledge would be greatly ...

Certainly there are companies in the US (like Kenwood) that develop HAM products that transmit. For development and QA they would likely need to test the product outside of a Faraday cage. How can ...

I am a disabled person and need help programming my uv-5r with all the pertinent emergency frequencies that apply to my area. Aurora, colorado. I'm not licensed ham and want to stay within the legal ...

I'm very new to shortwave listening and just got to grips with my RTL SDR HF dongle. Last night while on the 20m band, there were signals exactly every 50kHz, starting exactly at 14.000MHz, then at 14....

I am installing a yagi antenna that will receive signals from multiple omni antennas that are vertically polarized. Which way should the elements of the yagi point to match? Up and down, or horizontal?...

I have read about double-balanced mixers and as far as I got the theory right they should suppress carrier frequency. I am trying to build my own transceiver project and I cannot suppress the carrier. ...

I have a mobile mounted CB antenna that has an SWR of 1.5 on channel 20. Is it possible to use it with a 10 meter radio? I do not have enough room on my car for an additional antenna, so if it is ...

New Motorola XPR8300 repeater in place, but NO idea how to set up Talk Groups. HELP! Tommy NH7R

Today I received my first radiotelephone, Baofeng UV-5R HTQ. I saved some frequences and put the device in the MR mode. In one frequency, I make it scan through the saved frequencies, on the other one ...