15 votes

How do PTT buttons work?

The basic PTT (push to talk) button on the HT is a simple switch that is normally open and when it is pressed, the switch is closed (conducting). Internally to the radio, this applies power to the PA (...
Glenn W9IQ's user avatar
  • 18.6k
10 votes
Accepted

Confusion about radio-computer interfaces: TNC, CAT, TRRS, Wolphi Link, ...?

First of all, don't feel to overwhelmed! This can be a bit confusing at the start, but once you understand the pattern and historical development, things will get a bit simpler. So fist of all, you'...
AndrejaKo's user avatar
  • 2,893
10 votes
Accepted

How much current can Baofeng UV-5R provide on +V pin?

With no load, I measure 3.17V With 100kΩ load, 2.91V With 10kΩ load, 1.59V With 1kΩ load, 0.29V The math works out to a 10kΩ series resistance between +V and ground. As such the maximum power that ...
Evan Krall's user avatar
8 votes

How much current can Baofeng UV-5R provide on +V pin?

I would first measure the current draw of your ESP32 to rule out a fault there. The +V pin on the Baofeng microphone connection is probably intended to bias an electret microphone. These are ...
Phil Frost - W8II's user avatar
8 votes
Accepted

How do I put an RJ-45 connector on to repair a Kenwood MC-59 microphone cable?

Here's how to repair a Kenwood MC-59 microphone cable (ships with the TM-V71a, probably the 710, and a few LMR radios as well). First, if you didn’t know already, behind the rubber boot at the end of ...
user3486184's user avatar
  • 1,902
6 votes

Is a connecting computer sound output equivalent to connecting a "dynamic" mic?

A dynamic microphone is basically a speaker in reverse. A diaphragm moves a magnet in proximity to a coil, varying the magnetic flux though the coil and inducing a current in it. You can in fact use a ...
Phil Frost - W8II's user avatar
6 votes
Accepted

Signal in the center frequency of my SDR spectrum always

That is DC offset, either in the analog to digital converters, or their driving circuitry. The average voltage at the ADC's input is ideally exactly in the middle of the ADC's range, since this ...
Phil Frost - W8II's user avatar
5 votes
Accepted

Iskra sst 2030 radio speaker plug

To me, this looks very much like a "DIN Lautsprecherstecker": Positive is the small hole, negative the wide slot. Loudspeaker, if I ask google, is zvočnik in Slovenian – so the "ZV" label makes ...
Marcus Müller's user avatar
5 votes
Accepted

My radio and audio output keep changing using WSJTX on FT8

I'm not familiar with the failure modes of SignaLink devices, but in general, a USB device disappearing temporarily likely means that its internal microprocessor or USB interface chip has been reset, ...
Kevin Reid AG6YO's user avatar
  • 24.5k
4 votes

How to use HT microphone with two jacks (Kenwood connector) as a substitue for KX-3 microphone?

The Elecraft rigs have flexible interfaces for alternate microphone settings. However, there is only the single TRRS plug for a Microphone on the KX3. You should be able to wire up your own ...
K7PEH's user avatar
  • 2,998
3 votes

Iskra sst 2030 radio speaker plug

LEVI means LEFT DESNI means RIGHT ZV1 is speaker one ZV2 is speaker two S this radio has connections for two pairs of 4 ohm speakers. I guess LEFT ZV1 and RIGHT ZV1 are main speakers and ZV2 are ...
Pedja YT9TP's user avatar
3 votes

What is the external mic/speaker pinout for the Yaesu FT-4XR / FT-65R / FT-25R / SSM-16B?

I figured out a way to be able to trigger the PTT properly using a transistor. It requires a high value resistor. I used a potentiometer to find the correct position. Based on a feedback I had, I ...
Olivier F4IHA's user avatar
3 votes
Accepted

Looking for headset to use with BTech UV-25x2

There are standard connectors for microphones, speakers, and headsets, but unfortunately the pinout diagram (schematic) changes very frequently. There is no guarantee that a headset with a 3.5mm TRRS ...
rclocher3's user avatar
  • 9,192
3 votes
Accepted

How to use HT microphone with two jacks (Kenwood connector) as a substitue for KX-3 microphone?

In the end I decided to build a simple adapter. Most handheld microphones available at cheap prices have two-jack "Kenwood compatible" interface. They have 3.5mm TRS jack and 2.5mm TRS jack. The ...
Jindrich Vavruska OK4RM's user avatar
3 votes
Accepted

Is packet radio possible on Baofeng UV-5R and similar HTs?

In the end I used 'amodem' ( see https://github.com/romanz/amodem ). After a few calibration steps, I could get decent I/O rates - considering the nature of the medium. Compression of archives is ...
user400344's user avatar
3 votes

Is packet radio possible on Baofeng UV-5R and similar HTs?

The easiest way now is to get the Btech APRS-K2 Cable: it allows you to receive and send audio to the radio with a single cable. You can use it with the aprs.fi app or with a variety of software from ...
caleb's user avatar
  • 141
3 votes
Accepted

Easy Digi hum with isolated ground

TLDR: 60 volts AC divided by the transformer CMRR is much greater than 1 mA times the resistance of the wire installed. -- In the first case - the raspberry Pi was floating at 60 V AC above ground, ...
tomnexus's user avatar
  • 11.1k
2 votes

Is packet radio possible on Baofeng UV-5R and similar HTs?

Sure it's possible. You'll need some sort of Terminal Node Controller (TNC), either one implemented in hardware or software, plus a set of cables that plug into the 2.5 mm / 3.5 mm TRS ports. If ...
rclocher3's user avatar
  • 9,192
2 votes

What issues can I expect when using Bluetooth for packet radio?

Sounds a lot easier to reverse-engineer the Hand Controller Interface, especially since that comes with a handy RJ45 connector, which would make it cheap to build an adapter that allows you to poke ...
Marcus Müller's user avatar
2 votes

Is packet radio possible on Baofeng UV-5R and similar HTs?

I was able to get a Baofeng HT working with packet, but had to adjust a number of menu items. (The tricky one that is poorly understood is Squelch Tail Elminate or STE.) My suggestion, assuming you'...
Rob McNicholas's user avatar
2 votes

Is packet radio possible on Baofeng UV-5R and similar HTs?

I built a homebrew interface that uses a small USB soundcard with mic and ear 1/8" jacks. Each of those drives a 600:600 ohm transformer. On the radio side, the transformers drive the mic and ear ...
Dave Telling's user avatar
2 votes

Is packet radio possible on Baofeng UV-5R and similar HTs?

I recommend against using the modern inexpensive HT radios for packet, especially if you are buying the equipment on purpose for that application. You'd be much better off with 30-year-old used ham ...
Tadd KA2DEW's user avatar
2 votes
Accepted

What cable is needed in order to record audio from a Baofeng UV-5x3 on a computer?

I built an audio interface that connected from an HF radio to my Mac, a few years ago. Obviously, I was concerned with ground loops and hum and suchlike, because I intended to use the interface to ...
Scott Earle's user avatar
  • 4,599
2 votes

How should I measure RFI on the headset cable from a hand-talkie?

I doubt that SPICE modeling will be successful. There are required criterion that you do not have available such as the impedances at frequency of each device connection, the impedance characteristics ...
Glenn W9IQ's user avatar
  • 18.6k
2 votes
Accepted

SSTV decoder for already-recorded files?

I don't know of digital-mode software that has the capability to open a file, but that doesn't mean that it doesn't exist. However, there is a handy work-around to your problem: a virtual audio cable....
rclocher3's user avatar
  • 9,192
2 votes

Cannot transmit with direwolf ("Audio output start error")

So...I have a solution, but not an explanation. The original configuration was specifying the sound card as plughw:4,0. As I mentioned in the question, this worked ...
larsks's user avatar
  • 608
1 vote
Accepted

Design/Build a DIY Audio Attenuator and Splitter

Pulling some information from Electronics Stack Exchange, https://electronics.stackexchange.com/questions/38452/electronic-aspects-of-iphone-3-5mm-audio-output and https://electronics.stackexchange....
Chris K8NVH's user avatar
  • 1,042
1 vote
Accepted

Using an OPC-478 programming cable for CI-V

I finally obtained one of the described adapters, and I can confirm that yes, it does indeed work fine.
Duston's user avatar
  • 939
1 vote

What is the external mic/speaker pinout for the Yaesu FT-4XR / FT-65R / FT-25R / SSM-16B?

This doesn't quite answer your question, but may get you closer. This cable at Mobilinkd works on the FT-65R HT. They describe it as working with any radio that uses a uses a Motorola M1 style ...
Andy Oliver's user avatar

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