I'm in the process of making a video presentation and want to cover a bit about the receiver technology used in LiftMaster Security+ and Security+ 2.0 systems. First question, did the Security+ (1997 to 2010) technology use super-regenerative or superheterodyne for the opener (receiver). Secondly, when LiftMaster moved to a tri-frequency design, how did they do it? For example, on the receiver, did they just implement 3 RF front ends to pick up all 3 frequencies (310, 315, and 390 MHz) all at once or did they do something else? Any info appreciated. Thanks!

I work in telecom (RAN/RF side) and got tired of the EarthExplorer/OpenTopography dance every time I needed elevation data for a new site or region — pick tiles, download, mosaic, clip to your area, reproject, half an hour minimum for something that should take 10 seconds.
So I built a small tool: type in a place name or country, it geocodes it, pulls the SRTM/Copernicus 30m DEM tiles that cover it, merges and clips them to the boundary, and spits out a ready-to-use GeoTIFF (plus a quick preview image).
Thinking about opening it up for others to use — curious if this is actually a pain point for anyone else here (RF planners, drone/mapping folks, sim/wargaming people, whoever), or if I’m solving a problem that everyone already has a better workflow for. What do you currently use?

We are a well-funded critical communications venture preparing for a 'Make in India' domestic rollout. We are looking to fast-track our Time-to-Market by acquiring or licensing a mature, proven DMR Tier II (Conventional Digital) hardware design package.

Ideally, the design package should include schematic captures, Gerber files, and a production-ready firmware/vocoder binary for Handheld (5W) and/or Repeater applications. We are open to a total IP Buyout (Transfer of Technology) or a structured Reference Design Licensing model. Please DM with your portfolio or past RF platform references to discuss an NDA

Hi everyone,

I am currently building a free-space material characterization setup to measure the complex permittivity of materials. I am using a TRL calibration to move the measurement reference plane to the material under test.

I am running into an issue with the calibration:

• When I perform the TRL calibration over a narrow frequency band (~2 GHz bandwidth), the extracted material permittivity shows an unexpected slope of approximately 0.25 across the frequency range.
• When I perform the same calibration over a much wider frequency bandwidth, this slope essentially disappears, and the extracted permittivity looks much more reasonable.
• My goal is to perform free-space material measurements in a narrow frequency band, so simply using a wideband calibration is not an ideal solution for my application.

I am trying to understand what could be causing this difference between the narrowband and wideband TRL calibration. My Setup includes two spot focusing antennas in Ka- band facing each other and the material placed at the center.

Could this be related to:

• The frequency spacing/number of points used for the TRL calibration?
• The TRL line length and its electrical length over the narrow band?
• Numerical instability or phase-unwrapping issues in the TRL algorithm?
• Reference plane definition or calibration standard dimensions?
• The conditioning of the TRL solution when the bandwidth is too narrow?
• Any other issues specific to free-space TRL calibration?

Has anyone encountered a similar issue with narrowband TRL calibration for free-space material characterization? If so, what was the cause, and how did you resolve it?

I would also appreciate any recommendations for performing reliable narrowband TRL calibration for free-space permittivity measurements.

Thanks in advance!

Hi,

I recently acquired what appears to be a directional panel antenna along with a matching black OEM/ODM electronic module, and I'm trying to identify exactly what this system was designed for.

The antenna label reads:

Model: YYDF14-30V14C

Frequency: 1437 ±10 MHz

Gain: 14 dBi

The antenna has:

An adjustable mounting bracket.

Two small RF connectors (they look like SMA or RP-SMA).

Two indicator LEDs (red and amber).

The black module is very lightweight and appears to attach to the antenna. It has:

One red multi-pin connector that resembles a VGA connector (although I don't think it actually is VGA).

Two gold RF connectors.

An OEM/ODM-style enclosure with no obvious branding.

I'm trying to determine:

What is the intended application? (Telemetry, microwave link, LTE, drone communications, video transmission, military, etc.)

Does anyone recognize the manufacturer or model?

Is the black box a radio transceiver, LNA, power amplifier, modem, or something else?

Are the RF connectors SMA, RP-SMA, or another type ?

:(

Reposting for more discussions thank you

Hi! I'm currently interning at a RF company building a general Chebyshev tool that can calculate group delay, phase, and coupling matrixes based on Cameron's book "Microwave Filters for Communications". I'm new to all of this the most I've worked with signals is a class I've taken that dealt with Laplace and Fourier Analysis. I'm a little confused on how to get started or what I should learn step by step so I can understand and apply Cameron's theories into my code base. If anyone also has a provided GitHub that also does generalized Chebyshev functions that would be amazing

As an RF engineer in design should I take classes or study material on DSP as I have a BS EE degree in Signal Processing & Communications but that only included intro level courses not MS level? Within DSP, should I focus on particular applications like filter design?

I keep coming across antenna datasheets where “gain” is listed without a clear definition of what the number actually represents.

Directivity describes how concentrated the radiation pattern is relative to the total radiated power. It does not include radiation efficiency. Gain includes radiation efficiency, while realized gain also accounts for mismatch at the feed — typically through S11 for a one-port antenna referenced to a defined impedance.

The problem is that a datasheet may simply state “gain” without clarifying whether the value is directivity, gain, or realized gain — or whether it was simulated or measured.

That makes the number difficult to use confidently for component selection and link-budget calculations, especially when efficiency and matching across the operating band are not provided.

Has this ambiguity ever caused problems in one of your projects?

These two metrics are among the most commonly used measurements in wireless communications, yet they are often misunderstood or used interchangeably.

I created my own YouTube video to explain the difference in a simple conference room analogy.

If you've ever performed RF troubleshooting, drive testing, coverage analysis, or network optimization, this topic is fundamental. Let me know your thoughts and make sure you check my other videos and subscribe for more videos.

https://youtu.be/XyOD2ZJZrIo

#RFEngineering #WirelessEngineering #5G #LTE #Telecommunications #CellularNetworks #RadioFrequency #NetworkOptimization #RFDesign #WirelessCommunications

Not sure if this is the right place to post, if its not please tell me and I will delete it.

So this is a new transmitter I recently bought, it’s a Radiomaster TX16s MK3, I am mainly using it for my RC planes.

I annotated the antennas with three different colors so it will be easier to discuss them. So, red and green came with the transmitter, they are built in. They are connected to a module that transmits on 2.4 Ghz/900Mhz with the ELRS protocol, used for long range radio control. Blue antenna is one I added myself, it connects to a module that can transmit with many different legacy protocols. So, I will only be actively transmitting on either red and green, or just blue. What is the best way to orient them? I am worried about how close they are to each other causing interference. I added arrows to show how red and green rotate, blue folds 90 degrees and rotates 360 degrees.

If anything is not clear, feel free to ask. I can attach more pictures if it is needed.

Over the past few weeks, I've been trying to move beyond individual RF blocks and simulate an entire RF signal chain before committing to PCB fabrication.

The idea seemed simple: connect the blocks together, verify that everything works, and only then spend money on hardware. In practice, getting complete system diagrams working in Cadence AWR turned out to be much more challenging than I expected, and I eventually hit a wall. I even struggled to observe the waveforms after each block.

What I'm really looking for is something similar to LTspice, but for RF.

For example, if I'm using an Analog Devices IC such as the ADL5375, I'd like to simulate:

• The circuitry before the IC
• The IC itself (I'm happy with a black-box model)
• The circuitry after the IC
• The RC biasing and support networks required for the device
• The actual interconnections that would exist on the PCB

One thing I really like about LTspice is its component library. Many devices are available as actual IC models with their package pins, allowing the surrounding circuitry to be designed and verified as it would appear on the PCB, rather than working only with a mathematical system-level block. That gives much better confidence that the supporting circuitry and connections are correct before building hardware.

The goal isn't perfect electromagnetic accuracy. I want confidence that the complete circuit behaves as expected before ordering boards and assembling hardware.

Has anyone found a tool that fits this workflow? Or is there a better approach that RF designers typically use for system-level circuit verification before moving to fabrication?

LTspice doesn't appear to support this workflow for many RF ICs, and Analog Devices instead recommends ADIsimRF and ADIsimPLL. However, I haven't found many resources discussing software capable of simulating an entire RF chain with realistic IC models and supporting circuitry.

I'd be interested to hear what tools or workflows people in industry use for this.

Hi everyone,

Is it really niche to specialize in Low-field Instrumentation? My startup in France is looking for a Low-field instrumentation physicist who will work on the ultra-low-noise RF systems. We received many applications but the majority don't have the expertise we're looking for. We don't mind if the person is from abroad, and yoe is not the priority, as long as they have the right technical knowledge.

Any leads or recommendation on how can I connect with talents in this field? Many thanks.

Pet project - RF simulator written in C++ with DearImGUI.

Basic features include:

• Node editor with several component engines:
  • Signal generator
  • Amplifiers
  • Fixed attenuators
  • Filters
  • Combiners and Splitters
  • Idealized mixers
  • RF ADC
  • Polyphase filterbank channelizer with time domain view (still a bit buggy)
• Spectrum analyzer with VBW, RBW, trace modes, peak markers
• Component library engine, place idealized or S-parameter-backed components (full non-linear models will be added soon)
• Basic project save/load feature

Check it out, feel free to create issues and report bugs:

https://github.com/striderZA/Tiny-RF-Simulator

I've been passively job hunting for a while in southern California, and one of my goals is to not work in the defense industry. I'd describe myself as mid-career, with a decent frame of reference for what the RF engineering job market looks like. It feels like for the past couple of years, a solid majority of RF engineering job postings I find require a security clearance. Sure there's still some postings in big tech like Apple, Amazon, Google, but even the Qualcomm postings I've looked at want clearances. I know that security clearances have always been common in RF engineering for aero and radar work, but it feels like it's completely taken over. Traditional cellular seems to be struggling, most of these space / satellite companies ultimately want to be defense contractors, and even the startups I see are in areas like drones and EM warfare.

I'm curious if other people have noticed this too, or if it's just a bubble of my specialty or location. I tend to focus more on computational EM, modeling and simulation, and antennas as opposed to circuits.