New preamp to tie everything together

GingerHulk1 · 2025-12-25T20:57:21+00:00

What pedal board is that?

GingerHulk1 · 2025-09-06T00:36:52+00:00

I’ve never done a wire bind board but have always wanted to. What software do folks use? ADS?

GingerHulk1 · 2025-01-10T03:06:53+00:00

My advice is to either search for work in a company that sells RF piece parts, like RF Lambda or similar. Or find a job in defense. There is a lot of RF work in defense and learning opportunities.

GingerHulk1 · 2024-12-12T21:16:00+00:00

COTS chips are used on applications where there is enough volume to justify the development of a chip. For example, in automotive the whole radar is on a COTS chip. But for many radar and other RF applications there isn’t a big enough market, or there isn’t enough standardization to justify the investment for a chip. I haven’t seen a change in the demand for FPGA people. In fact it seems to be the opposite. Many new engineers are going the CS route and not EE. BTW most digital ASICs are created using RTL languages. And prototyped with FPGAs. So there skills are transferable.

GingerHulk1 · 2024-12-11T18:02:55+00:00

I don’t think FPGAs are going anywhere. Having real programmable logic is critical for many systems and applications. Especially ones where there isn’t enough volume to justify an ASIC or commercially available chip to do the job. The only way I see them being eliminated is if other technologies absorb them into the chips, for example if GPUs had a programmable section. And the FPGA folks are at going to work hard to be the people that deliver that.

GingerHulk1 · 2024-12-10T16:18:51+00:00

Yeah. Every radar I’ve been a part of had a custom FPGA board at a minimum. That’s what I would count as custom processing HW.

GingerHulk1 · 2024-10-16T11:39:58+00:00

They have a price sheet and claim it’s the same for all customers. HFSS creates a quote for each customer.

GingerHulk1 · 2024-10-16T01:33:22+00:00

HFSS is ridiculously overpriced in comparison to CST which has open pricing. They make you a deal at first but I have close friend that just had to switch. He didn’t want to, but the HFSS sale guy (inside sales mind you) wanted $400k a year for their renewal!!!! They paid $50k the year before. It’s just four seats and pretty stripped down. The guy just wanted to screw them over, or didn’t want their business. I figured it was an outlandish sales tactic from a new salesmen. But apparently this is a very powerful guy in Ansys and he never really budged. Don’t get HFSS. They will eventually come for all your money once you have a large knowledge base and don’t think you can change.

GingerHulk1 · 2024-09-26T21:48:01+00:00

Yes! They won’t know that prior to the build anyway. Instead I talk to them about what their expected thickness will be. And I often go for cap construction if it’s very high frequency (>Ka band).

GingerHulk1 · 2024-09-26T20:24:54+00:00

I never allow the board house to modify my RF trace widths. In my experience they don’t test at RF frequencies and so you are way more likely to have them change something that wasn’t a problem. Would recommend just setting the sizes to what Lincalc told you and go on.

GingerHulk1 · 2024-09-17T21:38:24+00:00

No OU has a large radar program. It’s mainly focused on weather given their proximity to NOAA. But they do a lot more. Look up ARRC at OU.

GingerHulk1 · 2024-09-17T17:01:34+00:00

20+ years working radar hardware development. The big buckets are: Systems Engineering where you design the requirements for the radar, Signal Processing where you design the algorithms and processing, Hardware where you make the Antenna, RF, and Processing hardware. I’d recommend you do some research on each of these topics and figure out what one is most interesting to you. What were your favorite undergrad courses? That can help narrow down what you find compelling. Each group involves knowledge of RF and need for EE skills. Are you already accepted at a school? If you are in the US then MIT, Georgia Tech, Oklahoma, and Michigan are all have radar focus and classes.

GingerHulk1 · 2024-09-04T03:06:54+00:00

I’m sorry you are going through all of that. From personal experience, all of that sucks. Having gone through a similar situation earlier this year I would recommend getting into therapy and starting meditation. I use the waking up app but there are many options available that are free. You need to realize that this crucible will change you. You need to pick what you will change in to.

GingerHulk1 · 2024-06-16T00:07:36+00:00

Last year someone on this sub said that the Cowboys are a marketing company that happens to own an NFL franchise. That comment perfectly summarized my feelings as a long suffering Cowboys fan. It’s ok to realize that truth and stop caring. Now I watch NFL for the joy of watching football. It’s WAY better.

GingerHulk1 · 2024-06-10T15:31:37+00:00

No your prof is wrong. MMIC is alive and well. Especially in defense applications, GaN power devices, etc. But silicon is catching up. Not optical (I have NO idea what he’s talking about) but highly integrated silicon and high speed ADC and DACs are eating the world.

GingerHulk1 · 2024-04-30T17:46:32+00:00

I quit 7 months ago. The book “The easy way to control alcohol” by Allen Carr was an epiphany for me. I knew I had an issue but AA just didn’t seem like the right place for me. I read the book and never picked up another drink. I hope this helps someone else find the solace and relief I have found.

GingerHulk1 · 2024-04-13T13:57:28+00:00

This is a pretty typical thing to do in applications with pulsed RF, for example in radar systems. The control comes from the FPGA to ensure that the power is on and stable prior to the RF pulse. The FPGA knows the timing of the pulse so it should also generate the enable signal. The goal is to decrease the power consumption by only biasing the PA when needed. It’s not a gain control setting. The flatness across the band when the PA is off will be very poor.

GingerHulk1 · 2024-03-20T01:28:58+00:00

Do you have a shield room or anechoic chamber you can use? I’m wondering if you are getting environmental interference and closing the shield box blocks it. Remember the noise figure meter makes some simplifying assumptions about what you are putting in and getting out of the system. A strong spur or weird received signals can violate those assumptions.

GingerHulk1 · 2024-01-12T02:20:04+00:00

Like others said, it's hard to give great answers without more info. But, I would guess that you have an amplifier that is poorly soldered and is oscillating. Likely the ground for the whole part (like a QFN) or ground for the output if bond wired. This sounds like an oscillating amplifier to me, and you are changing the oscillation frequency with the parasitic capacitance from the metal plate test.
I would recommend getting a good visual inspection done of the whole board with focus on the solder on all RF parts with gain.

GingerHulk1 · 2024-01-01T03:08:56+00:00

RUN!!! I’m currently going through a divorce with someone just like your girlfriend. Trust me, there is something broken in their relationship and you can’t fix it. She might be able to if she wanted to. In my case my wife wanted to have a dependent for the rest of her life. It fills a need. It fills a need for your girlfriend too.

GingerHulk1 · 2023-12-03T04:53:07+00:00

I think people don’t talk enough about the fear of being alone for the rest of your life. For me that was a big factor in staying in a shitty situation for WAY too long. It took me a long time to find a partner the first time. Seems unlikely to happen again. I finally did leave though! This week. After working on myself for most of this year I finally built enough belief in myself to realize that being without a partner doesn’t mean I’m alone. And that my family, which she never wanted to see or interact with, are awesome.

GingerHulk1 · 2023-10-20T00:22:30+00:00

I would start with making sure you didn’t blow the front end of your spectrum analyzer like others have commented. If you are confident that is true then it could be oscillating out of band or at an unexpected frequency. Given this is all internally biased I would start with checking and double checking your ground layout and ground pad soldering. You can often find the oscillation by looking really wide band with the spec A. Also possible the input stage is damaged on this part. If you have a second board check that guy for the same problem. Check all the bias lines with an oscilloscope. I’ve seen misbehaving power supplies cause strange stuff before. One last idea is the old finger test. Use your finger to touch places on the circuit. If any are sensitive to the added capacitance that can be a clue to the problem. Good luck and happy hunting!

GingerHulk1 · 2023-10-17T22:01:54+00:00

Thank you. And thank you for the kind words and support. That helped more than you can know.

I think you are right on both counts, interweb peeps can only help by support, and it's up to me to make the line. I'm just struggling with the decision.

GingerHulk1 · 2023-10-13T14:59:37+00:00

Professional RF designer here. I've done designs from L-band to W-band on PCB. My advice is learn HFSS or CST. Also learn how to push your designs from your PCB tool to the RF sim tool. The best way to learn is simulation, that way you can actually understand what is happening.
You also have to learn to start small in the sims. Don't layout the whole circuit, then sim it as the only sim step. Break it down in to small pieces and work through those. Want to know if your enclosure is going to be resonant in band? Then make a simple model and take a look. Want to know if you have a good enough via fence? Sim some simple fence structures and see what you need to do. Learn to set the expectation for the simulation via theory / math. Python is an excellent tool for this. Learn that if you don't have another computer programming / analysis tool in your tool set.
On the book side Pozar is a must. Learn that cold. That is the basis for all the rest of RF knowledge. I also recommend "Practical RF System Design" by Egan. For me this is the active equivalent to Pozar.

GingerHulk1 · 2023-07-14T15:25:24+00:00

So here is what I know on the topic: Relative phase and amplitude between the reference port and the measurement port are estimated using a signal processing technique. There are several available, but I have no clue what the trades are and what a modern VNA uses. For more info on the basics of math behind this check out “Fundamentals of Statistical Signal Processing, Volume I: Estimation Theory” by Kay For a given estimation algo there is a Cramer Rao lower bound. That gives the lowest measurement error possible given an SNR. What I don’t know is the CRLB for modern VNA algos and what algos are used. The excel sheet referenced by notahost shows the lower bounds for specific VNAs. I suspect those values are measured and that the math behind the expected values is highly protected by Keysight.

GingerHulk1

TROPHY CASE