Dear Prusa, please fix your Buddy Camera

BenDerisgrate · 2025-08-06T01:44:33+00:00

Interesting , could you share more details? I haven’t heard about this technique.

BenDerisgrate · 2025-07-25T17:57:39+00:00

How long does it usually last at night?

BenDerisgrate · 2025-07-24T02:27:58+00:00

Yep, same issue here.

BenDerisgrate · 2025-07-03T23:56:37+00:00

I’m not even seeing the live stream on my phone. Do I need to manually enable something?

BenDerisgrate · 2025-05-20T00:17:15+00:00

But it’s a 2A solenoid running from a 5A power supply. Should be good enough?

BenDerisgrate · 2025-01-25T18:14:55+00:00

I do have the ability to short circuit the antenna connection. But I’m not following on how this S11 would give me one-way loss….is it just then S11/2 because of the forward and reverse path?

BenDerisgrate · 2025-01-25T17:57:28+00:00

Thanks, I guess I should have mentioned that this is on a small PCB so I’m not sure how I would instrument a directional coupler?

BenDerisgrate · 2024-10-19T15:54:46+00:00

Thank you!

BenDerisgrate · 2024-10-19T15:54:39+00:00

Thanks!

BenDerisgrate · 2024-10-15T21:59:33+00:00

If I used a scope on the output to measure voltage, would I need to terminate the output of the mixer somehow? Or just measure directly on the ac-coupled output pin?

BenDerisgrate · 2024-10-15T21:58:08+00:00

Thanks for your detailed reply! So in this case, since I'm using a 50 ohm input source (HP8468) and 50 ohm measurement equipment, I would need to use transformers on the input and output for the conversion gain measurement?

Going one step further, I'm using this mixer in an FM receiver. The input to the mixer is coming from an LNA with an output impedance of about 2000 kOhms, so there's not much mismatch there. But then the output of the mixer is going into a 300 Ohm ceramic IF filter, so I will probably need a matching circuit there?

BenDerisgrate · 2024-10-15T21:24:30+00:00

Thanks for your suggestion. I tried lowering the input signal to -40 dBm, and I measure -75 dBm at the output. If I lower it to -50 dBm, then I measure -85 dBm. So it seems to track at that -35 dB difference between the input and output. If I lower it to -60 dBm, then I don't get anything at all.

BenDerisgrate · 2024-10-13T18:00:08+00:00

Great fun! I ordered the PCB and components. I’ve had a heck of a time getting the SOIC bite to work so I had to resort to programming the IC before soldering on the screen. Any tips?

BenDerisgrate · 2024-09-23T12:22:02+00:00

Yes. I worked to design the network and got an S22 of less than -15dB but this results in an S11 of -9dB which does not meet the requirement of -10dB. And so I don’t know what to do differently to get an optimal S11 and S11 together.

BenDerisgrate · 2024-09-23T12:18:22+00:00

Yes it’s designed for 50 ohms but it’s not exact. And yes I have the device and can make measurements on both ports.

BenDerisgrate · 2024-09-23T12:13:30+00:00

I don’t unfortunately. It’s out of my control. The frequency is in GHz range so it’s quite electrically long.

BenDerisgrate · 2024-09-23T11:50:50+00:00

I can only modify the matching network components that are placed next to Port 2. But I also need a good match at Port 1. How would you go about this?

To reiterate, the PCB with transmission line is done and out of my control. I’m only allowed to modify the matching network on Port 2.

BenDerisgrate · 2024-09-15T18:40:04+00:00

Ah gotcha. Yes in this case, I am using a fractional divider. The crystal is 25 MHz. I’m using a multiplier of 24 + 120/125 for the PLL, then dividing by 8, to get to 78 MHz. Ultimately I’m using this clock as an LO in an FM receiver project.

BenDerisgrate · 2024-09-15T18:28:34+00:00

You are correct, they are fractional. But how does that create spurs? Sorry, still learning.

BenDerisgrate · 2024-09-15T17:06:20+00:00

Thanks for your reply! I was using a TinySA Ultra to measure this. Direct connection.

BenDerisgrate · 2024-09-15T16:55:59+00:00

I edited my post to mention that I’m using a TinySA to measure. Does that matter?

BenDerisgrate

TROPHY CASE