The resistors are to determine the current of the amps for a given voltage so you could measure the input current rather than just the applied voltage as they specify an optimum current for the devices I think.
If you have an original MAR-8 then it is a bit of a different animal compared to any of the + versions. I believe the bias resistor was 120 ohms for 12VDC. And the gain is 32dB at 100MHz, 28dB at 500MHz and 22.5dB at 1GHz. Very hard to find datasheets for the original versions in the MAR series.
I looked through the MARs I had before I built a preamp with the 6 because it seemed to have about the lowest noise figure among all of them. On paper. The unit is not compatible with the Chinese prescaler SMA because the HF receive loop antenna required a male input and female output connection.
If memory serves me, the lower gain MAR's were usually the higher power output devices. Of course, memory hasn't served me for years now. It seems like the MAR devices were designed for gain, or for output power, or for low noise.
I have a communication service monitor that has mini circuits mar devices in them for mixing RF circuits. The color dot on the mar device indicates which one, mar1, ,mar4, 6, 8. I have a datasheet some where in my digital mess that has the color code.
@@brianclements1014 mar1 marking=AO1 color=brown mar2 marking=AO2 color=red mar3 marking=AO3 color=orange mar4 marking=AO4 color=yellow mar6 marking=AO6 color=white mar7 marking=AO7 color=violet mar8 marking=AO8 color=blue the newer devices have a + after the part number for ROSH other wise the same device just with no lead.
I should build a MAR amp for my cheap Chinese microwave range counter prescaler. It is not very hot by itself. This is good vids. I just tried to watch another channel this morning of a guy that talked like Squidward rambling on about a piece of obscure test equipment. He was booooring.
The input and output DC Blocking capacitor value needs to be 2400pF according to the evaluation board TB-432-8A+ Also why do you make a long stub at the RF Biasing choke ? Please get your RF amplifier boards reviewed by an basic RF expert.
Hello! I am beginner. Watched a lot of your videos. Can you teach me about the S11 and S21 indicators? Like how many dbm is excellent. How many dbm of Smith is not good? Can you make some tutorials on this?
I don't know much about RF circuits, but in the digital world, using a long lead power clamp is a recipe for disaster, especially in high-current-demand circuits.
The only thing I learned you have four boards and they have various RF gains other, Why is that? we the audience had to guess what the modules was used for. if you would start with what are doing and why you are doing it, we should care. you didn't explain anything to us.
I was given those MMICs and wanted to learn. I don't know much about them so was not in the position to teach you. I just hoped making the boards would be educational and might help someone. No, I don't know everything.
VNA set to -25dBm
Have a MARry Christmas. 🙂
🤪
I recall making one 2GHz amp with possibly MAR-6 around 1996. It worked well.
That green CRT on the HP VNA is beautiful to look at
The MAR-4 (the one with 8 dB gain) is a 4 GHz part. Of course the MAR-2 will outperform it at 1 Ghz!
Nice job calculating and laying out the boards. Have a great holiday.
Maybe the one with 8dB gain was intended to be used on the input of a 4 way splitter / coupler?
MAR8: Double-check the input impedance and consider replacing the input SMA connector. There seems to be an input impedance mismatch.
Thanks for the video.
I like the 3D printed torque wrenches on the SMA connectors.
De VU2RZA
www.pcbway.com/project/shareproject/SMA_Thumbwheel_Wrench_b3dc35b6.html
@IMSAIGuy Thanks for your prompt response 👍
Merry Christmas
De VU2RZA
You probably needed a pad to bring down the VNA's output to the MAR8 input and then calibrate the VNA with the pad. Prob a 10db pad.
The resistors are to determine the current of the amps for a given voltage so you could measure the input current rather than just the applied voltage as they specify an optimum current for the devices I think.
what's the drive level of your vna? make sure you're not pushing them (esp the high gain parts) into saturation.
Yes, indeed worth paying attention. I wondered for a brief moment why a 30dB gain LNA wasn't delivering 30dBm.
A higher gain MAR is more sensitive to the input level!
If you have an original MAR-8 then it is a bit of a different animal compared to any of the + versions. I believe the bias resistor was 120 ohms for 12VDC. And the gain is 32dB at 100MHz, 28dB at 500MHz and 22.5dB at 1GHz. Very hard to find datasheets for the original versions in the MAR series.
I think the original MAR-8 is the same as MSA-0886
I looked through the MARs I had before I built a preamp with the 6 because it seemed to have about the lowest noise figure among all of them. On paper. The unit is not compatible with the Chinese prescaler SMA because the HF receive loop antenna required a male input and female output connection.
Bandwidth, gain, return loss, and noise figure would give a pretty good characterization of these parts...
If memory serves me, the lower gain MAR's were usually the higher power output devices. Of course, memory hasn't served me for years now. It seems like the MAR devices were designed for gain, or for output power, or for low noise.
Also check higher voltage with the other parts, too, please.
Exceeding the MAR-8’s 1dB compression point? Input power should be less than -19dBm, and you did not say what input power you used.
Maybe the MAR's are all the same Die and they are binned into the different performance range ?
I have a communication service monitor that has mini circuits mar devices in them for mixing RF circuits.
The color dot on the mar device indicates which one, mar1, ,mar4, 6, 8.
I have a datasheet some where in my digital mess that has the color code.
I was under the impression that the colour of the dots follows the resistor colour code. Ie yellow dot for 4
@@brianclements1014
mar1 marking=AO1 color=brown
mar2 marking=AO2 color=red
mar3 marking=AO3 color=orange
mar4 marking=AO4 color=yellow
mar6 marking=AO6 color=white
mar7 marking=AO7 color=violet
mar8 marking=AO8 color=blue
the newer devices have a + after the part number for ROSH
other wise the same device just with no lead.
I should build a MAR amp for my cheap Chinese microwave range counter prescaler. It is not very hot by itself. This is good vids. I just tried to watch another channel this morning of a guy that talked like Squidward rambling on about a piece of obscure test equipment. He was booooring.
The input and output DC Blocking capacitor value needs to be 2400pF according to the evaluation board TB-432-8A+
Also why do you make a long stub at the RF Biasing choke ?
Please get your RF amplifier boards reviewed by an basic RF expert.
Hello! I am beginner. Watched a lot of your videos. Can you teach me about the S11 and S21 indicators? Like how many dbm is excellent. How many dbm of Smith is not good? Can you make some tutorials on this?
ruclips.net/video/Gu0b6ZSWJnM/видео.htmlsi=lQ26kTZr78gJknQe
@@IMSAIGuy 谢谢！ 我会努力学习的。
I don't know much about RF circuits, but in the digital world, using a long lead power clamp is a recipe for disaster, especially in high-current-demand circuits.
The only thing I learned you have four boards and they have various RF gains other, Why is that? we the audience had to guess what the modules was used for. if you would start with what are doing and why you are doing it, we should care. you didn't explain anything to us.
I was given those MMICs and wanted to learn. I don't know much about them so was not in the position to teach you. I just hoped making the boards would be educational and might help someone. No, I don't know everything.