Fumei 50w Duplexer review GMRS/Ham tuning with a cheap Spectrum Analyzer

Link: Duplexer
amzn.to/3XDEpA5
Here is the FUMEI 50watt Duplexer. I had three of these in service and the performance is great for the price. Tuning with the cheap Chinese Spectrum Analyzer in comparison to a quality machine. Thanks for watching!
PS: If anyone would like tuning, shoot me a email.

[@tracyd81621]

Hi, I just bought one of these poor man spectrum analyzers. Can you please do a video tutorial (or suggest one) on the basic operation of it? How to set center frequency? Span? Hook up points? Just a gloss over of what you've learned about it. Since there are no instructions for it, its like having a black box without a road map. Thanks!

[@RobertAnderson-ur8nd]

I have the exact same cheap Chinese one I actually bought it like 4 or 5 years ago and I just actually learned how to use it by watching your videos. Thanks for the help

[@DIGGINGDEEP007]

You’re welcome! Great skill to have.

[@christopherradic2183]

U/V UHF VHF Spectrum Analyzer Dual Band with Tracking Source 136-173MHz & 400-470MHz Specifications: - Frequency Range: 136-173MHz & 400-470MHz - Spectrum Dynamic Range: -127dBm-0dBm (practical sensitivity: -115dBm to 0dBm) - Resolution: 1dB - Tracking Source Output Power: ≈ -38 dBm - Interface: BNC-F - Power: External Power Supply DC 8 - 12V Description: - The upper right corner of the spectrum shows the spectrum mode, the display tracking for the spectrum plus tracking mode, which can be switched by long press F1 - The First Line: shows the center frequency & center frequency power - The Second Line: collects the strongest or weakest frequency, or the specified frequency and power (shows the strongest frequency in acquisition mode, show the weakest frequency in spectrum plus tracking mode, display the frequency and power of specified modes (please refer to “Steps to Adjust the Duplexer ") Steps to Adjust the Duplexer: - As adjusting the duplexer, the curve is only for reference. And the exact value depends on the power after the frequency in the first line. - Before adjusting the duplexer, you need to connect the OUT and IN ports via the connecting cable of the duplexer. Adjust the frequency of the first line to a desired frequency, have a look at the power value and write it down to complete straight-through calibration. And this value is about -30dbm. Connect it to the duplexer, if the value becomes -100dbm, that is, the isolation degrees of the duplexer is -70db. - The Third Line: frequency range (center frequency plus or minus), stepped frequency - F1: cursor movement center frequency, frequency range, step cycle selection (long press to switch between spectrum and tracking mode) - F2: Backspace - The Cursor Points to the Center Frequency: Using numeric keys to direct input or using up and down keys to adjust frequency step by step F3 F4: Adjust the frequency every 1M - The Cursor Points to the Frequency Range: The value is based on the center frequency plus or minus the range, for example: 0128000 as the center plus or minus 12.8 M, that is, the range is 25.6M Using numeric keys to direct input or using up and down keys increase or decrease the range - The Cursor Points to the Step: using the number keys to directly input or using the up and down keys to adjust the step change in 5K (The scan range will be slightly changed to fit the size of the grid) Package List: - 1 x U/V UHF VHF Dual Band Spectrum Analyzer

[@monkcheetah8203]

I have to tell my friend from work. He’s a big radio guy. Great video

[@mattm1817]

I believe you want to match the frequency and dBm on the second line to your center frequency and dBm on line 1. By doing such I’ve gotten both matching perfectly and on a flat pack I’ve got about-113 dBm to -127 dBm

[@DIGGINGDEEP007]

Very nice! Thanks for the input. I need to get back into the radio game someday soon.

[@rogercampos1906]

friend congratulations for the video i bought an analyzer like this with it i will be able to adjust duplexers in vhf because at the moment i cannot afford to buy a ringol 815tg

[@DIGGINGDEEP007]

Thank you! They will do the trick.

[@rogercampos1906]

Can I with this equipment adjust duplexer?

[@DIGGINGDEEP007]

Absolutely, I actually sold my regal unit and kept the cheap Chinese unit because I didn’t use it very much. I show the comparison in my videos and it gets it pretty close.

[@PowderMill]

Thanks,,.. Btw: I have the same Rigol DSA815tg.... It’s a great value indeed. I also have an Agilent N9340B “portable” spec analyzer with tracking generator which I purchased for field duplexer and Quantar pre-selector tuning. It was $6700!, The Rigol is just as good. Even though it only does 1.5ghz, it’s almost perfect for the task!

[@Ibelieve218]

i have input 462.675 but the other frequency how do i put that in since no instructions.

[@PowderMill]

Thanks again. Great information here.

[@Ibelieve218]

I have never seen the inside of one but one of my tuning rods does not work

[@nolibera5345]

Thanks for the video. What is the cheap chinese analyzer you used ? Prob going to go with this set up for my first try

[@DIGGINGDEEP007]

They are units on eBay and Amazon. Just search Spectrum analyzer with tracking generator duplexer tuning and a bunch will pop up. Before I purchased my Rigol unit, this thing did get the mobile Duplexers pretty close. It’s definitely cheap, but does work. It’ll come with no power supply or instructions. What I liked is the dynamic range was better then a lot of the other cheap Chinese test equipment. Good luck! Specification: - Frequency range: 136-173MHz 400-470MHz - Spectrum dynamic range: -127dBm --- 0dBm - Resolution: 1dB - Tracking source output power: ≈ -38 dBm - Interface: BNC - Power: need external DC 8 --- 12V - Adjust the duplexer steps photographed after contact the store to obtain

[@Gta2O13]

Question, do you know if there’s a better cheap analyze? I see the video is old though maybe you found a better cheap unit. I’m new to GMRS and spectrum analyzers and learning as I go.

[@DIGGINGDEEP007]

Not that I’m aware of. Thanks for watching!

[@jbx907]

whats the lowest freq can this chinese 50w duplexer go down to, i have the 50w vhf, it would only go down as far as 154mhz, i have to modify it to go down to 140mhz

[@XBKLYN]

Can you share some specs that you may have measured such as notch attention and through losses?

[@MarkPaterson71]

is there much loss with this duplexer? say if I transmit 50 watts is 50 watts going to the antenna?

[@KALAENTAXI]

Thank you for your video, I have the same duplexer and this is my first one, I bought the tinySA so it will help me tune it but my issue is i have zero experience on how to set it up so if anyone has any input or can make such a video would be great. Thank you

[@DIGGINGDEEP007]

The only thing with the TinySA the dynamic range isn’t that great for tuning duplexers. I think like 70 dB which limits you. You can probably get it somewhat close, but then you’ll always be in question.

[@KALAENTAXI]

@@DIGGINGDEEP007 understandable I guess (i say that since i have no idea how these work) the duplexer is set at 462 and 467 mhz so if i can find a way to be able to see that clearly on the screen then i can play with it and try to get is as close possible but my issue is i am not sure how to set it such as setting up the start, center and stop frequencies and so on, the menu is pretty clear for the basics but thats about it

[@KALAENTAXI]

@@DIGGINGDEEP007 or maybe a suggestion for an other alternative such as an other analyzer that would do the job without braking the bank

[@jbx907]

move the curser to the 200, and even have sa smaller span, to pin point it more, i go down as far as 50 on that 200

[@jbx907]

this is what i use

[@jbx907]

200 has a large limit span, to get more, bring it down to 100 and final 50.

[@Ibelieve218]

be great if we had some more inforrmation to go on!

[@Ibelieve218]

so how do i hook everything up!

[@johnwest7993]

How are they for frequency drift with temperature?

[@DIGGINGDEEP007]

I honestly have no idea! I’ve been out of the radio game for some time now, but still use GMRS from time to time. Thanks for watching!

[@Ibelieve218]

I have one and a spectrum analyzer

[@JoseCarlosdaSIlva-yc3dm]

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[@jorgezuni2818]

What’s your rigol model better 😂