Author Topic: Amazon attenuators, any good?  (Read 1826 times)

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Offline W4PJBTopic starter

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Amazon attenuators, any good?
« on: January 12, 2024, 04:31:11 pm »
Has anyone tested any of the inexpensive attenuators from Amazon, or have experience how they would compare to a much more expensive units from companies like Pasternack or MiniCircuits?

Here is an example:

https://www.amazon.com/BECEN-Male-Female-Connector-Attenuator/dp/B07DXPT3FT/ref=sr_1_8?crid=SM5W8UHDV7B3&keywords=30%2Bdb%2Battenuator%2Bn%2Bconnector&qid=1705076905&sprefix=30%2Bdb%2Battenuator%2Bn%2Bconnector%2Caps%2C92&sr=8-8&th=1

Thanks!
 

Offline fourfathom

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Re: Amazon attenuators, any good?
« Reply #1 on: January 12, 2024, 05:12:30 pm »
I've purchased a few attenuators from Amazon / BECEN.  They are usually OK, with decent performance up to 1GHz (at least the smaller-attenuation 10W SMA connector ones I've got)  Sorry, I don't have any test data handy.  But one 100W "50dB" N-connector one I got from BCEN actually just has about 40dB attenuation.  It was reasonably flat over my frequency range of interest, and it managed to handle the 50W or so I ran through it.  I put a "40dB" label on it and still use it.

These attenuators are commonly available from aliexpress.com, and they all look the same -- I don't know who actually makes them, or where "BECEN" gets theirs.  QA rejects, perhaps?

So if you are able to test the attenuator before using it, it's probably worth a shot.  If you want something with better-guaranteed precision Amazon/BECEN is probably not your best source.

And watch out for power ratings on Chinese attenuators and dummy loads.  I can buy the exact SMA dummy load, sold as "1W" and "2W" devices.  They get pretty hot at 1W.
We'll search out every place a sick, twisted, solitary misfit might run to! -- I'll start with Radio Shack.
 

Offline Bud

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Re: Amazon attenuators, any good?
« Reply #2 on: January 12, 2024, 06:18:13 pm »
For casual use or for Ham radio you can use those, they likely have a vanila axial resistor inside. For use with expensive test and measurement equipment and for measurements i would get one from Minicircuits. The Chinese ones may ruin your equipment connectors because of poor mechanical tolerances. That is beside poor attenuation accuracy, frequency range and return loss.
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Online DaJMasta

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Re: Amazon attenuators, any good?
« Reply #3 on: January 12, 2024, 11:11:08 pm »
For not so much more, you can get used or NOS name brand attenuators on ebay or similar - while they will probably work at least to some degree and that may be enough, as others have said, the real deal as a surplus part will likely be a lot more reliable and better manufactured provided the connectors are in good shape.
 

Offline David Hess

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Re: Amazon attenuators, any good?
« Reply #4 on: January 12, 2024, 11:12:38 pm »
But one 100W "50dB" N-connector one I got from BCEN actually just has about 40dB attenuation.  It was reasonably flat over my frequency range of interest, and it managed to handle the 50W or so I ran through it.  I put a "40dB" label on it and still use it.

I usually consider single stages of attenuation above 20dB to be questionable anyway.
 

Online DaneLaw

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Re: Amazon attenuators, any good?
« Reply #5 on: January 13, 2024, 07:08:26 pm »
Got two attenuators from "Becen" though with SMA-connectors, and they seem solid - as far as I can tell (with the price in mind).

One 5W -40Db that is rated for 3 or 4GHz weight around 45.5g and another 5W but way smaller,  also -40db and rated for 13GHz.
I don't have linearity to 13Ghz to check it, but with TinySA Ultra 30Mhz test-signal they both at least seem db accurate and were quite cheap at under 12 USD incl. 25% VAT & delivery.

« Last Edit: January 13, 2024, 07:12:30 pm by DaneLaw »
 

Online nctnico

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Re: Amazon attenuators, any good?
« Reply #6 on: January 13, 2024, 07:18:45 pm »
Now test the power rating using a DC power supply... See if they hold up. The fact the sticker is restricting is much of the airflow, doesn't look good to me.
« Last Edit: January 13, 2024, 07:20:19 pm by nctnico »
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Online DaneLaw

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Re: Amazon attenuators, any good?
« Reply #7 on: January 13, 2024, 07:38:06 pm »
The somewhat beefy silver 5W unit works fine with 5 to 7 watts, from handheld transmistters though gets a little hot after extensive tests, but that goes without saying..
- the small -40db 13Ghz jobby, Im not even gonna try to challenge its powerrating, its small... its not its questionable 5W power rating that appeals, more if it's linear a good part up in these higher frequencies, as most relative cheap attenuators drops of quite fast.
 

Offline mojoe

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Re: Amazon attenuators, any good?
« Reply #8 on: January 14, 2024, 06:16:01 am »
I just received a Becen 50 W, 50 dB attenuator. It's rated to 3 GHz. First thing, I checked it on my Lite VNA. Yes, it is 50 dB +/-1 dB or less out to 3 GHz. However, the return loss gets progressively worse past 500-600 MHz, and goes to hell above 1 GHz.

For my needs, this is OK. I doubt I'll ever need a high wattage attenuator at those higher frequencies.

As for the 2 W attenuators, see my other post in this section. They fair much better.
 

Offline Randy222

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Re: Amazon attenuators, any good?
« Reply #9 on: January 15, 2024, 10:19:56 pm »
There are two main specs you should ask from any maker of this stuff.

VSWR chart
DC ohms test to nearest 1mOhm

Actual power handling is gonna be a crap-shoot unless vendor actually specs out a DC power level point where the thing burns out or has some level of degradation.

If the unit says 0-3GHz and the VSWR goes higher than 1.5, garbage. Good stuff should stay around 1.2 (or lower) in the specified range.

If VSWR is 1.2 up to ~500MHz and you'll be under 500MHz, then perhaps you lable it "0-500MHz", but don't expect the little 10w item to handle continuous 10w.

 

Offline Solder_Junkie

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Re: Amazon attenuators, any good?
« Reply #10 on: January 15, 2024, 10:30:19 pm »
Generally cheap SMA attenuators tend to have a better return loss measurement than cheap N types. Being physically small, SMA types tend to have a better specification in terms of matching/return loss. I have bought eBay (Chinese) SMA attenuators and had no issues with them up to the limit of my test gear (3 GHz).

SJ
 


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