TinySA Ultra says max 4mw signal input. If I buy a 50watt 50db antenuator & use it for 5 to 50 watts in. Will the tinySA still read the lower wattage input thu that? Or will the antenuator just kill all the signal & be over kill? I ask because I want to be able to measure handhelds & mobile radios that do 5 to 50 watts.?

As others have said have an attenuation /power table close at hand. And think twice before pressing PTT

As the tiny SAultra reportedly measures best around the -20 to -30 dBm input range I have a large high power 40dB attenuator and a handful of smaller (1 ,2, 5, 10, 20) attenuators for use on the low power end of the big attenuator to get the Tiny SA working in its best range for fundamental and harmonic display?

I have a tinysa ultra on order. So just trying to plan ahead & figured I'd need an antenuator to make sure I didn't blow it up when transmitting into it making measurements. I just didn't know if it has settings to tell it what size antenuator is in front of the transmitter being tested or not. I know there's charts for db to watts. But trying to find a one size fits all solution was the initial thought here.

Here is a calculator you will find useful...

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I like my peak signals between -30 and -40 dBm. In general more attenuation than you think necessary produces the best signals. I use a total of 70-80dB attenuation testing 1-5 Watt direct inputs.?

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You're going to spend a lot on any attenuator that can handle 50 watts! Good luck!

Hi Bruce,

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I use a large wattage attenuator followed by a lower wattage step attenuator. ?The first is sized for the max power I plant to test (either 50 or 100 watt, 40 or 50 dB). ?This allows me to adjust the level for best accuracy and to validate that the SA is not suffering from signal compression.?

You will most likely spend more on the attenuators than the tinySA if you are going to measure anything over 10 watts.?

example of 2 watt step attenuator:

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I use one like this after a 100 watt 50 dB fixed attenuator?

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73

Evan

AC9TU

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Yes it does have a place where you can put in external gain to account for the attenuation or amplification for that matter. The ultra is a beautiful device as you will find out if you treat it properly.

Dave

So with all the various places like Amazon & ebay etc..

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I see antenuators in Amazon for cheap compared to some other name brand ones. Yet some have good reviews. So do you get what you pay for or are some of these cheaper ones being sold as new any count?

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One of my main interest is being able to measure 5 watt HTs to 50 watt mobiles.?

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I'd hate to get something that's advertised as one thing..then use it to find out it's junk & possibly blow up the tinysa.?

For your 50W mobiles, I would turn them down to their lowest power to test them.? A 50W attenuator is a pretty big thing.

For 50W, you would need a 10dB attenuator to get it down to 5W.? Then you could use a 20dB 5W attenuator to get it down to .05W.?

Then add another 40dB or more of quarter-watt attenuators to get it in the ballpark of where you want to be for measurements.

Hi,

One of my primary uses for the tinySA is measurement of harmonics and spurious mixing products in the output of transmitters in particular. The attenuator must have a flat 50 ohm response all the way to the highest harmonic(s) you must look for. I am a forty meter kind of ham radio licensee so I can use an attenuator that is flat to several hundred MHz and not have misleading results. Your use suggests operating frequencies around 400 or 500 MHz so multiply that up to seven times for what you need from your attenuator. Probably the least expensive devices are inadequate for your needs. With due care you could make your own but it will require a lot effort unless you own a very good lab and have experience using it. I spent a little more on some attenuators that are guaranteed flat into the low microwave region and I can verify them to low GHz with an inexpensive VNA. I have confidence in my measurements in the HF ham bands and lower frequencies. The quality of your measuring equipment is not a good place to cut corners. Just my own opinion gained from a lifetime of using critical metrology. YMMV.

73,

Bill ?KU8H

I'm main interested in HF up to 70cm use. Particularly 2M as well.?

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The reason I am curious about measurements of 5 to 50 watts is as stated HTs & Mobiles. But there's one other reason for a Yaesu DR2X repeater. I hear the transmitter is trashy on those on the 5 watt & 50 watt settings. So I bought this unit particularly just for looking at that machine. I have plans to use a 100watt amp on that repeater. Initially I was going to do a 5 in 100 out. But if the transmitter is trashy at 5 watts. Then that amp will just make the trash louder. I'm told the 20 watt setting is more stable.?

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I just wanted something that I can use for checking thibgs out & make sure the information inwas given was accurate or just someone being bias.?

The $80 Elecraft CP1 can be wired as a 30dB coupler that can handle 250 watts:

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John AE5X

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This is a particular problem with attenuators that use SMD ceramic substrate "chip" resistors.

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Older style carbon rod based attenuators could withstand quite severe overloads for a reasonable proportion of time, but SMD types tend to blow apart within a few mS, often at power levels that are not much above their rated value.

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I have replaced blown 50w "chip" based dry loads with 150w devices, just for this reason, even though the actual, long term, power dissipation remains the same, as it is limited by the capacity of the heat sink.

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Regards,

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Martin

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On Tue, Oct 15, 2024 at 08:30 AM, G8HUL wrote: