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Signal generator level

 

Is there any future plan to drop the minimum signal level output available below -115 dbm? This would be more useful for receiver sensitivity testing since most radios levels are around -117 dbm to -118 dbm.



Karl Steudl
2 Pilgrims Ministries/Acts412 Maintenance &?Communications
Batt.Chief/Fire Marshal ret.
Ham radio call N8XBD/GMRS call WPXT770

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Minimum output level used to be -120 dBm but not all HW was able to reach this level so the limit was set to -115 dBm
The limiting factor is leakage which can not be improved within current cost and space limitations
Adding a cheap external attenuator and setting the external gain to negative the attenuation solves the problem
--
Designer of the tinySA
For more info go to

 

My approach would be to use one of those small SMA connector attenuators. They're fairly inexpensive and you can get them in levels from 3DB to 30 dB. That's what I use.?

I even use it for low-level QRP work. The ones I use will handle two watts.

Watch 'Yer Top Knot and Keep Your Powder Dry,
?
James R. Harvey - The Wyoming Geezer -?Armed and Dangerous
PM ¡à Progress Lodge #22 ¡à Order of the Eastern Star



On Wed, May 7, 2025, 02:09 Erik Kaashoek via <erik=[email protected]> wrote:
Minimum output level used to be -120 dBm but not all HW was able to reach this level so the limit was set to -115 dBm
The limiting factor is leakage which can not be improved within current cost and space limitations
Adding a cheap external attenuator and setting the external gain to negative the attenuation solves the problem
--
Designer of the tinySA
For more info go to

 

Even my HP 8648C set to -136 dBm (the minimum internally available output) plus additional external attenuation leaks just a wee tiny bit!? Still good for receiver MDS evaluations.? I've never looked at the leakage from the HP 8640.? Maybe someday.....

Dave - W?LEV

On Wed, May 7, 2025 at 2:43?PM James Harvey via <wyominggeezer=[email protected]> wrote:
My approach would be to use one of those small SMA connector attenuators. They're fairly inexpensive and you can get them in levels from 3DB to 30 dB. That's what I use.?

I even use it for low-level QRP work. The ones I use will handle two watts.

Watch 'Yer Top Knot and Keep Your Powder Dry,
?
James R. Harvey - The Wyoming Geezer -?Armed and Dangerous
PM ¡à Progress Lodge #22 ¡à Order of the Eastern Star



On Wed, May 7, 2025, 02:09 Erik Kaashoek via <erik=[email protected]> wrote:
Minimum output level used to be -120 dBm but not all HW was able to reach this level so the limit was set to -115 dBm
The limiting factor is leakage which can not be improved within current cost and space limitations
Adding a cheap external attenuator and setting the external gain to negative the attenuation solves the problem
--
Designer of the tinySA
For more info go to



--
Dave - W?LEV
 

Yep my HP 8660 leaks a small amount but as long as proper cables are used it still seems to be accurate into a 50 ohm load. Within about 1dB.?
 

I have a whole set of those SMA 2 watt attenuators I use for a lot of things. They are in 1 dB increments between 1 and 10 dB, and 5 dB increments from there to 30 dB. I also have a Kay switchable attenuator that can be switched in 1 dB increments up to 110 dB. It is rated to 1000 MHz and appears to be accurate across that range.

Measuring MDS is very useful with the transverters I have that use 144 and 432 MHz IF's. I can use the TinySA Ultra to generate signals up to 10 GHz. I use an HP 475B power meter to accurately measure the levels of the signal.

Zack W9SZ

On Wed, May 7, 2025 at 5:27?PM W0LEV via <davearea51a=[email protected]> wrote:
Even my HP 8648C set to -136 dBm (the minimum internally available output) plus additional external attenuation leaks just a wee tiny bit!? Still good for receiver MDS evaluations.? I've never looked at the leakage from the HP 8640.? Maybe someday.....

Dave - W?LEV

On Wed, May 7, 2025 at 2:43?PM James Harvey via <wyominggeezer=[email protected]> wrote:
My approach would be to use one of those small SMA connector attenuators. They're fairly inexpensive and you can get them in levels from 3DB to 30 dB. That's what I use.?

I even use it for low-level QRP work. The ones I use will handle two watts.

Watch 'Yer Top Knot and Keep Your Powder Dry,
?
James R. Harvey - The Wyoming Geezer -?Armed and Dangerous
PM ¡à Progress Lodge #22 ¡à Order of the Eastern Star



On Wed, May 7, 2025, 02:09 Erik Kaashoek via <erik=[email protected]> wrote:
Minimum output level used to be -120 dBm but not all HW was able to reach this level so the limit was set to -115 dBm
The limiting factor is leakage which can not be improved within current cost and space limitations
Adding a cheap external attenuator and setting the external gain to negative the attenuation solves the problem
--
Designer of the tinySA
For more info go to



--
Dave - W?LEV



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