SPECTRAN V6 PLUS DANL (NF) with and without optional Preamplifier

#1 · 16/12/2020, 09:24

I am using a RSA250X without preamplifier. Which DANL do I reach with and without preamplifier?

The typical DANL without preamplifier (Reflevel @ -38dBm) should be within -165dBm/Hz which is an excellent value.

With preamplifier you should reach a whopping -170dBm/Hz (Reflevel @ -60dBm) or even better.

#2 · 25/06/2021, 13:14

How was this measurement done? With a zero span and 1Hz RBW?

#3 · 25/06/2021, 23:44

The setting does not really matter:

Sweep and real-time mode both offer quite the same DANL same with the RBW setting.

#4 · 21/02/2025, 05:10

Dear engineer,

Could you please tell me how I should set it up so that I can obtain the best DANL(-165dBm/Hz，Reflevel @ -38dBm)?

#5 · 21/02/2025, 07:41

Use the AVG Trace instead, set the marker to the AVG trace and use the Power Density marker funktion for direct DANL readout.

#6 · 23/02/2025, 19:26

Quote from Leo on 21/02/2025, 05:10

Dear engineer,

Could you please tell me how I should set it up so that I can obtain the best DANL(-165dBm/Hz，Reflevel @ -38dBm)?

Hi,

Here’s how to achieve an accurate DANL/NF measurement with my V6 Plus:

Connect a good 50 Ohm load to the Rx.
Measure a band with no current signals.
Use a 1/2 span.
Set IQ Power Spectrum to RBW with a 10 kHz bandwidth.
Set the Ref Level to -38 dBm with the amplifier enabled.

For reference, thermal noise at room temperature for a 10 kHz bandwidth should be around -134 dBm. Noise Power Calculator.

My V6 Plus, using an AVG Trace and power readout, gives me around -126.5 dBm/10 kHz. Let me round this up and set it to -127 dBm, this indicates approximately a 7 dB NF, or around -165 dBm/Hz. A few dB here and there, when putting temperature and Ohm load quality into the mix etc.

Try this instead of using splitting span, just use 1/2 and change the RBW in IQ Power Spectrum.

Regards

Kjetil Teigen Hansen