The Chinese AWG signal generator for RF/AM/FM alignment question (again)

[mrrstrat]

Guys,

I do a fair amount of work on old tube receivers and such - If you ask die-hard hams what is a good modern digital sig generator to radio alignment you typically get long drawn-out responses on why the 70 year old stuff is the best or a HP hernia machine frequ synthesizer (I have a fleet of this gear and am wanting to get to at least the last 10 years in technology by doing this with a digital full-featured rig). I am hoping for a more rational recommendation from other EEs (of which I am one too). My specialty kept me from being as good as some of the guys here for signal-processing gear selections :-)

Assume under $1500.00 for starters, but some of the gear like the Siglent SDG1032X look good if you can live without 100+Mhz.

[bdunham7]

The Siglent SDG2122X or a hacked SDG2042X works fine to 120MHz as long as you don't need FM Stereo--although there might be a way to implement that too with the correct modulation scheme.  You do need some attenuators to get signals down to -70dBM.  What I use when I need FM Stereo or a higher frequency is a recycled CMU-200.  You need to have the specific FM Stereo option and if you can get the audio options that's even better.  You should be able to find one under $1500 and although it is still pretty big, it is modern and not all that heavy.

[mrrstrat]

I figured as much - no real easy button solutions. The Siglent SDG2122X looks like a good option, but more than I want to spend right now. For a bit I'll stick with my Eico 324 and HP 3325A.

[Wallace Gasiewicz]

I believe the best tool for servicing both receivers and transmitters is a service monitor.You get a nice freq generator and spectrum analyzer along with audio generators that can be used to modulate the RF.
Unfortunately most of them in your quite reasonable price range are a bit older than 10 years and most are big.
I use an HP 8935

[M0HZH]

You need a communication service monitor. You won't believe how better life gets once you have all the tools in one unit.

I use the IFR COM-120B, it is excellent and can be found used in your price range.

[radiolistener]

it depends on your expectaions. If noise and jitter is not a big deal for you, you can use some cheap Chinese FPGA based generator such as FY6800. If you have more money, you can buy SDG2042X. But if you're needs low noise generator it may be worth to see for something more serious and expensive equipment

[M0HZH]

The problem with AWGs is they can't do low output levels (-70dBm to -130dBm, required for receiver troubleshooting / alignment) so you need an accurate external attenuator. And if the AWG is cheap, it will leak enough RF to swamp the attenuated signal anyway.

[radiolistener]

The problem with AWGs is they can't do low output levels (-70dBm to -130dBm, required for receiver troubleshooting / alignment) so you need an accurate external attenuator.

This can be easily fixed with a set of Chinese attenuators. I have the following values in my set: 1 dB, 2 dB, 3 dB, 5 dB, 6 dB, 10 dB, 20 dB, 30 dB, 40 dB. I recommend to buy several instances of 1 dB, 6 dB, 10 dB, 20 dB and 40 dB because they are used most of the time

[tautech]

Guys,

I do a fair amount of work on old tube receivers and such - If you ask die-hard hams what is a good modern digital sig generator to radio alignment you typically get long drawn-out responses on why the 70 year old stuff is the best or a HP hernia machine frequ synthesizer (I have a fleet of this gear and am wanting to get to at least the last 10 years in technology by doing this with a digital full-featured rig). I am hoping for a more rational recommendation from other EEs (of which I am one too). My specialty kept me from being as good as some of the guys here for signal-processing gear selections :-)

Assume under $1500.00 for starters, but some of the gear like the Siglent SDG1032X look good if you can live without 100+Mhz.

As others have pointed out the SDG2000X series might be better as they are 16 bit and also hackable to 120 MHz.

A recent customer selected SDG2122X for exactly your needs and is quite happy with its capabilities.
For $ 499 and some tweaking you can have one too.
https://siglentna.com/waveform-generators/sdg2000x-series-functionarbitrary-waveform-generators/

[amspire]

How about the Tiny SA (Spectrum Analyser) or Tiny SA Ultra? Both have a Signal Generator mode.

The Tiny SA does 100KHz to 350 MHz Sinewave and the Tiny SA Ultra does 100KHz to 800MHz sinewave. Harmonics in the output is probably about -40dB. The square wave output of the SA Ultra goes to 5400MHz.

The Tiny SA Ultra can output a pretty accurate -123 dBm to -17 dBm in 1dBm steps. I think the lower level accuracy is not great, so the real minimum output is probably around -105dBm.  To get a lower output, you could always just buy a 40db SMA attenuator. It can be set for AM, or FM modulation. Modulation frequency, AM modulation depth and FM deviation can be set. Sweep mode can also be configured.

I am not sure of the output range for the Tiny SA is but it is probably not as good as the SA Ultra. At US$119, I would definitely go for the SA Ultra.

Control is via a pretty good touch screen. And you get a decent Spectrum Analyser for the price!

The important thing is to buy the genuine product as there are lots of fakes that do not work properly. Check out the home page: https://www.tinysa.org/wiki/

The genuine product on Aliexpress is from the Zeenko Store. https://www.aliexpress.com/item/1005004934403303.html