Very wideband signal source

[Andrew Thornett]

I've found this signal sources on Crowd Supply that will go all the way up to 22.6 GHz! Ideal for ensuring your dish effectively picks up masers, H-Line, etc.

.......Only downside is the $1500 price tag = for some it might be worth the cost, if you have particular use case that would benefit from it.

Andy

[andrew....@googlemail.com]

Here is the link https://www.crowdsupply.com/atek-midas/dsg-22-6-ghz#products

[Marko Cebokli]

Very expensive.

I am quite sure this is just a LMX2820 and a microcontroller in a box.

You can get this for much less money. Just search Aliexpress for "LMX2820". Without a box, it's about 200 euros.

Marko Cebokli

06.03.2026 10:18, je andrew.thornett via Society of Amateur Radio Astronomers napisal

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[fasleitung3]

It seems that besides the controller/display/box they have added filters for various frequency bands.

Depending on the application that may give additional value. One of the applications for us is to have a reference frequency for water maser receivers with an otherwise uncalibrated LO. Since the unit can be connected to a stable 10 MHz reference, one should get a fairly accurate signal. This, however, would also work with the cheaper Ali-Express product.

Wolfgang

[Andrew Thornett]

How about these options on Aliexpress?

I just found this on AliExpress: LMX2820 HTOOL SL22 Signal Source 45-22600MHz Fan Heat Sink Three Language Modes P0-P7 Power Output Different Data Respectively https://a.aliexpress.com/_EQ13joo

I just found this on AliExpress: TZT LMX2820 45MHz-22.6GHz Wideband PLL RF Synthesizer Module High Performance Phase Locked Loop with SMA Female Connector https://a.aliexpress.com/_EzvoGfa

Andy

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From: 'fasleitung3' via Society of Amateur Radio Astronomers <sara...@googlegroups.com>
Sent: Friday, March 6, 2026 2:52:32 PM
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Subject: Re: [SARA] FW: Very wideband signal source

 

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[fasleitung3]

It looks like these two do not provide a connection for an external reference.

There are offers where you just get the plain board which show a SMA connector for reference. Then there are other where there is an additional display and pushbuttons for control. It seems (but not sure) these use the same RF board and therefore might also provide external reference.

Marko, do you have any hands on experience?

Wolfgang

[fasleitung3]

This is what I am referring to:

45MHz-22.6GHz LMX2820 Core Board + STM32 Main Control Board High Power Output Evaluation Board Low Phase Noise Development Board

[Andrew Thornett]

Here is one that appears to come with external clock connection:

I just found this on AliExpress: LMX2820 Evaluation Board, Development, High Frequency Matching Board, High Power Output , Low Phase Noise Source https://a.aliexpress.com/_EwTbhD6

But looks like much cheaper one here:

I just found this on AliExpress: 45MHz-22.6GHz LMX2820 Core Board + STM32 Main Control Board High Power Output Evaluation Board Low Phase Noise Development Board https://a.aliexpress.com/_EQpDGNq

I attach specifications for this latter one.

Is this what Wolfgang is talking about?

Andy

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Subject: Re: [SARA] FW: Very wideband signal source

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[fasleitung3]

Yes, this is what I was talking about.

The only caveat I have is that there seem to be some identical looking boards where the clock connector is rather an output than an input.

Wolfgang

[Andrew Thornett]

If anyone wanted to buy this how would they know which ones had clock as input rather than output? I presume they would need to get the one where clock was input?

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Sent: Friday, March 6, 2026 7:53:25 PM

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[Marko Cebokli]

Hello Wolfgang!

About a year ago, I bought a no box version. It consists of two 50x50mm boards, stacked together with a header and some screws. The top board has the microcontroller, display and buttons. The bottom one has the synth. It has both an on board oscillator and an SMA clock input. LMX2820 has two balanced outputs. No baluns on the board (to be broadband), all four lines are brought to the edge of the PCB, but only one output has two 3.5mm (SMA compatible) connectors. It gives 7dBm (a bit less on higher band) on a single line, works also with the other line not terminated.

The software is easy to use, it includes a sweep mode, you can specify start, end frequency, frequency and time step. 2820 is based on a 5700...11300MHz VCO, with a doubler for the higher band. Below 5.7GHz, dividers are used, so you get a square wave, second harmonic (theoretically zero) is about 30dB down, the third about 12. On the non-divided range, the second is a bit higher, third lower.

Haven't yet measured the phase noise, looks OK on the spectrum analyzer, in fact the 2820 specs are impressive - but of course, it also depends on the reference oscillator.

Not sure, if the ones sold now are the same.

Marko Cebokli

06.03.2026 17:57, je 'fasleitung3' via Society of Amateur Radio Astronomers napisal

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[Marko Cebokli]

About the clock connector: the oscillator output, 2820 clock input and connector are just tied together, so if the oscillator is on board, it will be an output, if not, and input.

Marko Cebokli

06.03.2026 22:16, je Marko Cebokli napisal

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[andrew....@googlemail.com]

So, would you recommend one of these Marko?

 

From: sara...@googlegroups.com <sara...@googlegroups.com> On Behalf Of Marko Cebokli
Sent: 06 March 2026 21:25
To: sara...@googlegroups.com
Subject: Re: [SARA] FW: Very wideband signal source

 

About the clock connector: the oscillator output, 2820 clock input and connector are just tied together, so if the oscillator is on board, it will be an output, if not, and input.

To view this discussion visit https://groups.google.com/d/msgid/sara-list/598f3e61735246862e267cb024927adb%40hamradio.si.

[Marko Cebokli]

As I said, not sure if what is sold now, is the same thing that I got. Other than that, the 2820 is a very fine chip, can produce a very clean signal, if fed a good clock, and the supply is well filtered, etc. This board does probably not extract the full performance of this chip, but it is still a very good signal source, and will give you a flexible LO for a RA receiver. It has no output power control, so it has limited use as a general purpose signal generator, you would need to use external attenuators for that. The output power is a bit low for driving passive diode mixers, but you can add a cheap MMIC amplifier, a big selection of modules (boards with SMA connectors) is also available on Ali. Or use an active mixer, Ali modules again. You will need a good clean 5V supply for the synth, normal USB supplies/power banks can be dirty, because virtually all are based on switching converters!

So yes, I think I would recommend it, as a good tool for a RF experimenter.

Marko Cebokli

06.03.2026 22:54, je andrew.thornett via Society of Amateur Radio Astronomers napisal

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[Don Latham]

I picked up a couple of these. Look at the data sheet for the LMX. If I remember right, the ref needs to be 100 MHz or if 10 is used, some degradation. I think there is some buzz on eevblog or sites like that.  Horrible memory, don't remember more. Good value for the $, however. One was board, one was cased. As with all Chinese stuff, poorly documented 

Don

 

------------
Don Latham
PO Box 404,
Frenchtown, MT, 59846
406-626-4304

 

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From: fasleitung3 <sara...@googlegroups.com>
To: sara-list <sara...@googlegroups.com>
Date: Friday, 6 March 2026 12:53 PM MST

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[Marko Cebokli]

The LMX2820 can use any reference frequency between 5 and 1400MHz. The phase detector works up to 300MHz in fractional mode, (400MHz integer), and the reference clock input has a set of dividers and multipliers. If you use a lower reference frequency and/or reference multipliers, the phase noise will be worse. Of course, you must program the chip to use the given reference frequency, and calculate the loop filter for the resulting phase detector frequency. As far I looked at the data, the 2820 has A LOT of registers, and is not very easy to program. That's why I bought the version with the controller. I still want to program this chip myself, someday :-)

Marko Cebokli

07.03.2026 07:47, je 'Don Latham' via Society of Amateur Radio Astronomers napisal

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[fasleitung3]

I have ordered one. I will report back about the experience once I received it.

Wolfgang

[Andrew Thornett]

Which one did you go for Wolfgang? Can you post URL.

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Sent: Saturday, March 7, 2026 9:16:39 AM
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Subject: Re: [SARA] FW: Very wideband signal source

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[Marko Cebokli]

One gripe I have about this device is, that the chip gets very hot. I measured 75C after a couple of minutes on the back of the PCB. The whole thing eats 600mA at 5V, which is expected, according to the 2820 datasheet. But fitting a small heatsink is certainly a good idea. The LM337 3.3V regulator in a tiny BGA, on the synth board, also sweats much.

It has a small two pin connector for the 5V supply on the synth board, but also a USB-C on the controller board. It can be supplied either way. When USB is connected, it is recognized as:

[19904.923133] usb 3-8: new full-speed USB device number 12 using xhci_hcd
[19904.948539] usb 3-8: New USB device found, idVendor=0483, idProduct=5740, bcd Device= 2.00
[19904.948544] usb 3-8: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[19904.948545] usb 3-8: Product: STM32 Virtual COM Port   
[19904.948546] usb 3-8: Manufacturer: STMicroelectronics
[19904.948548] usb 3-8: SerialNumber: 6D771F755650
[19904.950125] cdc_acm 3-8:1.0: ttyACM0: USB ACM device

I tried connecting to ttyACM0 with a terminal emulator, but could get no response. There is (of course :-) no documentation. On the controller board, there are also holes for two four pin headers, one is marked USART with R,T,GND and 3.3 pins. I haven't tried to communicate here. The other is marked DBUG, with SCLK, SDIO, GND and 5V pins.

The synth reference oscillator is 10MHz.

Marko Cebokli

07.03.2026 08:40, je Marko Cebokli napisal

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[fasleitung3]

This one:

https://de.aliexpress.com/item/1005006539334841.html?spm=a2g0o.order_detail.order_detail_item.3.57576368E6ymPY&gatewayAdapt=glo2deu

[Marko Cebokli]

Yes, this one looks exactly like the one I have.

Another idea: maybe the Chinese copied the firmware, and this would work over USB with the TI PC software? However, the TI demo board does not include a controller, you have to connect it with an additional TI box, called "USB2ANY". So, they would have to copy the firmware from that box.

Haven't tried the TI software, for at least three reasons:

1. Windows software. (maybe runs under Wine, but I don't care.)

2. Must register a TI account. (Does everyone really need to track me?)

3. It is export restricted. (God forbid the Chinese get their hands on this! Hahahaha)

Marko Cebokli

07.03.2026 11:10, je 'fasleitung3' via Society of Amateur Radio Astronomers napisal

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[Marko Cebokli]

Spectrum at 1GHz

Marko Cebokli

07.03.2026 11:20, je Marko Cebokli napisal

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[Marko Cebokli]

10 and 20 GHz

07.03.2026 12:12, je Marko Cebokli napisal

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