Author Topic: ERASynth: Open Source RF Signal Generator - Request for Feedback  (Read 9211 times)

0 Members and 1 Guest are viewing this topic.

Offline piranha32

  • Supporter
  • ****
  • Posts: 110
  • Country: us
    • random ramblings of an engineer
Re: ERASynth: Open Source RF Signal Generator - Request for Feedback
« Reply #25 on: April 22, 2018, 03:52:09 am »
I also noticed that when connecting from laptop it took a long time to connect, and then the web page tried to download a javascript library from code.jquery.org. It of course will not work, because there is no internet connectivity. OTOH when connecting using tablet everything worked flawlessly. The page is clearly optimized for mobile devices, so I guess they did very little testing with desktop browsers. I have no idea why connecting over wifi from a laptop takes so long.
Another thing that I could not get to work is frequency sweep. Regardless of settings, ERA always wants to sweep from 1GHz to 2GHz
« Last Edit: April 22, 2018, 03:56:33 am by piranha32 »
 

Offline orin

  • Frequent Contributor
  • **
  • Posts: 419
  • Country: us
Re: ERASynth: Open Source RF Signal Generator - Request for Feedback
« Reply #26 on: April 22, 2018, 05:30:30 am »
I also noticed that when connecting from laptop it took a long time to connect, and then the web page tried to download a javascript library from code.jquery.org. It of course will not work, because there is no internet connectivity. OTOH when connecting using tablet everything worked flawlessly. The page is clearly optimized for mobile devices, so I guess they did very little testing with desktop browsers. I have no idea why connecting over wifi from a laptop takes so long.
Another thing that I could not get to work is frequency sweep. Regardless of settings, ERA always wants to sweep from 1GHz to 2GHz


As a hotspot, I tried both from an iPhone and a Mac... I didn't try from a PC or Android.  Good catch on the jquery download.  I hadn't bothered trying to work out what was going on since the initial connection was so slow.

I'm now testing it with an 8568A spectrum analyzer and 5370A counter, controlling it from a Win7 laptop and wifi in station mode.  Seems to be about 3Hz low at 10MHz with the counter fed from a GPSDO.  Looks to be within milli-Hertz if I use a GPSDO as an external reference.  The OXCO might need some time to settle and the temp in the 'lab' is only 17 deg C at the moment.

All seems good up to 1.7GHz - the limit of the 8568A.  Now I need an SA that goes higher.

Edit: OXCO is currently drifting higher at about 0.1 Hz/hour according to Timelab.
« Last Edit: April 22, 2018, 07:35:37 am by orin »
 

Offline piranha32

  • Supporter
  • ****
  • Posts: 110
  • Country: us
    • random ramblings of an engineer
Re: ERASynth: Open Source RF Signal Generator - Request for Feedback
« Reply #27 on: April 22, 2018, 07:29:20 am »
On GPS-locked E7495A and ERA tuned to 10MHz TCXO seems to be spot on, surprisingly OCXO appears to be 14Hz low. The narrowest RBW is 30Hz, so it's not conclusive, but I did not expect such a big difference, especially for OCXO. Unfortunately I don't have GPSDO to lock ERA, so I can't tell how much of this difference comes from the reference XO, and how much is due to poor resolution of the instrument.

Update:
The same holds for ERA set to 2.5GHz. TCXO is much closer to the set frequency than OCXO. Frequency locked to the OCXO is ~7kHz low, and TCXO is ~1.3kHz over. If it wasn't for frequency drift while OCXO starts up, I would tell that the labels got mixed up. Also, the frequency in steady state seems to be constantly drifting by single Hz, but again, I can't tell how much of it comes from the SA itself.
Last, but not least, refreshing the diagnostics page during OCXO startup shows all three PLLs as locked through all the time as the crystal heats up. I did not expect the Xtal PLL to respond that quickly to sudden changes of ref frequency.
« Last Edit: April 22, 2018, 08:01:23 am by piranha32 »
 
The following users thanked this post: edensrock

Offline orin

  • Frequent Contributor
  • **
  • Posts: 419
  • Country: us
Re: ERASynth: Open Source RF Signal Generator - Request for Feedback
« Reply #28 on: April 22, 2018, 04:06:52 pm »
Well, a little digging and the Crowd Supply page claimed the OXCO is an AOCJYR.  There is a datasheet on Mouser:

https://www.mouser.com/datasheet/2/3/AOCJYR-10.000MHz-M5625LF-372124.pdf

Initial frequency tolerance of +/- 0.5 ppm and a shift due to reflow soldering of +/- 1ppm so I'm well within that limit.  Also, the 24hr +/- 1deg C holdover stability of +/- 4ppb is "After 30 days of continuous operation".  These things like to be kept powered up!

So, nothing untoward really, but I'll make an enhancement request of being able to specify the actual OCXO/TCXO frequency so the firmware can make a correction for these small offsets... unless it's already there and I missed it.

If ERA Instruments are listening in, I'd also ask that the LMX2 PLL LOCK diagnostic be greyed out if operating at a frequency at which it's not used.  (I checked the firmware source, its disabled 30MHz and below).  Otherwise, it's misleading to show "Not Locked" when running at 30MHz or below.

Oh BTW, it looks a lot nicer in person than the latest pictures on the Crowd Supply page and is very nicely built.  I look forward to getting rid of the huge Wavetek SG that sometimes refuses to phase lock right at the frequency I want to use!
« Last Edit: April 22, 2018, 04:14:28 pm by orin »
 
The following users thanked this post: edensrock

Offline edensrock

  • Contributor
  • Posts: 10
  • Country: tr
Re: ERASynth: Open Source RF Signal Generator - Request for Feedback
« Reply #29 on: April 23, 2018, 07:57:47 pm »
Hi orin, piranha32, jhenderson0107, chriswebb and ezalys!

Thank you all very much for your valuable feedback. We are indeed listening in, just haven't been logged-in for a while. We take all of the feedback seriously.

@ezalys
Why have you added wi-fi to this unit? I can't possibly understand why a device that has been designed to output a pure monochromatic signal has another radio stuck in it somewhere. I'd be a fan of adding ethernet, but definitely not wi-fi.
Wi-Fi module can be disabled using the web GUI or the PC GUI. If software disabling doesn't work for you, you can open the case and remove the ferrite bead L54 on the board. That will permanently power off the Wi-Fi module.


@piranha32
Mine arrived yesterday.

I could not get the wifi hotspot to work correctly.  It showed up, but connecting to it took a long time and once connected, the UI took minutes to show up and was unresponsive.

I used the serial interface to switch to wifi station mode and it seems to be working OK now.
Sorry about the broken links. The links somehow are working for me. I will update our campaign page with a link to our GitHub repo's root folder (https://github.com/erainstruments/).

@orin
Well, a little digging and the Crowd Supply page claimed the OXCO is an AOCJYR.  There is a datasheet on Mouser:

https://www.mouser.com/datasheet/2/3/AOCJYR-10.000MHz-M5625LF-372124.pdf

Initial frequency tolerance of +/- 0.5 ppm and a shift due to reflow soldering of +/- 1ppm so I'm well within that limit.  Also, the 24hr +/- 1deg C holdover stability of +/- 4ppb is "After 30 days of continuous operation".  These things like to be kept powered up!

So, nothing untoward really, but I'll make an enhancement request of being able to specify the actual OCXO/TCXO frequency so the firmware can make a correction for these small offsets... unless it's already there and I missed it.

If ERA Instruments are listening in, I'd also ask that the LMX2 PLL LOCK diagnostic be greyed out if operating at a frequency at which it's not used.  (I checked the firmware source, its disabled 30MHz and below).  Otherwise, it's misleading to show "Not Locked" when running at 30MHz or below.

Oh BTW, it looks a lot nicer in person than the latest pictures on the Crowd Supply page and is very nicely built.  I look forward to getting rid of the huge Wavetek SG that sometimes refuses to phase lock right at the frequency I want to use!
There is no frequency offset feature at the moment. We will try to implement it in the upcoming firmware fix.
 

Offline orin

  • Frequent Contributor
  • **
  • Posts: 419
  • Country: us
Re: ERASynth: Open Source RF Signal Generator - Request for Feedback
« Reply #30 on: April 24, 2018, 03:18:10 am »
OCXO 'warmup' so far.

Edit:

Counter is an HP 5370A using a Trimble Thunderbolt GPSDO for its reference.

'Warmup' isn't really the right word - 'aging' or 'drift' would be better.
« Last Edit: April 24, 2018, 05:00:00 am by orin »
 

Online KE5FX

  • Frequent Contributor
  • **
  • Posts: 915
  • Country: us
    • KE5FX.COM
Re: ERASynth: Open Source RF Signal Generator - Request for Feedback
« Reply #31 on: April 24, 2018, 06:21:20 am »
OCXO 'warmup' so far.

Edit:

Counter is an HP 5370A using a Trimble Thunderbolt GPSDO for its reference.

'Warmup' isn't really the right word - 'aging' or 'drift' would be better.

That should settle down nicely in a week or so. :) 

Looks like the manufacturer doesn't do any aging before shipment.  Probably not unreasonable when paying around $100 for a factory-fresh OCXO.
 

Offline orin

  • Frequent Contributor
  • **
  • Posts: 419
  • Country: us
Re: ERASynth: Open Source RF Signal Generator - Request for Feedback
« Reply #32 on: April 25, 2018, 05:08:35 am »
Took it to 15GHz last night using a 5342A counter.  Things didn't look good over 14GHz until I realized the 15dB Mini Circuits attenuator* I keep on the counter's input was only rated to 6GHz!  All was fine once I reduced the power and removed the attenuator.  This was as much a test of the counter as the ERASynth.  When I got the counter, it was sold as not counting on any range - but as far as I can tell, it counts just fine.

*It's very easy to blow the sampler on the input of these counters, so I keep the attenuator on it for protection.  The samplers are of course, unobtanium.
 

Offline 9aplus

  • Regular Contributor
  • *
  • Posts: 55
Re: ERASynth: Open Source RF Signal Generator - Request for Feedback
« Reply #33 on: July 03, 2018, 08:34:07 am »
Hi to all....
just to report that I finally managed some of my free time to make some test
My unit sn:015 ERASynth+ was delivered to UK site approx 5 weeks ago.

Have find out that USB PS declared for 2 A can not run the unit
but two USB ports from my notebook combined in one makes good enough PS source.
(Have another one declared for 2,4 A for second test tomorrow.)

PC was able to connect to wi-fi AP mode on first attempt, also managed to get
some signal out but not on all freq... for example on 145 MHz
It seems that some firmware update or direct serial port use is necessary.
To be continued...
 

Offline 9aplus

  • Regular Contributor
  • *
  • Posts: 55
Re: ERASynth: Open Source RF Signal Generator - Request for Feedback
« Reply #34 on: July 03, 2018, 05:53:52 pm »
Unit is happy with 2.4 A 5V PS sourced from one tablet ;)
Sweep is running...

« Last Edit: July 03, 2018, 05:56:33 pm by 9aplus »
 

Offline 9aplus

  • Regular Contributor
  • *
  • Posts: 55
Re: ERASynth: Open Source RF Signal Generator - Request for Feedback
« Reply #35 on: July 04, 2018, 07:24:32 am »
Direct serial port use working ok.
Win PC application working too.

Firmware upgrade is must...
That is on my to do list for tomorrow,
Arduino IDE / duo and ESP support already installed today.
 

Online KE5FX

  • Frequent Contributor
  • **
  • Posts: 915
  • Country: us
    • KE5FX.COM
Re: ERASynth: Open Source RF Signal Generator - Request for Feedback
« Reply #36 on: July 05, 2018, 11:20:34 am »
What tablet brand/model is this?
 

Offline 9aplus

  • Regular Contributor
  • *
  • Posts: 55
Re: ERASynth: Open Source RF Signal Generator - Request for Feedback
« Reply #37 on: July 05, 2018, 05:28:04 pm »
Lenovo MIIX300 10" tablet with additional keyb...
Original PS have USB port, so just another cable.

Here, still preparing firmware upgrade, I am RPI guy, not familiar with Arduino duo.
So trying to be 100% sure what I am doing, in attempt to not brick ERASynth+ ;)
« Last Edit: July 05, 2018, 06:01:24 pm by 9aplus »
 
The following users thanked this post: KE5FX

Offline 9aplus

  • Regular Contributor
  • *
  • Posts: 55
Re: ERASynth: Open Source RF Signal Generator - Request for Feedback
« Reply #38 on: July 24, 2018, 07:47:39 am »
On first try of firmware upgrade I have bricked my unit,
but after some advice through opened issue on:
https://github.com/erainstruments/erasynth-firmware
Second upgrade went well...
Through terminal commands unit is now working like charm.
Both web and Win application need some further debuging.
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf