methanol maser detection with a small dish

[Eduard Mol]

Hi all,

Over the past few months my father and I have been working on a small radiotelescope for centimetre wavelengths. I was interested in observing methanol and water masers at 12 and 22 GHz, but the mesh surface of my 3 metre dish is not  good enough for such high frequencies. Moreover, pointing and tracking by hand is very difficult at such high frequencies. Therefore, I decided to buy a smaller solid offset dish which was light enough for my HEQ5 equatorial mount. this solves at least most of the tracking and pointing problems. However, the dish has a diameter of only 1 metre, so its surface area is 9X smaller than that of a 3 metre dish. 

I decided to start working on the 12,178 GHz methanol line first. In an earlier thread on this forum (https://groups.google.com/g/sara-list/c/9OW8LU9LGvU) Michiel Klaassen and Wolfgang Herrmann pointed out to me that detecting water and methanol masers should be possible with a 3 metre dish. They also mentioned that 12 GHz methanol was easier on the receiver side because LNBs for this frequency range are widely available. 

W3(OH) should be one of the brightest methanol masers in the northern sky, Blaszkiewicz el al. (2004) mentioned a flux density of 793 Jansky. I calculated that with my 1 metre dish and an aperture efficiency of 0.5, an ~800 Jy source should give an antenna temperature of 0.1 kelvin. I tried to calculate the minimum integration time needed to detect W3(OH) using the radiometer equation. With a Tsys of 100 kelvin, an aperture efficiency of 0.5 and a bandwidth of 10 KHz I would need about an hour to detect a 0.1 K difference with an SNR of 5. Of course, this is the theoretical minimum integration time, so it might be much harder in reality. However, I decided that this was still worth giving a try.

I used an inverto Ku band single PLL LNB to downconvert the 12 GHz signal to L-band. the LNB has 2 local oscillators, I needed to switch on the high band 10.6 GHz LO, This is done by inserting 22 KHz tone. My father built a special power supply which delivers 12V DC with the 22 KHz tone superimposed, this is fed into the LNB via a bias tee. I tested how much the LO frequency drifts and found that it only drifted about 10- 15 KHz in a few hours. this is much less than the width of the maser line, so I decided it was not necessary to modify the LNB for higher stability. 

On the evenings of february 20 and 21, I tried to detect the methanol maser of W3(OH). Integration time was 2 hours on the first evening and 3 hours on the second. I also measured the Astra 3B beacon again after the observations to measure the frequency offset of the LO. On both evenings I detected a weak 0.1K signal at around -45.5 km/s. It looks quite convincing but I first want to make sure it is not some weird form of RFI.

To be continued....

Eduard Mol

[Eduard Mol]

Hi all,

I forgot to attach a picture of the dish so here it is...

Best regards,

Eduard Mol

Op ma 22 feb. 2021 20:35 schreef Eduard Mol <eddiem...@gmail.com>:

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[fasleitung3]

Hi Eduard,

In the literature it is reported that there is little variation in the Methanol maser emission in W3. So it is a safe assumption that it is still at about 800 Jy. Also, the profile of the spectrum does not vary much either. If you compare your spectrum with the one I posted in the thread you mentioned you will find that your second spectrum has about the features as expected from W3. The previous observation looks somewhat different, but this can be attributed to the limited SNR.

So in conclusion I would say this is really looking good. As you do more observations it will most likely become even more convincing.

Congratulations for this work. Doing this with a 1-m dish is an exceptional achievement in my view.

Best regards,

Wolfgang

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[Marcus D. Leech]

Nice result.  Keep up the good work!

Hmmmm. CCERA is about to have a 1.8m dish freed up.  Perhaps I should add "tracking mount" to my projects list.  We already have a
  handful of PLL Ku-band LNBFs--Avenger PLL321S-2...

[Michiel Klaassen]

Hi Eduard,

My congratulations; very, very well done.

Michiel

parac.eu

Op ma 22 feb. 2021 om 20:54 schreef Marcus D. Leech <patchv...@gmail.com>:

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[Eduard Mol]

Hi Wolfgang, Marcus and Michiel,

Thank you all for the congrats!

This week I will do some more observations on W3. I think I will also average all spectra of the different days together at the end of the project, that way I can get a better SNR and compare it to Wolfgangs spectrum.

I would also like to thank you all very much for the numerous times you have given me advice and feedback here on this forum.

Best regards,

Eduard

Op ma 22 feb. 2021 22:39 schreef Michiel Klaassen <vmin...@gmail.com>:

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[Marcus D. Leech]

On 02/22/2021 04:51 PM, Eduard Mol wrote:

Hi Wolfgang, Marcus and Michiel,

Thank you all for the congrats!

This week I will do some more observations on W3. I think I will also average all spectra of the different days together at the end of the project, that way I can get a better SNR and compare it to Wolfgangs spectrum.

Indeed, one could use a fixed-pointing dish and let W3(OH) drift through the beam every day, and slowly build up enough integration
  time to get decent results without tracking.

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[James Morris]

This is really inspirational, thanks for writing it up.

James W7TXT

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[Eduard Mol]

Hi all,

Last week I did four more observations of W3(OH). Integration times were 2- 3 hours. In order to account for the LO frequency offset I measured the frequency of the Astra 3B satellite beacon at 11446.8 MHz after beach observation session. After correcting for LO frequency offset and Vlsr correction, the peaks stayed at the same velocity. The radial velocity is between -45 and -48.5 km/s, which is slightly higher than the Astropeiler reference spectrum. I am not sure what could have caused this deviation. However, I am almost certain that the feature at -45 to -48.5 km/s is not RFI, because an RFI signal (which usually stays at the same frequency) would not stay at the same LSR- corrected velocity over multiple days.

The spectra plotted below have a higher spectral resolution than the two spectra I posted earlier, so the SNR is a bit less.

 

Finally, I also averaged all six results to get a better SNR. The four main features which can be distinguished in the Astropeiler spectrum and the spectra on Michiels website (under project MK 23) are also visible in this averaged spectrum.

In conclusion I would say that we have successfully detected the methanol maser, and the results are even better than expected.

Best regards,

Eduard

Op dinsdag 23 februari 2021 om 20:11:14 UTC+1 schreef morr...@gmail.com:

[fasleitung3]

Hi Eduard,

In my view you have clearly demonstrated by a careful experiment that your received signal indeed is from the W3 OH maser.

The offset in the measured velocity is about 2 km/s which is about 6.6 ppm deviation. I am not familiar with the stabilily of the Astra beacon but I would assume that it is significantly better than that. So your frequency measurement should be accurate enough. The deviation could then come from your VLSR correction. You could check your correction against the VLSR calculator which Steve Olney has brought back online just recently:

https://sites.google.com/view/hawkrao/hawkrao-calculators/vlsr-calculator

Best regards and again congratulations for your work,

Wolfgang

[Eduard Mol]

Hi Wolfgang,

Thank you for your comments again. I checked Steve Olney's Vlsr calculator, but I got the same results for the Vlsr correction, to within 0.2 km/s. So the ATNF calculator seems accurate enough and the Vlsr correction was not the cause of the velocity offset. I am now left with two possible explanations for the apparent frequency shift: either the frequency of the Astra beacon (11446.800 MHz) listed on UHF- satcom (https://uhf-satcom.com/satellite-reception/ku-band) is not entirely correct, or the signal I received is NOT from W3(OH). Alternatively, I could have made a little mistake somewhere...

Best regards,

Eduard

Op maandag 1 maart 2021 om 13:23:15 UTC+1 schreef Wolfgang Herrmann:

[James Morris]

I did some searching and it seems that there are multiple beacon frequencies for Astra 2E, including 11707.5

http://www.astra2sat.com/astra-2e-satellite/

I've also seen reports that the frequency you are looking at may be a nearby sat on a similar freq.

James W7TXT

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[Eduard Mol]

Hi all,

After some googling I found another reference for the frequencies of the Astra 3B beacons. According to frequencyplansattelites.org (http://frequencyplansatellites.altervista.org/Beacon-Telemetry_Europe-Africa-MiddleEast.html) the frequency of the beacon I measured was 11446.75 MHz. I could not find any official reference for the frecuencies of the beacons. Using 11446.75 MHz as the beacon frequency resulted in a slightly lower velocity of the W3(OH) signal. Now the deviation is less, but still about 1 km/s. 

Best regards,

Eduard.

Op maandag 8 maart 2021 om 08:43:04 UTC+1 schreef morr...@gmail.com:

[fasleitung3]

Hi Eduard,

one of the possibilities to verify your observation would be to check whether the observed line frequency changes as expected due to the change in doppler shift over time. You mentioned in your earlier post that the VLSR corrected line stays at the same velocity. If that continues over a somewhat longer period of time then this can only be the maser line with a very high probability. Since there seem to be some uncertainty with respect to the exact beacon there is maybe not too much of an issue with the small deviation from the expected velocity.

Unfortnuately we do some work on our 10-m dish and it is out of operation at the moment, otherwise I could have measured the beacon frequency against our precise standard.

Best regards,

Wolfgang

[Eduard Mol]

Hi Wolfgang, hi all,

Last week I tried to accurately measure the frequency of the Astra 3B beacon by using a beacon with a more certain frequency. I used the two beacons of the eshail2 satellite which mark the lower and upper boundary of the amateur radio downlink. These beacons are at 10489.500 and 10489.750 MHz according to the bandplan published by amsat-dl (https://amsat-dl.org/wp-content/uploads/2020/02/AMSAT-QO-100-NB-Transponder-Bandplan-Listing.png). After frequency correction using the eshail2 beacons I found that the the Astra beacon is at 11446.7266 MHz. Furthermore, there was a small error in my frequency correction. Now, with these issues fixed, the velocity deviation is much smaller, at most a few hundred m/s. 

I also did another observation of W3(OH) yesterday, and the line is still at the same LSR-corrected velocity. So it seems that the signal is indeed the methanol maser of W3(OH). 

I decided to call the little 1.1 metre dish setup the "mini maser telescope" from now on, hopefully it will see more masers in the future. I wonder if there are any other methanol masers which may be detectable with this setup.

Best regards,

Eduard.

Op maandag 8 maart 2021 om 21:05:39 UTC+1 schreef Wolfgang Herrmann:

[fasleitung3]

Hi Eduard,

Thank you for the update. This is a very nice confirmation that indeed your signal is from the W3 Methonol maser.

The next option would be G188.94+089. This, however, is only a about a quarter of the intensity of W3, so this is going to be tight.

See http://adsabs.harvard.edu/pdf/1993A%26AS...98..127C for details.

Best regards,

Wolfgang

[Eduard Mol]

Hi Wolfgang,

Thanks, next week I will try G188 if the weather is good enough. It will be a while before I post on the results, given the low flux density I expect that it will take multiple evenings worth of measurements to detect it.

Best regards,

Eduard

Op za 20 mrt. 2021 20:53 schreef 'fasleitung3' via Society of Amateur Radio Astronomers <sara...@googlegroups.com>:

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[Eduard Mol]

Hi all,

here a short report of last weeks attempts to detect G188.94+0.89 with the 1.1 metre "mini maser telescope". I have observed this maser on four evenings for about 2.5 hours. Because this object is much weaker than W3(OH), the maser line is barely visible with 2.5 hours of observing time. 

I averaged all the spectra from the four observing sessions (in total nearly 10 hours of observations), and I reduced the spectral resolution to 15KHz. There is a small peak at 10.9 km/s, this corresponds well with the velocities found in the literature. 

Detecting G188.94+0.89 with such a small dish is very challenging, it seems to be right at the limit of what is possible with a 1 metre dish but that also makes it more interesting and fun.

Best regards,

Eduard.

Op zaterdag 20 maart 2021 om 23:14:44 UTC+1 schreef Eduard Mol:

[Michiel Klaassen]

Hi Eduard,

That looks like a successful result to me; congrats.

If you just add the results from 23, 25 and 29 March together, perhaps you get a better result.

The curve will be broader I think; see also 

http://parac.eu/projectmk22.htm

You also can find more 12GHz sources to try to detect.

If you want, you can publish your results as a project page on the parac website; you have to write your own text; you can find an example there also.

Regards,

Michiel

parac.eu

Op di 30 mrt. 2021 om 17:06 schreef Eduard Mol <eddiem...@gmail.com>:

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[Eduard Mol]

Hi Michiel,

Thank you for your offer, I already wanted to publish something about this project when I am finished with my observations on 12 GHz. 

I usually avoid picking only the "good" observations and leaving out other observations, because doing so could result in creating a false- positive result. There are exeptions of course, for example when an observation is affected by strong RFI I will leave it out. 

That being said, below you see the result after averaging the spectra of March 23, 25 and 29. You can see that the signal to noise ratio is indeed a bit better. The width of the peak is about 1.6 km/s. I noticed that the width of the line seems to vary in the spectra you published on your website, it is about 1.3 km/s in the 2018 spectrum and 2.5 km/s in 2019.  So maybe, if this is not an artifact, the width of the maser line is variable. 

Best regards,

Eduard.

Op dinsdag 30 maart 2021 om 20:42:13 UTC+2 schreef vmin...@gmail.com:

[Hamish Barker]

impressive results guys!

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[Michiel Klaassen]

Hi Eduard,

When I did the measurements, I noticed that the results varied because of  the clouds passing through the beam. 

When the weather is bad, now I do not even start a session.

I do the integration in 5 minute parts so I can judge each part to be added in the end result

Further I used the Avenger and Octagon LNB with PLL. I also tried to stabilize the temperature with an PTC heater.

However it still was not stable enough, so I replaced the x-tal with a Leo Bodnar GPS disciplined oscillator signal.

So the frequency stability is also a struggle.

But once again; I am amazed by your results. 

Regards

Michiel

Op wo 31 mrt. 2021 om 07:57 schreef Hamish Barker <hamish...@gmail.com>:

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[Eduard Mol]

Hi Michiel, 

Thank you for your reaction.

On March 25 there were indeed clouds, so that could explain the poor result of that observing session.

Op wo 31 mrt. 2021 11:03 schreef Michiel Klaassen <vmin...@gmail.com>:

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[Michiel Klaassen]

I forgot to add below paper. 

They mention some small different radial velocities here also.

Michiel

parac.eu

Op wo 31 mrt. 2021 om 09:25 schreef Eduard Mol <eddiem...@gmail.com>:

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[Marcus D. Leech]

On 03/31/2021 05:03 AM, Michiel Klaassen wrote:

Hi Eduard,

When I did the measurements, I noticed that the results varied because of  the clouds passing through the beam. 

When the weather is bad, now I do not even start a session.

I do the integration in 5 minute parts so I can judge each part to be added in the end result

Further I used the Avenger and Octagon LNB with PLL. I also tried to stabilize the temperature with an PTC heater.

However it still was not stable enough, so I replaced the x-tal with a Leo Bodnar GPS disciplined oscillator signal.

So the frequency stability is also a struggle.

When you used the Avenger, did you inject a 22kHz tone to shift it into the high-band?

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[Michiel Klaassen]

Hi Marcus,

Yes; see 'circuit diagram'

regards

Michiel

parac.eu

Op wo 31 mrt. 2021 om 13:24 schreef Marcus D. Leech <patchv...@gmail.com>:

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[fasleitung3]

Thank you, Eduard, for this report.

Indeed this seems to be a successful observation. It is amazing that this can be done with such a small dish.

Best regards,

Wolfgang

[Eduard Mol]

Hi all,

Since I got some requests for images showing how the dish is mounted on the HEQ5 mount, I decided to share these images here on the forum.

I am also working on an article about this project, which will appear on the PARAC website.

Best regards,

Eduard.

Op do 1 apr. 2021 10:29 schreef 'fasleitung3' via Society of Amateur Radio Astronomers <sara...@googlegroups.com>:

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[drrichrussel]

Eduardo

You can also send me an article to put in the SARA journal.

Rich

SARA journal editor

Sent from my iPad

On May 6, 2021, at 5:30 AM, Eduard Mol <eddiem...@gmail.com> wrote:



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[Anthony]

Hi! This is an awesome design!! What radio observations are you able to make with this dish setup and the Sky-Watcher EQ6-R Pro? 

Thank you!

[Anthony]

Awesome!!

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[Eduard Mol]

Hi Anthony,

As you can read in this thread I use this dish for observing masers; these are a type of radio source that emit strong and often variable molecular spectral lines. They are often found in star forming regions, by studying them in detail astronomers can learn a lot about star formation. For us amateurs detecting a maser at all is already very challenging, because most of them are quite weak. My setup can detect the strongest few methanol masers at 12.178 GHz, and of course the Sun and Moon.

Op vr 7 mei 2021 01:56 schreef Anthony <itpart...@gmail.com>:

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[Anthony]

Wow! Nice! Thank you, that maybe something I'm interested in, once I get this skill down. 

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[Eduard Mol]

Hi all,

It has been a while since I posted on this topic. I have not been able to detect any new sources. I tried to detect G9.62+0.19 last November but it was a bit too low above the horizon at my location. 

I did make a new observation of W3(OH), however, this time by making a driftscan. Despite the short integration time of less than 15 minutes, the methanol maser line was still detected.

This demonstrates that W3(OH) can even be detected without a tracking mount. By averaging the results from several driftscans, it should also be possible to build up more integration time and achieve a better SNR.

Best regards,

Eduard

[Michiel Klaassen]

Hi Eduard,

Yet again an amazing result; congrats.

And with a standard LNB, so everybody can copy your method.

(This LNB is also very suitable for interferometer observations.)

Michiel

parac.eu

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[Dimitry UA3AVR]

Hi all,

here are my results for the W3(OH) line 12 GHz. Dish - 1.8 m, receiver head - a sat LNB with external LO (YIG based PLL 10.75 GHz, OCXO reference), T_{sys} is estimated about 110 K. IF receiver - USRP B200mini, soft and data processing tools - written by me in LabVIEW especially for the project. IF frequency - about 1431.3 MHz, noise RBW about 5 kHz. The measurements made yesterday morning near Moscow, taken about 2 hours long; the integration time is somewhat less really. The atmospheric attenuation did not exceed 0.1-0.3 dB, but some light clouds were possible on the signal path (taken into account).

Next, the smoothed plots (by cubic splines over 25 points). It seems detals of the line spectrum could be seen:

A real problem was to overcome unflat frequency response of USRP receiver. The width of W3(OH) spectrum is about 200 kHz; the unflat response of USRP is noticeble. The raw frequency plot looks like on the screen below:

regards, Dimitry UA3AVR.

среда, 12 января 2022 г. в 18:58:15 UTC+3, vmin...@gmail.com:

[Eduard Mol]

Hi Dimitry 

Nice result, well done! It is good to see others successfully observing masers as well. 

By the way, how did you calculate flux density while taking atmospheric attenuation into account?

Best regards,

Eduard

Op za 27 aug. 2022 om 07:12 schreef Dimitry UA3AVR <ua3avr...@gmail.com>

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[Job Geheniau]

Hi Dimitri,

How did you track the maser?

regards

Job

Op zaterdag 27 augustus 2022 om 09:55:12 UTC+2 schreef eddiem...@gmail.com:

[Dimitry UA3AVR]

Hi Eduard, thanks ...

>>how did you calculate flux density while 

>>taking atmospheric attenuation into account?

The flux can be estimated in following way. The atmosphere gases give a contribution to the system temperature, T_{atm} (1-e^{-\tau}), where e^{-\tau} is the atmospheric attenuation with opacity \tau,  T_{atm} ~ 280 K. This contribution is about 10 K or less for clear sky. The estimate for T_{sys}=110 K has the same order of uncertainty (about 15 K), but approximately T_{sys} is known and can be associated with the noise floor under a line shape. An attenuation to hunted signal can be taken into account after defining a zero on the Jy plot (which correspond to T_{sys}) and next mulipling by value e^{+\tau}.

regards, Dimitry UA3AVR.

суббота, 27 августа 2022 г. в 10:55:12 UTC+3, eddiem...@gmail.com:

[Dimitry UA3AVR]

Hi Job,

>>How did you track the maser?

Using automatic tracking, refreshing every 1 second, but it may be too often for this antenna. The traking program also was written by me with LabVIEW. The gear was calibrated by the Sun positions.

regards, Dimitry UA3AVR.

суббота, 27 августа 2022 г. в 12:18:55 UTC+3, jobge...@gmail.com:

[Anthony]

Hello Dimitry,

Fantastic work! Is that custom built USRP software or native to the USRP device? 

If that is the case, a USRP device used, what model version are you using B200, B210 or X300 series?

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[Dimitry UA3AVR]

Thanks a lot ...

>>Is that custom built USRP software 

>>or native to the USRP device? 

>>If that is the case, a USRP device used, what 

>>model version are you using B200, B210 or X300 series?

This is a native USRP. Somewhat old and I didn't check it for a fresh firmware, but it is native from Ettus Research. Exact model name is "B200 mini".

regards, Dimitry UA3AVR.

воскресенье, 28 августа 2022 г. в 00:33:49 UTC+3, itpart...@gmail.com:

[Anthony]

I am familiar with that  model. 

Would you mind sending me your email address to me, for further correspondence on the USRP device?.

Thank you in advance.

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[Marcus D. Leech]

On 2022-08-28 00:55, Anthony wrote:
> I am familiar with that  model.
>
> Would you mind sending me your email address to me, for further
> correspondence on the USRP device?.
>
>
> Thank you in advance.
>

Just to remind folks here.   I work part-time for NI/Ettus doing
tech-support for all USRP devices.   If folks have questions,
  or problems with their devices, don't hesitate to contact me, or use
the usrp-users mailing list for "community" support.

[Anthony]

Thank you, Marcus!

Now, if only you had influence over the USPR-B210 expensive chip shortage (AD9361), causing the extremely long wait time of 80 - 85 days! 😉

I'm not sure it's it shortage or the time it takes to produce the chip and its expensive cost?

I did find an Asia site that has a knock off version of the B210: https://www.aliexpress.com/item/32994444653.html. or https://www.luowave.com/en/

The only issue, Luowave's current batch of USRP-LO B210 does not have the RF indicator for RX or TX, as the Ettus, original B210. This came from Luowave's, sales engineer that I reached out to.

That said, I found it difficult to pay $1,939.14, for this limitation, when the official Ettus USRP-B210 has the RF indicator inherently architected in its design.

The Ettus long extended wait time was my only reason for considering a knock-off version. 

There are other B210 clones, but performance, power stability and warranty are major considerations. 

Not mention some of these clones are substituting the AD9361 chip for an inferior chip.

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[Marcus D. Leech]

On 2022-08-28 11:42, Anthony wrote:

Thank you, Marcus!

Now, if only you had influence over the USPR-B210 expensive chip shortage (AD9361), causing the extremely long wait time of 80 - 85 days! 😉

I'm not sure it's it shortage or the time it takes to produce the chip and its expensive cost?

I did find an Asia site that has a knock off version of the B210: https://www.aliexpress.com/item/32994444653.html. or https://www.luowave.com/en/

The only issue, Luowave's current batch of USRP-LO B210 does not have the RF indicator for RX or TX, as the Ettus, original B210. This came from Luowave's, sales engineer that I reached out to.

That said, I found it difficult to pay $1,939.14, for this limitation, when the official Ettus USRP-B210 has the RF indicator inherently architected in its design.

You mean the TX and RX LEDs?

The Ettus long extended wait time was my only reason for considering a knock-off version. 

There are other B210 clones, but performance, power stability and warranty are major considerations. 

Not mention some of these clones are substituting the AD9361 chip for an inferior chip.

They may use the AD9363, which is only "inferior" in that it has a smaller tuning range, maxing out at 3.8GHz.
  It's the chip that's used in the ADALM Pluto, for example.

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[Anthony]

Yes, the LEDs. Not sure that's a big deal, but for the price, shouldn't there be RX & TX LEDs. 

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[Marcus D. Leech]

On 2022-08-28 11:56, Anthony wrote:

Yes, the LEDs. Not sure that's a big deal, but for the price, shouldn't there be RX & TX LEDs.

The main thing about the "clones" is that they're not spectacularly cheaper than the real thing, and I'm not allowed to
  provide support for them (obviously).

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[Anthony]

FYI:

Hello dear Anthony,

We have sold many products on AliExpress, but only recent sales orders are displayed on AliExpress.

We prefer to let customers transfer money directly to us, because we have to wait a long time to receive payment for transactions on AliExpress.

Our products are the same as ettus products in performance and usage, but this batch of b210 has no RF indicator for receiving and transmitting.

Because the fpga chip of b210 is very expensive and out of stock, the production cycle of b210 will be very long. Our b210 has already produced a batch before, and there are still some in stock.

------------------

Best Regards,

Xiaoqiao Chen

Sales Engineer

Luowave SDR Co., Ltd.

https://www.luowave.com/en/

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[Anthony]

Valid point on support. That was my other question for Luowave, support which the response from them wasn't a confidence booster in purchasing their B210 version. 

Where as Ettus, distributor NI for purchasing the B210 has an very positive customer support satisfaction rating from BBB, Pilottrust and Google. 

Spoke with NI sales-support, they are holding true to the 80 - 85 day delivery of a B210. I will purchase one and attemp to sell the KrackenSDR.

Have a great day or evening everyone! 😀

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[Larry Mayfield]

Not sure where  you arelocated, but Digikey says

RF Transceiver ICs | Electronic Components Distributor DigiKey

For thatIC

Larry

Pahrump…

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[Anthony]

Yep, I reached out and spoken with DigiKey too, though their site says end of September 2022 i believe.That date is not firm.

This other oranizarion, Tequipment, which shows the B210 in stock, but their actual timeline is 16 or 19 weeks. But again their reviews show customers delivery dates come and past. Tequipment.net

Tequipment does not update this information to customers and therefore have hit or miss (mix) reviews. 

So I reached out to them on a real time, no nonsense delivery date for the Ettus USRP-B210. They responded back after a few days stated they are requesting this information from the distributor, which I imagine is NI. Haven't heard back from them yet, it's been a week, plus.

I also reached out to Marcus, and he was unfamiliar with Tequipment. 

Marcus also recommended Digikey as well, but all these distributors or resellers have the same issue, the FPGA chip, extended long production times. Maybe due to past or post Covid19 issues, don't know.

But thank you very much Larry, I appreciate it! 

I wish I had purchased the B210, when Marcus first made me aware of its existence. 

I chose the KrakenSDR because of cost and its potential as a coherent SDR, but didn't realize as Marcus put it, the futzing around with it, would take just to work with GN Radio or any RAS software. Outside of using the Heimdall DAQ Server software for a TCP Socket connection with the KrakenSDR is another piece to take into configuring the Kraken...

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[Larry Mayfield]

Another

 

ad9361xbcz | Octopart  which says they have at least a path to them depending on the extra ,letters on the end of the basic \model num.

 

larry

Pahrump

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[Marcus D. Leech]

On 2022-08-28 12:46, Anthony wrote:
>
>
> I chose the KrakenSDR because of cost and its potential as a coherent
> SDR, but didn't realize as Marcus put it, the futzing around with it,
> would take just to work with GN Radio or any RAS software. Outside of
> using the Heimdall DAQ Server software for a TCP Socket connection
> with the KrakenSDR is another piece to take into configuring the Kraken...
>

I'll note with a certain amount of "Sad Trombone" in the background,
that Carl Laufer has just produced a Gnu Radio interface
  for the KrakenSDR, which requires that you run the Heimdall DAQ as a
server, and Gnu Radio "talks" to it via TCP.  This is
  not a horrible interface, in fact, if it were my product, I'd
pre-package it with a rPi4 with the DAQ software configured to
  auto-start when the system comes up, and pretend that "stack" of
KrakenSDR and rPi4 was "The Radio", and have my
  host PC talk to it via a dedicated 1GiGe interface--much like you can
with several of the Ettus radios.

This is super-new, like a week old.   Until I find time to experiment
with it myself, I pass no judgement good or bad on it.
  It has been the case up until this point that the KrakenSDR project
was struggling to get a Gnu Radio interface written,
  because their team weren't Gnu Radio people, and they were focused
very much on the D-F aspects of this radio,
  rather than the more-generic "N coherent radio channels" aspect.

[Anthony]

😊

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[Anthony]

Thank you! I'll check it out today. 🙂

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[Anthony]

On Sun, Aug 28, 2022 at 11:56 AM Anthony <itpart...@gmail.com> wrote:

Yes, the LEDs. Not sure that's a big deal, but for the price, shouldn't there be RX & TX LEDs. 

Thanks, Marcus, for clarifying.I knew there was a reason for inferiority or I should say limitations with the AD9363 versus the AD9361. 😊

[Dimitry UA3AVR]

I can't find this maser line (W3OH 12 GHz, CH_3OH, II class) in the database https://maserdb.net/. The object W3(OH) is well found but no methanol lines 12 GHz are associated. Why? Found 12 GHz methanol lines belong to objects in southern hemisphere mainly.

понедельник, 22 февраля 2021 г. в 22:35:22 UTC+3, eddiem...@gmail.com:

Hi all,

Over the past few months my father and I have been working on a small radiotelescope for centimetre wavelengths. I was interested in observing methanol and water masers at 12 and 22 GHz, but the mesh surface of my 3 metre dish is not  good enough for such high frequencies. Moreover, pointing and tracking by hand is very difficult at such high frequencies. Therefore, I decided to buy a smaller solid offset dish which was light enough for my HEQ5 equatorial mount. this solves at least most of the tracking and pointing problems. However, the dish has a diameter of only 1 metre, so its surface area is 9X smaller than that of a 3 metre dish. 

I decided to start working on the 12,178 GHz methanol line first. In an earlier thread on this forum (https://groups.google.com/g/sara-list/c/9OW8LU9LGvU) Michiel Klaassen and Wolfgang Herrmann pointed out to me that detecting water and methanol masers should be possible with a 3 metre dish. They also mentioned that 12 GHz methanol was easier on the receiver side because LNBs for this frequency range are widely available. 

W3(OH) should be one of the brightest methanol masers in the northern sky, Blaszkiewicz el al. (2004) mentioned a flux density of 793 Jansky. I calculated that with my 1 metre dish and an aperture efficiency of 0.5, an ~800 Jy source should give an antenna temperature of 0.1 kelvin. I tried to calculate the minimum integration time needed to detect W3(OH) using the radiometer equation. With a Tsys of 100 kelvin, an aperture efficiency of 0.5 and a bandwidth of 10 KHz I would need about an hour to detect a 0.1 K difference with an SNR of 5. Of course, this is the theoretical minimum integration time, so it might be much harder in reality. However, I decided that this was still worth giving a try.

I used an inverto Ku band single PLL LNB to downconvert the 12 GHz signal to L-band. the LNB has 2 local oscillators, I needed to switch on the high band 10.6 GHz LO, This is done by inserting 22 KHz tone. My father built a special power supply which delivers 12V DC with the 22 KHz tone superimposed, this is fed into the LNB via a bias tee. I tested how much the LO frequency drifts and found that it only drifted about 10- 15 KHz in a few hours. this is much less than the width of the maser line, so I decided it was not necessary to modify the LNB for higher stability. 

On the evenings of february 20 and 21, I tried to detect the methanol maser of W3(OH). Integration time was 2 hours on the first evening and 3 hours on the second. I also measured the Astra 3B beacon again after the observations to measure the frequency offset of the LO. On both evenings I detected a weak 0.1K signal at around -45.5 km/s. It looks quite convincing but I first want to make sure it is not some weird form of RFI.

To be continued....

Eduard Mol

[Eduard Mol]

Hi Dimitry, I am not sure why the W3(OH) 12.2 GHz maser is not included. It seems like the 12.2 GHz line is not observed very often, probably because there is a stronger methanol maser line at 6.668 GHz, and because of RFI from satellites in the 10-12GHz band. There are some published observations of W3(OH) at 12.2GHz, see for example https://adsabs.harvard.edu/pdf/1993A%26AS...98..127C.

Best regards,

Eduard 

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[Dimitry UA3AVR]

Hi, Eduard, thanks ...

... i guess it was not my mistake and this line is missed in the databale really. For info about this line i used a bit later paper form the same group, https://articles.adsabs.harvard.edu/pdf/1996A%26AS..116..211M

regards, Dimitry, UA3AVR.

понедельник, 5 сентября 2022 г. в 22:27:14 UTC+3, eddiem...@gmail.com:

[Dimitry UA3AVR]

Hi all, 

here is my result for G188.9+0.9. Intergation time is about 1.5 hours, dish 1.8 m. The peak level and velocity are about expected:

The line about 18 km/s is unexpected, lays above the noise floor certainly and is not a receiver artifact. Possibly a weak RFI:

regards, Dimitry UA3AVR.

вторник, 30 марта 2021 г. в 20:06:51 UTC+3, eddiem...@gmail.com:

Hi all,

here a short report of last weeks attempts to detect G188.94+0.89 with the 1.1 metre "mini maser telescope". I have observed this maser on four evenings for about 2.5 hours. Because this object is much weaker than W3(OH), the maser line is barely visible with 2.5 hours of observing time. 

I averaged all the spectra from the four observing sessions (in total nearly 10 hours of observations), and I reduced the spectral resolution to 15KHz. There is a small peak at 10.9 km/s, this corresponds well with the velocities found in the literature. 

Detecting G188.94+0.89 with such a small dish is very challenging, it seems to be right at the limit of what is possible with a 1 metre dish but that also makes it more interesting and fun.

Best regards,

Eduard.

Op zaterdag 20 maart 2021 om 23:14:44 UTC+1 schreef Eduard Mol:

Hi Wolfgang,

Thanks, next week I will try G188 if the weather is good enough. It will be a while before I post on the results, given the low flux density I expect that it will take multiple evenings worth of measurements to detect it.

Best regards,

Eduard

Op za 20 mrt. 2021 20:53 schreef 'fasleitung3' via Society of Amateur Radio Astronomers <sara...@googlegroups.com>:

Hi Eduard,

Thank you for the update. This is a very nice confirmation that indeed your signal is from the W3 Methonol maser.

The next option would be G188.94+089. This, however, is only a about a quarter of the intensity of W3, so this is going to be tight.

See http://adsabs.harvard.edu/pdf/1993A%26AS...98..127C for details.

Best regards,

Wolfgang

Am Samstag, den 20.03.2021, 09:14 -0700 schrieb Eduard Mol:

Hi Wolfgang, hi all,

Last week I tried to accurately measure the frequency of the Astra 3B beacon by using a beacon with a more certain frequency. I used the two beacons of the eshail2 satellite which mark the lower and upper boundary of the amateur radio downlink. These beacons are at 10489.500 and 10489.750 MHz according to the bandplan published by amsat-dl (https://amsat-dl.org/wp-content/uploads/2020/02/AMSAT-QO-100-NB-Transponder-Bandplan-Listing.png). After frequency correction using the eshail2 beacons I found that the the Astra beacon is at 11446.7266 MHz. Furthermore, there was a small error in my frequency correction. Now, with these issues fixed, the velocity deviation is much smaller, at most a few hundred m/s. 

I also did another observation of W3(OH) yesterday, and the line is still at the same LSR-corrected velocity. So it seems that the signal is indeed the methanol maser of W3(OH). 

I decided to call the little 1.1 metre dish setup the "mini maser telescope" from now on, hopefully it will see more masers in the future. I wonder if there are any other methanol masers which may be detectable with this setup.

Best regards,

Eduard.

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[Eduard Mol]

Hi Dimitry, 

Nice results, congratulations!

G188 is very difficult to detect because it is considerably weaker than W3(OH). 

There are lots of satellites which use the 10-12 GHz band, so it is indeed very much possible that the spike at 18km/s is just RFI.

Best regards,

Eduard 

Op zo 11 sep. 2022 om 15:41 schreef Dimitry UA3AVR <ua3avr...@gmail.com>

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[Dimitry UA3AVR]

Thanks, Eduard ...
... this maser is well detected, but NGC 7538 was not seen after 2 attempts, nor even a hint of presence. Altgough its expected peak flux is almost the same.

regards, Dimitry UA3AVR.

понедельник, 12 сентября 2022 г. в 09:33:42 UTC+3, eddiem...@gmail.com:

[Eduard Mol]

Most masers are variable, so it is quite possible that NGC7538 has become too weak to detect over the years. I found a more recent 12.2 GHz methanol maser survey on Visier (https://vizier.cds.unistra.fr/viz-bin/VizieR?-source=J/ApJS/258/19); NGC 7538 (G111.542+0.776) is listed there with a flux density of 90 Jy in 2017. That is probably just too weak for detection with a small dish.

Op ma 12 sep. 2022 om 11:29 schreef Dimitry UA3AVR <ua3avr...@gmail.com>

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[Dimitry UA3AVR]

OK, Eduard, thanks for more database reference ... as i see, maserdb.net shows no detections of NGC 7538 at all.

понедельник, 12 сентября 2022 г. в 16:37:52 UTC+3, eddiem...@gmail.com:

[fasleitung3]

Here is our observation of the methanol maser at W3 in 2019. There seems to be no significant change of the spectrum since the observation shown in the paper cited below.

I do not have an absolute calibration of the intensity, the spectrum was taken with 10 min integration time with a 10m dish.

Best regards,

Wolfgang

[Michiel Klaassen]

Hi Wolfgang,
Yes, I have also published a graph of W3(OH)@12GHz on my website,
but because of the infinite genocide of the russians in Ukraine I have blocked russians from my site and the Camras forum.

Michiel

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[Eduard Mol]

Guys Please no political stuff in this thread. I know I am not the admin/moderator of this forum but as the initiator of this thread I don’t want to see this ending up in a lot of off-topic debate. This is a radio astronomy forum. As long as everyone here keeps their posts on the topic of radio astronomy (or anything related) there is no problem.

Op wo 14 sep. 2022 om 20:06 schreef Michiel Klaassen <vmin...@gmail.com>

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[Dimitry UA3AVR]

I must apologize my above plots with G188.94+0.89 observations are not correct. There was a mistake with VLSR calculations misleading with the lines interpretation. 

The wider line below is more likely a maser line due to its width about 1 km/s and close to expected position; and the left narrow spike at 2.2 km/s is a probable RFI.  

regards Dimitry UA3AVR

понедельник, 12 сентября 2022 г. в 09:33:42 UTC+3, eddiem...@gmail.com:

Hi Dimitry, 

[Eduard Mol]

Hi Dimitry,

At least you found the mistake. In the beginning I also had some trouble with getting the Vlsr correction right.

I remember that the G188 methanol line was about 1-2 km/s wide, so this makes much more sense now. Narrow spikes are often RFI.

Best regards,

Eduard 

Op ma 19 sep. 2022 om 09:47 schreef Dimitry UA3AVR <ua3avr...@gmail.com>

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[Dimitry UA3AVR]

Hi, Eduard.

It was a stupid mistake, - just forgot to change default RA&Dec in the VLSR calculator (they was set by me for previously hunted W3 OH object, the calculator based on codes from page http://f4klo.ampr.org/vlsrKLO.php). The mistake was found in attempts to detect Cepheus A line 12 GHz. VizieR tells about 277 Jy in peak for 2017, https://vizier.cds.unistra.fr/viz-bin/VizieR-5?-ref=VIZ63286480155bd9&-out.add=.&-source=J/ApJS/258/19/detections&recno=244 . It would be a detectable level.

My result for Cepheus A is negative, not detected.

понедельник, 19 сентября 2022 г. в 13:23:46 UTC+3, eddiem...@gmail.com:

[Dimitry UA3AVR]

Hi, Eduard,
as i guess, W3(OH) line 12 GHz is missed in https://maserdb.net/ because of this database initially created for variable (or Mira) stars masers. W3(OH) is not one of such masers and behaves rather stably.

Regards, Dimitry UA3AVR.

понедельник, 5 сентября 2022 г. в 22:27:14 UTC+3, eddiem...@gmail.com:

Hi Dimitry, I am not sure why the W3(OH) 12.2 GHz maser is not included. It seems like the 12.2 GHz line is not observed very often, probably because there is a stronger methanol maser line at 6.668 GHz, and because of RFI from satellites in the 10-12GHz band. There are some published observations of W3(OH) at 12.2GHz, see for example https://adsabs.harvard.edu/pdf/1993A%26AS...98..127C.

Best regards,

Eduard 

[Eduard Mol]

Hi Dimitry,

That would indeed explain why the W3OH 12GHz maser is missing. MaserDB seems to be reasonably complete in most cases but this underscores that it is sometimes helpful to look for other resources as wel…

Op do 2 feb. 2023 om 16:49 schreef Dimitry UA3AVR <ua3avr...@gmail.com>

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