Has anyone characterized the Nooelec SAWbird

[Paul Tagliamonte]

Hello, SARA!

I'm looking at picking up a Nooelec SAWbird (as seen in the Scope in a
Box project), and I'm wondering if anyone with better equipment than
me has done the work to understand the performance of the SAWbird.

I'm interested in how linear the output is given an input, how the
filter impacts the output frequency within the passband, and what type
of phase noise this introduces. Does the SAWbird have an internal
oscillator for a LO or is it mostly done at RF because it's fairly low
in frequency? How about the 5v MicroUSB power input, does that impact
any of the above? Low/high voltage, amperage?

Thank you all very much!
Paul

--
Paul K3XEC

[Marcus D Leech]

It’s an LNA not a down converter. Phase noise specs aren’t usually a parameter for amplifiers.

There is a data sheet for the product on the NooElec website.

The front end part is a TQP3M9037. You can look at the data sheets for that part for linearity specs.

Sent from my iPhone

> On Mar 9, 2023, at 2:29 PM, Paul Tagliamonte <pa...@k3xec.com> wrote:
>
> Hello, SARA!

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[Marcus D. Leech]

On 09/03/2023 20:07, 'Alex P' via Society of Amateur Radio Astronomers wrote:

Here is a plot of the SawBIrd H1 Bandwidth

Here's the datasheet for the LNA:

https://www.nooelec.com/store/downloads/dl/file/id/97/product/322/sawbird_h1_datasheet_revision_1.pdf

[b alex pettit jr]

On Thursday, March 9, 2023 at 08:07:13 PM EST, 'Alex P' via Society of Amateur Radio Astronomers <sara...@googlegroups.com> wrote:

Flter characteristics of the SawBIrd H1 Bandwidth  from my VNA

From Data Sheet

Alex KK4VB

[Paul Tagliamonte]

Thank you everyone who replied with data!

A big part of my question (perhaps I should have ordered it better) was stuffed at the end -

Has anyone taken readings under different power conditions? Like, fed with 3.1v (below spec), 3.3v, 5v, 6v (over-spec but below the chip max), under-amperage states, or even noisy power input -- how does that impact the output amplified signal and passband? Is applied voltage related to output signal strength or is it regulated so that anything over 3.3v means it's operating with no change to the amplifier output with applied voltage?

Thank you to so many of you helpfully replying with information! I very much appreciate you!

   Paul K3XEC

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[Marcus D. Leech]

On 10/03/2023 10:09, Paul Tagliamonte wrote:

Thank you everyone who replied with data!

A big part of my question (perhaps I should have ordered it better) was stuffed at the end -

Has anyone taken readings under different power conditions? Like, fed with 3.1v (below spec), 3.3v, 5v, 6v (over-spec but below the chip max), under-amperage states, or even noisy power input -- how does that impact the output amplified signal and passband? Is applied voltage related to output signal strength or is it regulated so that anything over 3.3v means it's operating with no change to the amplifier output with applied voltage?

Thank you to so many of you helpfully replying with information! I very much appreciate you!

   Paul K3XEC

Noise on the DC input will both couple directly to the output (depending on "shape" -- there is an L filter on the input), and
  also modulate the gain and linearity specs.

In general, with HEMT amplifiers, in my experience, lowering the Vdd a little bit improves the noise-figure at the expense of
  linearity, and vice-versa.  The NooElec LNA doesn't have an on-board regulator, so you can do these experiments yourself.
  Me, I just run them "as intended".

We use them at our observatory on our 12.8m dish without any problems (particularly once we placed a low-loss, broadband
  filter up front -- thanks to PE1RKI).

I'll note that the data sheet for TQPM9037 shows performance curves for both Vdd=5V and Vdd=3.3V.   At 5V, the output
  p1dB is about 20dBm.  With 3.3V, it's about 4dB lower, with very-little effect on noise figure.  So, with this particular
  part, there's little incentive to run it at lower input voltage, unless you're in a very power-constrained situation.

So, unless you're trying to use this part in a heavily-congested RF environment, I don't understand the purpose of the
  questions.  The LNA module works more-than-adequately for 21cm observations.  Does it compete with the very-best
  purpose-built-for-science LNAs (cryo or otherwise)?  No.   Both ourselves and Astropeiler Stockert have used them in
  some actual science endeavors, so they can't be all bad. [To be fair, Stockert replaced them on the big dish with
  some custom ones from Sander Weinreb which have *stunning* room-temp performance, but not all of us can
  benefit from Sander's generosity].

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[Paul Tagliamonte]

On Fri, Mar 10, 2023 at 10:23 AM Marcus D. Leech <patchv...@gmail.com> wrote:

On 10/03/2023 10:09, Paul Tagliamonte wrote:

So, unless you're trying to use this part in a heavily-congested RF environment, I don't understand the purpose of the
  questions. 

To test - I am in a very congested environment, but that's not why I'm interested since I'll be shipping this off to a friend's observatory to run it for a few months after it's working. Well, if it works anyway.

I'm considering using a number of SAWbirds inline in a phased array configuration to put some of my beamforming code to work to electronically steer what is otherwise a drift-scan.

I want to be sure that I account for as many sources of noise in this configuration as possible, since minor noise in this configuration can sometimes wreak havoc. I'm new to the RA sport, but wanted to repurpose code I've already got working/validated for other RF projects to see how it fares on the H1 line.

  Paul

[Marcus D. Leech]

On 10/03/2023 10:37, Paul Tagliamonte wrote:

On Fri, Mar 10, 2023 at 10:23 AM Marcus D. Leech <patchv...@gmail.com> wrote:

On 10/03/2023 10:09, Paul Tagliamonte wrote:

So, unless you're trying to use this part in a heavily-congested RF environment, I don't understand the purpose of the
  questions. 

To test - I am in a very congested environment, but that's not why I'm interested since I'll be shipping this off to a friend's observatory to run it for a few months after it's working. Well, if it works anyway.

I'm considering using a number of SAWbirds inline in a phased array configuration to put some of my beamforming code to work to electronically steer what is otherwise a drift-scan.

You mean, serially?  As in one after the other?  I would not do this without some attenuation between.  They have about 42dB
  gain, so unless you're running long cables, and the receiver is deaf as a post, you only need the one right up at the antenna.
  We use ours with a roughly 12m run between the feed and the receiver, and it works fine.

I want to be sure that I account for as many sources of noise in this configuration as possible, since minor noise in this configuration can sometimes wreak havoc. I'm new to the RA sport, but wanted to repurpose code I've already got working/validated for other RF projects to see how it fares on the H1 line.

Well, for *noise*, it's the noise figure that matters, and these have about 0.4-0.5dB of input-referred noise with, as I said, about
  42dB total gain--which means that unless you're inserting copious amounts of attenuation after the LNA, it will utterly
  dominate Tsys--this is just standard noise-chain analysis from Friis.

What you care about for beam-forming in this situation is understanding the *phase lengths* of the individual cables between
  the antennas and the receiver.   Those will necessarily change with temperature to a MUCH larger degree than the LNAs, and
  "group delay over temperature" is a parameter that is almost never measured for LNAs.  Your cable plant will utterly
  dominate there.

  Paul

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[Paul Tagliamonte]

On Fri, Mar 10, 2023 at 12:07 PM Marcus D. Leech
<patchv...@gmail.com> wrote:
> You mean, serially? As in one after the other?

No, an array of antennas and amplifiers (antenna, amplifier, to a
coherent SDR channel) will be fed into one/a few SDRs locked to the
same clock / 1PPS trigger (depending on the hardware I pull off the
shelf, maybe a few USRP B210s would be best suited here, but I'd love
to try it with a cheap option, maybe a few HackRFs or a
Kerberos/Kraken SDR I've got sitting around). Each SDR channel would
be tied to an independent amplifier and antenna.

Anyway - I think I'll leave the thread here to die off unless someone
has something mind-blowing to add :) -- I got enough information where
I bought 4 SAWbirds on a gamble, and will try to test it locally to
understand performance in this arrangement.

Thank you all for your help,
Paul

> To view this discussion on the web visit https://groups.google.com/d/msgid/sara-list/27887472-e1fa-8e97-d7a2-62077287f4ca%40gmail.com.

[Marcus D. Leech]

On 10/03/2023 13:20, Paul Tagliamonte wrote:
> On Fri, Mar 10, 2023 at 12:07 PM Marcus D. Leech
> <patchv...@gmail.com> wrote:
>> You mean, serially? As in one after the other?
> No, an array of antennas and amplifiers (antenna, amplifier, to a
> coherent SDR channel) will be fed into one/a few SDRs locked to the
> same clock / 1PPS trigger (depending on the hardware I pull off the
> shelf, maybe a few USRP B210s would be best suited here, but I'd love
> to try it with a cheap option, maybe a few HackRFs or a
> Kerberos/Kraken SDR I've got sitting around). Each SDR channel would
> be tied to an independent amplifier and antenna.
>
> Anyway - I think I'll leave the thread here to die off unless someone
> has something mind-blowing to add :) -- I got enough information where
> I bought 4 SAWbirds on a gamble, and will try to test it locally to
> understand performance in this arrangement.
>
> Thank you all for your help,
> Paul
>

Ah, OK.

I will warn you that two USRP B210s sharing clock and 1 PPS will have
random and unpredictable phase offsets with
  respect to one another (due both to the 2XLO mixer in the AD9361 chip
and other aspects of the PLL synthesizers).
  Now, that's "just" an offset, and you can eliminate it by measuring
it at startup, which is pretty-much what
  KrakenSDR does.

Good luck, and I think we'd all like to hear of any results...

[Lester Veenstra]

Just saw this:
https://www.ebay.com/itm/385345892701?hash=item59b867b15d:g:bQYAAOSweYtjvmEI

Will order and test

Lester B Veenstra K1YCM MØYCM W8YCM 6Y6Y W8YCM/6Y 6Y8LV (Reformed USNSG CTM1)
les...@veenstras.com

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