LNB Offset Testing (sorry, no more free LNBs)


#1

We have an LNB that appears to have a very stable crystal. In Chicago over the past month, it’s been starting up with an offset of less than 1 kHz. The weather has not been too extreme here, so I don’t have a great baseline for testing. I’m guessing that spring is not going to be terribly conducive to testing wide temperature swings and startup offset of the LNB. That being said, there is no reason to wait for the ideal time.

If you have your receiver online, I’m happy to send you a free LNB–with the hope that you will share your results with the forum. We are interested in seeing how stable the offset is at startup across a range of temperatures.

Shipping is free. Just email your order number to [email protected] with the subject “LNB Testing”. The LNB will go to the address on file. When you swap out your LNB, you’ll need to switch it in the Tuner App and restart.

@kenbarbi @maxboysdad @thomslik @ac8dg @lmantuno @tylerhoot @mw1mdh


#2

Does the LNB need to be receiving a signal for this test? Could it be characterized by placing the LNB in a temperature chamber, stabilizing at many different temperatures and performing startup tests? Or does it need to be outside, accurately aimed, to collect any useful information about its startup temperature performance?


#3

Couple of question…

  1. the second option on tuner lnb states othernet dual band. Usually that is triggered by the impressed 20khz tone on the feed line to switch from the ‘upper ku’ to the lower ku band. Is this what that setting functions as… ?

  2. I have been running a DRO (non-pll) lnbf since the beginning of the year… aside from some initial adjustments of to 11.9019 (ie… about a ?? kHz change from the listed standard) it really hasn’t fluctuated much. Note : I watch the frequency offset in the ‘status’ and made the L.O. setting to minimize the ‘offset’. I lose lock if the offset is greater then 100,000 — meaning the AFC can’t compensate

  3. If you could just publish a make/model of the ‘test’ lnbf, rather then trying to coordinate delivery, it might be easier since I have setup a ‘custom’ mounting bracket. some of my installs don’t use the standard 40mm ring (or the 25mm smaller reduced ring)


#4

Is this what you mean by “switch it in the Tuner App”? Ken

image


#5

@kenbarbi Yes, that’s correct.

@ac8dg 1–yes. 3. It’s our own LNB that will likely replace the Maverick. This LNB does have a 40mm neck.

@wbrown Yes, we could rent a chamber or set up an RF test environment at a facility with a chamber, but I won’t have time to do that until late June. I figured this way might be more fun for some people. It does not need to be operating under live conditions for characterization, though we always tend to test that way since live is so accessible.


#6

sending the email now @Syed


#7

Email sent. Ken


#8

Not sure if you can tell from https://status.othernet.is/
or telemetry, but the planned dreamcatcher/edup for testing has
a MAC address of E8:4E:06:35:08:43 it’s ip will be usually
placed somewhere SE Michigan or Ohio based on my ISP

Physically it will be in NW lower Michigan


#9

Sent mine also.
Jerry


#10

Sent.


#11

I am interested to participate if there are enough LNBs to go around. Email sent.


#12

Thanks for the interest. All of the free LNBs are being shipped out today. Sadly, there are only a few more free one left for testing, which are being sent to Canada.


#13

Please establish the parameters that are of interest — (possible ideas )

  1. Ambient Temp at install location
  2. Initial temperature of lnbf (measure on external casing)
  3. Stabilization time or dwell time before applying power to the feedline
  4. Changes after applying bias-t voltage
  5. Electrical parameters observed in the skylark diagnostics – over a time period
  6. Tuner parameters observed in ‘status’ screen – over a time period
  7. Solar heat gain, wind induced temperature loss, changes in ambient temp,…
  8. Initial time to achieve a ‘lock’ or a first packet decoded
  9. Methods that force an interruption of service

#14

Yes exactly. We need a list of key parameters to check, and the timing of the observations such as: at start up, 5 minutes later, 20 minutes, 12 hours, etc. Ken


#15

Here is a starting point. Feel free to edit.

https://ethercalc.org/73s31bqonz2i


#16

I’m polling statistics at 5 second intervals so it should be dead easy to get you graphs and long term numbers. Weather will be a little more difficult, but I can probably guess that (or at least get some trend data) by sniffing my neighbors’ weather sensors with rtl_433

Unfortunately the othernet github repos don’t contain everything to rebuild an image otherwise I’d send some patches. There is a bunch of duplicated code between various scripts, and I’d really like to extend the tuner status API endpoint to also include board temperature (I bet that has at least a slight, but measurable, impact on receiver performance.


#17

received… L.O. is listed 9.75 / 10.6 installing… now

Edit 1: [ OK ] Bias-T is configured on: 0x8b
[ OK ] Bias-T voltage is set to 14.2V
[ OK ] LNB power is configured on
[ OK ] LNB detected, normal current flow: 0x23
[ OK ] Bias-T Voltage normal

Edit 2: changed LNB type to othernet dual band
then apply button
Got… “unexpected error” — in java script

rebooting - shutdown -unplug- re-power- restart

now [ OK ] Bias-T is configured on: 0xbb
newlnbf


#18

That offset is amazing. Off by 74 hertz, out of almost 12 billion hertz.


#19

seems stable. as I watch it. looks like an sr-320 lnbf

Good job.

snr on MKI was +4, this one drops it to -1 as you can see… 90cm dish


#20

Worse SNR? That’s strange. I haven’t seen this. Was skew adjusted?