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BuffyTheSaint

Oracle and EZ Tracker Problem

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I recently purchased an EZOSD and EZTracker antenna sytem from Zoltan at NG Hobbies and wanted to use it with my Oracle diversity controller. I have two Lawmate 2.4Ghz rx's hooked up to a 11dbi diversity patch antenna. I determined which rx was vid2 using the Oracle setup instructions. I hooked it all up using the right audio channel inputs and output. On the bench, I was able to get 100% good packets on vid2 but no good packets on vid1, manually switching between both rx's. I was able to get good packets from both rx's when hooked up to the EZTracker individually. I then took vid1 right audio input and moved it to vid1 left audio input, leaving the rest of the audio cables on the right. I then received 100% good packets.....????? Has anyone had or heard of this problem before? Is it an internal problem with the Oracle? Any help would be appreciated.

It seems to work this way so I'll have to try a test flight setup this way. Zoltan also suggested I test it with vid2's audio directly to the tracker, bypassing the Oracle. My EZTracker telemetry was set to fast and I had to turn down the audio on the EZTracker to " LOW 124 132" to get it to work. The photo is the way my setup works.

Buffy.

post-5638-125104684357_thumb.jpg

Edited by BuffyTheSaint

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Very strange! I think it would be easier for you to troubleshoot things if you plugged your A/V monitor's amplified speaker into Oracle instead of the EZTracker decoder. That way you can hear what the EZTracker hears.

If that does not help you figure out the problem then let's test out Oracle's audio switching circuit. The [?] indicates the steps where you should post what you found.

(1) Remove ALL the A/V cables from Oracle.

VID-1, Audio Right Test:

(2) Plug your A/V monitor's speaker into the A/V Audio Right Output.

(3) Using only one of your A/V receivers, plug its video cable into Video Input 1.

(4) Plug its Audio cable into Aud-1 Right Input.

(5) Do not plug anything else in.

(6) Turn everything on

(7) Use the front panel button to select Vid-1

(8) Verify that you hear audio (with the A/V Tx off you will hear a nice strong hiss sound). [?]

(9) While the Vid-1 is still selected (front panel switch) try the audio cable in the three other Audio Inputs. All should be silent. Good/Bad?

VID-1, Audio Left Test:

(10) Plug your A/V monitor's speaker into the A/V Audio Left Output.

(12) Move the A/V receiver's audio cable to A/V Aud-1 Left Input.

(13) Verify that you hear audio. [?]

(13) While the Vid-1 is still selected (front panel switch) try the audio cable in the three other Audio Inputs. All should be silent. Good/Bad?

VID-2, Audio Right Test:

(14) Plug your A/V monitor's speaker into the A/V Audio Right Output.

(15) Using only one of your A/V receivers, plug its video cable into Video Input 2.

(16) Plug its Audio cable into Aud-2 Right Input.

(17) Use the front panel button to select Vid-2

(18) Verify that you hear audio. [?]

VID-2, Audio Left Test:

(19) While the Vid-2 is still selected (front panel switch) try the audio cable in the three other Audio Inputs. All should be silent. [?]

(20) Plug your A/V monitor's speaker into the A/V Audio L Output.

(21) Move the A/V receiver's audio cable to Aud-2 Left Input.

(22) Verify that you hear audio. [?]

(23) While the Vid-2 is still selected (front panel switch) try the audio cable in the three other Audio Inputs. All should be silent. [?]

Please report your findings at all the steps that have a [?].

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I was able to do some testing today. Here are the results. When I say YES it means I heard the audio packets from the EZOSD.

Buffy

(8) Verify that you hear audio (with the A/V Tx off you will hear a nice strong hiss sound). [?]

YES

(9) While the Vid-1 is still selected (front panel switch) try the audio cable in the three other Audio Inputs. All should be silent. Good/Bad?

Aud2 R YES

Aud2 L YES but quieter

Aud1 L YES but quieter

(13) Verify that you hear audio. [?]

YES

(13) While the Vid-1 is still selected (front panel switch) try the audio cable in the three other Audio Inputs. All should be silent. Good/Bad?

Aud2 L YES

Aud2 R YES but quieter

Aud1 R YES but quieter

(18) Verify that you hear audio. [?]

YES

VID-2, Audio Left Test:

(19) While the Vid-2 is still selected (front panel switch) try the audio cable in the three other Audio Inputs. All should be silent. [?]

Aud1 R YES

Aud1 L YES but quieter

Aud2 L YES but quieter

(22) Verify that you hear audio. [?]

YES

(23) While the Vid-2 is still selected (front panel switch) try the audio cable in the three other Audio Inputs. All should be silent. [?]

Aud1 L YES

Aud1 R Yes but quieter

Aud2 R YES but quieter

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Well, you've got me scratching my head. What is odd is that you have audio from just one input jack bleeding into all four audio channels. About the only thing I can think of that is causing this would be if the EZTracker audio level was much too high. I don't have an EZTracker to try so unfortunately I can't replicate your tests.

Let's try this. Repeat the test, but leave the video transmitter turned off. This will allow the video receiver to produce standard hiss (because there is no RF signal). The hiss will be prominent and at a normal audio level.

If you still hear audio (hiss sound) at the jacks that should be silent, then your Oracle has something wrong with it. That is something that I can fix. :) However, if the audio outputs pass the tests, then this would indicate that the EZOSD's audio amplitude is not typical 1V line levels. If that is the case then hopefully the EZtracker has a way to reduce its audio modulation level.

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I was able to do a test with the vid rx powered only. For each of the four different setups, I received "hissing" on each audio channel that you would expect. I received a bit of hissing on the opposite audio input on the same side(left to left or R to R). I received a tiny bit of hissing when going to opposite channel(L to R's or R to L's). When the audio input was removed completely I had no hissing on my monitor. The only setting on the EZOSD is the telemitry speed, fast, norm or slow. The audio levels for each speed is about the same. I can adjust the audio on the EZTracker module, but I think it's just an input setting and is downstream of the Oracle.

Buffy.

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There should not be any audio from the other inputs when they are not in use. For example, if you are only putting standard "line level" audio levels into Audio 1 Right, there should not be any audio heard from the unused Audio 1 Left or the two unused Audio 2 inputs. However, the audio can "bleed" over if the provided audio signal is excessively high. Also, the volume on your amplified speaker should be on a normal setting (not at a high level).

Honestly, the problem seems very odd. I would be more than happy to help you arrange getting your Oracle checked out if you want to do that. Just use the contact form on the dpcav.com site and request an RMA to send it in for evaluation (please reference this discussion).

- Thomas

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Can you post a link to the 2.4GHz Transmitter you are using?

Thomas,

Buffy is using a standard 1W 2.4Ghz LawMate transmitter and 2 standard 2.4Ghz LawMate receivers. (RX2460).

Zoltan.

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Zoltan, Thanks for the info. Any chance you know the amplitude of the telemetry signal coming out of the Lawmate Rx?

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Zoltan, Thanks for the info. Any chance you know the amplitude of the telemetry signal coming out of the Lawmate Rx?

I am sorry Thomas, I don't. I am using a 1.2Ghz Lawmate TX/RX with the EzOSD, but I do not have the oracle in that installation. Is there a way I could measure the amplitude?

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It would have been awesome if you had some bench testing experience using Oracle with the EzTracker. But, if you can measure the 1.2GHz receiver's audio telemetry signal (with o-scope) to see what the maximum amplitude is then that would be good too.

This problem may be related to the particular 2.4GHz system that is being used (such as some have more audio input gain than others). Or, it may be a defective Oracle. Anything is possible.

I emailed the EZTracker makers a few days ago asking about the telemetry levels and never heard a thing back from them. So, I am in the total dark on what the issue may be. I understand that buffy is sending his Oracle in to dpcav.com for a checkout. My fingers are crossed that Oracle is defective since that is something we can solve without any fuss.

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Do you have a scope?

Terry

Hi Terry, nice to see you. I have 2. A Rigol and a Welleman... Which one should I use? :):)

I will try to measure the output on the LawMate 1.2Ghz system. I have to note that we already replaced Buffy's 1W transmitter, and one of the receivers which we tought it was defective - however I tested it out with regular audio signal and I did not see anything wrong with it. To make sure that this is not coming from the defective receiver, we replaced that receiver as well.

The EzAntennaTracker has a trimpot on it to adjust the incoming levels. Maybe there is an issue of the 2 receviers being on different audio levels, when the EzTracker can understand one, the other one may be too faint or to loud to be understood by the EzAntennaTracker...

I cannot test a 2.4Ghz at the moment because I don't have any left in stock...

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Any info you can provide would be helpful. Honestly, I was hoping a quick email to Immersion RC would have gotten me up to speed on these things. But, it has only been 4-days, so maybe they will respond soon.

Since the 1W Tx came from you, perhaps you can fill in some of the blanks. Have you ever noticed if the mic input is more sensitive than the average Tx? That is, if you install a Tiny-Mic on it, is it louder than usual? Also, do you have any other customers using the Oracle with the EZTracker?

Maybe there is an issue of the 2 receviers being on different audio levels, when the EzTracker can understand one, the other one may be too faint or to loud to be understood by the EzAntennaTracker.

That would certainly be a concern. Everything is suspect, so I will add it to the list. But, this problem seems more odd than that, at least at this point.

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It was easier this way. I still have to figure out how to copy and save fils from my Rigol scope to USB memory...

Here is the first video:

Second video:

Third video:

all these are with siglthly different scope setting.

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Thanks for taking the time to post the telemetry amplitude measurements. They are all under 3Vpkpk, so Oracle is expected to be fine with them.

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What bothers me is the blleding from one channel to the other - that is not something whihc should happen. Also it seems that on one channel he gets the good packlager on the right as it should be and on the other on the left. Is it possible that the channels are mixed somehow?

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What bothers me is the blleding from one channel to the other - that is not something which should happen.

The bleeding should not happen if the audio is standard line level.

Also it seems that on one channel he gets the good packlager on the right as it should be and on the other on the left. Is it possible that the channels are mixed somehow?

That would be grand if it was the problem. But the rear panel A/V jacks are properly labeled and are not swapped.

If the audio levels are excessive (>5Vpkpk) then bleeding and chaos will occur with the audio channels. That is why I have been trying to establish the telemetry audio levels being used with the EZTracker when it is connected to a 1W Lawmate system.

I have no idea what is going on and at this point I am hoping this is a broken Oracle. The audio I/O is tested on every Oracle, so this is not something that has been reported before and has not been seen during in-house testing.

There's a reason for everything and hopefully this is all resolved soon. My fingers are crossed that it will all make sense after the Oracle is tested at the repair shop. Hopefully the Oracle is the guilty item.

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I heard from Immersion RC yesterday and they reported that its telemetry audio signal is 1Vpkpk. So, as long as the audio is not amplified by the video Tx or Rx it would be compatible with Oracle. However, they mentioned that some video systems will amplify it >5V, which would certainly explain the strange behavior with the Oracle.

BuffyTheSaint, do you have access to a o-scope so that you can measure the telemetry signal coming out of the receiver? If it is just high audio amplitude, then it can be solved by making some patch cords with audio attenuators (couple resistors).

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We hope to have this issue resolved soon. In the meantime, here is an update:

The Oracle was thoroughly checked out at dpcav.com and was operating correctly. During this time Buffy was able to borrow a o-scope and he found that the telemetry signal from the wireless A/V receiver was 8Vpk-pk! This excessive audio voltage will indeed cause severe audio bleeding when it is plugged into Oracle. Finally, the smoking gun was identified.

So, Buffy will attenuate the audio levels from the video system with some resistors. Assuming we picked the ideal resistor values, that should fix it. Fingers are crossed -- Hopefully he reports good news soon.

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We hope to have this issue resolved soon. In the meantime, here is an update:

The Oracle was thoroughly checked out at dpcav.com and was operating correctly. During this time Buffy was able to borrow a o-scope and he found that the telemetry signal from the wireless A/V receiver was 8Vpk-pk! This excessive audio voltage will indeed cause severe audio bleeding when it is plugged into Oracle. Finally, the smoking gun was identified.

So, Buffy will attenuate the audio levels from the video system with some resistors. Assuming we picked the ideal resistor values, that should fix it. Fingers are crossed -- Hopefully he reports good news soon.

Sorry the late reply everyone, but I was busy with other things and forgot about this thread. I made up two 10k resistor mini extentions that I put in line with the RX audio out cables and Oracle inputs. ImmersionRC suggested a 1k resistor across the EZOSD right audio out to the EZOSD ground out, which I did. I hooked it all up as it should be and powered up my FPV gear. I tried various audio cable setups to try and get the audio to cross over but it did not!!!!! Yeaaaa!!. Not a peep from channel to channel like it did before the resistors were added. I then hooked up the EZ antenna tracker and received a good 75% good packet(audio level at OK) rate when manually switching the Oracle. It did not matter what Rx was I/S, the good packets kept coming. This will definately maintain a good track on the plane. It seems the problem is resolved. I did not try the scope after the mod. If I get a chance to get over to my buddy's, I'll post the scope results.

I'd like to thank Thomas, Zoltan and ImmersionRC for helping me resolve this issue. I hope it benifits others.

Regards, Buffy.

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I made up two 10k resistor mini extentions that I put in line with the RX audio out cables and Oracle inputs. ImmersionRC suggested a 1k resistor across the EZOSD right audio out to the EZOSD ground out, which I did. I hooked it all up as it should be and powered up my FPV gear.

I know this thread is a little old, but I have exactly the same gear, and symptoms. The 2xLawmate Rx and the Oracle, and the EzTracker. I built two of the attenuators documented in the iTelemetry manual for the iPhone, and that seems to help, but only to 60% good packets on slow mode.

I went round to a friends place today and put the output on an oscilloscope and the EzTracker seems to like it best when you attenuate the Lawmate signal from the raw 7ish volts down to about 2.1v yielding about 60% good packets. There was almost no DC component in the signal so no need for capacitors. I tried a range of voltage lowering circuits but for some reason the sweet spot is very tough to reach.

I will try the 1k resistor on the EzOSD output and the 10k inline between the Lawmate Rx and the Oracle and see if it does better.

If you have any further experiences with this equipment combo please post!

Cheers,

J.

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Do you have 100% good packets when Oracle is not used?

Exactly which Lawmate Tx do you have?

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