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anthonyrc

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About anthonyrc

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    RC-Cam'er
  1. It looks like one needs to be very careful with the AWM630... my datasheet attached. AWM630TX_SPEC_Ver_A2_3.3V_1_.pdf
  2. Are you sure that the 10mW is 5v?, their datasheet claims 3.3v (AWM630)?
  3. This was a bit of a confusing post. I checked with Airwave, and they haven't heard of a 200mW version of the 633, nor of a 5v version. The 500mW 633 expires rapidly as the input voltage approaches 4v.
  4. I haven't heard anything from them since they explained that I was worrying about nothing. My requests for a datasheet, or futher explanation as to why they deviate from industry standards have gone unanswered. Really quite dissapointing.
  5. I did reply, questioning their expert diagnosis of the problem, and asking for a datasheet with a little more info than the one they publish on the web. Even that 'other' company, Airwave, who produces those modules with incredibly poor sensitivity can manage to produce a datasheet with some real specs on!
  6. Finally!, a mail from Lawmate, everything is clear now, this problem just doesn't exist..... Dear Sir, Sorry to reply you late. According to your urgent question. Its seem your client have some mis-understanding for this technical issue. 1. All our TX & RX are all adjusted well with their I/O impedance parameters to be able to work perfectly with the general CCTV cable or device under the standard 75 ohm impedance parameter. There is no any concern the problem you mentioned will be occured. 2. The 340 ohm you mentioned is the impedance parameter for the part of wireless transmission inside our wireless system. It doesn't concern at all to harm the compatibility for our TX module working with any general CCTV system & device (75ohm). The two parameters mentioned above, they don't relate with each other at all for your ref. Should you have any further question pls feel free to contact me directly at your earliest convenience.
  7. Still no response from Lawmate... frustrating, I can't wait to hear their explanation for this.
  8. It could be that it was a mod, but if affects several models (100mW, 500mW), so its a bit surprising. I just ordered a 500mW and a 1W unit, to run some tests, exactly the video level test that you mention, plus some flatness tests, I'd be surprised if the impedance mismatch looks good in the frequency domain. This odd termination did affect my OSD, I have a workaround, but it frustrates me that it is neccessary. I am still amazed that these things ignore such a well established standard. When the KX131 is hooked directly to one of these transmitters the pk-pk composite signal is 1.6v, instead of the 1v expected.
  9. Still no reply from Lawmate, but I can't wait to find out why they did this. One thing I'm wondering is whether these modules are designed to be externally terminated. No idea why they would want to do this though... Puzzling stuff.
  10. I'm not sure its a bad Tx, 4 transmitters of various types have been tested this evening (in 3 countries), and all show this. One was an older range-video unit, two 500mW lawmates, and a 100mW. Kilrah kindly popped open his 100mW unit and traced it out. There is a 270 ohm resistor in series with the input, which then terminates to ground through a 70 ohm resistor (or there abouts). Strange stuff, I've no idea why they would do that. I did try to find a full datasheet for any of these LawMate units, but no luck so far, at least not with anything that shows the input impedance.
  11. Has anyone noticed that the input impedance (at least measured using a DVM) on some recent Lawmate transmitters is around 340 ohms? Older gear measures around 70, as one would expect. Strange stuff...
  12. Mark, Kilrah, good stuff, glad to hear some sense being injected into this thread! To re-quote something that I wrote in the rcgroups forum: "when the panic sets in that you're beautiful new FPV ship is a mile away and you don't know how to get home, you would take an arrow drawn out of old socks, or a font created by a 2 year old" I think its going to be a while before this type of 'skinning' and fancy fonts will be available on low-cost hardware, and to be quite honest, even if it were possible today, it would be of zero interest to me, as a FPV flyer. What is far more important to me (again, as an FPV flyer, and not a developer), is the right information, available to me at a glance, presented in as simple a form as possible. As an example, last night I lost radio contact about a mile out, the Berg 7P went in to failsafe mode. A quick look at the display showed that the altitude was quite low (100m), and the motor had stopped (current indicator at zero). Tx antenna was pointed straight up to regain control, and the first priority was to get the plane heading home, a quick glance at the 'heading to home' showed exactly how to do this. With the plane gliding home, next priority was to get the motor restarted, looks like the failsafe had reset the ESC. Throttle up, throttle back, then back up, and the current indication starts rising.. All of this happens within a few seconds, and shows the value of these OSDs as not only a 'fun toy', but as a safety device for FPV flight. The last thing that I was worried about while all this was happening was the font, or the skinning of the controls :-)
  13. Very nice!, I've never seen such detail in a FPV cockpit!. So we should talk ... I had a crazy urge last year to cross the English Channel via FPV. Figured that its 21 miles at its narrowest point, and two FPVers, one in France, one in England, could hand-over 1/2 way. This means a video system and uplink capable of just over 10 miles is required... shouldn't be too crazy. Finding a day with zero wind in that part of the world would be a challenge I guess.
  14. Very nice!, and an entertaining ending :-)
  15. I don't know for sure, but some of the commands documented for the EB-230 might explain the behaviour of the SparkFun units (which default to 38,400 baud, and emit GGA at 5Hz and VTG at 1Hz).
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