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LarryF

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Everything posted by LarryF

  1. You can get the antenna away from the recorder using this antenna: https://www.lectrosonics.com/accessory-links/product/acoaxtx-specify-block.html This co-ax antenna has a "built in" ground plane. Best Regards, Larry Fisher
  2. The important point of the story was since the Subway tuna was cooked, the DNA was altered to the point they couldn't tell what kind of fish it was from. That and fishermen tend to call the fish they caught that which will bring the highest price. Best Regards, Larry Fisher
  3. Typically Lectro has fixed designed in problems at no charge. I can't imagine this isn't covered. Check with service. Best Regards, Larry Fisher
  4. Lectro has a hardware fix for the problem. 1 800 821-1121
  5. Wes, our production manager, said long ago, "If you design an 'Idiot Proof' device, Mother Nature will just come up with a better idiot." Best, LEF
  6. Why would we? We don't make any money on selling software, firmware or mushware. I talked to Gordon at lunch and he said there is no easy way to permanently brick a unit with serial commands that isn't easily fixed with the usual downloads from the Lectro site. If you can play with the commands to make the SRc more useful, Babbage bless. Gordon will post here about who to talk to at Lectro. At the moment he is getting his hands dirty, remodeling the production offices. Some of the ne'er-do-wells at Lectro took pictures saying, "Now I can show my wife that Gordon does do work here." Best Regards, Larry Fisher
  7. Misprint and has been corrected in the manual and spec sheet. LEF
  8. Hi Brent, In our extensive walk tests with and without many reflective metal surfaces, the digital systems had as good or better range than the older higher power, digital hybrid units. That was one of the other reasons the newer units have been able to trade increased battery life for reduced power. A good bit of the range improvement is due to different diversity techniques; even more improvement is due to the type of error checking in the modulation, i.e., how missing bits are restored in weak signal conditions. As with all full digital, the audio is either perfectly on or totally off. In my walk tests several years ago, I was very impressed with the softness of the digital dropouts. At NAB, the indication of a digital dropout, was a brief cessation of crowd noise. Since speech has a lot of dead periods, the digital dropouts can go by unnoticed. I assume (that word) they still work that way. Keeping in mind that I am a Lectro Fanatic, my recommendation is try them out for range and see if they meet your expectations. Best Regards, Larry Fisher
  9. Several things have driven the differences: One- Rules and laws (FCC and CE) have changed since the SM was designed. This has affected both usable frequencies, power levels and FM deviation for Parts 74 and 15 in the US. Two- Full digital transmission requires both FM and AM components in the RF signal. To stay within the bandwidth rules, neither component can be distorted by the output stage. The FM component of the RF signal is no problem but to keep from clipping (compressing) the AM component it is necessary to use an output stage that is not overloaded, i.e., has headroom. This means a digital 50 mW signal needs an output capable of 150 mW or more. A 250 mW digital signal would require an output that consumes more power than a 750 mW FM design. Battery life and heat become a big concerns. Hence, lower power levels. Best Regards, Larry Fisher
  10. Would work well in the situation you are describing. Lef
  11. https://www.lectrosonics.com/press-releases/1282-lectrosonics-introduces-the-dbsm-single-battery-and-dbsmb-dual-battery-bodypack-transmitters.html The times for lithium and alkaline batteries are in the users' manuals on the web site. Since these times are a little longer than for the digital hybrid versions, the NiMh will go longer in these units also. I assume (that word) they will put the NiMh info up later. Believe it or not, if you imply you can use different chemistry batteries in a transmitter, the labs are requiring that they duplicate all the tests. This amounts to 10's of thousands of dollars just to list a different battery type. Sounds like a racket to me since all internal voltages are highly regulated, independent of battery type. Best Regards, Larry Fisher
  12. Measure the resistance between the center pin of the antenna's BNC (or SMA) connector and the connector shell with a multimeter. If you don't have one, you can buy cheap multimeters for for $11 and up on Amazon. Everyone needs a multimeter. The reading will be several Ohms (lead resistance) if it is a short or very high reading (greater than 10,000 Ohms) if it is open. Multimeters measure DC resistance which is what an antenna bias supply is. If the reading is greater than a thousand Ohms, the antenna won't short the bias supply. This measurement is not the antenna impedance (universally 50 or 75 Ohms) since that is an AC, not DC, impedance at RF frequencies. Best Regards, Larry Fisher
  13. Speaking of tumbleweeds and wagons: https://riverearth.com/tumbleweed-connection/
  14. Open (high DC impedance)? , not shorted (few Ohms of resistance) ? Seems backwards. LEF
  15. Count me as a "don't". I have trouble with the zeros and ones on power switches. LEF
  16. Check the antenna output and see if it is "open", I.e., not shorted. Most are open circuits at DC and can be hooked to DC bias without needing a DC block. Lef
  17. The best version ever: https://www.bing.com/videos/search?q=simpsons+paint+your+wagon+episode&docid=608024252287692810&mid=69C117A6D8259D49F0A169C117A6D8259D49F0A1&view=detail&FORM=VIRE
  18. Here's a half hour experiment that will tell you more than all the brainpower on this forum: put the bowties a foot in front of your bag in free air and record a walk with the transmitter in a straight line. Announce distances as you walk such as counting your steps. You can also announce landmarks as a double check. Go far enough that you will have dropouts. Now, on the same frequency and with the same transmitter position, try the bowties in your proposed positioning. Compare the two recorded results. Then you can tell us if this is a good idea or not. And you won't have to wait a month. Best Regards, Larry Fisher
  19. In New Mexico, April comes in like a coyote and leaves like a roadrunner.
  20. LarryF

    Antenna combiner

    Wisycom quotes "Output" third order intercept (Oip3) rather than the more useful "Input" ip3. The output ip3 number always looks better and therefore is commonly quoted. For instance, a device with a 20 dBm output ip3 (good) and 30 dB of gain (bad design), has an input ip3 of -10 dBm (poor). Specifically, high gain, low noise gain stages can have a good output ip3 but a lousy input ip3. And input ip3 is the important spec. Having said all that, the Wisycom unit is low gain, moderate noise, and high current. Looking at the 7 dB of gain, fudging a few dB of filter loss and 7 dB of splitter loss the input ip3 is probably about 14 dBm. All in all, good numbers. I just wish they would quote the more descriptive numbers. Best Regards, Larry Fisher
  21. LarryF

    Antenna combiner

    The input third order intercept is only -5dBm (minus 5 dBm), according to their web specs of -35 dBm intermod products at -15 dBm two tone input. To convert to input third order intercept, subtract -15 dBm from -35 dBm for 20 dB difference. Add half of 20 dB to -15 dBm input and you have a -5 dBm third order input intercept. That isn't great in today's RF environment. Best Regards, Larry Fisher
  22. For a quarter wavelength whip antenna, 16 cm would be 470 MHz. You can use the numeric length guide on Lectrosonics.com to get a reasonable approximation for your frequencies if you want to trim to your blocks. https://www.lectrosonics.com/downloads/category/1-accessories.html?download=22:amj Best Regards, Larry Fisher
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