LarryF

Some of the young punks here, that have only been around for ten years, don't have the memory skills of their seniors. ;-) LEF

We have tested the D4T transmitter and the Quadra transmitter next to our receivers and found no detectable bleed. A little more subtle point is we also found there was no induced RF noise in un-bypassed lavalieres or unfiltered audio inputs. The occupied bandwidth is so wide (5 MHz) that there is very little energy at the audio frequencies. On top of that, the modulation method has a relatively low AM component. Best, Larry F Lectro

Hi John, Very cute. If we can help with info in the future, let us know. Cheers, LarryF Lectro

Hi Bob, Great idea. Will work on a Lectro version that will keep the little nylon nubbin that protects the metal plating. Wish we had thought of it. Best, Larry F Lectro

The "a" in LMa added the servo input and the circulator in the output. LEF

It is correct that the LM's did not have isolators; however, the LMa's do. If we had any marketing sense, we'd put the presence of the circulators in our data sheet. So, for all current transmitters and for all planned transmitters, there are circulators (isolators) in the output stages. This also includes the IEM and D4 915 MHz transmitters. Best, Larry F Lectro

Bends in the antenna make very little difference in performance. I just grab the bend between my fingers and bend it in the other direction more and more until it looks straight. If you get too many kinks in it, you can tell the client it's a fractal antenna. Best, Larry F Lectro

We are designing a better flexible antenna and will cheerfully replace the current PITA version. LarryF

We are well, well aware that customers have alternatives. That's why we made an effort to reduce backlogs, have in fact reduced the backlogs by half, and are continuing to reduce them. "Nearly six months" sounds inordinately long. I would appreciate you PM'ing me, with models, dates and dealer so I can see what happened and if it is correctable in the future. All info will be kept to ourselves. Best Regards, Larry Fisher Lectrosonics

Hi Rado, Whoops. I should have gotten of that. A bend won't hurt anything and doesn't even change the antenna's tuning much. They can be straightened many times without causing the cable to break. Cheers, LarryF

Jeff! HELP! LEF

Doesn't the moderator have any control over this forum? <|) LEF

I assume that the "n" in "band" was exxtra and it was "bad next to the connector" and I also assume that it was broken insulation? Broken insulation is ugly and a little floppy but electrically OK as long as the center wire is still isolated from the SMA shell and there isn't a lot of salt air around to eat through the galvanize on the steel rope. It could be made pretty again with a little section of heat shrink. The LMa is easy to disassemble and the service department could walk you through it if necessary. Best, Larry F Lectro

On a very positive note, we have cut our backlog in half from 2 months of sales down to 1 month of sales just since the beginning of the year. That one month is average. If you place an order with a stocking dealer, you could get the system(s) immediately or 1 to 3 months later. The 3 months cycle occurs if we are completely out and just starting a production cycle on that product. We are aiming to reduce the backlog even further and get into a kitting situation where we can keep products as sub assemblies and get down to a 3 week cycle. The problem has been that we have been behind the growth curve, filling orders, and we haven't been able to put money and labor into building up sub assemblies. That situation is great for us but it isn't good for our customers. So, we have been reducing the time from order to delivery and are working to reduce it further. Best Regards, Larry Fisher Lectrosonics

Hi Rado, I would like to see those 3 antennas and I'll replace them for free if they are ours. The failure rate on the steel rope antennas has been extremely low (??). You can replace the antennas on the LMa but it requires a good soldering iron and solder wick to clean the PCB mounting hole. Best, Larry F Lectro

As far as I know, the pro dealers will work with you on a demo. In the worst case, I can't imagine that if you were unhappy with the D4 performance, they wouldn't allow the refund to apply to an SR. Of course if you scratched your initials in the case they might get a bit crotchety. Best, Larry F Lectro

I was not clear, but it is not of any use to put the Vaseline on the threads of the SMA. A pin head of Vaseline is placed inside on the white female insulator. When the SMA is screwed down the Vaseline spreads across the face of the two mating insulators into any little gaps around the center conductors and the gap between the insulators and the shells. It does not affect the RF in the least. Petroleum is a very good insulator and a low loss dielectric. Some of us remember when oil filled capacitors were a top choice for speaker crossovers and high voltage supplies. Best Regards, Larry Fisher Lectrosonics

Hi Derek, You realize, I take my life in my hands when I describe new products but the WM is getting pretty close to release. Here's the stuff: Two AA's for longer battery life. Variable power. Membrane switches. LCD display. Battery compartments sealed from main board area. Can be controlled by RM remotes. Will be larger (two batteries). Servo mic voltage adjustable from a menu: line level, 0V, 2V and 4V mic bias. Still uses the Lectro 2 wire waterproof mic connector like the MM400. Battery door o-rings will be new foolproof design, i.e., can't be overtightened. Volume control o-ring eliminated (menu select gain) and two frequency door o-rings eliminated (menu select frequency). Basically, it is an SMQv with a waterproof mic connector but shaped like a larger MM400. The unit is close to completion but needs FCC, CE, etc., testing. We can do an SMA antenna connector rather than a fixed antenna, as on the MM400. The removable antenna is a potential leak site. Therefore, the one question up in the air is the desirability of a removable SMA antenna. A fixed antenna is absolutely waterproof and loss proof. The standard Lectro whip SMA antenna is a more flexible setup as far as packing the unit and running remote antennas but needs a little more care. We would seal the female SMA as much as possible but belt and suspenders waterproofing would probably require occasional application of a dab of provided Vaseline in the connector when it was screwed off and on. The current MM400 has a fixed antenna and customers seeem to be OK with that setup. The fixed antenna would be a little less cost, say $15. Voting is now open. Best Regards, Larry Fisher Lectrosonics

The MM400 can survive total immersion with a few caveats. The o-rings should be snug but not crushed. Brutal tightening of the battery door will push the o-ring out of its groove. A small speck of Vaseline will add additional protection on the o-rings. They are silicone, so NEVER use silicone grease; the silicone oil in the grease will slowly soften them to where they fail. Use the waterproof mic connector kit to make up any additional microphones. Make sure the batteries are bone dry when they are put in the unit. Rinse off all saltwater after ocean use and dry before opening. All that said, we have users doing surfing movies with good success as well as SeaWorld use. By the way, they don't radiate RF well under water; they simply survive until they come out of the water. The milled aluminum housing is similar to the SM's. Best, LarryF Lectro

Yes. It gives you more flexibility and you can use less selective receivers in a pinch. LarryF

Hi Marc, Handholding support is available from Lectro. If it ends in tragedy, you can still send it in and get a nice sympathy card to boot. Maybe flowers if it really goes south. Cheers, LarryF

Hi Johnathon, With 411's this is a safe setup. I would still separate the inbound frequencies and outbound frequencies as much as reasonable, i.e., low end of 24 and high end of 25. It is also always a good idea to get physical distance between transmitter and receiver antennas. It may not be really necessary but it also doesn't hurt. Every little bit of advantage can make a difference in a marginal signal situation during multipath. Best, LarryF Lectro

Hi Derek, All wireless systems have "limiters" in a sense; they either reduce the input or intermediate gain in a controlled manner or clip the audio output into a square wave. We prefer the controlled manner. More importantly, until you are within 4 dB of maximum output of the DSP, the 400 series leaves the signal path alone. The only reason we react 4 dB before max output is to provide a soft roll over into the firm compression region. In contrast, the D4 has no limiter since we assumed it would be fed with a mixer that has limiters or will be fed by an AES input that has its own maximum output. The Lectro preamp in the 400 series transmitters is not a conventional preamp or at least no one else uses a similar topology. The virtual ground preamp's gain in the 400's is set by the ratio of the input resistance and the variable feedback resistance of the gain or volume control. The elegance of this scheme is that the noise and gain of the preamp is very low when the input resistance is very high. The high input resistance is the condition when the input is setup for line level. Another way of saying this is that the preamp can be a pretty good mic level preamp when the input resistance is low and an excellent line level amp when the input resistance is high (line level wiring). The preamp topology that gives preamps a bad name is the system supposedly used in some crappy camera inputs (whose manufacturer's name shall not be spoken on a quality sound forum). They reduce the good line level signal to a mic level and then send it to the mic input and amplify it back up using the mic preamp and its volume control to get the signal back to a high enough level for the camera recording system. This is the worst of all worlds, adding mic preamp noise and distortion to an innocent, well behaved line level signal. There may be some confusion because the resistor network on pin 5 of the Lectro servo inputs (400's) looks like a pad. Note that the 2.7k shunt resistor is before the 10k series resistor. This is the wrong order for a pad. The 2.7k to ground is only to define the external line level impedance at no more than 2.7k. In the real world, most line level outputs are much lower impedance than this and the 2.7k effectively disappears. The 10k series resistor defines the input impedance to the virtual ground preamp and turns it into a line level, low gain amplifier. In fact at minimum gain settings, it can actually have less than unity gain, i.e., loss. In line level operation, the input stage adds no measurable noise or distortion to the final results since its line level performance is orders of magnitude better than the remainder of the signal chain. Best Regards, Larry Fisher Lectrosonics

Yes. Larry F Lectro

Hi Geordi, LPDA's (sharkfins) are not as directional as many people suppose. See this data sheet for a pretty typical pattern from any manufacturer: http://www.lectrosonics.com/images/TD-sheets/alpseriestd.pdf Note that you are down 6 dB at +- 90 degrees in the horizontal plane and down 6 dB at +- 45 degress in the vertical plane. Six dB is about half the range. Since they start out with 4.5 dB more gain than an omni antenna, it is safe to say they are very usable at their 6 dB down points, i.e., +- 90 degrees. You are dead on about the use of an amplified antenna. They should be used only when necessary to overcome cable or splitter loss. Otherwise, they add problems due to excess gain. If anyone is thinking of using an amplified (powered) antenna, I recommend a discussion with a knowledgeable manufacturer to see if they are necessary for the given circumstances. Just to be clear, an LPDA, helical, or Yagi is not an amplified antenna per se and does not cause overload problems with good receivers at any distances greater than say five feet. A directional antenna raises the signal level without increasing the noise floor. The noise floor of a 50 Ohm antenna of any gain figure (without an amplifier) is just the noise of a 50 Ohm source (resistor) at the temperature of the sky or objects that it is pointed at. The signal is gained up by the antenna gain but the noise floor is not. The only thing you lose with a directional antenna is the ability to pickup from all directions. Once again, Mother Nature balances things out with gain being proportional to directionality. The more gain you have, the less you see. All this to say, there is no operational downside to using a directional antenna (LPDA) if the talent is mostly to the front half of the antenna. However, there are cost, size and/or bandwidth trade offs for directional (gain) antennas. Best Regards, Larry Fisher Lectrosonics