LarryF

An 1/8 Watt resistor is ok in any typical audio attenuator application in line level applications. For instance if you had a continuous 10 Volt audio signal (+20 or +22 dBm depending on reference) feeding a 1000 Ohm resistor, the resistor would only need to dissipate a 1/10 Watt max. (Power = Voltage squared divided by the resistance.) So 10 squared divided by 1000 is a tenth Watt. In short 1/8 or even 1/10 Watt resistors are fine. Best Regards, Larry Fisher

If turning off the remote control function helps solve the whine, then that is 100%, definite indication that you need the updated firmware for the transmitter, as suggested by Paterson. Best Regards, Larry Fisher

I appreciate the help that some posters have given but I want to correct two numbers: 1. BNC interconnects have much less than a decibel of loss at wireless frequencies. We ran tests with a Network Analyser on BNC barrels (tying two BNC cables together) and found almost no loss and minor reflections at up to 800 MHz. Losses due to the barrels were less than a quarter decibel. This means if you have two 25 foot cabels and need a 50 foot cable, tie them together with a barrel and go onward with no worries. This can simplify the lengths of cables in your inventory. A 100 foot cable can be made of two 50 foot cables. 2. A typical shark fin antenna (log periodic, LPDA) does have commonly 7 dB of isotropic gain. However isotropic gain is kind of a theoretical number since isotropic antennas don't commonly exist. The better comparison is dB referenced to a dipole or 1/4 wave antenna (whip) which have a isotropic gain of 3 dB. Therefore, an LPDA gives you a 4 dB advantage over the most common low gain antennas. One last comment: If you have high loss in cables, splitters, etc., remember to apply the gain before the lossy elements since applying gain after losses just gives you an amplified, noisy signal. Best Regards, Larry Fisher

Static can be very hard on electronics. CE approval requires testing a device against static discharge. This a good thing for the consumer but not 100% foolproof. Get some antistatic spray and spray the padding on the floor. This will stop static for a month or so before it needs to be reapplied. You may need to air the room out before breathing the solvents that carry the antistatic compounds in aeresol spray cans. Here's one that looks like it is water based with a pump sprayer: https://smile.amazon.com/Anti-Static-Control-Spray-oz-Size/dp/B0026GV5IW/ref=sr_1_6?crid=2MIJS0CZLMAHL&keywords=antistatic+sprays&qid=1669647320&sprefix=antistatic%2Caps%2C175&sr=8-6#customerReviews Best Regards, Larry Fisher

+1. A whip antenna next to a bag of salty water (the talent) is so messed up already, that the tiny loss from a connector is literally lost in the noise. Best Regards, Larry Fisher

Insulation is generally transparent to RF, i.e., it's not there. Best Regards, Larry Fisher

Hi Jhop, That depends on just what is in that pipe. If it is premium tumbleweed, there are 28 Beta units out for sound mixer destruction and mayhem. If the units survive with no hiccups, the tumbleweed induced visions may replace "...visions of sugarplums". If there are problems that we missed in our testing, then as Mike Sepich said long ago in Engineering, "We will ship no whine before its time". Best Regards, Larry Fisher p.s. Supply problems can mess up our planned timelines. We used to be able to get prototype boards in 5 days and production boards in 2 weeks, paying a 50% premium. Now prototype boards are 4 weeks and production boards are a months or more away. So if there is a major redesign problem with beta units, Q4 2022 products become 2023 products. The engineers do take Elmer Fudd's modified advice, "Be vewy vewy quiet, I’m hunting pwoblems!, He-e-e-e-e!"

The current can get upwards of 0.6 Amps, which really nails a dying alkaline battery. LEF

The li-ion rechargeable battery has to have a sensing circuit to turn it on when there is a load, otherwise it would stay on all the time and run down in a day or so from the voltage converter residual drain. My guess is that in the two battery setup in the SMQV, the higher voltage li-ion battery is turned "on" while the other battery sees more than its full voltage at its output and thinks it is looking at an open circuit, i.e., not in a device. It stays off. At some point the first battery begins to die and the second battery sees less voltage than open circuit and tries to turn on. If it starts to power the SMQV, then the first battery sees less of a load on its internal cell and it tries to turn back on. My guess is that the SMQV doesn't know what to do with rising and falling voltages and shuts down. Having three switching power supplies all sensing the input voltage (two outputing in the two batteries and one inputing in the SMQV) , I'd be very suprised if the various units didn't go into oscillation. It would require a scope hooked up to the units to decipher the problem. By the way, the Lectro transmitters will operate at full power down to 0.9 Volts, so as to get every bit of power out of an AA battery. Best Regards, Larry Fisher

Parallel. Larry (Odd Designer) Fisher

Here's a link that shows you how to do some simple tests, a few of them are quite telling: https://www.lectrosonics.com/wireless-faq/audio-tests.html Click on the links in the page to get more knowledge depth on each test. Past these "simple tests" and using some interfering devices described by John Gooch above, you are at the mercy of the company building the wireless. Here's where you hope they have tested the wireless devices under beastly conditions and/or sent out enough beta test units to find subtle problems. Best Regards, Larry Fisher

As Johnny said, clean the threads and repeat the wiping until you see no traces of dirt left on the cloth or paper towel. Then apply a pinhead amount of silver grease on the end of the threads such that inserting the screw will drag the silver paste along the length of the threads. Letro will send a tiny vial of true silver paste at no charge. Remember, it only takes a pinhead on clean threads. Also, don't use "silver" thermal conductive greases intended for computer CPU's; these are "silver" colored and not electrically conductive. Stay with the free Lectro grease. Best Regards, Larry Fisher

It is actually a lot more complicated than a simple 3, 4,or 5 Volt level. The recommended 5 Volt spec is with a resistor of 4.8k as used in some popular wireless. The actual voltage at the DPA mic is only 1.5 Volts and that voltage is fairly well fixed by the DPA circuitry, a compound FET and bipolar transistor circuit. The resultant current draw with that 4.8k resistor and 5 Volt setup is slightly less than 1 mA. The servo bias circuit on the Lectro units was chosen to maintain about 4 Volts across the more common single FET mics. Since the servo bias circuit is trying to maintain 4 Volts and the DPA mic is trying to maintain about 1.5 Volts, large, noisy, current arguments ensue. This is perfectly resolved with the recommended resistor value shown in our wiring recommendation. The full audio Voltage swing is available with that choice. Why does DPA recommend 5 Volts? Because with the internal resistors in some transmitters, it requires 5 Volts to get the optimum current (700uA) to the DPA mic. In an imperfect world, when the user has to use lower voltages, the user could just substitute a lower value internal resistor to keep the current at 0.7 mA (700uA). The downside is you would need to be able to get to the internal transmitter resistor. However, it is rarely a problem, since the DPA mics are very tolerant of various current values. Best Regards, Larry Fisher

The pilot tones were chosen by the hex switch setting on the much older equipment (200 and 400 series). If the two 16 position switches were set at A-12 on any block, the pilot tone for A-12 was chosen. To be specific A-12 on block 21 would have the same pilot tone frequency as A-12 on block 22. This didn't cause problems because the carriers of the blocks were separated by at least 25.6 MHz. Choosing the pilot tone based on the hex switch settings saved lots of memory, which early on was in short supply. Block 470 introduced problems since identical carrier frequencies on overlapping blocks had different hex switch settings. With newer Lectro gear covering multiple blocks this became a "Gotcha". Today with new processors with LCD displays and more memory, we wouldn't have done it that way. I do think we could have made better decisions about block 470 even with the old gear. However, once we screwed up, continuing compatibilty forced us into living with it. "RTFM" is not really really an excuse for a poor decision but there you have it. Best Regards, Larry Fisher

My error. I've mixed them up. The DSQD is in production, not theDSR4. We are going to need more foam. LEF

An aluminum shortage was holding up delivery of extrusions for the front panels. Mind you, aluminum is one of the most common elements on the face of the Earth but deliveries were almost a year late. We've had to mount some sound absorptive foam to the production manager's wall. Not to quiet his frustrated screams but to prevent a concussion when he pounds his head against the wall. A quantity of aluminum finally came in and just today a small quantity of units have been given to shipping. There is a substantial backlog but the Damn dam has burst. Best Regards, Larry Fisher

One of the more subtle ones. Lef

https://www.lectrosonics.com/april-press-releases/11-lectrosonics-introduces-wa520-wireless-antenna.html?highlight=WyJhbnRlbm5hIl0=

If an amplifier is used for gain, both the desired signal + any noise present are both gained up by the amplifier. Some receivers look at the noise level to make diversity decisions and squelch decisions. Excess amplifier gain can upset those systems. There is a place for amplifier gain for such things as balancing out losses in long cables (after the amplifier) or balancing out losses in splitters (after the amplifier). Trying improve performance by wildly amplifying signal and noise is a loser. Introducing loss and then trying to amplify it back up is also too late. Directional antennas have gain for the desired signal with no increase in noise. There is no reason to attenuate this stronger signal as the noise level is low. The stronger signal can overcome cable and splitter losses and still have a good signal to noise ratio at the receiver input. FM and Digital Hybrid systems are immune to desired signal overload. You can have a transmitter right on top of a receiver antenna with no overload. Full digital systems are not quite as bullet proof but good designs have variable gain amplifiers in the RF or IF signal path to overcome the strong transmitter RF signal problem. So in sum, keep RF amplifier gain before all the lossy cables or splitters and within a few dB of the losses. For directional antenna gain with no noise gain, it should never be a problem. Best Regards, Larry Fisher

Mini 8 is an improved .250" cable and is only slightly better than RG-58. The larger 9913F is .400" and is much lower loss. (The F suffix is for "Flexible" as the center conductor is stranded. The stranding does lead to slightly more loss than the solid core 9913. Remember the "ironclad" rule of thumb, "If it is smaller, it has higher loss" Best Regards, Larry Fisher

Yep. LarryF

Yes. Lef

Sorry but no such luck. There are internal balancing resistors that come into play when ports are unterminated or poorly terminated, i.e., not 50 Ohms. You still have a 3 dB loss with a single out but the input is balanced to 50 Ohms. Best Regards, Larry Fisher

The MiniCircuit parts split the input power into two outputs, each having half the power. That is why the "insertion" loss is 3 dB or half the power. There is very little loss, it's just split in half (-3 dB). The single input to the MiniCircuit part remains at 50 Ohms even though you are outputing to two 50 Ohm devices so you have an excellent match to the 50 Ohm antenna. Also, the two output ports are isolated from each other by about 20 dB or more, so accidental garbage (local oscillator) on a receiver input doesn't interfere with the other receiver. The BNC "T" does none of these. The input impedance and output impedances are at best 25 Ohms, there is little isolation between ports to receivers and the losses will be greater than 3 dB. The fact that the antenna and receivers aren't seeing 50 Ohms, may shift passbands or filters of the antenna and receivers. Now the disclaimer: All these effects may be small (other than isolation) and totally unnoticeable in an environment with good signals. On the other hand, the 2 way MiniCircuit splitter is not very expensive and is the correct solution. However, if I were in a situation where one antenna had to drive two receivers and all I had was a BNC "T" , I'd use it in a microsecond. Best Regards, Larry Fisher

Bill Ruck knows his RF. Best Regards, Larry Fisher