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Wire-Lists#15: 4 Things To Check Before We Fix Your Equipment

(and 9 things to look at before we do)

Social Media WireLists15 300pxWe often receive equipment in for repair, with the nebulous explanation of “it doesn’t work.” Here are some suggestions to make the troubleshooting and repair process easier:

Before you send your unit in, first check four things. These account for 15-20% of root causes of items we receive, and checking them might save you some headache:

  1. Did you check to see if the batteries are good? Even though we advise to use fresh batteries at the start of projects, not everyone does. Dead batteries = dead equipment.
  2. Did you check the frequency that you intended to tune to? Transmitters and receivers sometimes “don’t work” or don’t communicate with each other because they’re not synched to the same frequency. Or, the frequency that the user is attempting to use is unavailable or is full in that city or country (frequency scans sometimes lock into what is available, not what is allowed or optimal!). We recall one customer who was working onsite and inadvertently tuned to the local Public Safety band! Some specifics on these issues are detailed in Wire List #2.
  3. Are the compatibility modes the same? Just like with frequency, incompatible modes can make transmitters and receivers perform poorly or just not work.
  4. If there is firmware available for your unit, did you check to see if an update is needed?. Not all firmware updates are necessary to the functioning of the unit, so you’ll want to read through the list for your product to see if the behavior you’re seeing was addressed with an update. To make sure that you stay on top of new firmware releases, sign up to receive the RSS feed alerts.

What if you checked the above and your unit is still inoperable or not working properly? Before you call us, it would be helpful to write down the exact model number, serial number and the actual firmware version that is installed on the unit. We will look up your unit, then provide you with a Repair Order number (RO#) and instructions for sending it in. Also, we’ll ask you what kind of batteries you were using, and information about the rest of the signal chain, so please have this information available as well.

The following details will be extremely helpful to the technician that works on it, and it will save them from having to spend valuable time playing CSI:

  1. Did the unit expire during use? Did you turn it on and get no signal or power? Or did you turn it on and it didn’t work (after checking the above)?
  2. What’s the symptom of your issue? Many people report what they think the cause of issues to us (i.e. – “I think the battery contacts are the issue”). What we need to know is the symptom (i.e. – “The unit has fresh batteries. I turn the knob and it does not come on or light up”).
  3. Where was the unit physically when it failed and what was the environment like? Detail is important, and more is best. In the case of a transmitter, was it on a belt or on the talent? What were the operating temperature and humidity level like (hot or cold, dry or humid)? What was the application (A concert stadium? Movie set? Theater? In the wild?)
  4. Did it fall into water…or something else? You can tell us – we truly have heard it all (talent dropping units into the toilet happens a lot). Knowing that the unit got wet, sprayed or submerged – and knowing in what – might guide our repair process. Some liquids are more damaging than others.
  5. Is the problem constant or intermittent? For example, are you not getting any signal at all…or is it cutting in and out? How often is it happening (Once an hour? Every 15 minutes?)? Please be aware that in the case of an intermittent problem, a rush repair is almost always impossible, since we need time to assess, duplicate and trace what you are seeing.
  6. Did you open the case or tinker with the unit in any way? This doesn’t necessarily void the warranty, so don’t be afraid to tell us if you opened the case to assess the situation.
  7. Do you notice any specific smells coming from the unit? Does it have a heated plastic smell? Or does it smell burned or like a chemical? Is it leaking any fluid, without having come in contact with any?
  8. Make sure that you write down the serial number of your unit and have not intentionally removed it. It goes without saying that you shouldn’t purchase any Lectrosonics equipment without first verifying that the serial number is legible and in place. We maintain a database of units that were reported lost or stolen, and if the serial number is missing from a unit we receive, that is our first suspicion that it might have been stolen or misplaced at some point. Resales are not normally an issue, but please be aware that our Authorized Service Centers cannot repair units that have had the serial numbers intentionally removed, and we will return a unit to its rightful owner if we receive one that has been reported stolen.
  9. If the unit is making a noise, try to get a recording of it and save that recording as a WAV file, which travels easily through email. Similarly, if you’re getting an error message, a video of it happening would be helpful. You can use a cell phone to make these recordings. These are extremely helpful to us, especially when we’re unable to duplicate the complaint in our testing. Our techs may recognize the sound as something they’ve heard before – this will likely cut down on the time it takes to evaluate the course of action.

While we’re discussing repairs, did you know that sending problem units to the Mothership is not your only option? We have factory authorized service centers. Oftentimes, their lead times are shorter than sending them to HQ:

In New York City – Jaycee Communications – 718-428-7818 or This email address is being protected from spambots. You need JavaScript enabled to view it. (Please note that they are the only center that can repair 185, 190 and 195 series units, other than us)

In Canada – Lectrosonics Canada – 416-596-2202 or This email address is being protected from spambots. You need JavaScript enabled to view it.

We also have Lectrosonics-trained personnel around the world that we can refer you to for simple component level repairs, such as a knob that broke off. You can see a full list here. If the problem is complex – like a board assembly or a tuning and alignment – the unit needs to come to us or an Authorized Repair Center.

We proudly build our products to withstand nearly anything that you can subject them to. But if they’re not working as designed, we or one of our Authorized Repair Centers can help. Also make sure you check out our Service Bulletins and Tech Notes. There is a wealth of information posted that might shed some light on your issue.

Wire-Lists#14: My Transmitter Took A Bath! Now What? 5 Steps To Help (plus a bonus tip).

Social Media WireLists14 300pxWe all know that stuff happens, in spite of your best intentions. You can try to protect your transmitters, even using covers like we always tell you to, but they still might get dunked. Talent may drop them, instead of their cell phone, into the toilet. Or a boat might capsize while you’re filming a river scene*. The end is the same: your transmitter sank and is now soaked. Now what?

Before we start, a disclaimer: If you have the option at all to send your unit to HQ or an Authorized Repair Center, do that. Do not follow any of these steps if you choose to do that. These should be considered emergency steps that you can take on location, when no better options are available and your alternative is wrapping for the day or scrapping the project.

  1. First, remove the battery as quickly as possible. Turning it off is not enough. In fresh water with the battery in the unit, you have a few minutes before serious damage results. In salt water, it is a matter of seconds, as salt is destructive – it both hardens and eats into the boards. Regardless, get the battery out of the unit fast. What you do next depends on what kind of water the transmitter fell into.
    a) If your unit fell into fresh water, chlorinated pool or tap-sourced water, you should rinse it with clean or distilled water.
    b) If it fell into sea water, rinse it with any liquid that has less salt in it than the sea water and contains no sugar. This is where you might have to get creative. If there isn’t bottled water available, you can use diet soda (as it has no sugar) or any alcohol that doesn’t have a lot of additives, like plain, clear vodka. A clear alcohol rinse is the best option if you have it available to you, because it evaporates water and it cleans off dirt or oils that may have been in the water.
  2. How to rinse: Quickly submerge the entire unit with the battery door open into water or alcohol. Or pour a light amount of water or alcohol into the unit and quickly slosh it around. Do this once or twice more with a fresh batch of water or alcohol.
  3. Tilt the unit so that the liquid runs off and away from the boards inside. After the final rinse, shake the unit to remove the liquid. You can also use canned air to facilitate the process. Do not touch the boards or anything inside with your fingers. The back cover can also be removed to help get liquid out of the inside.
    Whatever you do, DON’T use any petroleum distillates (ie, contact cleaner) inside the unit at this or any other time. We’ve seen this suggested in online forums as a moisture fix, and it’s a bad idea. Contact cleaners are fine for battery contacts or connectors when applied sparingly with a Q-tip – you just don’t want them sprayed inside the unit where they can pool. This can sound confusing, because the labeling on most contact cleaners will say something like, “for use with most plastics.” The problem is that the labeling doesn’t tell you which plastic, and to some plastics, contact cleaner can be aggressive. And worse, human tendency is to assume that “a little is good, so a lot should be better.” It’s best to just not do this at all.
  4. transmitter in waterWarm the boards to dry the moisture left from the final rinse. You can use whatever you have available that throws off tolerable heat – sunlight, scene lights, engine block, etc. There isn’t any recommended temperature; as long as you can hold the components lightly and not burn yourself, the temperature should be OK.
  5. After several hours (or more) and when the unit is completely dry, put in a battery and power it up. Be patient – even a little leftover moisture can defeat the purpose, so give this step time.

If you work around water on a regular basis and size is not an issue, you might consider investing in or renting a watertight WM transmitter. Although we build our transmitters to withstand heavy use and abuse, and our Repair Department has been known to work miracles, there are no guarantees when moisture is concerned. However, if you’re on location and (pun intended) are dead in the water, following these suggestions can make the difference between a delay in your schedule and a need to replace what cannot be fixed.

* Bonus Tip: Transmitters don’t float. But if you’re working in or around moving water, you can attach a fishing float or bobber to any body-worn transmitter to increase the chances that you’ll get it back if it escapes. If filming in darkness or low light, use a glow-in-the-dark one!

Wire-Lists#13: Three HM Transmitter Hacks (aka “MacGyvers”) for Desperate Situations

Social Media WireLists13 300pxLet’s be upfront: While we don’t advocate hacking any of our products, sometimes things happen on the job that prevent you from stopping what you’re doing and sending your unit back to us. Necessity is the mother of invention and the work has to be done (preferably without alarming your client or your employer as to your ability to do it), so here are three temporary fixes, à la MacGyver, for your HM or HMa (or older UH) transmitter:

  • Challenge #1: Are you on-site, notice that mics you’re attaching are wobbly and realize that you’ve lost the thrust washer (circled in red) on your XLR connector? They can come off unexpectedly, especially if you’ve had the transmitter for a while and the parts have had opportunity to move around and wear. This part is not just a washer that you can find in a hardware store – it is specially machined for the purpose, and you need to order one from the factory. But you’re in the studio, at a show or in the wilderness filming. Now what?

    Fix 1a

  • Crisis Aversion #1: For a temporary fix, wrap a rubber band or two around the XLR and check the mic tightness. Adjust the amount of rubber “wraps” until the mic-to-XLR connection is just snug enough. The rubber should be almost loose around the XLR to get the maximum springiness. This should get you through the job until we send you a new part. It’s a good idea to check your transmitters before putting them away, and ordering new washers to have on hand before they’re needed.

    Fix 1b

  • Challenge #2: When plugging your HM transmitter into a boom or mic, you notice a little too much “play.” Or worse, you’re picking up a bad connection sound when it’s rotated or not quite positioned correctly. This happens because the edges of the connector flange (circled in red) get worn and rounded off with use. There isn’t much you can do to prevent that, since it is metal-on-metal friction that causes it, and a good metal contact is integral to the product working correctly. Sometimes the mic socket or locking notch becomes worn as well – it’s a good idea to check that, too.

    Fix 2a

  • Crisis Aversion #2: As a temporary fix, you can add a small O-ring to the XLR tip - such as the one found on a regular female XLR plug. Our 35877 is used in this example, and it can be found in our ORINGKIT/WM. This will provide a tight fit. A permanent and more preferable fix will be to replace the XLR section (or have the microphone housing replaced), which is not that expensive, but this will get you through that one project.

    Fix 2

  • Challenge #3: Do you ever worry about getting moisture into the ends of your XLR? Or maybe you’re working in an environment that is unexpectedly wet. How do you protect the open end of the HM?
  • Crisis Aversion #3: This fix requires a bit of advance planning, or at least a trip to the hardware or auto parts store. Depending on what’s available to you at the time, you can try a large rubber vacuum line cap (such as for automotive parts) or caps for furniture legs. The best solution – especially if you have time to get one in advance and have it in your bag - is to use our HM Cover (part #HMCVR) that was designed for this purpose.

    Fix 3

We want to stress again that we hope you’re not taking shortcuts on a regular basis. If your HM or any of your Lectrosonics equipment isn’t working up to par, or if you work in situations that stress your equipment, call your representative or our repair department for help and advice.

What kinds of “MacGyvers” have gotten you through jobs? We’d love to hear about them!

Wire-Lists#12: Popular Receiver Antenna Combos

Social Media WireLists12 300px copyLast week, we shared a grid with transmitter/antenna combinations. We couldn’t leave out receivers! This grid is slightly different than the one for transmitters because of how receivers are used. While transmitters are usually placed on or near the subject, receivers often sit stationary or are portable, within bags or mounted on cameras. Receivers also have different connectors – an elbow antenna is going to be a logical choice (although a straight style can work equally well depending on the application. Or, you can use an adapter).

Keeping all this in mind:

  1. Available blocks are: 470, the range from 19 to 33 and 941/944 (not all blocks are available in all countries – check before you order or visit).
  2. The prefix “AMM” refers to a straight whip antenna with SMA connector, “AMJ” refers to a jointed/elbow antenna with SMA connector, “ACOAXTX” refers to a dipole coax cable antenna with SMA connector and “ACOAXBNC” refers to a dipole coax cable antenna with BNC connector.
  3. In general, receiver antenna lengths are not as critical as those for transmitter antennas. Plus, due to the overlap of some blocks and bands, any antenna that you choose for one block will usually work nearly as well for an adjacent block.
  4. As long as it is the correct antenna for the block you’re using, an antenna for an LR can also be used on a Venue 2 or any receiver in that block, connector-dependent (again – adapters are available). You can also use your transmitter antennas for receivers – an antenna is an antenna. We’ve tried to make things interchangeable when we can.
  5. Remember that when receivers are close to transmitters, you want frequency separation. Ideally, you should also have physical separation as well, but this isn’t always possible. Putting a 941 receiver right next to 941 transmitters in a bag can desensitize the receiver, and your range will suffer. A better choice will be to look at one of our remote antennas, such as the PCA900 (adapter required) or ACOAXTX-944, or keeping the receiver (or transmitter) outside the bag.

Is there a particular type of antenna that you’d find useful for us to offer? Email us and tell us about it!

WireLists Lectrosonics Popular Antenna Combos Receivers 2

Wire-Lists#11: Popular Transmitter Antenna Combos

Social Media WireLists11 300pxAre you packing a project bag, or trying to be prepared for anything you might encounter? This handy grid will make your life a lot easier when coordinating the antennas that you should bring with you to accommodate all of your transmitters. Four things to note:

  1. Antennas for the LMB and SSMs are fixed antennas. They cannot be swapped out, except to repair them.
  2. Available blocks are: 470, the range from 19 to 33 and 944 (not all blocks are available in all countries – check before you order or visit). The prefix “AMJ” refers to a jointed antenna, while the prefix “ACOAXTX” refers to an antenna with a coaxial SMA connector.
  3. In general, due to the overlap, any antenna that you choose for Block 470 will also be compatible with Blocks 19 and 20.
  4. As long as it is the correct antenna for the block you’re using, an antenna for an SMV can also be used on a WM or any transmitter in that block, connector dependent. We’ve tried to make things interchangeable when we can.

Is there a particular type of antenna that you’d find useful for us to offer? Email us and tell us about it!

List 12 Popular Antenna Combos 2 2

Wire-Lists#10: 1 Tip to Identify Types, and 9 Ways To Prevent Wireless Mic RF Drop-Outs

Social Media WireLists10 300pxEvery wireless mic system has two parts: a transmitter connected to a microphone or source and a receiver that picks up the transmitted signal. Both of them have antennas - one to put out the signal and one (or more) to receive it. The area between the antennas is where most drop-out issues occur.

Start by identifying what kind of drop-out you're dealing with:

a) RF drop-out can be seen on the RF Meter. The meter will drop as the drop-out occurs. With Wireless Designer or with a DSQD receiver, the 10 second RF history display can help with identifying which channel/s are experiencing RF dropouts.

b) Pilot tone drop-out can be seen on the Pilot Tone Indicator. If the RF Meter shows sufficient RF signal, but the Pilot Tone Indicator shows a loss of Pilot Tone, try bypassing the Pilot Tone. If the audio is now acceptable, the problem is Pilot Tone drop-out.

c) Audio drop-out is your issue when you see a strong RF signal, and the Pilot Tone is present but audio is dropping out.

In all cases, especially when you suspect RF drop-out, the user should verify that there is no RF signal (or very little) with the transmitter off. RF interference can cause drop-outs that can impact RF reception.

If I'm reasonably sure that the problem is RF, what should I do?

VRM2 Wireless Designer Drop out

Wireless RF drop-outs are most often caused by improper equipment installation, set-up or use. This graphic illustrates what Wireless Drop-out (in this example, on a VRM2) looks like on a Wireless Designer screen. You can see a few very quick drop-outs just prior to 45 seconds and a long drop out that begins just prior to 55 seconds. The squelch row shows a squelch condition as the RF metering dips, which is indicative of RF drop out.

You can save yourself a lot of time by taking the approach of Occamís Razor (i.e., the most obvious culprit is usually the problem) and confirming first that you donít have a defective cord, transmitter or receiver, or that you are not taxing the known limits of your system. If youíve already done that, consider:

  1. The most common cause of RF drop-outs is improper passive antenna placement. You should be able to see the antennas and the transmitters when standing in the same place. Antennas should be mounted up and away from the receivers. If your signal is weak, try moving them closer together if possible or practical. Less than optimal antenna placement can cause low signal strength at the receiver or create unpredictable dead spots. If possible, using longer coax cables then employ in-line RF amplifiers to compensate, or use active antennas that have the amplifiers built in. If using amplifiers, only boost enough to compensate for the losses of the cables.
  2. If using a handheld transmitter, be sure not to cover the antenna, which is near the bottom. We covered this in a recent Wire List. Instead, hold the transmitter closer to the capsule without covering it.
  3. If you are using a belt-worn or bodypack unit with an external antenna, make sure that the antenna isn't bent or covered. It's very easy to get them caught in your guitar strap or wrapped in or under your shirttail. Not only is being bent bad for the antenna, but it severely hampers the signal it puts out. You can get shorter range and more drop-outs with a bent antenna. Even small bends can create issues (the unseen wires that make up the antenna can become stressed and broken from bending), so when in doubt, replace the antenna. They're only a few dollars, so it makes sense to have a few on hand for quick swap-outs.
  4. Most radio energy (this is frequency dependent) is attenuated when traveling through bodies, walls or wood, and it can't go around corners (although it does reflect off of metallic surfaces). If your receiver is on one side of a room and your talent is on the opposite side, you're forcing the signal to travel through anything that is between them. Using an amplifier or a splitter usually wonít compensate for this; we explain why in FAQ #016. Instead, place your transmitter and receiver in closer, unobstructed proximity.
  5. If you have two or more performers on wireless, assign them frequencies as far apart as possible to avoid interference. Avoid channels in the 617-652 and 663-698 MHz bands, as the FCC now prohibits them for wireless microphones. The FCC outlines the specifics on their website, which is updated frequently as the regulations are refined.

    Just because you shouldn't tune to these bands doesn't mean it doesn't happen accidentally, so be aware of that possibility and double-check. We experienced more than one instance where a customer accidentally auto-tuned, experienced interference and discovered that their problem was that they were connected to a public safety band!
  6. Multiple systems must be carefully coordinated to avoid frequency interference with each other. The best way to do this is to use wireless systems from the same manufacturer or set, and use frequencies that are already pre-coordinated (intermodulated) not to interfere with each other. There are a number of software programs that will make the required calculations and assign non-interfering frequencies. Our own Wireless Designer software is a great tool for use with Venue, Venue 2, DSQD, and Duet systems. Our FAQ #100 explains how you can troubleshoot intermodulation.
  7. Know your noise. Before you assume that the cracking sound you hear is static, first confirm that it is not the rustling of clothing or your wire rubbing against something.
  8. Use covers to keep moisture out of your transmitters (we make several!). Moisture is nearly impossible to remove once it's gotten inside the unit's case. Moisture under components and in through-holes eats away at any copper in its path (connectors and wiring) and hampers any signal attempting to travel that path. This creates what is known as "path distortion," and this is difficult to self-diagnose without a spectrum analyzer or taking the unit apart. A good amount of drop-outs that are attributed to "noise" are really due to path distortion due to unseen corrosion.
  9. Using more than one receiver (diversity) is excellent insurance against drop-outs. To achieve this, both antennas must be connected at least 6" apart, and generally more is better. Multi-path conditions that cause drop-outs are common in indoor environments, because that wireless signal will bounce off of everything metallic in that room. There are various ways you can position the antennas for your specific scenario, which we outline in FAQ #003.

Being mindful of the type of drop-out you have as well as these tips can help you diagnose and prevent drop-outs. And as always, if you need us, weíre here! Give us a call, or troubleshoot your issue with other Fanatics on our Facebook discussion page.


Wire-Lists#9: Three Wireless Designer Tips and Tricks

Social Media WireLists9 300pxIf you own one of our rack receivers, you’re no doubt familiar with Wireless Designer. We specifically developed it to be intuitive and easy to use. Here are three things that you might be unaware of that can enhance your experience and utility when using this software:

Firmware Updates

Lectrosonics RSS FeedKeeping your firmware updated is critical to ensure that your equipment performs as designed. Did you know that we have an RSS feed at the bottom of our Firmware page that will alert you when you need to download an update? If you don’t already have one, search and install an RSS reader for your browser of choice or download a mobile RSS app to get notifications. Then visit the Support page and click on the RSS icon.

If you’d rather not or are unable to set this up automatically, you can look at the change log for each product (following the same link above) to see if there are updates. Any firmware files that start with “wd_v” followed by a date can be used by Wireless Designer. Manually download the files, connect to Wireless Designer and run the Update Wizard (access by choosing Connect – Update Firmware – choose your equipment from the menu tree) from the top menu. The Wizard will tell you whether or not your equipment is up to date. No guesswork!

Walk Test Recorder

Walk Test Recorder

The Walk Test Recorder within Wireless Designer allows you to learn extent of coverage for a wireless channel in a particular setting. Operating range limits and dropout zones can be observed by walking a transmitter around a location and recording certain properties of the received signal. The recording, which displays graphically, can be rewound to an earlier point in time and replayed and is saved to a file for future reference. This is a great feature that allows walk testing to be done by a single person without help. The steps are simple:

  1. Connect to the receiver/s, then click (at left) on the specific frame you want to use for the test.
  2. Create a new file for recording and name it. This is a critical step and not obvious.
  3. Select channel to test
  4. Select parameters to record
  5. If you want to record audio, check the box and select source.
  6. Connect the headphone output of the receiver to your computer’s audio input, and select the headphone output channel on your receiver (should be the same one you selected for the walk test in Wireless Designer)
  7. Start recording; stop when scan is complete
  8. Replay the walk test recording as needed. When playing back after recording, make sure you move the scrollbar at the bottom of the frame (circled in red) to the desired time period.

 Frequency Scan and Coordination2

Frequency Scan & Coordination

This feature picks the modules within your unit that have the best coverage, scans all of the available frequencies for RF levels in the area and helps you choose the most optimal (meaning, that has the least interference) frequencies out of what is available in the connected units. This is a real time-saver when you have to coordinate more than one unit, because it accounts for all units connected to the system and allows you to create custom channels and user groups– even with non-Lectrosonics units!

  1. Start the system scan. Frequencies with active RF are shown below as yellow spikes
  2. Stop the scan when you feel that you’ve captured enough of the range – usually it is best to let it go one full round 2. Export to Frequency Coordination, then go to that tab in the software. A tutorial on how to do Frequency Coordination, if you don’t know or need a refresher, can be found here
  3. Once you do this, you can deploy the settings to all of the units in your system
  4. Important tip: Custom channels utilizing stored data only include the custom settings you’ve saved

Fitting All Receivers on One Screen

Once you have all of your receivers connected, you can see all of them on one screen or zero in on a section by using Ctrl + or Ctrl – (it’s the same for Mac and PC) to zoom in or out.

Rececivers on screen

Wireless Designer is our only product for which all of the Help files are online. Be sure to check our Support documents and revision history here.

We also have a wealth of Wireless Designer information, specific to product, on our YouTube channel.

Take some time to explore other features and capabilities of this very versatile tool by visiting our online documentation support pages at And let us know if you have suggestions of things that would be helpful, or things that you want to see!

Wire-Lists#8: Why Are You Holding Your Mic Like That? The Dos and Don’ts of RF Attenuation

Social Media WireLists8 300pxWhat do all of these musicians have in common? Hint: It’s the way they’re holding their mics. Someone, somewhere gave them a lesson in attenuation.

Lectrosonics Listicles 8 Singers

What is RF attenuation and why should I care about it?

As you know, what most refer to as “wireless mics” are actually wireless hand-held transmitters. A transmitter is any device that sends out a wireless signal – electromagnetic waves via a transmitting antenna – to another device that interprets those waves, called a receiver.

Attenuation is a reduction in strength of a radio frequency (RF) signal during transmission and is measured in decibels (dB). Material surrounding radio signals is referred to as the “medium” through which the signal travels. Attenuation measurement in decibels is ten times the input signal power divided by the signal power at an output of a specified medium. For radio frequencies, attenuation refers to the way in which the strength of waves lessens while going through open air, walls, the human body, and other features present in the environment.

How should I be holding the transmitter and why?

Antenna bottom of transmitterThe transmitting antenna of an HH, HHa or DHu is located at the bottom of the transmitter.

Antennas like ones used in the handheld transmitters don’t contain boosters (like you see in cell phones or radio towers) that can amplify a signal. They passively radiate, assuming that they have a clear field to do so. Holding the transmitter at the bottom, as shown here, will greatly reduce the RF level that is radiating out. Your hand, being a dense medium, prevents the waves from radiating adequately to reach the receiver.

Hold mic wrong way hz

The graph below shows the RF level of an HH transmitter at a given distance from the antenna, but connected to an RF spectrum analyzer, which measures output in dBµV, or decibels relative to one microvolt. It’s a simple way to measure differences, which can be small, in signal output. The antenna was covered and you can see that the level measures 70.0 dBµV:


Next, the transmitter is held in a way where the antenna was not obscured. A position like this, with your hand closer to the capsule, is the correct way:

Hold mic right way hz

The RF level now measures 100 dBµV, which shows that the signal being put out by the transmitter is not impeded. Big difference!


So, holding your hand-held transmitter incorrectly can result in a loss of 30 dB – or more, which will definitely affect the operating range of the system. This can be avoided by simply holding the transmitter in a way that does not obscure the antenna. Don’t forget to tell your pastor, CEO, singer or anyone else about the correct way to talk or sing into a handheld transmitter!

Wire-Lists#7: Cold Weather Care for Transmitters, Mics and Receivers

Social Media WireLists7It’s Winter time again! And unless you live in a tropical climate, Winter means one thing: COLD. Regardless of the time of year, many of you also run sound in perpetually cold locales, such as the Arctic Circle, Siberia or Mongolia. Contrary to popular belief, electronics, unlike Husky dogs, don’t actually like the cold. Your transmitters and recorders can deliver reduced performance and even fail to work below certain temperatures unless you take precautions. Here are four areas to pay attention to when operating or storing your equipment over the next several months:

LCD Displays

LCD displays – such as the ones on our transmitters and receivers - use liquid crystal fluid (more like a gel) in the display. Like all other non-solids, the liquid crystal can freeze in cold conditions. Ideally, you should store any equipment with an LCD display in consistent temperatures between 40° and 100°F to keep the liquid crystal from freezing.

What happens if you’re working in extreme cold – such as an outdoor location shoot with wind, snow and ice? Even if you had stored it in a warmer area, the equipment will invariably get colder as you work. When the surrounding air reaches the freezing mark of 32°F and below - equipment will still work, but you may notice the display responding much slower than usual.


A side effect of cold is reduced battery power. Why? Because batteries create power through the flow of electrons from one terminal to another. In cold temperatures, the internal resistance increases and this flow slows considerably, making the battery output more power than normal to power your unit. For example, at -4°F , most batteries will be at 50% of their normal performance level. This results in batteries that don’t last nearly as long as you expect. One way that you can somewhat circumvent this is to replace the batteries at the end of each cold workday, which makes sure that you are starting off each day with fresh power. This is a best practice for your workflow regardless of the temperature. Our FAQ #087 discusses the effects of cold weather battery issues in detail:

Circuit Boards

Circuit boards can also be damaged by cold, because they expand and contract with temperature fluctuations. Over time, this can cause poor connectivity at the board level. Condensation is another killer for cold electronics in areas with high humidity. When you bring a vented unit into warm, humid air after it has been sitting in the cold, the condensation can be bad enough to cause electrical shorts on circuitry. We have never seen this issue with regard to our products, but that doesn’t mean it couldn’t happen. Do you want to be the first it happens to?


Cables can get stiff and brittle in the cold. They will still work as designed but will be a bit more fragile. Any additional stress on a cable also stresses the wires inside.

6 Ways To Prevent Cold-related Malfunctions:

  1. When you bring equipment out of the environment in which they are stored, do so gradually, so that the display can acclimate to the ambient temperature. A good rule of thumb is to let the unit acclimate for a minimum of 4 hours before turning it on.
  2. To prevent any chance of circuit board damage from condensation or expansion/contraction, again, acclimate gradually.
  3. If your equipment rides in a bag set-up, consider using portable hand warmers (like the type you use in your pockets for winter sports) inside the bag. Place them in proximity to, but not near or touching the unit. Another low-cost insulator is newspaper.
  4. If they’re being used on talent, bundle transmitters between layers of clothing to trap body heat. Do not put them on bare skin, as skin will deposit moisture and oils onto the unit. When it is cold, bodies actually sweat more, not less, in the effort to regulate body temperature.
  5. If your cables are going to be in freezing temperatures for a period of time, avoid excessive flexing if they are already stiff. If you have the budget and find yourself in this situation often (like documentary filmmakers or those that run sound for outdoor events), your best bet is to purchase thicker cables that are made for use in the cold. Loon Audio makes a great coiled cable that is lauded on a few of the sound tech newsgroups.
  6. This last tip is critical: Before going from the outdoors to indoors, put any equipment that has metal parts (recorder, transmitter, mic) into a Ziploc baggie with silica gel pouches while still outside. Close it with as little air as you can (squeeze the excess out before you zip). You can even put the Ziploc into another and close that – it works like an airlock. Bring it inside and let it rest 15-30 minutes before you put it away (remember to remove the batteries). The silica gel will absorb any humidity, preventing it from condensing on the cold metal.


Wire-Lists#6: Preventing Pogo Pin Failure In Your SSM

Social Media WireLists6 300pxAre you having issues with battery drain or inconsistent power in your SSM, in spite of using fresh batteries each time? Are you hearing an odd, intermittent scratch-click that you can’t trace to any of your other equipment? If you’ve checked everything else, the problem might just be a pogo pin.

What is a pogo pin?

A pogo pin, which is a common term for the positive battery spring contact and is used in the design of all electronics using prismatic (square) batteries, is so-called because it acts like a toy pogo stick. Though they look like solid pins if you look into the battery case, pogo pins are two part housings, with an integrated helical spring inside that applies a constant normal force against the back of the contact plate. This spring counteracts any unwanted movement which might cause an intermittent connection with batteries. They’re very small parts – smaller than a pencil lead - that can cause big problems if they malfunction. Pogo failures don’t happen very often with Lectrosonics products, but they can happen. Most maddeningly, if one is the cause of an SSM’s visit to Repair, it’s one of the less obvious, head-scratcher things that can happen. As they say, You learn something new every day. Fortunately, the causes of most pogo pin failures are 99.9% within your control (the other .1% being manufacturer defect).

This photograph shows a pogo failure that ended up being caused by a compressed/bent/jammed pin. Why is this a problem, and what can you do to prevent it?

Lectrosonics pogo pin damaged

The role of pogo pins in electronic devices

First, a short tutorial on prismatic batteries and how they relate to pogo pins:

Prismatic batteries – the square batteries that are used in the SSM and likely more units that we design down the road - have highly compressed cells and are popular in small footprint electronics like ours. They have nickel tabs, shown as small square windows, for contacts, recessed around 1mm from the battery top. Two sample configurations of the many that are possible, showing their relationship to the pogo contacts, are shown below. There isn’t a pogo “standard” as far as configurations. Each battery manufacturer designs their own (Panasonic manufactures custom ones for our SM). Equipment designers,  if they are using off-the-shelf batteries, then design products to utilize the most efficient batteries available that fit the need.

Lectrosonics pogo pin diagram

The battery contacts that are built into the equipment need to have sufficient travel to penetrate the recess and apply sufficient contact pressure to minimize contact resistance. Resistance, for those of you who are unfamiliar with the mechanics of electronics, is the measure of opposition to current flow in an electrical circuit. Minimum travel of 2.5 mm and minimum force of 200 grams are used to create the energy that powers your electronic device and assure reliable performance in high-drain devices. This requires POGO pins that are flexible, but not too flexible. It’s a fine balance.

I think a pogo pin is bent (or I’ve been told that’s the case)! What happened?

An easy way to check for a damaged pogo pin in an SSM is to lightly – very lightly – press on it with a Q-tip or the eraser end of a mechanical pencil. If you apply slight pressure to the head, you should feel it compress. If the pin doesn’t move at all, it’s confirmation that it is damaged and needs to be repaired. If you hear an intermittent slight scratch or click that you can’t trace back to anything else, it may also be a pogo pin, trying to expand and contract and getting stuck.

Pogo pins can be damaged in the following ways:

1. Putting batteries in the wrong way. This is the reason why we engrave battery direction on our housings and are so explicit in how we explain battery installation in our manuals – because inserting batteries incorrectly can damage these delicate pins.

2. Corrosion damaged the pin. The most common way that this can happen is from sweat. And it’s why we are so insistent on using a covering of some kind for high-moisture applications. Once the moisture gets in, you can’t get it out!

3. Incorrect cleaning. This can also cause damage and corrosion. Never spray any type of contact cleaner or petroleum-based solvents (such as WD-40) directly onto pins. Instead, apply a small amount onto a Q-tip or paste brush and apply only to the contact pins while holding the unit upside down. This will prevent liquid from seeping inside.

Don’t be one of less than a dozen annual SSM pogo pin failure cases! Follow the steps here and you’ll be good to go for years to come.

Wire-Lists#5: 4 Ways to Mangle Your Mic

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We think of lavaliere mics as being indestructible because they’re self-contained, but the fact is that some seemingly innocuous things can wreak havoc on them. And you often won’t realize that you have a faulty lav until you listen to your recorded tracks and realize that they just don’t sound right (talk about wasted time!). Here are 4 ways that you can mangle your mic:

  1. Keeping the mic attached to the transmitter it’s being used on, and wrapping it around the unit body when you’re finished. This is a BIG no-no. Over time, doing this can weaken the inner threads of the wire, or worse, break the 5-pin connector. There is no inexpensive fix for these if they happen. Disconnect your lav when you’re finished with your project and store it in its case.
  2. Allowing the lav to come in direct contact with skin. We realize that you want to hide the lav on camera if possible, and the easiest way to do that is underneath clothing. It is best to keep a layer of fabric between the lav cord and talent’s skin, for the simple reason that sweat is corrosive. Lav wire encasements are slightly porous, and over time, sweat can leech inside, corroding the copper wires underneath. Like wrap damage, there is no easy fix for this.