SR10 Needs Ground-Loop Isolation
When the SR10 is powered from the bike, and connected to audio devices that are also bike-powered, ground loops are formed between the devices and any electrical noise present on the bike's electrical system is heard through the SMH10. When connected to both a radar detector and a two-way radio, the noise is strong enough to trigger the audio from the SR10.
Removing the devices from bike power eliminates the ground loop and the noise goes away.
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Hey Peter
Funny timing... over the last 2 weeks I have been setting up a system pretty much identical to what you describe... as of yesterday it's finally working!
I also had the group loop issue - if you haven't solved yours yet, you can get a small ground loop isolator 3.5mm adapter and run that between the detector and the SR10. That seems to have solved my ground loop feedback there so far - local car audio stores should have them in stock.
And +1 on the idea... ground loop iso. built into the unit would really help quite a bit.
Thanks!
DanO
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Hey Dan,
I'm aware of the ground loop isolators with 3.5mm connectors. I have one for the radar detector but haven't installed it yet.
My bigger issue is the two-way radio. I have a ground loop between that and the SR10 as well. It's better without the radar detector connected, but still bad enough to trigger the SR10 if the SR10 is powered from the bike. Not only is the two-way radio bike powered, but it's also connected to an external antenna which is itself grounded to the bike. The problem there is that a simple off-the-shelf ground-loop isolator wont work as the PTT of the radio is triggered by shorting the grounds of the speaker and microphone jacks (Kenwood style connector). I'm going to have to build a custom isolator for that which will preserve the PTT function and isolate that as well (preferably with an opto-isolator). Having the isolation built in to the SR10 in the first place would have been the right way to handle this.
I've seen conflicting pinouts of the SR10, some list a +5V line and others list that pin as a n/c. It would help to get some confirmation from Sena if there is a +5V output on the Hirose connector of the SR10 or not, as I need it to power the opto-isolator and would like to avoid bringing in another power source (with yet another ground point).
I'm also considering replacing the regulator/rectifier on the bike to try to get a cleaner power signal to begin with.
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Hi Peter, Did you ever get this built? If so would you be willing to post the schematic and parts list? Cheers, Matt 0 -
Hi Matt, I have the parts (including a set of Hirose connectors for a single cable connection to the SR10) but haven't had the time to put it together yet. When I have it finished I'll post the details. I did open up the SR10 and confirmed that there is _not_ a +5V feed available on the Hirose jack. My design at this point is to simply use a 12V power feed from the bike and perform the PTT function via a relay. (I'm also adding a second output from the bar-mounted PTT switch as I want to use that to control a garage door opener as well.)
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Thanks Peter, I look forward to it. It also struck me that an alternative if you are just using the a radio with the sena was to isolate the SR10 power supply from the bike with a simple isolated DC-DC converter. Something like a Tracopower TEL 5-1212 (or TEL 5-1211 if you wanted to do the 5v conversion and use a USB Lead). 0 -
Yeah, I understand how ground loops are formed. I also know about aftermarket isolators (and am currently using one between the radar detector and the SR10). The problem here is that those kind of isolators (such as the one you linked) don't work between the SR10 and a two-way radio, particularly where the SR10 needs to bridge the ground between the speaker and mic connections for the PTT function. Which is why I have to build a custom unit (and you might have noticed had you actually read the thread rather than responding to the title).
My primary point is that this kind of isolation should have been built in to the SR10 to begin with, especially since building an isolator that will work with two-way radios is probably beyond most of your users (and it's also yet another box that has to find a place under the seat).
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I agree Peter. Although my set up is not quite as complex as yours sounds, I have wired all devices up to bike power, including the SR10, and was quite frustrated when trying to eliminate the "noise" I heard when the SR10 was being powered by the bike. Disconnecting the SR10 from bike power eliminated the noise altogether. However, that kind of defeats the whole purpose of it being able to be bike powered to begin with. Ugh! Thank you for your insight. It is most valuable. Until they come up with a solution, I may give the ground loop interface a try, as it may work in my configuration.
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I, too, have the ground loop problem with my SR10, radar detector and ham radio, which are all powered from the bike (GL1800) power. I would be very interested in any solutions that are designed. Seems like a lot of extras are going to be required. r.l.burkett@gmail.com Thanks, Bob 0 -
Hi Peter!
I have the SR10 hooked up to my Yaesu VX-6r and am having the same hair pulling issues as you. I would be very interested in you solution for this. I have subscribed to this thread but here is my email address as well. refplusten@gmail.com
This issue is keeping me and my friend from even using our SR10's with our radios. Hoping SENA is paying attention to this as I would not recommend this hub until this issue is resolved.
Steve
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Adam Schoolsky from Rocketmoto.com called me with an answer to this issue.
It's called an 'isolated power supply'. Rocketmoto.com has them in stock but the guy who makes them (the only one I can find on the net) has them on sale right now on his website.
http://davidnavone.com/zencart/index...products_id=29
This will make it seem like you have a completely separate battery and completely different ground and therefore completely eliminate the noise and popping sounds.0 -
I understand the 'isolated power supply' function, but it is hardly practical for me to add $250 worth of isolated power supplies on top of the cost of the SR10, SMH10, my ham radio and GPS to get clean audio! Sena should really have considered this in their design.
I am working on another less expensive option to get around this design flaw...
~Bob
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I understand and I agree, however, here is a site and they are currently on sale for $125 for anyone else that is interested.
http://davidnavone.com/zencart/index.php?main_page=product_info&cPath=5&products_id=29
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Bob- I agree that the SR10 should be taking care of this.
Refplusten- Thanks for your research and additional info with the link for the isolated power supply. It definitely looks like a viable option, albeit a little expensive.
I have procured one of the ground isolators from Amazon, and it seems to work quite well. Am still in the process of trying different wiring configurations to see which works best for me.
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All,
I am experimenting with a setup using isolation transformers for audio isolation and a relay for PTT. I am incorporating a 3rd channel for my GPS audio. As I have a Goldwing, my goal is to have the SR10 and my isolation setup in the left faring pocket...unless Sena comes up with something new!
I will advise my results.
Regards to all,
Bob
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I'm running a Kenwood 3101 with a Passport radar on my SR10. The Passport has the ground loop isolator sold by Passport (at an exorbitant cost!). A Samsung phone connected to a Zumo 660 are also part of the set up. All devices except the phone are bike powered. The Zumo and the SR10 connect to an SMH10R. The + power for all devices is fed directly off of the battery through a single, fused relay which is triggered from a keyed source. All - ground leads are also direct to the battery. Connections are made via a simple terminal strip - not a separate fuse panel. No line filters, no isolated power supply.
The result ... No Noise . Maybe the single ground loop isolator in the system for the radar is possibly making the difference? And/or the fact that everything ties directly to the battery? Don't know.
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Just my two cents here. Why not just utilize the internal battery for the SR10 and the battery for your handheld? I've found the SR10 and SMH10 to last at least two full days of riding before recharging as long as I remember to turn them off during long breaks. Most handhelds will operate a full day on its battery before recharging (unless you are a "Chatty Cathy" type) In any case, I always carry a spare battery for my radio when I'm out and about. No ground loops, no fussing with bike power. When I'm on trips I only use bike power to charge my devices at the end of the day (it doesn't pull much juice for an overnight charge up). My phone uses bike power when I'm riding only because I listen to music and it drains pretty fast otherwise. It's multipoint paired to my SMH10 so it doesn't even go through the SR10 or any other gizmo on my bike.
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Ken, in my case the ham radio is connected to a bike mounted antenna and gets ground there even when running on its internal battery. The SR10 is also connected to a Valentine One radar detector which is bike powered (and doesn't have a built-in battery). So I get a ground loop no matter what. Running with the ham and SR10 on internal batteries the noise is minimal, but still there (a regular audio isolation transformer is between the SR10 and the Valentine One). When the SR10 and ham are bike powered, the noise makes the system unusable. Furthermore, this is all mounted on a sport bike and is under the rear 'seat' which is a bit of a tight fit. Ideally the SR10 would be mounted inside a fairing panel where it's inaccessible without tools and having it bike powered also turns it on and off with the bike. When traveling on multi-day trips getting to all the various hardware to turn them on and off is a bit of a pain, let alone removing the SR10 and ham to charge the batteries. The ideal configuration is for it all to be bike powered, no muss, no fuss, and never worrying if it's charged.
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I agree Peter that having everything permanently installed and on bike power would be ideal in your situation. I don't think your setup was what Sena envisioned when they developed their products so I can't really fault them for bad design. As far as an external mounted mobile antenna for VHF and UHF, most of these antennas don't require a ground plane and are not impaired by the lack of one. In the case of a motorcycle, there really isn't one anyway so you could certainly isolate that connection with the frame of the bike and eliminate the ground there. Just a thought.
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Ken:
Long before the SR10 was released for sale, I spoke with the engineers from Korea. I discussed the ground loop issue in detail, and was assured that isolation was built-in to the unit. Same deal for the SM10. I've been in this motorcycle audio game for way longer than Sena has even been a company. I did try to head this off early on, but obviously it didn't make it into the design. Now that they understand the issue, I do hope that any next generation products will take this into consideration.
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Hey guys!
My set up has been fixed with the use of an isolated power supply (Yeasu VX-6R with SENA SR10 w/ the included PTT switch and an external antenna mount ALL powered by a switched power supply from my 2010 BMW R1200GSA). No popping, clicking, whining or noise of any kind. Testing the set up with a hand held from the house boasts a +5 mile range, so the power output is finally what it should be and does not diminish). Very happy with the results... not too excited about buying an isolated power supply to make all this work I must say but I am happy that the problems I had are now completely gone. I also made sure that the antenna mount for my NGP antenna was isolated from the frame of the bike as during my trouble shooting phase I found that just touching the mount to the frame (while not transmitting) caused some static. Not sure if that particular issue would have continued with the addition of the isolated power supply but I don't think it's a bad idea to isolate the comms system from the bike ground anyway. (this is the one I used {I am not affiliated} http://davidnavone.com/zencart/index.php?main_page=product_info&products_id=29 ). Also would like to personally thanks Adam from RocketMoto for helping me with this issue. 100% solved.
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No one on this thread mentioned that the newer BMW's and some others utilize a CanBus electricial system. If your pulling power and ground off of an accessory plug or any other place other than directly from the battery it will likely cause all sorts of problems. Many bike accessories, unless CanBus compliant, will not function at all. Eliminating any ground contact with the bike will solve most all problems. Last resort is the isolators mentioned.
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Gee, Ken - that hasn't been our experience. We have *hundreds* of BMW customers that run low-power accessories (or trigger accessory fuse panels) from the accessory socket or other CanBus powered points, mostly without issues. Connecting two audio devices that have a common power supply (from the bike, as an example) with inter-connected, unbalanced (common) grounds on the audio side, will cause a noise problem - or potentially damage one device or both - CanBus not withstanding. This is the nature and root cause of a ground loop. Two ways to resolve; Either isolate the power input side with a DC-DC converter, or use isolation on the audio side. So, I must differ with your opinion - Isolators are not really a last resort. It's first resort, since device manufacturers most often take a lower cost approach by making unbalanced audio interfaces.
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Well Adam, It appears you are quite the master! Obviously being the idiot here, I would never assume to challenge your expertise. That being said, You have a valid solution for those that absolutely need to permanently install all their stuff and power it from the bike. But it is also quite clear by the product design that the unit was not intended for a permanent installation. If so, it would have a hardwire connection, and it would have a permanent mounting solution. It would not have or need an internal battery, it would not need a PTT on the case, and it would not have a relatively fragile micro USB power connection that can vibrate out. For what it is and the price point of the product, it fits a big niche in the market that no one else has been able to duplicate as successfuly and relatively inexpensively so far. Could it be better? Of course, and the firmware updates for the SR10 and SMH10 Sena has made and continue to make have improved the product significantly since introduction.
Part of the problem here and in many suggestions that people make, no product will ever be all things for all people. Unless you can convince Sena that a large portion of their market demands permanent installations, then I think your adaptation solution is the best you or anyone else can hope for at this time.
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Ken, given that "Optional 12V bike-powered kit with on/off control by ignition switch" is one of the feature bullet points listed on the Sena web site for the SR10, I don't think it's reasonable to claim that the unit wasn't designed for being powered by the bike. This is a use case advertised by Sena and it should function when powered by the bike without the need for isolators rivaling the cost of the unit.
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Peter - It's true the feature bullet point lists that but if you notice there is no such accessory for sale on their website or part number listed. I still don't think it was initially designed with that in mind just based on the reasons I earlier stated. I would hope if it comes out the ground loop problem would be addressed. Would that ignition switching be CanBus controlled or only for old school wiring? Or both? The usb plug is still a weak link to permanent power although the duct tape in everyone's emergency kit is a good solution. Maybe that and ground loop problems is why it isn't listed yet as an accessory product. You can certainly call Sena Support and ask. They have been quick and helpful in the past with me. If they got one and it works and it's cheap, I may try a permanent mount but my tankbag solution is pretty good and I don't have to carry around comm gear all the time. Let me know what you find out.
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Ken, You better check Sena p/n SC-A0103 Bob 0 -
I did Bob. That is for a 12volt cigarette lighter charger, not the switched power connection mentioned by Peter.
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That accessory also comes in the SR10 package. Unfortunately it doesn't match the european accessory plug that BMW's have but once again the ground loop problem would still exist. I use it in my car to charge an older cellphone I have.
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Ken, Check again! I have two of them and they are p/n SC-A0103 Sena SR10 Cigarette Charger with On/Off switch. It turns the SR10 on and off when power is applied and removed from the accessory socket. See photo attached. Bob
image.jpg0 -
Here is the Sena link: http://www.senabluetooth.com/products/acc_SC-A0103.php Bob 0
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