Lemons Radio Tech (Page 1 of 5)

Placeholder for answers.

I was debating on which section to put it in. Thanks for the shove off the fence.

Questions:

What are my options for my in-car microphone?

What are my options for my 'push to talk' button?

What are my options for in-car radio mounting?

What are my options for in-car/on-car antenna?

What are my options for wiring the whole dangblasted thing together?

Power source?

Pit radio headset?

Multi-car teams?

Just throwing out ideas.  I have very little to no information to provide.

We really need to get Troy to add to this topic.  I bought my radios with his input, and some stuff he made, and it works great.  He has done a lot of trial and error to get the knowledge he has.

1. What kind of radio and what frequency?

The most common frequencies are UHF and VHF, MURs and 800 MHz are other options. I think some guys even use CB but I don't know what frequency they use. For racing applications UHF seems to be the most popular. GMRS radios fall in the UHF frequencies from 462-467 MHz.

There are 23 GMRS channels and each channel is 25 kHz.
(http://www.fcc.gov/encyclopedia/general … rvice-gmrs)

    462.5500         
    462.5625
    462.5750
    462.5875
    462.6000
    462.6125
    462.6250
    462.6375
    462.6500
    462.6625
    462.6750
    462.6875
    462.7000
    462.7125
    462.7250
    467.5500
    467.5750
    467.6000
    467.6250
    467.6500
    467.6750
    467.7000
    467.7250

For kinds of radios, most common are handhelds (walkie talkie style) and mobiles (CB style).

I put handhelds in 3 groups: GMRS/FRS, Chinese Gray Market non-FCC approved business radios and lastly full on FCC approved business radios.
       
GMRS/FRS radios:

Often referred to as bubble pack radios. Midlands and Motorola Talkabouts are two very common radios in this category. These radios are advertised primary with range in mileage which is grossly overestimated. Midland GXT1000s do claim to be 4 watts with a 36 mile range where the 35 mile Motorola Talkabouts like the MR350R and MT352R only list mileage. These radios are the least expensive option and are the most limited. That said two way communication while the car is on track is very useful even if it's limited. So if you can see the car you should be able to communicate. It may only be while close to the pits so you need to understand you radio coverage.

IMPORTANT DETAIL: Motorola Talkabouts are made and sold by Giant International not Motorola corporate! They are good but not a genuine Motorola product.

These radios have fixed antennas so radio placement is much more important than a radio using an external antenna. For these radios try to get them high in the car with the antenna pointed straight up. Some guys have gone so far as to drill a hole in the roof and poke the antenna out. Attempting to maximize the antennas functionality usually compromises the drivers ability to reach and adjust the radio. These are some of the reality of these radios.

With my limited experience, I have already experienced many unhappy Midland users. I do believe they have a little better range than the Motorola Talkabout MR350R or MT352R but the lack of volume is a problem. I have had many people ask about running a Boosteroo with their Midlands. The other issue is dying batteries. The battery pack on the Midlands does not last very long and they perform better using alkalines. They do come with a cigarette lighter adapter for the desktop charger which can be used in car. So it's a bit cumbersome but functional. The Motorola Talkbaouts on the other hand have much move volume and both the MT352R and MR350R both have convenient Mini-USB charge ports making it easy to plug them into the car. The pricing on the Motorolas has fluctuated a bit over the past year. The MR350R was about $60 a pair from BestBuy.com for a long time. The MT352R is basically the same radio with a 1300 mAH high capacity battery rated for 15 hours where the MR350R is rated for 8 hours. The MT352Rs are around a $100 and the MR350R has gone up and down some so some online shopping could save you money on either.

Most Midland users I have dealt with were so frustrated they stepped up to business radios. Only a few moved to the Motorola Talkabouts. Even with the limitations of the Motorola Talkabouts most teams using them have been satisfied.

If you are going to use GMRS/FRS radios, I recommend the MT352R.

The Chinese Gray Market non-FCC approved Business Radios:

Before I get into all the non-FCC approved ones, there is one FCC approved radio in this price range. The Olympia P324 is a Kenwood clone sold by Giant International. These are available for under $100.00 each. My BIGGEST and really only complaint is there is no battery eliminator!!!

***I do not recommend buying any kind of business radio for endurance racing that does not offer a battery eliminator!! (That means no Blackboxs.)***

So, getting back to the Chinese Gray Market non-FCC approved business radios (That there is a mouthful) These are the eBay/Amazon specials. Yep the Baofengs, Puxings, TYTs and Motorola GP68s. Aside from the Motorola GP68s all of these radios are Kenwood clones/knock offs. I consider these the most bang for the buck. No they are legit and I have called eBay and asked about all these radios for sale on their site. If the FCC comes after someone for these, they should also go after the source, eBay and Amazon. Since they aren't FCC approved, I am surprised to see them being sold on eBay and delivered to our door steps. Legit or not, lots of teams use them with very good results.

NOW, it's to late for me to continue. Glad to see this post and I will fill in what I have learned through our trackside trials and tribulations later. Good night.

We went the cheap route, and went with the Midlands.  This is what we have learned with them.

When mounting in the car make sure the antenna is in an open spot.    Through are lazy method of getting power to the radio we actually mounted the radio in the car on a charging base.  To place it in a secure spot it ended up on the dashbar  which has the antenna sticking up just a bit in the windshield.  This somehow ended up giving us some pretty decent range.  Autobahn we can chat the whole track, and road america it was very clear everywhere except between the Kink and Canada corner.  one of the issues with these radios is that you often end up sharing channels, so we can gauge our setup to other cars and by having the antenna sticking up a bit, and probably the lack of any complicated electronics in the car, we seem to do better with range than a lot of the teams.

The other thing is make sure you understand how the privacy function works.  The make it sound like switching it on encrypts your conversation, but atleast with the midlands all it does is make it so you can't hear the other teams.  So if you set it be aware that you may unintentionally be over talking other teams and seeming like an ass.  Also the team on your channel may have information you want.  I spent 3 laps trying to tell a team that the reason they hadn't seen their car was because it was broke down in turn 1.

Troy,

What do you know about the Chinese HYT tc500's?  They seem to be Blackbox knock-offs and you can get battery eliminators for them.  As a Blackbox investor I also wonder if the HYT bat eliminators will plug and play w/ my absurdly expensive Bbox radios.

I have run a HYT 500 battery eliminator with the Blackbox 500 radios I have.  Worked well.  There are a few different Blackbox models though, just like the Hyt.  I assume that if the battery mount matches, it is going to work. 

I'm not sure why, but I thought that Hyt made the radios that Blackbox private labeled...  Certainly Hyt makes more information available about the radios than Blackbox does.

I don't have many answers for lots of Chris' technical questions up top, but since this stickied thread will probably draw a fair share of folks seeking how-do-I-do-this type answers, here's how we have done things so far. We've run 16 races on this equipment, give or take, and it's still somewhat a work in progress, but I'd say it's 95% stable at this point and this is what I've learned.

Handhelds: we run mainly Motorola GP68's. We started with SP10's and SP50's that I was able to pick up cheaply on eBay back in '10. Added the GP68's as the SP's died out. The nice thing about the 68's is that they are fully-programmable by the user, so you don't need Motorola's proprietary secret handshake software. That flexibility is also the downside, as any user can accidentally re-program the radio so that it doesn't work anymore if you don't have the keyboard locked. I think that Troy thinks that there is something funky with the mic circuit on the GP68 versus the other Motorola non-GMRS/FRS radios, but I'll let him discuss that if/as he sees fit.

That said, if I could find something else that would work with my existing Motorola-based equipment and that worked better, I'd use that instead. I really like the SP50's but they are getting hard to find, and I don't have the equipment to program them anyway.

Car Radio: After a lot of back-and-forth using the SP50's in the car and getting anywhere from somewhat poor to somewhat good results, we switched to a Motorola mobile radio last year and it has done a lot of good things for stabilizing the quality of comms with the driver. We just run a magnetic-mount NMO antenna (of which I need to have the cable length modified, apparently). The plus side of the mobile radio is that it has stronger transmission signal than the handhelds and runs on car power, so you don't have to worry about finding a battery eliminator; of course, if the car is 100% dead, so is the radio, but you'll be coming back in on the hook in that case anyway so the radio is sort of irrelevant at that point. But it sends out a strong signal which means we can usually get driver transmissions nearly everywhere the car is on track. Cons are that the radio is not user-programmable and as far as we've been able to sort out, using it requires a somewhat pricey car harness that routes to the 16-pin connector on the back, and it really really works better if you're using good helmet kits. Speaking of which:

Helmet Kits: we started out using the cheapest helmet kits we could find, and our comms sounded like it. We now are shooting for high-quality mics in every driver helmet and it really makes a big difference. Maybe a bigger difference than transitioning from the handheld in the car to the mobile radio in the car. We are using a NASCAR-style harness, so the drivers can get away with using earbud-style headphones, but I use dedicated mono headphones in a DIY earmold (using a DIY earplug kit from Cabela's) and I like those a lot better. I still tape them into my ears with electrical tape, even when under a balaclava.

Frequencies: we are on UHF 450-470MHz somewhere, depending on how we have the mobile radio programmed.  We try to monitor all of our programmed radio channels when we are at the track on Friday so that we have minimal interference, but that's been pretty hit-or-miss because most of the other teams aren't broadcasting much on Friday compared with Saturday and Sunday. So we have to be kind of flexible on what channel we are running on during the race.

Aside: sometime in the last 2 years, I tried to get licensed by the FCC to use specific frequencies the way that the big race teams do (Cup, Indy, etc.) and it was an unmitigated disaster. I work with forms, rules, government bureaucracy and bureaucrats, and the application of rules to forms all day long in my day job, and it was a nightmare trying to get licensed, to the point where I literally abandoned my efforts (and $200 filing fee) because it was so impossible to decipher. If somebody knows how to navigate this maze successfully, I would love to talk with you about subscribing to your newsletter.

Headsets for non-drivers: I picked up some used Nextel Cup officials' headsets for our crew to use when talking to the drivers. I think they're pretty effective, but I don't find them very comfortable, but they are useful when at a louder track.

Push-to-talk button: we have ours on the steering wheel at 9:00, and I prefer it there. You always have your left hand on the wheel, so that makes it easy to find. I've driven in cars that have it velcroed to the wheel in some other position, or near the gearshift lever (but not on the gearshift), or on the gearshift lever, and all those other places are just less convenient. If you make your drivers look down to find a PTT button, they are not looking at where they are driving, and we should minimize that.

Notes on Good Comms: Both driver and crew need to remember that the radios work better if you press the transmit button, wait a second, and then begin speaking. Speak slowly, speak loudly (but don't yell), don't mumble, and keep your questions or announcements short and to the point. It really does work best if you end every transmission with "over" if you have said anything more than "roger." It isn't the worst idea to repeat important transmissions back to the sender: "Pit in two laps, copy". But really, the biggest enemy of clear comms is just not pressing the transmit button before you start to speak (side note: when driving, pay attention that you aren't hamfisting the transmit button while driving, the crew doesn't want or need to hear road noises over the radio).  If you want to hear effective comms, I recommend scanning the aviation bands, those guys have it down cold in a life-or-death business. Our comms don't have to be that good, but it can't hurt to try.

And a couple of semi-random tips that we've learned mostly the hard way:

• If you run a battery eliminator, you may also need to run some sort of noise filter to keep alternator whine out of your radio circuit.

• If you have the ability to do so, put a coiled cord headphone extension between the car harness and your helmets. When your drivers exit the car without remembering to unplug their helmets first, the extra length will keep them from falling on their butts, and the cord will take the brunt of the damage, rather than your car harness.

• Mount your helmet mics so that they exit from the driver's side of the helmet and plug in on the driver's side of the car, rather than on the side of the helmet that is toward the middle of the car. This makes it a lot easier for your teammates to help plug in your helmet kit (earbuds to kit and kit to car harness) when you forget to do that.

• Wherever you mount your in-car radio, make it easy for the driver to change the volume. It is annoying to have a too-loud radio in your ear and not be able to do anything about it.

Finally, in my experience, the drivers want and need to hear from the crew less than you think they do. If they need information (like lap times), they will ask for it. I am of the Kimi school on this : let them concentrate on their job, they know what they are doing. Good radio comms are an invaluable tool, but they become valueless if they become distracting to the driver.

Cheers.

We're using the Midlands, and are generally happy with them. I have a harness in the car, and each driver has their own helmet kit that gets connected when they jump in. For the tracks we run we have coverage just about everywhere on the track. Some notes from what we've learned.

- It is possible to wire in a boostaroo. I have one as part of the in car harness. It makes a huge difference.

- The connectors that come with those helmet kits are fragile. I've had pins bend a few times now which cuts out something like your mic, which makes life hard. Might replace with a more robust connector.

- the battery packs seem to last just fine for us. We'll finish the day with 2/3 battery left, and just throw them on a charger overnight.

- the push to talk button isn't always easy to use with gloves. I'm going to replace mine with something easier to push and make sure it's pressed. Kind of tempted to use the horn button on the steering wheel.

I'm interested in what everyone else is using so i'll keep an eye here and may seriously consider upgrading.

You don't need to sweat the exact length. The words "base loaded" mean there is a coil in the bottom to make the antenna electrically correct as far as efficiency goes.

Most of the UHF mobile antennas are designed to cover 450MHz to 470MHz in one chunk.

That would be a better antenna to run versus the stubby 1/4 wave.

Oh boy, the sellers are playing a dangerous game.  In the past I did Part 15 work for a handheld wireless meter reading device, and it was a real education.

It's illegal to market anything without FCC blessings, let alone sell it. If a foreign national sins against the FCC, they are subject to deportation (green card or no) - and the FCC are people of little humor.  Some Taiwanese gents were deported around 1993 because they were marketing and selling PCs without FCC testing.

In addition, using these devices is a Federal offense.  But the likelihood of FCC "sniffing" the area around the race track is low, unless there are complaints of interference.

Our bosses decided to market our unapproved devices at a huge wireless show.  The other RF engineer and I warned them to not tempt the might of the FCC, since the FCC shows up at these shows and goes sniffing for signals. 

I would've been especially guilty 'cause I have a General Radiotelephone Operator's Permit and know better.