Batboard

I need to make a decision on a portable radio to use in racecars (Pro 2000, GT1, Winston Cup).

In the past, I've always used the GP300 and they've been great. Now they're gone forever.
The P1225 is no good- it shakes apart. The SP50 is no good- it breaks when you drop it.

What's everyones experience with the CT250?

This radio only needs 1 or 2 channels in the UHF band and has to do 4 watts. The HT750 seems to hold up well, but $$$$ versus reliability is the issue here. Is the CT250 durable enough?

HI:

Although many may like the CDM / PRO / HT
750+ Series, I have several race car teams
I support.

All of them either use MT1000's, HT600's /P200's , HT1000's which
are some of the work horse radios.

Although they are no longer made, if you
can find good used radios in your area from
a vendor at a good price, I would consider them. They are Commerical Grade radios where
the other lean more towards the Consumer Grade.....

If you can't find anyone in your area, please
feel free to email me...

Monty

I'd like to stay with GP300 or P110 because all of the cars' harnesses are set up for that jack configuration. Anyone know of a good source of used 300's?

HI:

I have a few Premium ones in great
condition if you are interested.

Email me direct @ [email protected]

MS

try the all mighty e-bay for a used gp300, picked one up for about 150 the other day..

http://www.ebay.com

I'll throw in a vote for the CT250, if
no one else will. It is based upon the
Pro chassis, and many think this is a bad
thing, but I can tell you from experience,
they are very durable radios. Initial
QC problems notwithstanding, I have always
found them to take a lot abuse, even the
display radios can handle a beating.

Plus, they are Motorola supported, with
warranty coverage, always a plus.

Tony

I think we're gonna give the CT-250 a try in a Pro2000 car. I understand there is an adapter to use the GP300's accessories on this radio. Anyone know the part number?

....in fact, does anyone have the part number for the correct accessory connector/cable assembly for this radio and a pinout? (Basically, a speakermic cord/connector)

You shouldn't need an adaptor, GP300
accy's work anyway. Lapel mics for sure,
have not tried headsets, but I see no
reason why the wouldn't work either.

Tony

So what you are saying is these radios have the GP300's plug? I assumed they had something similar to the new HT series.

What about a programming cable?

CT series have a Gp350 style plug and you need the same style adapter as you need for the gp350 to use GP300/p110/gtx accessories. Personally, I'd go with a GP350. I can get 16 channel ones brand new for $225.00 with MDC1200 and its basically a GP300 with a little more curvy body. A lttle more tried and true than the CT Series.

HI:

Just a liitle tech note:

Although one can chose any radio desired, be
aware ( and I would have spares ) the GP300/P110 / GP350 ect mic connector is
a pretty poor design.

I have replaced 100's of those dam cords and
the jack on the inside of the radio as well.

The Jack will die even if it has not been used for some period of time, then failures
( or intermittent conditions ) begin to show
up after use.

If you truly plan to use something like this
in a industrial application, I would make some precautions to protect that " Cable "
=>Made in China<= so that the wires do not
break.

I have found the wires leading into the Mic
Plug through the cable support " Break " at the point of where the cable support is located at both ends.

The Size is a measly 22 strands of
of .002 in dia.

Using a good contact conditioner on the
ends would not be a bad idea either. Less
is Best....( In other words do not saturate
the plug ) Most already know this, but I have
to toss in the extra.

MS

<img src="http://www2.4dcomm.com/metrotech/wire.jpg">

Darn it, Monty's right again.
I have changed hundreds of the GP300 spkr/mic jacks and cords.
Some race cars I have looked carfully at have two higrade plugs, one 2.5mm and the other 3.5mm and they use aircraft grade shielded cables. But they use a cheep Switchcraft 1/4 mic jack for the headset connector. I sujest to use a aircraft grade jack there too.

I know what 'ya mean. The 1/4" jack is required because most helmets have the 3pin stereo-style jack. Some of the Winston Cup cars use the 4pin aviation style. Shielding is VERY important on the cabling, as these ignitions systems don't have resistor wires and other on board electronics will interfere. The radio end almost has to be the GP300 style, as most car harnesses are set up for this already. The GP350 is a great alternative to consider over the CT 250. Is this radio still in production yet?

Also, I see some of the other companies that sell the car harness for the GP300/350s claim that you must use an isolation transformer in the audio circuit. What do you all think of this? I built these harnesses without them and it works just fine. A transformer in a box only adds to things that can fail and in a Formula car, there's not even enough room for one more cable, let alone an impedance matching network.

Hi Jim;

In addition to a response, you might look
at the following information at the bottom
======================================

The GP300 / P110 Radio was built on a
fairly good design with some " incorperated"
design flaws so techs could make some monies
fixing them. ( thats part of marketing )

The GP300, P110 is still a good radio, and
you just might consider a good one to keep
your stock all the same.

As radios get cheaper on price, so does the
performace and reliability.

There is a Major difference in Used Radios
as well...Radios that have only been used
on occassion are many times a better investment in even NEW radios that may be subjected to being returned 2 or 3 times a year ( even under warrantee )

Depending on your pocket book, will manytimes
guide what you will spend, but know this, you
get what you pay for. One of my Racecar Teams
Esau Racing spends 100,000.00+ on a car, and
does not buy cheap radios for thier team

Shorting the Communications expense could be
costly under a yellow flag condition and the
driver is not able to commuicate with the Pit
or the Observers in the stands.

Kiss off a 100,000.00 Car because of poor
commuications? ( It only takes one time )

Also, anytime I see a 3 Pin Stereo type Plug,
it gets cut off and replaced with a KING Plug
and Jack, and I only use the BEST cable possible. Some of this cable is used in the
David Clark Head-Sets and adaptors.

Fortunitely, I have never had a Cable Failure
logged to date. They may cost a few bucks more, but I also have another team that uses
MX Radios, and even today will not part with
them. They were purchased Brand New, and Only
used at the tracks, and well, they even surprise me...

Anyhow, in general, all of these radios will
probably ( and I have my fingers crossed ) will do OK for you...But finding a good quality radio is truly becomming harder to
find every year.....I guess that is a reason
Saber Radios are so popular among the die hards..Its hard to find the quality of a
3000.00-4000.00 radio for the price of 200.00-300.00.

One can find Brand New FRS radios for 100.00, but quality?? Forget it. Spend
300.00 More, and one can find a Saber.

Building Cables is a " Art " and well, some
use good parts, some are using garbage..So
be forwarned....

As far as some matching networks being
employed, well, I am sure who ever assembled
the system had a reason. It was probably done
to make the audio sound clear, and perhaps to
be compatable with another Drivers Helmet.


<b>Probably will get into trouble here, but
many inquires have prompted the issue.

1. The External Mike Cords are made in China
and are made up of 20+ strands of .002 dia copper wire enclosed in a cheap poly-
vinyl coating

When persons make accessory items, soldering
to these small wires ( even twisted ) can
break very easy. Hence the importance of a
interface box when/if external devices are
used.

2. The External Jack is another focal point
of problems. Many times if debris enters in
the Jack Housing it can contaminate the sensitive contacts, and cause deteriorations
of the small ( white ) spongy supports. These
supports loose their capacity to allow the contacts to apply pressure on the supports, and they too deteriorate over a period of time even if not used often.

3. Also, the External Mic wires " Break " inside where the Cable supports are located
both at the plug, and Jack/

4. Exposing the Cables to Extream Cold or Heat will accelerate the process

IT IS VERY important that when the external
jack is not in use, the rubber cap be firmly
in place. If it has been removed, get a replacement

To replace these components from a component
price stand-point is cheap, the labor on the
other hand is a different ( and can be ) expensive issue.</b>

Monty
<img src="http://www2.4dcomm.com/metrotech/pl_jk.jpg">



<font size=-1>[ This Message was edited by: [email protected] on 2002-02-03 01:55 ]</font>

I'd love to switch over to a REAL headphone plug, but with Formula racing you may have 5 different drivers in one car each season and they all have the common 1/4" plug on their helmets so they can jump in any car. One local shop "rents" their Formula Continental car on a weekly basis- if you have the twenty grand and insurance, you can race the weekend!
If you have a team with strictly one driver, I'd definitely upgrade. Once #84 gets back from the Daytona 500, I'm changing the 1/4" over to something better. What I like is that all of these companies market their car harness as "with MIL SPEC connectors" and they have an OEM GP300 speakermic connector and the 1/4" stereo jack. I guess since it has a good connector on the PTT button, that makes it a MIL SPEC harness?

As for the radio plug on the GP300, what do you recommend since the "Chinese" one is scrap? Is it better to use two seperate plugs instead ?
I use David Clark cable too and have never experienced a failure. Some of the "Confederate state" based racecar radio specialists use a really shiny and pretty cable, but it's just plain junk and cracks after two years. Only one of these companies uses the impedance network and I still can't tell any difference in audio quality. I prefer direct, as it's compact and you can build a cable neatly with only cable, connectors and shrinktube.

Now that we're on the subject, do you know of a good supplier to purchase molded "earbuds". I'm also looking for a supplier for a decent behind-the-head headset (preferrably with a built-in PTT button). Some of the smaller teams don't want to spend the money for David Clark's product. I know there has to be somebody that makes something decent for around $150.
The guys are getting really tired of being screwed over by the out of state companies.

Email me directly, if you would. I'd like info on some "reconditioned" GP300s if you have them. I'd rather not get anything from eBay or elsewhere.

jim
[email protected]

thanks!

Look at Otto Engineering for both behind the head double muff headsets with inline PTT buttons, as well as molded ear buds (they come in left or right molds; small, medium or large.) They actually make a complete racing harness package, but as with most situations, we found that it was better to buy the parts and custom fabricate the harness, and wire the connectors and steering wheel PTT button. We're Otto dealers and can help with their products if you need.

We've had success with the 4 pole Nexus connectors. I was under the impression this was a fairly common connector in the racing world (at least in SCCA and IMSA). Since the one team we sponsor is a closed wheel car, we installed an SM120: It's been going strong for 5 years now, as has the Nexus connectors.

Most of the SCCA crowd uses the 3-pin. IMSA and most NASCAR and some GT1 use the 4 pin.
There's really no rule for who uses what, buy each sanctioning body seems to stick with the same within.

CT250/450 radios do NOT use the GP350
style connector. The CT250 I have in
my hand right now uses two-plug GP300
style accessories. Period.

If anyone here has a CT250 with a
GP350 side connector on it, I'd pay
money to see it.

Tony

Jim,

I manage the radio equipment for a stock car team and we have had no problems with the 1225s in the car we have two in the car with a switch to change radios with out changing the harnes. our two radios are in seperate compartments in a radio box mounted to the roll bar near the driver. each compartment has a foam insert that fits snugly on the radio and in the compartment giving it about .5" padding all the way around. We race on a short track series where there is a lot of bumping and rubbing during the race and we've been using the same two 1225s for the last 2 years with no problems.

I need some help with programming a gp300 and have some experience in protecting the radio's...email me and maybe we can swap notes. [email protected]

I have found a better connector for the 1/4 inch three conductor jack. Neutrik NJ3F6 series locking and they have a non locking one too. Neutrik makes pro audio connectors for XLR ect;

I have two 16 channel GP300's that I want to use in my race car. Being a low bucks operation I don't want to layout $500+ for a car harness & antenna if I can put it together myself. Any and all ideas, schematics, leads appreciated. I'm located in Westchester NY.

DJM

Tony Soprano wrote:You shouldn't need an adaptor, GP300
accy's work anyway.
Tony

Hey goomba - where you been?
Haven't seen you here for a while - how's the espresso?

I need to build a harness for a GP350 radio right now. I remember using a transformer for the mic, which I have found in here in the hardware archives (PICO-A1025 M27/174-01), but I can't find a schematic for the harness itself and i've slept many moons since. Anyone have a clue on how to wire this up?


BTW, we use the UHF HT1000 for the racecar all the time (the GP350 loom is for a vintage piece). Much easier to build. Just one capacitor in the audio side. the connector for the helmet is a Nexus, mics are Gentex. Other than having to use MRSS and lug around a slug PC just for programming them, they make for a pretty bulletproof setup. Been using them since switching from GP300s about 9 years ago.


Thanks in advance