Batboard

M returned the radios today, in nice brand new boxes, same serial #'s but different radios, no explanation except that they could not be repaired, These work just fine when installed, no extra work, so guess what it must have been defective. Well I guess I will glue my hair back in. LOL

Well off to California on Sunday, going I-40 to Little Rock, then I-30 to Ft. Worth, I-20 to I-10 then to LA, anyone along the way that might want to meet for coffee?

Stan

That was a wild ride ! Thanks for posting the outcome.

where are you moving to in LA ?


Dan....

Lakewood

Just got mine back in today except they sent me new radios with new serial#s

I wish they would have given an exp. I would love to know what they screwed up this time at M

Have a safe trip to Cali.

Vince

...and you didn't even have to change alternators!!!

Sorry, I just had to say that, Alligator!

I am glad to hear that problem is resolved!
I would venture to guess that the radio was leaking RF back out the main power cable on transmit that was getting radiated into the cars electronics and causing the alternator to look bad.
Just a guess guys!

Hello.

This seems to be a problem.

I figured there was a problem with the install, we went with older micors because of this problem, never tried to go further.
Maratracs are not TSOed, thus, I cannot say much about the strange things that happened to the avionics, I simply went with what works.
The aircraft in question 2 hughes/switser 500s and 2 bell 204bs had real issues.
Ground support now runs micors, the idea is to run one kind of radio in everything.
The maratrac was sold at a loss, but just one.

I agree with Will.

Another possibility is that RF was present on the cable between the control head and the suitcase and radiating into a factory harness it is near.

On 2001-11-29 15:55, Will wrote:
I am glad to hear that problem is resolved!
I would venture to guess that the radio was leaking RF back out the main power cable on transmit that was getting radiated into the cars electronics and causing the alternator to look bad.
Just a guess guys!

Good theory, but if you'll recall, USPSS installed the Maratrac in another vehicle, and when transmitting alongside the Crown Vics, the alternator in the Crown Vic still screwed up, not the vehicle the radio was actually in, so that couldn't have been it. We may never know, cause Motorola ain't telling.

Todd

Hello all, just a note on this, a local county that is also on UHF installed 11 new maratracs into a bunch of park maint. vehicles, no problem there but at the repair shop they were also working on crown vics, all of a sudden the mechanics working on the vics had belts flying off in their faces, like 3 CV's, they could not figure it out, these cars were about 300 ft away byt they were tuning the engines so they were running when the maratracs were getting final install. I told them about my problem and they said yeah right. Well they started the crown vic and every other vehicle in the shop and keyed a maratrac, 6 belts at the same time, froze the alternators during the key and took out the belts, many different ford vehicles but all 2000 and 2001. These maratracs came from the same shipment as my original ones. WOW Motorola has a problem. Now I think I might ask for some new belts LOL

With all that in mind, I wonder if the "smart" regulator in the new Ford has a clock circuit, like many comuters, in it's electronics. Now....if this is the case and it's clock speed (frequency) is the same as some reference oscillator frequency in the Maratrac and it this freq. was radiating from the Maratrac on the feedline........................

just a thought

If anyone has a 00-01 Vic and a lowband Maratrac with the problem, why don't you put your spectrum analyzer on the RF output and see if there's anyhthing other than the desired frequency there? Try the power lines too. Try the control head cable??

On 2001-11-30 09:34, USPSS wrote:
Hello all, just a note on this, a local county that is also on UHF installed 11 new maratracs into a bunch of park maint. vehicles, no problem there but at the repair shop they were also working on crown vics, all of a sudden the mechanics working on the vics had belts flying off in their faces, like 3 CV's, they could not figure it out, these cars were about 300 ft away byt they were tuning the engines so they were running when the maratracs were getting final install. I told them about my problem and they said yeah right. Well they started the crown vic and every other vehicle in the shop and keyed a maratrac, 6 belts at the same time, froze the alternators during the key and took out the belts, many different ford vehicles but all 2000 and 2001. These maratracs came from the same shipment as my original ones. WOW Motorola has a problem. Now I think I might ask for some new belts LOL

freezing an alternator is no easy task...
think about it - you have bearings and a
shaft spinning - what is acting has the
brake to suddenly sieze them up ?

the only possible scenario is for the field
windings to suddenly toggle polarity to the
point where it becomes the brake to stop
the rotation of the core....

interesting problem....

On 2001-11-29 21:45, Cowthief wrote:
Hello.

This seems to be a problem.

I figured there was a problem with the install, we went with older micors because of this problem, never tried to go further.
Maratracs are not TSOed, thus, I cannot say much about the strange things that happened to the avionics, I simply went with what works.
The aircraft in question 2 hughes/switser 500s and 2 bell 204bs had real issues.
Ground support now runs micors, the idea is to run one kind of radio in everything.
The maratrac was sold at a loss, but just one.

WHOA !! hold up - you're installing non
TSO'd equipment in helo's ? And the A&P
guy allowed this to occur ? If this happened
in my operation, heads would roll !

This is a SERIOUS safety issue, I don't
have my FAR's in front, but I'm 100% certain
the cavalier installation of "add on" radio
equipment that is not TSO'd or otherwise
approved is against all the regs that are
in the book.

I've seen instances were defective digital
engine controls when hit with high RF go
berserk and literally destroy the engine
by overtemping the turbine section, or over
revving it to the redline - and that's a 6
figure repair right off the bat !

You would be wise to check if any waivers
are in effect, and thoroughly document all
relevant paperwork.

A multimillion dollar helo is no crown
vic !

That's exactly it. Something is making the digi-reg command the field to a 100% duty cycle. Throwing or breaking the belt- this shows just how much one of these alternators can generate without proper control. An average serpentine belt can transfer 20 horsepower easily with no slippage. If you are throwing a belt, imagine how much energy is being converted (mechanically, as heat ....and electrically). 746 watts= 1 HP (average law)
operating voltage at load- 13.4-13.8 VDC
160 amps X 13.6v = 2176 watts available.
2176 / 746 = 2.92 X 1.3 = 3.796 HP to generate the full 160 amps it can produce.
The 1.3 is a given average frictional loss number commonly used that compensates friction of bearing, brushes and belt.

If it only takes 4 HP to run this alternator at full load and a serp. belt will transfer 20 HP efficiently, what in the hell is going on inside of this alternator?

Most American built alternators will produce 120-140 volts AC (before the rectifier) if you supply the field with full unlimited current. If the regulator were to go to 100%, the output of the stator may be in this range and be exceeding the PIV rating of the cheap rectifier diodes, causing the current produced to go straight to ground. If this IS the case, I know what it will do- smoke a belt.

I'd really like to see this one myself. I've run into may quirks with these alternators, but never anything like this. Most are tied to the operation of the LCM. I can think of several things, but I just gotta see it!

It would be interested in reading operating system voltage at the #6 black/orange wire on the alternator to ground when this "unknown" happens.

End of math and physics class!

Hello.

Yes, the install of non TSOed radios is legal, however this must be documented.
This is most common in aircraft run by police or the media, scanners, TV transmitters, that sort of thing, not connected to the audio panel, not directly connected to the DC bus.
I have never seen a trunked radio that is TSOed, Moto', GE, or LMR.

This is lowband, and the testing is very extensive, everything is noted, if there is a hint of a problem, this is resolved, to the point that we require testing to be done if someone wants to bring a digital camera on board, laptops are normally prohibited.

Thank You.

Hi:

I too am still interested in this problem !!

I mentioned a few times to use a proper
Spectrum Analizer ( and not one from a IFR1200 as they do NOT have the resolution or
the dynamic range compared to a Tek 492 ect.

With a good RF Spectrum Analizer one should
be able to find the appropriate problem wether it be from the Radiation of the Antenna or leakage through the Control / or DC cable.

NOT to say the RF Anaizers are worthless in
most Service Monitors, but they truly have
limited dynamic range in order to address
a problem of this nature.

Spectum Displays in Service Monitors lack the
capabilities of Wide Sweeps with detail resolution. A small problem ( or spur ) @ -120db could not be seen by a average Service
Monitor, but could easily be seen by a other electronic device and not been seen by a service monitor

If Anyone out there has a Maratrac that has
this problem, I would like to examine the radio in question for a short time.

Perhaps I will have a oppertunity to see this
problem on a hands on basis.

There should be a ( SRN ) Service Report Notice made on this issue since it involves
a Saftey Issue on Emergency vehicals.

Monty

<font size=-1>[ This Message was edited by: [email protected] on 2001-12-02 15:22 ]</font>

I seem to agree with cowthief on the issue of a commercial non-TSO aircraft radio install. I believe the process would involve an FAA STC(Supplemental Type Certification) for the aircraft and that in itself is quite an exhaustive application and test procedure.

A visit to the FAA website and looking at the application for such did mention the susceptability of Electronic Engine Controls to RF so this apparently is commonplace.

As an A/P, FCC Licensed Technician working on commercial aircraft avionics installs for over 14 years it still amazes me that RF can get into the avionics and cause havoc. The degree to which everything is done is very precise and even AC circuits have different grounding points than DC circuits. Bonding of components typically is measured down to the 1 milliohm range! Shielded and twisted pair wiring is the norm. As more and more aircraft rely on electronic instead of mechanical controls this will certainly, I feel, present more problems of this type.

That new police weapon which puts out an EMP pulse and stops a car dead in it's tracks shows what an electronic RF overload, if focused and strong enough, can do to electronics.

Eddie
N4UMJ