Codan and car acceleration

[Samo84]

Hello

I have codan NGT SRx installed in my car, I found that while using 9KHZ frequency and specifically when calling another station, while this call and while the car is moving , the car acceleration goes down ( RPM goes to 0 ) and the car stopped responding to speed pedal !


while using another frequency, like 5K or 11K there is no issues !

Can anyone help me please ?

Thanks,

 

[ridgescan]

Sounds like you have the newfangled "drive-by-wire" cable-less throttle system, and it operates on some harmonic of that HF frequency. Probably nothing you can do about that. Thank God it doesn't cause sudden acceleration! I'd post this at Eham too.
By the way MODS this should be in the Amateur Radio forum for better replies.

 

[Samo84]

It is really strange as I have the same system on other cars and they work well, why this car!
strange I can not do anything in regards?

Thanks

 

[prcguy]

I would try a dummy load at the end of the antenna cable to see if the car still has a problem. If the car runs ok with a load in place of the antenna that leaves radiation from the antenna or common mode RF current on the antenna cable getting into the vehicle computer as the problem.

I had a similar problem in a Toyota but only when running 500 watts and it was a combination of RF on the amplifier power cables and antenna cable. The vehicle engine would almost die when I transmitted.

I placed RF chokes on the coaxial cable leading to the antenna and that made things better. I found if I placed a second battery (100AH gel cell) right at the amplifier it finally fixed all the problems at high power. I then found the battery was probably bypassing a lot of RF being a low impedance load across the amplifier power cables and tried some big capacitors in place of the battery.

My final solution was replacing the extra 100AH battery with a 15 Farad 16V capacitor right at the 500w amplifier power input. This bypassed a lot of RF getting into the vehicle DC power system and also smoothed out the voltage to the amp during SSB peaks.

You might also make sure the antenna is well grounded. If not the coax can become part of the antenna and radiate, which will get more RF into the vehicle electrical system and computer.
prcguy

 

[Samo84]

Thanks prcguy,

Well I did some tests and found the below:
when removing the tuner cable from the codan whip antenna, the call s ok and I could use the HF system as well, but when I plugged it again, along with the antenna cable it did not work on 9KHZ only,

do you think we can do something regarding the tuner cable ?

Thanks ,

 

[prcguy]

I am not familiar with your specific Codan antenna tuner but the cable must provide power to the tuner and that can also allow RF to get into the vehicle electrical system and engine computer.

If you can find a large ferrite ring as in this picture and wrap some of the tuner cable around it you should fix the problem. http://palomar-engineers.com/wp-content/uploads/20131222_125533.jpg

I would also do the same for the antenna coaxial cable. There are different types of ferrite and I know type 43 works well for making an HF choke and type 31 is also good for the lower HF range. When you mention 5KHz, 9KHz and 11KHz I am assuming you mean 5MHz, 9MHz and 11MHz in the HF band.
prcguy