Jump to content

RF-Static discharge.....Vehicles?


johngooch

Recommended Posts

Ok, here is the situation and i am a little confused.  I have heard

this problem before but on a recent job it was magnified a great

deal.

I had five characters in the back seats of 12 passenger van.  The

characters were wired with a variety of Lecto UM-400, SM and SMD

transmitters-Sanken COS-11.  Blk 26 and blk 27. I was recording to

PD-606 loaded up with Lectro-411As.  Recorder powered by internal

batts and the 411s powered by BDS system.  Shotgun, CS-3e.  All good

solid canare star quad cable.  Nothing exotic here.  I heard it before  on a different job

driving slower with less characters and recording to my PD-6.

I was hearing loud pops in my audio that were in time with hitting

potholes in the road as we drove.  These increased with

speed(65-70mph).  All audio was affected including and especially my

boom.  No amount of moving the recorder boom or my cabling changed

anything.

My theory(Hi Larry!), The seats in these vans are not well equipped

with much padding and shoddy springs.  I am guessing the springs

create a static discharge that is released with every pothole.  The

boom was much worse and was more of a constant-pothole or not.  I am

guessing that also combined with bad contacts on the distributor

cap(ford econoline style van), that is what caused some of my problem?

It was a pretty humid day if that is factor.  I do not know the dew

point or the moon phase:)

In past jobs(in the VHF Vega Dynex days)  where i had to wire actors

who had to interact on a bed, i have heard horrible discharges. So hot

that they bled into adjacent audio channels.  That was the only time i

have heard it outside of a vehicle.

Thanks!

John Gooch.

Link to comment
Share on other sites

My only understanding of vehicle mechanics is that with todays electronic ignition systems is that they put off quite a bit of electromagnetic interference.  Spark plugs with resistors in them are the only way to solve it. 

That being said, I have had issues with static interference with my Lectro 211's in some vans where stepping on the gas would caus it as the RPMS on the engine raised.  I think it has to do with a bad alternator ground.  I'm wondering if this is being magnified through the vans seats like you mentioned and being transfered to the transmitters.  My only thought for a solution at the moment is anti-static material on the seats to see if it goes away. 

Just a guess !

Link to comment
Share on other sites

My only understanding of vehicle mechanics is that with todays electronic ignition systems is that they put off quite a bit of electromagnetic interference.  Spark plugs with resistors in them are the only way to solve it. 

That being said, I have had issues with static interference with my Lectro 211's in some vans where stepping on the gas would caus it as the RPMS on the engine raised.  I think it has to do with a bad alternator ground.  I'm wondering if this is being magnified through the vans seats like you mentioned and being transfered to the transmitters.  My only thought for a solution at the moment is anti-static material on the seats to see if it goes away. 

Just a guess !

It's not the seats or the springs. It's from the ignition/electrical system in the van.

Eric

Link to comment
Share on other sites

Thanks for your replies.  If it has to do with ignition/electrical system, why is the problem amplified by hitting potholes and physical shock.  I honestly think it has to do with the combination of problems.  The electrical system combined with some sort of static discharge.  I have heard this before when i wired talent in a bead.  But really, i am still just guessing what the problem is and i still welcome all theories!

john

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...