mizzotch
04-03-2007, 10:55 PM
Hi guys,
I just finished up doing a HAM HF mobile install in a friend's 07 Explorer XLT w/ V8. The setup consists of: Icom IC-7000, Tarheel antenna mounted to the roof rack using a custom bracket and a Turbo Tuner.
Grounding- I did LOTS of it using 5/8" width tinned braid.
-1 strap from radio chassis to front seat bolt
-2 straps on hood hinges (1 on each side)
-1 strap on each of the four side doors
-1 strap from engine (dipstick tube bolt) to fender ground point
The antenna feed is actually an NMO mount which is grounded to the roof by design. From the mount there is a about a 1 foot coax jumper going from NMO mount to Tarheel.
The antenna and tuner works like butta- it tunes up very quickly and I have verified the SWR with an antenna analyzer.
The noise is almost certainly radiated noise from the coil-on-plug (COP) ignition system. There was no difference in noise strength when I used an external power source to run the radio. Ironically, the noise is strongest on the 20M band (a solid S8 signal). As you go down to 40M and below, the noise is far less and non-existent by the time you get to the AM broadcast band. As you go up to 15 M and 18M, the noise is still pretty strong but it's almost dissapeared by 10M. Also, as the antenna tunes onto freq. the noise gets stronger- it's obviously the antenna which is picking it up.
The cure- I really have no clue what would be the definitive cure. Since the COP ignition is a relatively new design, most of the advice for curing ignition noise is not applicable.
Just for an experiment, I covered one bank of the COP coils with aluminum foil and used clip leads to ground the foil to the stock ground strap- needless to say, it didn't work.
The only other things I can really think of is possibly using ferrite beads or capacitors on the wires going to the COP coils.
Does anyone have any real-world experience (or can think of something I haven't tried) with eliminating the COP noise for an HF mobile install?
I just finished up doing a HAM HF mobile install in a friend's 07 Explorer XLT w/ V8. The setup consists of: Icom IC-7000, Tarheel antenna mounted to the roof rack using a custom bracket and a Turbo Tuner.
Grounding- I did LOTS of it using 5/8" width tinned braid.
-1 strap from radio chassis to front seat bolt
-2 straps on hood hinges (1 on each side)
-1 strap on each of the four side doors
-1 strap from engine (dipstick tube bolt) to fender ground point
The antenna feed is actually an NMO mount which is grounded to the roof by design. From the mount there is a about a 1 foot coax jumper going from NMO mount to Tarheel.
The antenna and tuner works like butta- it tunes up very quickly and I have verified the SWR with an antenna analyzer.
The noise is almost certainly radiated noise from the coil-on-plug (COP) ignition system. There was no difference in noise strength when I used an external power source to run the radio. Ironically, the noise is strongest on the 20M band (a solid S8 signal). As you go down to 40M and below, the noise is far less and non-existent by the time you get to the AM broadcast band. As you go up to 15 M and 18M, the noise is still pretty strong but it's almost dissapeared by 10M. Also, as the antenna tunes onto freq. the noise gets stronger- it's obviously the antenna which is picking it up.
The cure- I really have no clue what would be the definitive cure. Since the COP ignition is a relatively new design, most of the advice for curing ignition noise is not applicable.
Just for an experiment, I covered one bank of the COP coils with aluminum foil and used clip leads to ground the foil to the stock ground strap- needless to say, it didn't work.
The only other things I can really think of is possibly using ferrite beads or capacitors on the wires going to the COP coils.
Does anyone have any real-world experience (or can think of something I haven't tried) with eliminating the COP noise for an HF mobile install?