Radio reception

I have a lot of static on FM that should not be there. I replaced the antenna stub a few years ago, making it better. Is there an electrical test for this, so i don't needlessly buy another antenna stub? Anybody test their antenna?

Replaced antenna mast or base? If the base wasn't OEM VW, it may already be bad- or if water was allowed to enter. There are some tests you can do via VCDS, and also some via the head unit alone.

Watching!

I had very poor reception for a few years then when FM had almost no reception I started checking it.
I took the antenna off the base and tried a long (3 FT (US) wire in the stud on the base.
Better, but not acceptable.
I pulled the headliner down enough to get the antenna wire off the base and hooked the wire to the cable going to the radio.
It was much better reception and I did tape the wire to the roof for a while.
It was 1 wire from a network patch cable.
I removed the antenna base and opened it, components fell off the board inside, lots of corrosion.
I put a inexpensive antenna booster above the headliner, grounded to the antenna wire, tapped power from the light up there.
Worked great again.
Finally got a new looking base off a totaled VW going to the junk yard.
Radio worked again.
Removed the amp.
Got a power injector from Crutchfield when I replaced the VW radio.

vwdsmguy said:

I have a lot of static on FM that should not be there. I replaced the antenna stub a few years ago, making it better. Is there an electrical test for this, so i don't needlessly buy another antenna stub? Anybody test their antenna?

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OE or aftermarket head unit?

If aftermarket, was a powered coax antenna adapter (i.e., w/ a blue 12V+ wire) used when installed?

If OE, a "FERN ON/OFF" test can be performed from the head unit that checks whether the antenna base amp is functional. Access procedure for the test varies with model of head unit.

Pretty much most bases fail after a while. You can actually just r+r by getting rid of the board wiring straight to the antennae. Someone wrote a nice thread.
I just bought a new base.

I broke down and bought an OEM base for the wife's car not too long ago. Aftermarket HU which I didn't feel was getting decent enough reception (felt it worse than with my stock one- and I have a stupid stubby antenna even!). At first she seemed to state that it was better, but later on it seems like it really wasn't any better. Looking back at this install I cannot recall what I'd done vis a vis the power wire: I know that I went with a powered base (very confusing).

Have to wonder whether the circuitry in the base even really does anything. If one removes the board and wires directly I'm wondering whether that means that one disconnect the blue wire hookup from the HU. (thanks, Bob, for mentioning this- in all the research that I'd done on trying to improve reception I hadn't run across anyone mentioning this)

I broke down and finally bought a new aftermarket HU for my car- couldn't wait to figure if I was going to doom myself to worse reception or not. I'm going to try and do some checks when I have everything apart.

I just finished the installation of a new HU (JVC KW-V830BT) in my car and while I was testing I discovered that the FM reception wasn't all that great. I yanked the stubby antenna mast off and put on a stock mast and reception improved dramatically. I realize that a stubby is not a good idea, but changing it out previously had little impact.

The stock mast that I installed was off a parts car that I'd had, the vintage of that mast is unknown. I know that masts do a lot of flexing which breaks them down; so, one should keep this in mind.

My final verdict will be in when I have my wife assess reception on her commute.

Did you get a power injector for the amplified base?
I got one from Crutchfield.
I plugs into the radio antenna hole & the cable going to the antenna. Tapped power from the feed to the radio that is hot in run, but not when cranking.
With what looked like a fairly new base and tiny stub antenna off a wrecked VW I had fair reception.
I used my original longer 6 inch antenna on the newer base and the reception is satisfactory.

No, the instructions from Crutchfield said to NOT use that power wire. I cannot recall whether I'd hooked it up in the wife's car or not. At this point I seem to feel that reception is better in my car than the stock HU and with the setup in the wife's car. In the name of science I think I'll see if I can get my wife to drive my to/back from work and let me know what she thinks: problem is is that if it's a lot better then I know I'll be tearing into HER car!

The antenna base on my car is, I believe, a cheapie (I think I might have gotten it from FixMyVW.com). The one in the wife's car, and the antenna mast, is OEM right from VW: when something starts messing with me I go directly with OEM to help reduce chasing my tail. What is hard to measure, however, is how each HU's FM tuner compares. The Jensen VX7220 in her car is fairly decent, had a nice FM sensitivity number (some units, even higher end ones, have really crappy numbers). This JVC is rated 9.3db: odd in that its predecessor was rated something like 7.3db!

UhOh said:

No, the instructions from Crutchfield said to NOT use that power wire. I cannot recall whether I'd hooked it up in the wife's car or not.

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If this is the adapter you're talking about, you definitely do need to connect the power wire if you're using an aftermarket HU with an OE amplified antenna. Crutchfield might have said no power wire connection necessary if using an OE HU or a non-amplified antenna or both. Not connecting the power wire defeats the purpose of this "combiner adaptor", i.e., it combines 12V+ with the RF signal in the coax cable to power the antenna amp. OE HUs supply and combine the 12V+ at the antenna output jack.

Slightly different, but somewhat the same.

I DO see the following on that page (seems that the info that I have said not to- I'll double-check):

When installing the adapter, the blue wire should be connected to the antenna turn-on lead of your new car stereo. Please check the stereo's manual for more information.

All I can say is that the reception seems to be good.

UhOh said:

Slightly different, but somewhat the same.

I DO see the following on that page (seems that the info that I have said not to- I'll double-check):

When installing the adapter, the blue wire should be connected to the antenna turn-on lead of your new car stereo. Please check the stereo's manual for more information.

All I can say is that the reception seems to be good.

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That looks like the adapter I got.
Maybe hook up the power lead and drive it a few days to see what happens.

You know, I'm really not wanting to yank out that HU. The bezel snaps in more snuggly than a gator chomping down on a pelican! (same bezel is in the wife's car too)

Won't be until next week that I'll be able to do some closer evaluation (look to have my wife drive my car). I'd like to be able to have all three cars available at the same time- I could evaluate them all at one time, in the driveway.

Had the wife drive my car. Reception really isn't any better than in her car (for the areas she travels; I seem to sense that it's better in the areas that I drive).

So, I did not hook up the power lead to the antenna wire in my car. I'm pretty sure that I did this in the wife's, but I cannot recall for sure. One day I'll pop out the HU in her car and see. Will report back (though it's likely going to be a couple months or so from now- I have no time for anything other than urgent matters).

My stock radio has poor FM reception, and almost no AM at all. Is this a sign of a failed RF amp?

robm2 said:

My stock radio has poor FM reception, and almost no AM at all. Is this a sign of a failed RF amp?

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Probably the antenna base.
To check I pulled the back headliner down, unplugged the antenna lead and attached about 6 ft (US) of thin wire (1 wire from an old network cable) to it.
Ran it out the back above the hatch and forward.
Bit of Duck Tape to hold it down.
Radio was much better.
Messed with a different antenna (above the base) and no help.
Took the base apart and components fell out from the circuit board.
Finally got a used base that looked very new (compared to the car it came off of) and the radio was all right again.