Jensen Radio Antenna Upgrade

RCB

Has anyone changed the antenna in a 400? If so to what and did you experience noticeable improvement in fm reception ? Thanks.

Verna

There have been a few 320 owners who changed their antennas. Try a search for “fm antenna” or maybe just antenna. 

MuttonChops

RCB said:

Has anyone changed the antenna in a 400? If so to what and did you experience noticeable improvement in fm reception ? Thanks.

I carry an extra 16-inch antenna that is used when too few radio stations come in.  I don't like how it looks so don't leave it installed all the time + the 16 inch  would be damaged by my winter T@B cover.

This is the antenna

https://www.amazon.com/gp/product/B07JQ9WFHY/ref=ppx_yo_dt_b_asin_title_o04_s00?ie=UTF8&psc=1

Have limited data on how well it helps.  At today's camp site;
== the standard antenna could pick-up 1-FM and 0-AM stations
==16 inch antenna gets 3-FM and 1-AM station.
== However, only station I can manage to listen to, based on music content,
    is the standard antenna station . . .

BrianZ

I recently tried to replace our radio antenna with a slightly different longer one, but it made no difference at all.  Then I found this one which can be connected inside

It plugs into a female antenna port.  There are two such ports that I know of - the one at the back of the radio (or top left actually), and I found one inside the pump access door behind the toilet at right, into which the outside antenna cable was plugged.
So, I got one of these Y-connectors..

..so I could add the new inside antenna while leaving the outside one connected..

I ran the new antenna cable into this same compartment & put all the cables back inside the wall.  I used a stiff wire to feed the new antenna cable inside the wall behind the TV, down below the driver side bench seat, then under the shower & into the pump compartment..

Not shown above is the fish wire, but this shows that the connector will fit through the TV's cable opening, so this is where I started.  From here, the antenna end of the cable has a few feet of length left, which can allow it's position to be changed to fit the local situation. (like fiddling with the old rabbit ear antennas).
  
In any case, this made a huge difference in our FM radio reception, allowing many more stations than we were getting before.  I should note that our radio reception had gotten worse, and I suspect that something at the outside antenna mount may have changed or weakened the signal.  In any case, the difference is huge right now while parked in our driveway.  It remains to be field tested on our next trip.
Here's where I stuck the new antenna for now..

I can't say whether this one will work for you too, but it might be worth a try.
The Y-connector could also be located behind the unit itself, if you want to route it some other way for a different location.

BrianZ

Update to my last message:

On the other hand, on a different day & parked at a slightly different angle, reception wasn't quite as good as my first try reported above.  Also, I  noticed that when I  stood directly in front of the unit, with one hand close to the front of it where all the controls are, even without touching it, the reception for my favorite station improved very noticeably.  If I moved to the side or removed my hand, some static returned.  Go figure!  Not sure if anything changed after our last trip, so will double check connections.  Otherwise, a powered antenna on the roof may be my next experiment.

BrianZ

Our Next Antenna..
Jensen Marine AN150SR AM/FM Amplified Antenna 

I recently read these words of wisdom:
"YOU are an antenna! If you improve reception by standing near or touching the radio or antenna, your system is telling you it needs a better antenna."  As I recognized this was exactly our situation, it also seemed to validate what I already believed. 

So, I've been doing a lot of reading about antennas in my quest to improve the FM radio reception for our Jensen AWM968 unit. I've learned a lot and realized that this is a very complex issue that is highly dependent on the local situation (distance, terrain, interference, etc), including the antenna.  Or, I should say "antennas", because your radio antenna needs to pair well with the broadcasting station's antenna when it comes to orienting your antenna for optimum reception.  While there may be pros & cons to either a vertical or horizontally positioned antenna, most FM stations can accommodate both by using a circularly polarized radio signal.  (You can look up a station's FCC license & find out which kind of signal polarization they use).

Despite the possible limitations, when it comes to improving your FM radio antenna reception there are a couple of common themes that emerge..
1.  An outside location is better than indoors.
2.  A higher location is better.
With these principles in mind, I figured the ideal location should be somewhere on the T@B's roof.

Since I have previously had success with amplified tv antennas, I figured it may be worth trying an amplified FM radio antenna, and I found that Jensen makes one for marine use.  And our T@B is much like a boat when it comes to water exposure, vibration,  fiberglass construction, mobility, etc.  Using the radio manufacturer's own antenna ought to be an advantage when it comes to performance, so I got this one..

Jensen Marine AN150SR AM/FM Amplified Antenna https://www.amazon.com/dp/B000FOUWNQ

And following the principle of "outside & higher is better", I chose to mount it on top of the roof vent, (after temporarily removing our AeroFlow vent cover).  I mounted it horizontally, as recommended, but along one side of the roof vent, where the tilt angle could be changed if needed..

It comes with pre-applied double stick foam tape under the center & at each end, so mounting was just a matter of cleaning the surface with alcohol.  Wiring was the bigger challenge, but not terribly difficult.  As you can see, besides the 7ft coax cable, there is also a ground wire at the antenna end, plus a 12V power line at the connector end.  I had to extend all three to wire it up.  Here are the mounting instructions..

I then replaced our vent cover, and ran the wires down into the trailer through the A/C vent..


Below shows how I routed the wires through the A/C cabinet - had to cut a notch in the wood above the fan (top arrow), then fish them down through the wall following the same route as the A/C power cable to the converter area under the bench seat.

The cables weren't long enough & ended inside the wall, so I added a white extension to the black ground wire, plus the following extension for the antenna cable..

Stereo FM AM Radio Antenna Extension Cable 10 feet / 3m Motorola DIN Plug Connector Coaxial Cable for Vehicle Truck Car Audio Stereo Head Unit CD Media Receiver Player https://www.amazon.com/dp/B07T7VP5YS

Below shows the black antenna extension & red power line (which I also extended)  that I routed forward under the bathroom floor, behind the toilet, & through the wall into the Jensen stereo cabinet (where power line is controlled by an on/off switch - see here for that wiriing: https://tabforum.nucamprv.com/#/discussion/comment/122847).  The white ground wire is connected to the ground bus bar on the floor.  So, there were three spaces where I had to use a stiff wire to fish cables through the walls.

Finally, I put the wires inside a 3/8x1" plastic surface-mount conduit (below), which I  stuck to the roof with 3M heavy duty outdoor double stick tape, and wedged it against the two roof vents to resist the wind when traveling.

The conduit has a top & bottom that snap together & it has a very low profile..
https://www.lowes.com/pd/Wiremold-Non-Metallic-60-in-L-White-Raceway/3129263

Was it worth the effort?  I believe so, yes!
We are now getting more FM stations than ever before, and a stronger signal without static and which doesn't fade in & out when you move around inside the trailer.  AM radio is another story, and not one I care about anyway.

I tested disconnecting the power lead to the antenna, and there was an immediate & significant deterioration in signal strength of a previously tuned station with a strong signal.  So that tells me the powered antenna is making a real difference, even though it only uses 6 milliamps (72 milliwatts or less than a tenth of a watt) of power.

What I also found interesting was that the ability to tilt the antenna by cranking the roof vent up or down can actually be a very useful feature in certain situations.  I knew that a horizontally mounted antenna might theoretically have poor reception if the antenna's long axis is pointing directly at the broadcast tower (they work best when the antenna is perpendicular to the direction of the signal).  Vertically mounted antennas don't have this limitation, but have others.

As it turned out, where we have our trailer currently parked next to our driveway, the new antenna was pointed almost directly at my favorite station's tower, and the reception was not good.  However, by cranking the knob on roof vent to open it & tilt the antenna upwards to orient it more perpendicular to the signal direction, I was able to fine tune it for a reliably clear sound.  My wife's favorite station, also about 10 miles away but at the ideal 90 degrees in another direction, came in perfectly clear & tilting made no difference (because it's still perpendicular at any tilt).

I don't think this limited sucessful antenna testing in an area with nearby stations (FM radio range is typically up to 40 miles or more) can be extrapolated to the typically more remote locations of most campgrounds in fringe areas of coverage. I do know it's significantly better than it was before at our home location.  I don't know if this Jensen unit will ever be as good as a decent car radio (which I believe are built to higher standards for travel), but I think we may now have a much improved chance of using the radio when possible.  I expect that both distance & terrain will be a challenge at campgrounds here in VA, which are often in remote areas, in river valleys, & between mountains.

Ref:
https://weru.org/listen/improving-your-reception/
(Just a random radio station's tips)

Tundra57

Great write up and analysis.

BrianZ

Thanks, @Tundra57. 
To complement the improved radio reception, I also replaced the stock speakers with a new pair of speakers..
KICKER DSC50 DS Series 5.25" 4-Ohm Coaxial Speaker https://www.amazon.com/dp/B01BLVF3TE
Had to drill 4 new screw holes, but otherwise a direct replacement, and with improved sound quality that offers a cleaner, crisper sound in my opinion.

Tundra57

A man after my own heart lol.