Amplified AM/FM Antenna Wiring

**commodor47** · 11-24-2009, 07:02 PM

Our 2003 2720 SL (purchased from a private party in February, 2004) did not have a radio/CD player installed when purchased. It did have the factory installed Jensen Marine Amplified AM/FM Antenna as well as the necessary wiring terminating in the access area above the refrigerator. A few years back I installed a radio in the pre-cut slot above the refrigerator. The FM reception was poor and often non-existent. We opted to use the CD player exclusively - for several years. A few weeks ago I decided to track down the poor FM reception issue.

[FONT=&quot]Thanks to the help of Mike J. Laupp, III (mjlaupp), Dick Carver, and Moderator Bill, I was able to trace the antenna wiring in an attempt to resolve the poor reception issue. In the process I took several photos of the wiring and have posted them on:

https://photos.google.com/album/AF1Q...hRgSwjm3pFxhUg

The amplified radio antenna is a Jensen Marine AN150SR AM/FM Amplified Antenna. On our TM it is located on the back edge of the upper shell, street-side. Two wires emanate from the antenna head; one is the ground wire and the other the RF cable. The ground wire is attached to a metal strip in the back corner of the upper shell. The RF cable runs down just inside of the bag seal to a wire harness coming out of the bottom of the upper shell and is enclosed in black webbing. The webbing is looped and eventually feeds down the back of the upper shell support arm, inside a rectangular channel. Near the top of the channel, covered by the webbing, is the radio RF cable bullet connector. It is connected to an RF cable extension. The extension cable continues down the channel to a point under the TM where it enters through the floor of the lower refrigerator access area. Many other wires enter or leave the TM in this section. Also located in the channel, about 1/3 of the way down, is the red power wire for the amplified radio antenna. It is joined to another red wire by means of a bullet connector. This connector was heavily corroded and did contribute to my poor reception. I thoroughly cleaned the connector and applied a dab of dielectric grease – and made sure the connection was secure. The result was much improved FM reception. However, there was no red light visible on the antenna head. I did verify 12-volt power is present in the red wire, both below and above the bullet connector.

The Jensen web site troubleshooting guide suggested a bad ground could be one reason the red light fails to come on – and that was the next thing I worked on. The ground wire screw looked corroded and the edges of the closed loop connector had evidence of aluminum oxidation. I removed the screw, being careful not to break off the head. The existing connector was removed and new one crimped in place. The contact area was cleaned, removing all the aluminum oxide – and the ground wire was reconnected to the metal track. However, the antenna head red light did not come on.

At this point I suspect either the amplified antenna head is not working or there is a kink in the wiring, which is preventing the proper function of the antenna. Any further work will have to wait until spring. I have ordered a replacement antenna and plan on using jumpers to confirm my suspicions – and will report my findings to the board.

Dick

11-26-2009, 04:39 AM

Very nice -- thanks for sharing this.

Wavery · 11-26-2009, 01:49 PM

Dick,

It appears that this trailer has lived fairly close to the ocean for a period of time. It shows signs of some pretty serious corrosion (judging from the pics).

If I were you, I think that I would check all of the ground wires and connections on the trailer, starting from the battery and working back.

I would recommend using heat-shrink on all of the wire connections.

These connectors have built in heat-shrink. They are designed for marine grade wiring and are excellent at keeping moisture and corrosion out. I used them on my sailboat for many years without issue.
http://cgi.ebay.com/ebaymotors/480-p...ssoriesQ5fGear

Just a note........just because you detect 12v before and after a connection doesn't really tell you if the connection can carry a load. Your multimeter or test light could show 12v @ .5A but when a load is placed on the wire the voltage could drop dramatically if there is resistance in the wire. It's good to check the resistance on the wire before and after the connector. Another test is to check the voltage @ the battery, then check the voltage @ the radio with the radio on.

A few years ago, I was having furnace issues. I was getting 12.4V @ the battery with the blower on but the igniter wouldn't light. When I tested the voltage @ the furnace, I found 11.1V. It took me hours to trace down the source of the resistance. It ended up being one of those darn wire nuts, clear on the other side of the camper. Now, I replace those things with the heat-shrink connectors whenever possible.

**commodor47** · 11-26-2009, 06:30 PM

Wayne,

Thanks for the additional troubleshooting information - which I will pursue in the spring. The original owner lived in Wilmington, NC; we spent several weeks on Hunting Island State Park, SC; and a week at San Clemente State Park, CA. In addition, Western MA has a fairly wet and damp summer - good catch on the rust in the photos. I will check all grounds for corrosion and look into using heat shrink connectors.

Dick

Wavery · 11-27-2009, 12:07 AM

Quote:

Originally Posted by commodor47

Wayne,

Thanks for the additional troubleshooting information - which I will pursue in the spring. The original owner lived in Wilmington, NC; we spent several weeks on Hunting Island State Park, SC; and a week at San Clemente State Park, CA. In addition, Western MA has a fairly wet and damp summer - good catch on the rust in the photos. I will check all grounds for corrosion and look into using heat shrink connectors.

Dick

One more tip. When you replace a connector, be sure to cut the wire back until you get to nice shiny copper colored wire. I have had to cut away 3-6" of black wire before getting to good wire.

**commodor47** · 05-03-2010, 07:45 AM

Follow-up to my amplified radio antenna:

Spring has arrived – time to tackle the non-functioning amplified radio antenna.

Yesterday my son helped me bypass the original amplified radio antenna with the replacement. Sure enough, the replacement worked. The red indicator light activated and the radio pulled in many FM stations.

The process of replacing the existing antenna was a bit of a challenge. Once the wire bundle in the upper shell support arm was accessed, the webbing had to be moved down and out of the way. The webbing was secured at the base of the wire bundle with electrical tape. The tape was removed. The upper end of the webbing goes into the base of the bag seal, next to the AC power cord for the upper shell. About an inch into the bag seal is another band of electrical tape. Although much harder to accomplish, it also needs to be removed.

Disconnect the ground wire to the existing antenna head. Cut the OEM RF cable about 10 inches from the antenna head. Securely attach the replacement antenna RF cable and use the OEM cable as a pull. Pop open the rectangular (nearly flat) channel closest to the vertical bag seal to access the RF cable run. Slowly and carefully pull the replacement RF through the small opening in the corner of the bag seals (where horizontal bag seal meets vertical bag seal). The RF cable bullet connector makes for a tight fit. Then slowly pull the replacement cable through the bottom of the bag seal – which is even tighter. It will be easier if the AC power cord anchor is removed ahead of time.

Several new photos have been added to my album and should help in understanding the steps involved.

https://photos.google.com/album/AF1Q...hRgSwjm3pFxhUg

Nice to have a working radio - again.

Dick

05-03-2010, 02:50 PM

Quote:

Originally Posted by commodor47

we spent several weeks on Hunting Island State Park, SC;

If you see an Elkmont there, next winter, it will probably be us, on our way to/from Florida. Love that area. And the shrimp ... oh boy.

Panamapat · 04-29-2014, 08:36 PM

Quote:

Originally Posted by commodor47

Follow-up to my amplified radio antenna:

Several new photos have been added to my album and should help in understanding the steps involved.

http://picasaweb.google.com/commodor...naWireRouting#

Nice to have a working radio - again.

Dick

Dick - really nice job of photographing and labeling the the images - clearly helps understand what you did.

Pat

**commodor47** · 04-30-2014, 05:01 AM

Quote:

Originally Posted by Panamapat

Dick - really nice job of photographing and labeling the the images - clearly helps understand what you did.

Pat

Thanks Pat - appreciate the compliment.

Dick

tgpmd1 · 04-30-2014, 06:05 AM

Thanks Dick. Our new-to-us 2720SL did not have the factory installed radio. I'm getting ready to install a radio with a DVD player, SD card input, etc. and I'm sure these pics will really help. Going to try to replace the phone plate with a video output jack. Look like there is a vapor barrier between the fridge and the area I need to connect to the radio/player.