Amplified Antenna Connection

smily · 08-27-2002, 08:34 AM

I have the typical TV Coax connection beside the refrigerator, above the credenza on my 71 Overlander.

Does any one know if this is an amplified connection?

I have removed the face-plate from the wall and there is a small PC board with two coax connections on it.

One connection reads from antenna and the second connection reads to bedroom connection.

I do not get very good recpetion at all. There are other campers near by and they get great reception.

I have visually inspected the antenna and the coax down lead is connected to an 75 ohm adapter at the antenna, (classic folding aluminum Di-pole antenna), the wiring looks reasonably in good condition unless there is something unseen that is a problem.

I am considering a new amplified faceplate but it is 35 dollars.

I am curious if the existing connection is already amplified and how can I test the amplification?

Any takers?

Smily

thenewkid64 · 08-27-2002, 08:53 AM

The amplified plate has a switch and light that tells you it is on in most cases. If there is not a switch of some sort then you have a non amplified or non working amplifier unit. The description of your trouble would lead me to belive that the $35.00 would be well spent.

74Argosy24MH · 08-27-2002, 08:55 AM

There should be power on the back, a switch on the front if it is amplified. If there is no power you will have to run it to make the amplified version work.

The signal from the antenna is thousandths of a volt. All connections need to be clean and tight. The signal travels through the solid wire in the center, ground (and the shielding) is the braiding around the outside; it connects through the screw adapters and must also be clean. Same for the antenna, clean solid connections.

John

ALANSD · 08-27-2002, 09:09 AM

I have the amplified switch and it works well, the difference in reception is very noticeable when it is on. The former owner of my rig had it wired wrong, and it did nothing. Be sure the cable coming in and the one to your tv are connected to the right plugs.
You also might be sure your TV is set up for the correct input, as most have various settings for cable/ line/antenna and so on.

smily · 08-27-2002, 09:16 AM

My outlet does have indicator light and the light illunminates when the switch is actuated. I always did suspect that the outlet was amplified but I was looking for verification.

I am going to try the new amplifier but it is a pricy experiment.

The only place that I have not visually inspected is where the down lead cable penetrates the skin of the AS. The PO coated the area with roof sealant and it is all gooped up so I cannot see the integrity of the cable at this location.

I will check integrity today with the old Voltmeter, (ohm meter).

What scale should I use to verify the 75 ohm resistance?

Maybe my adapter is corroded at the antenna. it is a boot that is taped up. I assume that this adapter converts the 300 ohm antenna to 75 ohm coax down lead.

Smily

thenewkid64 · 08-27-2002, 10:25 AM

To test the amp, you could get a set of rabbit ears and connect them to the input side of the amp. Connect a tv to the output side and check for the diffrence on and off. The old twinlead wire became brittle and was often replaced with the 75 ohm down lead. To check for proper wiring, I would disconnect it from the antenna and amp, then check the center to the skin as well as shield to skin for continuity. If you have no continuity thats good. I would then check center to shield for shorts as well. If all checks ok then it is on to the 300 to 75 ohn converter at the antenna. They are just a simple transformer but if not properly installed or if the connections get corroded you can have problems. If you replace it be sure to get one rated for exterior use. As mentioned above the current traveling on the antenna wire is beyond measurment without specialized tools.

BTW be sure to power off the amp and disconnect it befor testing the wires as an Ohn meter works by injecting voltage (minor amounts) thru the wire, this could be enough to blow the amp.

smily · 08-27-2002, 10:46 AM

Went to the local RV store and found and amp witout the 12 volt socket for only 12 dollars. My TV is 110 only so I do not need 12 volt socket.

I just wanted it for testing anyway.
I have seen a "change" in the signal when the original amp was powered on but still the reception was bad.

I anticipate that I will find wiring to be brittle as you identified in previous post.

I will also check the 75-300 ohm adapter and correct accordingly.
I will post results later.

Smily

P.S. Electric Brakes kicked butt this past weekend. It took some getting used to but very satified with braking ability.

smily · 08-28-2002, 06:00 AM

I went home and removed the adpter at the antenna. I replaced both the FC connector and the adapter with new components that I had laying around in the garage.

I then went inside the trailer and turned on the TV......

Reception is still bad, maybe a little better but still bad.

I then proceeded to replace the amplified receptacle above the credenza with a new one that I bought for 12 dollars.

The indicator light on the new amplifier did not illuminate but the reception was excellant, Hmm........

I toggled the switch on the new amplifier and there was no difference in the reception whether the switch was in the on or the off position but the reception was great.

I determined that the new amplifier did not work at all, (no wonder it was all by itself with no price sticker on it).

Any way I re-installed the old amplifier and the reception was bad again.

Ah Ha! The amplifier was causing the reception to be noisy.

I had an amplifier in the house that I had bought to connect several TV's in the house to a single source. ( never got around to installing it in the house).

I did a temporary install in the AS and Wow! what a picture.

I am going to go ahead and buy the original replacement amplifier and install it soon.

Thank heavans that I did not rquire a new TV Antenna.

Smily

ALANSD · 08-28-2002, 08:40 AM

Congratulations...it's always a kick when something is able to be self-repaired.

jaiman · 09-03-2005, 01:57 PM

My 81 still has the original antenna that works fine. The old style wiring (for lack of the real technical name) has corroded off the antenna and I got to thinking that I would like to install new coax outlets inside the front as well as the rear. The amplifier works well and I would obviously like to keep it inline. Can I just connect a coax converter to the amp or is there other considerations I need to make or a better way to do this. I'd rather not attempt to re and re the existing wires that run through the frame.

Thanks in advance

Jai

jaiman · 09-03-2005, 03:25 PM

Once I removed the plate that houses the amplifier, 12v plug and the amp switch there are 2 extra wires that are designated to Coax. I hooked up a coax converter to them and it works great. Easy and professional fix. I drilled a hole just above the amp and installed a normal household cable outlet.