Antenna issues

[evesdropper]

I apologize for the long post as I am trying to be thorough. I have been fiddling with this for a few days and I am stumped. Any assistance is appreciated.

Patient is a 2021 Forest River Cherokee Wolf Pup 16pfbl. Driven BT3200 radio. King Jack power injector. Fixed omni antenna
Issues are:

1. Poor to non-existent radio reception
2. No digital channels detected during tv scan

What I have done:
Test #1:

1. Traced and labeled all coax wires I could find.
2. At the King Jack Power Injector, I verified power to the jack. I also verified power is supplied to the antenna when the button is pressed.
3. Connected the antenna to the proper port. removed the splitter from the equation and connected the radio coax directly to "TV2" port on the jack.

No change. Radio reception is non-existent. Power button on or off. No change


Test #2:
I used a new RG6 cable and went from the radio to the jack. taking the factory cable out of the equation. No change powered or unpowered.

Test #3:
I used an adapter and connected the new radio RG6 directly to the antenna bypassing the jack. The antenna would be unpowered in this setup. No change

Test #4:
I touched the center wire only to the center wire only of the antenna rg6. Instantly spectacular reception on the radio. even better than the auto store antenna

Test #5:
Connected an RG6 to the TV. Extended a 25' extension cord out of the camper and touched only the center wire on the RG6 to the ground pin on the extension cord. Then did the channel scan. 13 digital channels found vs 0 found connected to the antenna.

Test #6:
Connected my multimeter to the rg6 from the antenna. Center pin and shielding do not have continutity and read 0 ohms resistance.

Given test #4 and #5 results, I am guessing I am looking for a bad connection or something between the antenna RG6 end inside the camper and the antenna? I hate to disturb the lap sealant or whatever they used on the mount. Is there anything else I can try?

[mac1_131]

Test #6, is that with antenna connected or disconnected up top?

You'll need to do that to determine if the short is the coax or the antenna itself.

You've correctly verified your radio and TV are just fine.

Either the coax going to the antenna is shorted or the antenna itself is bad/shorted.

[larry2c]

This might just be a typo but 0 resistance is a short. I believe you want infinite resistance between the center wire of the cable and the shielding.

[evesdropper]

Originally Posted by mac1_131

Test #6, is that with antenna connected or disconnected up top?

You'll need to do that to determine if the short is the coax or the antenna itself.

You've correctly verified your radio and TV are just fine.

Either the coax going to the antenna is shorted or the antenna itself is bad/shorted.

Antenna is still on the roof. My only access to it is the RG6 presumably connected to it. I have not been up on the ladder yet.

[evesdropper]

Originally Posted by larry2c

This might just be a typo but 0 resistance is a short. I believe you want infinite resistance between the center wire of the cable and the shielding.

Digital multi-meter says 0. If it was a short, I would expect the continuity test to make a tone right? That doesn't happen. I will dig in further after work today. Hopefully I can find the issue without removing the antenna.

[bubbles]

Originally Posted by evesdropper

Digital multi-meter says 0. If it was a short, I would expect the continuity test to make a tone right? That doesn't happen. I will dig in further after work today. Hopefully I can find the issue without removing the antenna.

0Ω would be a direct short (no resistance). Typically the tone selection is for checking diodes. Set the meter to, say, 200Ω and check for an open. If it reads anything there is a problem between the shield and conductor. Of course both ends of the coax should be disconnected.

[upflying]

I also had no radio reception until I added an automotive style, spring loaded antenna on the roof. Now I pick up every station.
I also had a fixed pod style TV antenna on the roof, no TV reception until I added a Wingard batwing on the roof. TV now picks up 30 or more channels..depending on location of course.
FR obviously depends on the owners to upgrade after purchasing.

[mac1_131]

An amplified antenna will show some resistance, not 0 and not infinite either.

Just a rough guess would be around 50-100 ohms.

I think you're going to have to get up on the roof to figure this out.

[Tabasco_Joe]

Poorly installed F connectors can often have a short. Techs fail to trim the foil or the braid (ground, varies by coax quality) correctly and get a short behind the connector face. Sometimes you can see it by looking closely.
From your ohm meter readings seems likely. Before I'd crawl on the roof I'd replace the connector on the wall jack end. Murphy's Law says it's on the far end, but once in a while even Murphy's law is wrong.

[evesdropper]

OP here.
Had to pull the antenna from the roof as the connectors were unreachable. This is likely the cheapest Omni antenna King makes.

Cable was loose but tightening it made no difference. connected the antenna to the injector with a new cable and got 18 digital channels. I pulled a new RG6 to the roof. Bad cable has a break somewhere inside.

New question. Is there a better omnidirectional antenna I could put on the roof? Mine is tiny and not even listed on King's website. OA1000 seems like the model they list for retail sale.

[Tabasco_Joe]

Originally Posted by evesdropper

OP here.
Had to pull the antenna from the roof as the connectors were unreachable. This is likely the cheapest Omni antenna King makes.

Cable was loose but tightening it made no difference. connected the antenna to the injector with a new cable and got 18 digital channels. I pulled a new RG6 to the roof. Bad cable has a break somewhere inside.

New question. Is there a better omnidirectional antenna I could put on the roof? Mine is tiny and not even listed on King's website. OA1000 seems like the model they list for retail sale.

Hard to say as almost none of the sellers provide the specs you need to compare. Having played with a few in my attic I don't think there is much difference. Good thing is the Chinese can make reasonable good, cheap, low noise amplifiers. Digital signals used for today's broadcast TV is somewhat tolerant to distortions you might get if the amp is overloaded.
If it was me I'd pick a lower priced one on Amazon with good reviews. You can always test before completing install and return to Amazon if you have issues or don't like.

BTW, I'm an RF engineer with experience designing similar circuits.