Antenna mounted near ducting

[JohnDistai]

Hi, I'm an inexperienced scanner listener considering a new antenna. I listen primarily to simulcast, but may try for air and rail. I'd like your opinions about an internal mounting location. My house has a chimney passage which houses the metal ducting for our gas fireplace (currently unused). There's room to mount an antenna inside the passage, but it would be 6" from the metal ducting. What are your thoughts about this?

Thanks in advance!

 

[mmckenna]

What are your thoughts about this?

It's going to make the antenna directional away from the duct. May make it difficult to hear things from the direction of the duct.

You also need to consider everything else up in the attic: Foil backed (vapor barrier) insulation, wiring, plumbing, etc. Plus your antenna may be closer to RF noise generators in the house. If mounting in the attic is your only option, be ready to try different locations until you find one that works well for you.

 

[mass-man]

Inside a brick passage 6” from duct! Get above it all...antennas of almost every variety don’t like being near metal! It will mess with the pattern, probably block signal from that direction and is just not ideal! High and clear of obstacles is the antenna mounting mantra!!!

 

[buddrousa]

I would not put anything inside a brick chimney also the air space around the pipe is isolation from heat that the pipe may conduct.

 

[iMONITOR]

I would not put anything inside a brick chimney also the air space around the pipe is isolation from heat that the pipe may conduct.

There's also a lot of condensation and corrosion inside a chimney.

 

[JohnDistai]

It seems there's a slight misunderstanding. On the outside of my house it looks like a chimney. This is a vertical chase (an OSB box) sided with Hardiboard siding. The only thing in it is a gas fireplace flue vent. We don't have gas logs, so the fireplace isn't used.

 

[mmckenna]

It seems there's a slight misunderstanding. On the outside of my house it looks like a chimney. This is a vertical chase (an OSB box) sided with Hardiboard siding. The only thing in it is a gas fireplace flue vent. We don't have gas logs, so the fireplace isn't used.

Yeah, I think some made assumptions.

None the less, mounting an antenna that close to the metal flue pipe is going to create some issues. Wether or not those issues prevent this from working can only be determined by you installing it and seeing what happens.

If you are asking for "opinions" or input, I'd suggest finding a better place to mount the antenna away from the metal flue pipe.

 

[JohnDistai]

When LMR 400 runs near metal objects (like that flue pipe), passes above a furnace, or comes near 14/2 electric cables, do those items add RF noise?

 

[mmckenna]

When LMR 400 runs near metal objects (like that flue pipe), passes above a furnace, or comes near 14/2 electric cables, do those items add RF noise?

Coaxial cable near metal won't result in problems.

Running it near a furnace with a noisy motor might. Electrical wiring can.

 

[JohnDistai]

Okay, thanks.

If I buy a Stridsberg multi-connector and I don't have a receiver for each connection, do I need to do anything with the empty connection ports?

 

[900mhz]

Terminate unused ports. It is a smart engineering practice.

 

[JohnDistai]

What do you terminate them with?

 

[900mhz]

50 ohm terminators. if the ports are BNC female, you will need 50 ohm BNC male terminators.

 

[JohnDistai]

Thanks!