Base antenna-high noise floor?

[press1280]

I've got a Sirio 17 foot base antenna mounted to my deck. It's almost perfect SWRs (under 1.1). Question is, all my radios seem to get a constant 7 pounds worth of background noise, is that normal? I've also been doing tests where I transmit from my mobile back to the base and I'm not so pleased with the range (fades out around 3 miles, no hills or anything). I've talked to a neighbor pretty clearly at almost double the range.
Its not grounded, could that be the answer or something else?

 

[WB9YBM]

Question is, all my radios seem to get a constant 7 pounds worth of background noise, is that normal?

Depends on what's in the area, for example my neighbor 2 houses away has a power transformer (from the electric company) that spat out quite a bit of hash (especially when it was going bad), and it got worse when it got humid.

 

[press1280]

I don't think there's anything like that nearby. It's fairly rural here, and the power lines are all below ground in the neighborhood.
I also forgot to mention its a 75 foot run using Wilson's LMR400 equivalent, which I *think* is good.

 

[prcguy]

Just for fun power the CB from a battery and turn off the circuit breakers in your house one by one while watching your noise floor. Could be you have some computer equipment or a switching power supply that's trashing out the CB band. If you find a breaker that cleans things up then your on track to find the noise source. If the whole house is dark and you still have the noise maybe another hobby is in order.

I don't think there's anything like that nearby. It's fairly rural here, and the power lines are all below ground in the neighborhood.
I also forgot to mention its a 75 foot run using Wilson's LMR400 equivalent, which I *think* is good.

 

[russbrill]

I've got a Sirio 17 foot base antenna mounted to my deck. It's almost perfect SWRs (under 1.1). Question is, all my radios seem to get a constant 7 pounds worth of background noise, is that normal? I've also been doing tests where I transmit from my mobile back to the base and I'm not so pleased with the range (fades out around 3 miles, no hills or anything). I've talked to a neighbor pretty clearly at almost double the range.
Its not grounded, could that be the answer or something else?

How high is the Base of the antenna above ground??? You want to be at least 10ft above your roof line. So if the highest point of your roof is 14ft, the Base of the antenna should be at 24ft above ground. A half-wave length (20ft) above the highest point of your roof is even better. Your range will improve and the noise floor might drop.

 

[press1280]

Yea the base is a few feet below the roof line. I’ll see about raising it up somehow.

 

[russbrill]

Yea the base is a few feet below the roof line. I’ll see about raising it up somehow.

Channel Master is a good source for Masts and installation accessories, view here TV Antenna Installation Accessories For Home | Channel Master ...

You should use Insulators in your top guy wires, three per line at 5ft spacing.. I use these from MFJ MFJ-17A01, 1/4~ GUY WIRE CERAMIC INSULATOR | MFJ Enterprises Inc ...

Have fun and be safe..

73,
Russ

 

[prcguy]

Raising the antenna a little will probably not have any effect on the noise unless the source is right under the antenna and even then 10ft probably wont change much. A higher antenna is better for distance but if this first effort is to reduce noise then concentrate on that as you can always raise the antenna later for better distance. Otherwise you can waste a lot of time and $$ randomly changing everything for potentially no improvement on the noise.

It would be like having a car with rough idle and you start replacing battery cables and fan belts and transmission fluid and the alternator and the muffler, etc. Concentrate on the problem with a clear agenda to identify if the noise is within your own house meaning you can control it, or if its further away and out of your control.

 

[prcguy]

Duplicate, oops

 

[russbrill]

Raising the antenna a little will probably not have any effect on the noise unless the source is right under the antenna and even then 10ft probably wont change much. A higher antenna is better for distance but if this first effort is to reduce noise then concentrate on that as you can always raise the antenna later for better distance. Otherwise you can waste a lot of time and $$ changing everything for potentially no improvement on the noise.

Hey PRC,

Merry Christmas and Happy New Year... The OP was also stating he wasn't happy with the Range performance.. I suspect the noise is in his house with the antenna mounted low and near the roof, so additional elevation MAY help with the noise floor.

 

[slowmover]

Circuit breaker test is an ideal start.

 

[prcguy]

Maybe, maybe not. Its much easier to turn off all the breakers and test for that over raising the antenna first then seeing what it does. I like to troubleshoot first, identify the problem then fix the problem over shotguning potential solutions and finding out they have nothing to do with the problem.

And happy happy to everyone out there. Hope 2021 is full of good working stuff and no problems.

Hey PRC,

Merry Christmas and Happy New Year... The OP was also stating he wasn't happy with the Range performance.. I suspect the noise is in his house with the antenna mounted low and near the roof, so additional elevation MAY help with the noise floor.