combining antennas

[astrodanco]

Now the tricky part, most antennas, even band specific perform well outside the intended operating band. The radiation patterns and efficiency degrades quickly.

Hu????? Do they perform well? Or does teh pattern and efficiancy degrade quickly?

I'd recommend replacing the word "perform" with the words "perform to some extent or another" and replacing the word "well" with the words "a long way." So we end up with something like, "perform to some extent or another a long way outside their intended operating band." I'm not a particularly good writer myself, so I hope that isn't just more unclear wording.

 

[N_Jay]

Now the tricky part, most antennas, even band specific perform well outside the intended operating band. The radiation patterns and efficiency degrades quickly.

Hu????? Do they perform well? Or does teh pattern and efficiancy degrade quickly?

I'd recommend replacing the word "perform" with the words "perform to some extent or another" and replacing the word "well" with the words "a long way." So we end up with something like, "perform to some extent or another a long way outside their intended operating band." I'm not a particularly good writer myself, so I hope that isn't just more unclear wording.

How about:
"Any random conductor will act as an antenna, the efficiancy and the pattern (which is just a measure of its efficiancy in a particular direction) is neither good nor bad in itself, and can only be measured in comparison to anonther conductor or random or specific measurments."
:wink: :twisted: :wink: :twisted:

 

[triryche]

OK, I read through this entire thread and I MUST chime in!!!!

I will stay away from any deep scientific logic and state just my tests and results..

1. A TV splitter, T-adaptor splitter, BNC Splitter, or any type of splitter does not work AT ALL for combining two antennas to a scanner. Specifically a directional yagi type. I have tried this using numerous different splitting devices and signals on all bands get worse because there is no isolation in a splitter.

2. Using a multicoupler turned around with two antennas coming in also does not work when one of them is directional. I have tried this with the Stridsberg passive model. The signals from the directional antenna (in my case a 9 element Yagi for 800 MHz) were satisfactory however VHF and UHF frequencies were greatly attenuated and AM signals were loaded with birdies. You are combining signals received on each antenna. Thus mixing a good signal with a bad causing a less than desired total signal.

3. By the time you get done spending all the money on duplexers, connectors, and feed line you might as well have bought another scanner to monitor the specific band the yagi is for.

Again, these are not technical manual caliber expirements here. These are just some results I got while learning that trying to combine 2 antennas for a scanner was a waste of time. :roll: Other's may have had different results.