BNC T-Connector for 2 Antennas?

[OffRoadjunkie]

Anyone know if there is any nominal degradation in receive signal with one of these connected to 2 antennas? This is for a scanner and there doesn’t seem to be a one size fits all antenna. How about using this 50-ohm T-connector with 2 antenna styles (maybe high and low) connected to a single 10 ft. feed?

http://www.therfc.com/bnc.htm
item # 149000A000

Thanks!
-Robert

 

[mkh]

I use this with proper connectors. It can connect two radios to one antenna aor two antennas to one radio. NEver had any problems with it.

http://www.grove-ent.com/SWC01.html

 

[kc8zdf]

I use a bnc t connector for my scanner in my moblie truck with two 800mhz comtelco antennas to just recive not transmit. And I think it would better for rec... I don't know if this is how it is suppose to work but when I only had one antenna up on my truck I would get alot of the conversation breaking up. So now that I have to antenna that are the same and same amount of coax it works pretty good.

 

[wesm1957]

I am using a T-connector right now for my Pro-96 and 996T for 800 mhz. I have a dead spot in my apartment. I have an antenna on the window sill for now and both pick up 800 just fine that way. I am building a small yagi antenna to pick up 800 better since I am unable to put any antennas outside here.

 

[OffRoadjunkie]

Thanks for the info. I have read that the least amount of connections/adapters the better. I was wondering if there is any loss...

-Robert

 

[n3umw]

T connector is not a good idea

A T connector when used with a piece of coax acts as a notch filter.
http://www.kyes.com/antenna/coaxfilter.html

The frequency is dependent on the coax's velocity factor and the coax length. This notch repeats at multiples of the frequency.

What will happen is that each radio will see a different set of frequencies notched depending on the coax lengths.

A better way is to use a TV splitter. They work well at scanner frequencies (25-1.3GHz).

I use a TV splitter and RG6 coax with F/BNC adapters for my scanners. The coax is fairly low loss, small, cheap, and even though it is 75 ohm, it works perfectly for receiving not transmitting.

 

[Universaldecoder]

I'm using something called a splitter/combiner. Here is a pic of one made by Mini-Circuits...
They have a white paper on their website that discusses the principle behind this, and the downfalls of using a BNC T connector (which by the way is made for Ethernet Networks).

ANother company is RFBay Inc, they too make splitter/combiners. In my opinion this is what you should be using...not the BNC T-Connector.

Here is a pic of one installed on my car. I feed an Antenex 800mhz Phantom Elite and a Larsen 150/450 mhz into it. The output goes to a BCD996T.

http://www.radioreference.com/forums/showthread.php?t=63012

I started off with the Mini-Circuits I got cheap off of Ebay. It was built to some Motorola Spec. I tried my hardest to get info regarding the build number, but Mini-Circuits would not release the specs to me (customer confidentiality in regards to Motorola). I eventually replaced it with an RFBay unit, and I did see an improvement.

 

[madnachos]

I'm using something called a splitter/combiner. Here is a pic of one made by Mini-Circuits...

I also have a Mini-Circuits (ZAPD-4) splitter that I got for about $15 off eBay. Uses N-connectors and is supposed to be good to over 5ghz. Works great.

 

[kb2vxa]

Hi Robert and all,

Before this discussion gets out of hand (again, we've been through this before) if you connect two antennas in this manner you'll have a phased array with highly unpredictable directional characteristics. If the antennas are for different bands use the search function with the key word "diplexer" and you'll find discussions on the application of this device. If they're for the same band or bands you're begging for trouble no matter how you combine the signals unless a directional phased array is what you're looking for and that's another discussion entirely.