One antenna for two scanners

[jerneedog]

Hey all,

I am wanting to use two scanners with one antenna.
I currently have the Outdoor VHF-Hi/UHF Scanner Antenna and I'm wanting to use this one antenna for
two hand held scanners.

I came across this Scanner Antenna Splitter and was wondering if this is a good way to do this?

Could someone lend me some help and some links to other setups or
a better setup to go with?

 

[LarrySC]

After spending lots of $ and time building splitters and switch panels I just bought a regular TV/VCR splitter and AB or ABC switch. I'm in a signal overload area and have never noticed any loss. I converted all ant's and scanners to "F" connectors and RG-6. Been that way almost 20 years. Never plan to change it. IT WORKS.

 

[jerneedog]

With the AB or ABC switches for TV/VCR, does that mean you have to switch
the switch to the scanner you want to listen to?

I'm wanting to share one antenna with two scanners, with both scanners on
and using the one antenna at the same time.

 

[N_Jay]

With the AB or ABC switches for TV/VCR, does that mean you have to switch
the switch to the scanner you want to listen to?

I'm wanting to share one antenna with two scanners, with both scanners on
and using the one antenna at the same time.

TV splitters (good ones) or that scanner splitter should work. You will lose about 3.5 dB of signal, but if you not listening to anything marginal now, that should not be a problem.

Also, I think the Fee iPod link in your sig is advertising.

We click, we get spam, you get something of value. (Well not really, it's a pyramid, so I doubt you will ever get the iPod, but lots of unknowing people will get spam.

 

[jerneedog]

Well...I didn't order that setup, instead I just went to Radio Shack and picked up a BNC T-Adapter and two 6' cables with
BNC conectors on them and hooked it all up for two scanners to share one antenna. Not sure if this is the best way
but it was the cheapest route for me right now and it seems to work just fine.

 

[N_Jay]

Well...I didn't order that setup, instead I just went to Radio Shack and picked up a BNC T-Adapter and two 6' cables with
BNC conectors on them and hooked it all up for two scanners to share one antenna. Not sure if this is the best way
but it was the cheapest route for me right now and it seems to work just fine.

Its probably the worst way, but even then it sometimes works.

The best part about scanning is you never know what you miss.

 

[allen5565]

Try this. Yes, it's expensive, but on the up side, you won't lose any signal strength. http://www.stridsberg.com/prod01.htm

 

[N_Jay]

Try this. Yes, it's expensive, but on the up side, you won't lose any signal strength. http://www.stridsberg.com/prod01.htm

Sure, Its that easy. :roll:

A pre-amp is a pre-amp.
It doesn't matter if it is in a splitter or separate.

They can help, but not every time.

 

[kb2vxa]

Hi guys,

Ho boy, between you I see quite a number of ways to introduce signal loss and intermod.

First, any "signal splitter" introduces 3dB loss PER PORT so split 2 ways and you have half the signal, 4 ways and you have 1/4 signal and so forth. One receiver per antenna or use a coaxial switch (not a coax switch) is the only way around loss.

Again with the amplifiers. What better way to introduce intermod than introduce a strong signal and drive a linear amplifier into non-linear operation? That's just in the amplifier itself we're talking about here, then they tend to overload the receiver's front end and the same thing happens, the RF amp turns into a mixer and mixing products show up all over the place.

While there may be bandpass and/or bandstop filters ANY in band or out of band (on another band the amp operates on) the amplifier itself is a "DC to light" device that may be overloaded and driven into non-linear operation if not into saturation.

The bottom line is no matter how "high quality" this amp or active splitter is it is still suceptible to strong signals so unless you live out in the country far away from any and all transmitters you may expect problems. The exception I had great success with was a Motorola preselector, a 5 section helical filter followed by an amp giving 10dB gain. Being highly selective, that is for a 500kHz band segment it made my commercial RCA tranceiver hotter than the devil's butt in summer, but then again it's not made for scanners.

Then nobody has mentioned any noise figures, gee, wonder why. These devices are sold to scanner buffs largly ignorant of the requirements of "weak signal" work that hams have been doing all along on VHF and UHF. Preamplifiers are sold for use on Amateur bands but they have published specs including noise figures, low noise is critical for pulling in weak signals without burying them in noise generated by the amplifier itself.

Then again my experience has shown they're pretty useless for FM reception due to the characteristics of an FM receiver (limiting action). When switched on they bring up the S meter reading but what comes out the speaker sounds just the same as it was originally, the limiters kick in. Oh, they work great on SSB, the one in my IC-706mK2G makes all the difference in the world on 2M and 70cM.

 

[Al42]

Then nobody has mentioned any noise figures, gee, wonder why. These devices are sold to scanner buffs largly ignorant of the requirements of "weak signal" work that hams have been doing all along on VHF and UHF. Preamplifiers are sold for use on Amateur bands but they have published specs including noise figures, low noise is critical for pulling in weak signals without burying them in noise generated by the amplifier itself.

Not to mention capture ratio, which is a whole 'nother can of fish bait.

 

[N_Jay]

Then nobody has mentioned any noise figures, gee, wonder why. These devices are sold to scanner buffs largly ignorant of the requirements of "weak signal" work that hams have been doing all along on VHF and UHF. Preamplifiers are sold for use on Amateur bands but they have published specs including noise figures, low noise is critical for pulling in weak signals without burying them in noise generated by the amplifier itself.

Not to mention capture ratio, which is a whole 'nother can of fish bait.

I would love to hear how you see capture ratio come into play with regard to a pre-amp?

 

[Al42]

I would love to hear how you see capture ratio come into play with regard to a pre-amp?

With regard to the need for one, mainly. If the signal is "capture ratio" above the noise, there's nothing (useful) a preamp will do. And, if the preamp raises the signal "capture ratio" above the noise, that's all that's needed for full quieting. Having the signal 40 db above the noise might be nice, but it's not going to do anything a 20-db-over-the-noise signal won't do in a good receiver.

 

[N_Jay]

I would love to hear how you see capture ratio come into play with regard to a pre-amp?

With regard to the need for one, mainly. If the signal is "capture ratio" above the noise, there's nothing (useful) a preamp will do. And, if the preamp raises the signal "capture ratio" above the noise, that's all that's needed for full quieting. Having the signal 40 db above the noise might be nice, but it's not going to do anything a 20-db-over-the-noise signal won't do in a good receiver.

Capture ratio is typically with regard to TWO signals, not a signal and noise.