Position of 800Mhz antenna in the home

[justdan]

Hi folks.
I'm new to the scanning thing ... so new I'm still in the planning stages of buying my 1st scanner, antenna, coax, etc. I'll mostly be listening to the 800Mhz band on my new base scanner -- it'll be a Uniden 996T when I order it.

I want great 800Mhz, omni-directional reception but want to do it without putting an antenna outside of my house. So my choices, I believe, are either an 800Mhz duckie on the unit or an antenna up in the attic w/ coax run to my scanner. I see that a number of folks (and some kind of study) says the Seeker duckie is the best duckie for 800Mhz. My question, finally is would you just attach the Seeker to the unit or would you put it up in the top of the attic and run coax to it? It would be <= 25ft of coax (probably RG6) from scanner to the attic. Putting it in the attic would probably raise the elevation of the antenna about 12-15 ft. Another option I guess would be another type of omnidirectional 800Mhz antenna in the attic ... but I don't know of any others better than the Seeker duckie.

Thanks for all of your advice. I have learned bunches from reading all your RR forums!
-Dan

 

[Al42]

There are 800 MHz colinear antennas that have considerable gain and aren't prohibitively expensive. Considering that cable has quite a bit of loss at 800 MHz, unless you want to spend almost as much for the cable as you will for the scanner, I'd keep a duckie as close to the scanner as possible - it has no gain to lose.

 

[kb5udf]

Mag Mount

A readily available 3db mag mount 800 mhz antenna, stuck to something metal
naturally, easily outperforms ducks in my opinion, and can be had quite cheaply.
Most such antennas come with about 9-13 feet of coax attatched.

My advice, assuming uniden engineered a receiver that is able to handle the modest gain of such an antenna, is that since you are getting it as a base unit, you might as well
use a an ant. with at least 3db of gain. On the other hand, if when you get it out
of the box, whatever el-cheapo ant. they include perfectly receives all the systems you
want, then why bother (but I don't think that's likely).

Jean B.

 

[RISC777]

On the other hand, if when you get it out of the box, whatever el-cheapo ant. they include perfectly receives all the systems you want, then why bother (but I don't think that's likely).

Jean B.

Exactly. if the stock antenna does the job as you want it to, no need for any additional investment.



And another idea to throw into your thinking is to get an antenna made for a vehicle, but not a mag mount. An NMO 800 antenna with a base and cable is a similar but different approach than the mag mount idea that was suggested. There are some that would need some metal at the base for the ground plane, but there are also NMO antennas designed to not require a ground plane eliminating the need for a square of metal at the base. And, they can be cut to tune it specifically to the frequencies you want to monitor.

Perhaps not a 'simple' suggestion, but posted to give you more food for thought.

Besides, without questions no learning occurs.

 

[pslcrabber]

I just got an 8ft fiberglass whip for my house CB antenna and out of curiosity I plugged my scanner into it last night and I am getting great 800mhz reception. The antenna is laying across a large shelf in my bedroom at the time untill I get my ground plane kit in. Who knows how good it will do once I put it on top of the house.

 

[kb2vxa]

Hi Crabber and all,

A CB antenna is for CB only so if it's receiving anything else the signals must be extremely strong. If that's all you want there's no point in going any farther but if you want proper reception out of town use a proper antenna as high as practical and the best coax your budget will allow. For that matter a whip without a ground counterpoise is just as useless for CB.

 

[VintageJon]

Here it's a 1/4 Wave ground plane hung from the ceiling. fed with 10 ft. of quality coax.

At shop ot's a 3/4 wave ground plane hung from ceiling fed with 10 ft. of fair quality coax.

Both work very well. The shop is weird radio-dead area and the 3/4 is better than the 1/4
while it's just the opposite here at the house! Antenna/environment/radio/coax all work together so milage-may-vary.

73's,
Jon

 

[blinddog50]

Dan,
Being in Cary you shouldn't need anything more than a good duckie( RS 800 mhz recommended).
Most of the freqs. that you'll listening to are or now switching to VIPER.
The best 800 duckie that I have found, if you can find one in your attic or at a yard sale, is an antenna from the old bag phones from the early 90's.
If you can find one of these and add a GRE super amp you should do alright.

 

[kb2vxa]

Hi Jon and all,

You omit one very important fact besides a 3/4 wave has a slight bit of gain over a 1/4 wave and which it is depends on the band in question. For example a 2M 1/4 wave is 3/4 wave on 70cM and should be a close approximation of both on the respective VHF and UHF "scanner bands". Taking that into account I suspect that what you're listening to in one environment doesn't hold true in the other OR it's the environments themselves rather than the antennas.

Let me explain that gain thing for those who don't know how it's done. It's all in the vertical radiation angle, a gain omni is designed as to hug the horizon flattening out the pattern and giving greater range. Sit on a doughnut and you'll see what I mean, just don't do it in front of a cop or he'll arrest you for cuelty to doughnuts which happen to be his favorite food and that makes it a felony.

Thanks for making a good point Jon, with so many variables it takes experimentation to come up with a good receiving station. There is no such thing as "one size fits all", what's good for the goose may choke the gander. THAT'S why I always say "do your OWN homework", anything else is cheating and it often backfires when your receiver gives you an F.

Dan, as long as you're talking cell phone antennas there are mobile gain antennas that will boost the signal and avoid the problems often encountered with an amp. For reasons explained time and time again there is no point in trying to make up for an antenna deficit with an amp, that's just begging for trouble. That's why those antennas are sold in the first place.

BTW, the phrase is "Better things for better living through chemestry, DuPont." Frankly you'd do better with Xena than Xanax. (;->)

 

[justdan]

Thanks to all who responded to my query, your insights are most appreciated. Per some of the responders, I think I'll take the "as needed" approach to upgrading the antenna ... seeing how the unit works w/ the stock antenna or RS duckie first & go from there based on how it sounds & your advice above.

Now that I've got the green light from the Mrs., I can order the scanner And then the playin' starts.
Cheers and thanks!!
-Dan

 

[kb2vxa]

Hi again Listens and all,

OK, way to go BUT when you use the "stock" whip antenna for 800MHz it should be 9" long. That's 3/4 wave where it works best and the way I started before I got a cell phone antenna for it. Why not just shoot the moon? Here's how I went about it briefly.

A friend gave me a trunk lip mount Andrew 3dB gain antenna which like a mag mount needs a ground plane surface to work against. I got a 4" square steel electrical box cover and soldered 4 3" wires to it in the corners making the ground plane a bit larger than necissary but too big is better than too small. I drilled some holes in it and using self tapping screws put it on an aluminium L bracket, mounted the antenna on it and screwed it to the wall. I don't have one of those skirted noisemakers to complain so I do what works for me, your particular way of mounting it will likely be more aesthetically pleasing. It finally ended up mounted on the main mast outdoors with the rest of my antenna farm but that's just me, my lights are all green BEFORE the playin' starts. (I just love to rub it in, don't I? (;->)

OK, you have one of THOSE so maybe a mag mount stuck to a bit of sheet metal sitting on a shelf would keep her quiet. Don't fiddle about, just jump to it and skip those interim steps that aren't a stairway to heaven, take the express elevator and get there before the devil with the blue dress on catches you.

BTW, no apologies to Robert Plant or Mitch Ryder but thanks for the inspiration.