Base scanner antenna setup

[lu81fitter]

I am looking at upgrading my antenna setup for my base scanner. I monitor the Illinois STARCOM 7/800 system, UHF 450-470, and VHF 140-165. I live about 35 miles north of Peoria, IL , right along the Illinois River.
I have one of these ---> www.theantennafarm.com/catalog/laird-technologies-abscanc-1048
Would a good groundplane kit be enough to monitor systems with that antenna? (Looking to pick up STARCOM towers from Congerville and Metamora, and also from LaSalle.) They come in very weak now.
My current setup is a homemade groundplane with a mag mount NMO. The connectors are less than desirable.
I will be getting new coax and connectors. The coax will be about 45 feet long and the antenna is about 20 feet AGL.
Are there other options?
Also options for coax... I was thinking RG-6. It will be receive only.
Thanks for your considerations.
Tim

 

[DJ11DLN]

It should work fairly well. I have a similar setup with a Larsen tri-band/ground plane kit and I'm very happy with it.

 

[mmckenna]

That antenna would have some gain on UHF and 7/800MHz. Theoretically, all other things equal, it -should- work better than a discone.
Look at one of the online coax calculators and compare cables. RG-6 would probably be fine.

As for if it'll work, you'd need someone local to answer that. A good test is to take your scanner up on the roof of your house with the stock antenna and see if you can receive it. If you can, this antenna should work fine. If you can't hear it at all, likely you've got some topographical shielding going on that is blocking things.

 

[lu81fitter]

I'm looking for a good groundplane kit.
Was considering this ----> www.theantennafarm.com/catalog/laird-technologies-mbcn-7531
I know it says its only up to 512 MHz, but I was thinking that just meant the radials were longer.
Is there a significant difference in groundplane kits?

 

[lu81fitter]

That antenna would have some gain on UHF and 7/800MHz. Theoretically, all other things equal, it -should- work better than a discone.
Look at one of the online coax calculators and compare cables. RG-6 would probably be fine.

As for if it'll work, you'd need someone local to answer that. A good test is to take your scanner up on the roof of your house with the stock antenna and see if you can receive it. If you can, this antenna should work fine. If you can't hear it at all, likely you've got some topographical shielding going on that is blocking things.

The scanner is a Uniden BCD996P2. I know there are some topographical issues, but the signal I have now is weak and I have a less than desirable setup. Was thinking this would improve things. Just looking for suggestions where I may modify my current way of thinking. "Another set of eyes" on a situation can't hurt.

I'll take a look at those coax calculators. Thanks for the recommendation.

 

[mmckenna]

I'm looking for a good groundplane kit.
Was considering this ----> www.theantennafarm.com/catalog/laird-technologies-mbcn-7531
I know it says its only up to 512 MHz, but I was thinking that just meant the radials were longer.

It'll work fine for what you are doing. As the frequency goes up, the radials would get shorter anyway. For receiving use, it won't make a big difference.

Is there a significant difference in groundplane kits?

Not really, other than how they do the cable. The N connector on the base is what I would have recommended.

Just pay close attention to weatherproofing the connections. While N connectors do have a gasket, adding additional to the outside is standard procedure.

 

[mmckenna]

The scanner is a Uniden BCD996P2. I know there are some topographical issues, but the signal I have now is weak and I have a less than desirable setup. Was thinking this would improve things. Just looking for suggestions where I may modify my current way of thinking. "Another set of eyes" on a situation can't hurt.

I'll take a look at those coax calculators. Thanks for the recommendation.

What is your current antenna setup?

 

[mmckenna]

OK, found the old messages you sent me.
It'll be an improvement, but how much is hard to say.
With topographic shielding, height can be a benefit. Getting it up high might address the issue, but that can add cable length, which can detract from performance.

Really, the only way to know is to give it a try.

 

[lu81fitter]

Thank you for taking the time to look for my old messages. I will continue with this upgrade. I know that my location is not the best. But it's worth a try. I'm not expecting miracles, but just wanted some input.
Thank for your efforts.

 

[mmckenna]

With the right info, it could be figured out before doing any install, but that's a lot to do via chat boards. Knowing the location of the transmitter (it's on the FCC license) you want to listen to and your location, put those in Google Earth and use the "ruler" function to draw out the path. Use the "absolute" setting under altitude. That'll show you if there is an unobstructed path. Even if the path is obstructed, it might work as reflection off hills, buildings, etc can bring the signal in from other directions.

You can go a bit further, using the distance, you can figure "free space losses" to figure out how much signal will be lost between the transmitting antenna and your antenna.
If you knew the ERP (transmitter power - feed line losses x antenna gain), sometimes on the FCC license, you could figure out how much signal was leaving the site. That could tell you (roughly) how strong the signal would be reaching your antenna.
Then you could figure in your feed line losses and you'd get a pretty good idea if there would be a usable signal at your radio.

But, by the time you do all that math, you could probably stick the antenna up there and figure out the same thing.

Google Earth can be a useful tool for this sort of stuff. I've be using it at work to proof out a proposal to do a multi hop microwave link to one of our (very) remote sites. Being able to visualize paths on Google Earth can help quite a bit.
However, it's still fun and worthwhile to stick an antenna up on a pole and give it a try.

 

[trp2525]

...I will be getting new coax and connectors. The coax will be about 45 feet long and the antenna is about 20 feet AGL...
Also options for coax... I was thinking RG-6. It will be receive only...

I'm looking for a good groundplane kit.
Was considering this ----> www.theantennafarm.com/catalog/laird-technologies-mbcn-7531...
Is there a significant difference in groundplane kits?

I have a similar setup on my roof with an Antenna Specialists MON731 scanner antenna which is essentially a ground plane kit with an N connector mated with an Antenna Specialists all-band MON series NMO antenna. (BTW the MON731 was discontinued back in October 2005: https://www.universal-radio.com/catalog/scanants/3376.html) Your choice of a ground plane kit with an N connector is definitely better than an SO-239/PL-259 termination especially for the higher 800-900 MHz frequencies.

My antenna is approximately 30 feet AGL with a total run of 65 feet of RG-6 coax (quad-shield with a solid-copper center conductor). I terminate at the antenna end with a high-quality F compression connector (similar to what the cable and satellite companies use) mated with a high-quality F-to-N adapter. At the scanner end I terminate with a high-quality BNC compression connector designed specifically for RG-6 coax and that eliminates the need for any additional adapter at the scanner end.

My reception with this setup is excellent and certainly meets my needs. I previously had an ST-2 Scantenna mounted in the same exact location with the same RG-6 coax length and the overall reception with my ground plane antenna is definitely superior.