Crazy idea for antenna maybe

[mdel747]

Hi guys well i finally got my scanner took forever on ebay must be a good one every one wanted them

I ended up getting a BC796D it comes with power but no antenna , So heres the problem and the question ,

I live in a tight valley with tall hills on 3 sides of the house , so i need a antenna that will get out of the valley , up in back of the place it has a old farm , foundation only really but there is power lines running up there , power is not on fuse is taken out off the lines at the pole at the house , Runs about 1/4 of a mile up the valley ,

so is there a way to use that pair of power lines as part of a antenna system ?

Or use them to run up to the tel-pole up at the old barn and hang a antenna up there ?

or what would you suggest ? ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,

OK HMMM i think i found the answer and its ,,,,NO it will not work to much loss of signal in that type of wire

how about running over head cable between the poles like the phone lines run its a 4 pole run to the top ?

I included a pic so you can see what I'm talking about

 

[conve36]

How far are you talking about running the cable? Using the existing lines is out of the question. But depending on what frequency you want to monitor, you may be able to run some RG-6 TV cable...

 

[mancow]

Maybe put a 996 or similar up there with a wifi link to a pc running proscan. That is, provided you have a way to run power and a secure environment.

 

[talkpair]

I think the power line thing as an antenna idea is out.......They sold a gadget back in the 70's for television reception that never really took off....It plugged into a standard outlet, and was supposed to replace the need for an outdoor antenna on over-the-air televisions.

The first thing I'd do would be to survey for yourself, using a regular outdoor antenna. Temporarily test the reception at both the house and the proposed site and compare, just to see if it's worth the trouble taking the next step.

Pick some stations in distant cities, or counties and compare the reception.......NOAA weather radio can be helpful for this purpose, only pick one of the stations you don't normally listen to that is further away....just to see if you can pull it in.

I have a somewhat similar situation you describe, except the distance between the two points is less than 200 feet.
I solved it by building my tower at a higher point and putting the radio equipment in an enclosure at the base of the tower, and pipe only the audio (speaker) over a twisted pair telephone cable buried back to the house, along with a power wire.
You have a few options for power......have the commercial power restored, solar power, wind power.......or just buy a couple 12 volt car batteries and alternate them between charges.

The options for getting audio back to the house aren't as easy......twisted pair or coax would probably work, but with the distance involved, i'd be afraid that the induction from the first close hit of a lightning strike would take out your scanner.......

It's "possible" that an old 49 Mhz baby monitor could 'repeat' the audio from the scanner that distance, but couldn't say for sure.....those devices are designed to be always in transmit mode.

If you're a real geek, and are line-of-sight, you could probably stream the audio over a wifi connection between the two points.

It just takes a little creativity.

The biggest drawback for my setup, however, is the lack of access to the front panel of the scanner.......I have to hike out to the tower to add / delete / change channels.

This can be a real pain if something unusual is happening, and your scanner gets caught on the local cop that sits and runs license plates all night long.

I really have my scan-list fine tuned where I don't really mess with it much.

Hope I've given you some ideas......and Good Luck !

 

[n0nhp]

If I understand correctly, the power lines are open on both ends, If so you can make an antenna out of one of the wires. You would be making a "long wire" at scanner frequencies. As such the antenna would be very directional along the wire. If this is ok (your target transmitters are in the same direction as the wire) run a piece of coax up the pole and sit back and listen. Just make sure to remove all (ALL) possibility of the lines becoming re-energized.

Bruce

 

[prcguy]

I agree here and the wires are probably hundreds of wavelengths long at VHF and UHF which can have a ton of gain off the ends at slight angles. If the wires are heading away the the rough direction of the stations you want to hear they may be usable. If there are only two in parallel it may be possible to terminate them with a few hundred ohms of resistance at the far end to make it directional instead of bi-directional. This is a job for EZNEC if someone has time to model it.
prcguy

If I understand correctly, the power lines are open on both ends, If so you can make an antenna out of one of the wires. You would be making a "long wire" at scanner frequencies. As such the antenna would be very directional along the wire. If this is ok (your target transmitters are in the same direction as the wire) run a piece of coax up the pole and sit back and listen. Just make sure to remove all (ALL) possibility of the lines becoming re-energized.

Bruce

 

[mdel747]

scanner will be here Monday or Tuesday , the seller found a antenna he said and will send it along ,
i will see what i can get at the house , then load my power box on the 4 wheeler and run up to the top and see what difference there is ,

 

[mdel747]

guess i will ask a wire question , if i was to run a wire for the antenna up the 300 or so yards

what type would i need ?, and would i need a booster ( like for TV ) on the antenna end as there is a outlet on the pole up there i would only have to energize the lines again OR would the booster work at the house end ,

just asking as i could price things out if needed

 

[petnrdx]

Coax loss.

RG-6 is going to loose about 2.5 dB per 100 ft at 150 mhz, about 8 dB per hundred at 800 mhz.
AND RG-6 is the wrong impedance (75 ohm instead of 50 ohm).
While the impedance mis-match isn't a big deal, it causes a bit more loss.
Any cable that you can afford is going to have more loss than the gain you might get.
Even good RG-8 type coax is still going to loose around a dB per hundred ft at 150 and around 5 dB at 800 mhz. And those cables are going to run 500 bucks for a 1000 ft roll.
Probably the best option is a directional gain antenna on a mast or tower that it pointed at the transmit site you most need to listen to.

 

[mdel747]

RG-6 is going to loose about 2.5 dB per 100 ft at 150 mhz, about 8 dB per hundred at 800 mhz.
AND RG-6 is the wrong impedance (75 ohm instead of 50 ohm).
While the impedance mis-match isn't a big deal, it causes a bit more loss.
Any cable that you can afford is going to have more loss than the gain you might get.
Even good RG-8 type coax is still going to loose around a dB per hundred ft at 150 and around 5 dB at 800 mhz. And those cables are going to run 500 bucks for a 1000 ft roll.
Probably the best option is a directional gain antenna on a mast or tower that it pointed at the transmit site you most need to listen to.

for a tower to get over the top the hill would have to be 100/150 foot tall ,
the scanner got here today I'm letting it warm up before i try her out

ebay seller gets a 5 star for quick shipping

we will see if it gets anything in once it warms up

 

[petnrdx]

Coax

It should not need to warm up...
Maybe you would have to be 150 ft up for true "line of sight", but you will be surprised how much you can RX that is refracted over the hills around you.
Assume your scanner receives a signal that is "understandable" at around -110 dB.
Probably whoever you want to listen to is transmitting at 100 watts, which is +50 dB.
If they use a "gain" antenna with a net of 3 dB, that means the system has a +100 dB signal.
You receive at -110 dB that is a margin of 210 dB total.
Do some research on the location of the system you want to monitor to find out how far away it is, and use one of the on-line path loss calculators that calculates for the freq band you want to listen to.
With that you should be able to see if it is WAY outside the possibility of being heard.
There are LOTS of other variables, but if the calculator says your path loss is 300 dB, there is no way to make that work.
But, if the path loss is 150 dB, and the signal is 210 dB, you could hear it if you find a "hot spot" even down over significant hills.

 

[petnrdx]

Boy, did I screw that up.
Lets see who catches my misteaks...
Never calculate when you are tired.

Should be +53 dB, difference of 163 and all the other values adjusted accordingly.

 

[mdel747]

that makes sense , I'm trying to find the freq for around here now , SW Wisconsin Iowa Richland grant sauk county's ,

i found i was looking threw the pdf i have for it and i find it;s not a BC796D its a BC785D it looks to have the apco card in it when i looked in the little door on the back , i don't know what the difference is in the 2 models ( ebay listing said BC796D ) so i don't know

is there any free software to program this unit ,( looks like you need a masters deg, for it lol )

 

[mdel747]

as you can tell this is my first scanner sooo i am clueless to half of the stuff is said on the forum

but it makes sence to get it up in the air with out getting over the top ,

 

[petnrdx]

Scanner.

Having a P25 card would be nice if that is what it is.
I have only been thru that part of WIS a couple of times, but it seems to me that it is more rolling hills, not mountains.
So, hearing VHF or UHF dispatch agencies could be fairly good if they use repeaters.
If you are wanting to hear simplex mobiles (meaning direct, not thru repeaters) then they would have to be much closer.
You might be able to hear public safety grade repeater systems 25 to 50 miles away.
Just depends on the topography.
When in doubt, try it.

 

[n0nhp]

ProScan isn't free but will give you un-crippled 30 days. If you get a RR premium membership, it will suck down the frequencies right off the site and program them into your radio.
In the mean time go to the database button on the top of the page and navigate to your area and plug a few freqs in.
Good luck
Bruce

 

[mdel747]

ProScan isn't free but will give you un-crippled 30 days. If you get a RR premium membership, it will suck down the frequencies right off the site and program them into your radio.
In the mean time go to the database button on the top of the page and navigate to your area and plug a few freqs in.
Good luck
Bruce

OK thanks i upgraded and downloaded the proscan , only to realize i don't have the RS-232 to usb
i thought i had every cable out there well have one on the way now ,,

but maybe it will give me time to figure out the proscan program , any hints

 

[prcguy]

You don't want to use the free space line of site calculators for terrestrial links, they cannot calculate ground reflections and will be off as much as -30dB to +6db over reality.There are calculators for terrestrial links but I have not found a free one yet.

Also, what is -110dB and +53dB? Do you mean dBm? Without a designator they are just meaningless numbers the way they were presented.
prcguy

It should not need to warm up...
Maybe you would have to be 150 ft up for true "line of sight", but you will be surprised how much you can RX that is refracted over the hills around you.
Assume your scanner receives a signal that is "understandable" at around -110 dB.
Probably whoever you want to listen to is transmitting at 100 watts, which is +50 dB.
If they use a "gain" antenna with a net of 3 dB, that means the system has a +100 dB signal.
You receive at -110 dB that is a margin of 210 dB total.
Do some research on the location of the system you want to monitor to find out how far away it is, and use one of the on-line path loss calculators that calculates for the freq band you want to listen to.
With that you should be able to see if it is WAY outside the possibility of being heard.
There are LOTS of other variables, but if the calculator says your path loss is 300 dB, there is no way to make that work.
But, if the path loss is 150 dB, and the signal is 210 dB, you could hear it if you find a "hot spot" even down over significant hills.

 

[davidmc36]

i don't know what the difference is in the 2 models ( ebay listing said BC796D ) so i don't know

Have a look at these wiki entries. You can see some differences in the types of systems they will cover. that may or may not cause you any concern.

BC785D - The RadioReference Wiki

BC796D - The RadioReference Wiki

 

[davidmc36]

It should not need to warm up...

Being delivered to WI in December it would likely be a good idea to allow the scanner to come to room temp before turning on with all the condensation that could form.