HDTV antenna question

[chad_96]

Hello all,

Came across an interesting thread of using a indoor/outdoor amplified HDTV antenna on a SDS200. Some with successful results.

I found This HDTV antenna I linked has been successful for someone, and thought for the low cost I would try it.

I just have a couple questions. The specs state the impedance is 75 Ohms. Would this be a concern as typical antennas and coax are at 50 Ohms? That's if I understand that correctly...

The next question is, if anyone could help me out, if I wanted to use a small length of coax to get it a little further, would I need to use a 75 Ohm coax for an extended length? I have a small length of lmr-240uf coax but obviously it's 50 ohms and not sure how that would work, or if at all with the HDTV antenna being 75 ohms.

I think those are the only questions I could think of about trying out a HDTV antenna. Any help on my questions would be greatly appreciated. If anyone has any other advice or such on it, I would greatly appreciate it as well.

Thanks all.

 

[mmckenna]

Hello all,

Came across an interesting thread of using a indoor/outdoor amplified HDTV antenna on a SDS200. Some with successful results.

I found This HDTV antenna I linked has been successful for someone, and thought for the low cost I would try it.

I just have a couple questions. The specs state the impedance is 75 Ohms. Would this be a concern as typical antennas and coax are at 50 Ohms? That's if I understand that correctly...

Not an issue.
Most scanner antennas are not 50Ω across their designed coverage.
And most scanners don't provide a true 50Ω load to the antenna.

It will not hurt anything.

The next question is, if anyone could help me out, if I wanted to use a small length of coax to get it a little further, would I need to use a 75 Ohm coax for an extended length? I have a small length of lmr-240uf coax but obviously it's 50 ohms and not sure how that would work, or if at all with the HDTV antenna being 75 ohms.

That would work fine.
Or, just go to Home Depot and get some RG-6 the right length to reach from the antenna all the way to the scanner. It's super easy to install the F or BNC connectors sold along with the coax. Nearly fool proof and will work better than multiple lengths of cables with lots of extra connectors.

I think those are the only questions I could think of about trying out a HDTV antenna. Any help on my questions would be greatly appreciated. If anyone has any other advice or such on it, I would greatly appreciate it as well.

Thanks all.

You might find better performance if you rotate the TV antenna 90º. TV stations broadcast with horizontal polarization. Most LMR stuff is vertically polarized.

 

[chad_96]

Not an issue.
Most scanner antennas are not 50Ω across their designed coverage.
And most scanners don't provide a true 50Ω load to the antenna.

It will not hurt anything.



That would work fine.
Or, just go to Home Depot and get some RG-6 the right length to reach from the antenna all the way to the scanner. It's super easy to install the F or BNC connectors sold along with the coax. Nearly fool proof and will work better than multiple lengths of cables with lots of extra connectors.



You might find better performance if you rotate the TV antenna 90º. TV stations broadcast with horizontal polarization. Most LMR stuff is vertically polarized.

Thanks for the assistance!

I will try the 4' lmr-240UF with the adapter for type F first and see how well the antenna works for me when it arrives. We don't have a very good home improvement store anywhere near by, nor a home depot, that sells stuff like that anymore. So I will have to do that on the next trip to the front range area for the RG-6.

Appreciate the help!

 

[a727469]

I always wanted to try something like this. Does anyone have real life experience with one besides the Inland since it probably cost more to ship than the price of the antenna and I do not see it on Amazon where I could get free shipping? Must have good Vhf since most communications in my area are there.
Thanks

 

[chad_96]

I always wanted to try something like this. Does anyone have real life experience with one besides the Inland since it probably cost more to ship than the price of the antenna and I do not see it on Amazon where I could get free shipping? Must have good Vhf since most communications in my area are there.
Thanks

Believe it or not, I bought the inland AN-5008 through microcenter with shipping for $22. That's the only reason I am going to try it out.

There are threads I read about people using them. Just type HDTV antenna in the search, or, Inland HDTV antenna, and you should get some of the threads of folks using them.

Hope this helps you in your decision a little. Have a good day.

 

[merlin]

Some things I looked at using HDTV antennas.
The 75 ohm impedance is of little or no concernwith receivers, most of those will match anything from 35 to 100 ohm.
Amplified, well extending coax, an extra 100 foot of RG6 will have minimal loss across 88 MHz to 1 GHz.
If your SDS200 is as sensitive as my BCT15X, a preamp is hardly needed with outdoor antennas, I use 6 DB attenuator on mine or I have overload issues. Indoors, I wouldn't go over 5 Db gain.
As mentioned, HDTV antennas are horizontally polarized, mounting to vertical will improve signals but also directional, so a means of rotating the antenna is something to consider

 

[merlin]

A factoid: There really is no such thing as an HDTV antenna, they are just a TV antenna, nothing more.
What they market as HDTV antennas they work best above channel 6. Most NTSC stations re-broadcast from translators from 108 to 960 MHz

 

[a727469]

I thought a factoid came out of a flying drone🙂

 

[nd5y]

Most NTSC stations re-broadcast from translators from 108 to 960 MHz

There are no TV stations or translators between 108-174 MHz or above 698 MHz.

 

[wtp]

Key points about HDTV antenna frequencies:

• VHF: Covers channels 2-13, considered "low-band" VHF (channels 2-6) and "high-band" VHF (channels 7-13).
  
  
• UHF: Covers channels 14-51.

or from 54 to 698

 

[Ubbe]

I had a UHF TV antenna as my only scanner antenna for maybe 10 years. One thing to remember about the yagi types are that they usually increase in gain the higher you go withing their frequency range but then drops off sharply above its upper frequency. But going lower in frequency usually only drops off gradually. If using a TV antenna to receive 800-900MHz frequencies then probably a different type like a logperiodic one could be more suitable.

My yagi antenna for my TV was designed for up to 600MHz and when a new channel appeared at 695MHz it was totally dead. I removed element after element and when only the main dipole remained I finally got some signal. Then I bought a new full band TV antenna.

The TV antenna for the scanner worked fine down to 410MHz and also worked satisfactory at VHF and airband, better than a single VHF dipole.

/Ubbe

 

[chad_96]

I had a UHF TV antenna as my only scanner antenna for maybe 10 years. One thing to remember about the yagi types are that they usually increase in gain the higher you go withing their frequency range but then drops off sharply above its upper frequency. But going lower in frequency usually only drops off gradually. If using a TV antenna to receive 800-900MHz frequencies then probably a different type like a logperiodic one could be more suitable.

My yagi antenna for my TV was designed for up to 600MHz and when a new channel appeared at 695MHz it was totally dead. I removed element after element and when only the main dipole remained I finally got some signal. Then I bought a new full band TV antenna.

The TV antenna for the scanner worked fine down to 410MHz and also worked satisfactory at VHF and airband, better than a single VHF dipole.

/Ubbe

Thanks for the reply Ubbe.

I'm trying a indoor desktop type HDTV antenna, more so as an experimental antenna. Will be for 800mhz band. Just concerned of any possible damage that could happen as the product information states it has a gain of 30 dB. Don't want to end up destroying the scanner over an experimental situation. I have seen another person using the same antenna and works well for them. But, of course, they are in a different state and area and I'm not aware of their specifics.

I will attach a picture of the antenna. I'm not sure what type of antenna it would be considered, other than obviously a TV antenna. I do have a cheap yagi off Amazon I'm going to try out as well.

 

[wtp]

for reception only, there are no rules.
it is what works best for you.
from a paperclip to a $6,000 antenna if it works, use it.

 

[mmckenna]

Just concerned of any possible damage that could happen as the product information states it has a gain of 30 dB. Don't want to end up destroying the scanner over an experimental situation.

Consumer antenna gain numbers are pretty much meaningless. They get overly inflated to impress those that don't understand that you can't cram 30dB of gain into an antenna that small.

If the antenna has a built in preamp, then it may be legit, but all it's going to do it amplify what little signal it gets by 30dB.

It's not going to damage your scanner unless you lived next door to a TV transmitter.

 

[chad_96]

for reception only, there are no rules.
it is what works best for you.
from a paperclip to a $6,000 antenna if it works, use it.

I tried the paperclip method also...

Was just released from the burn unit down at the local hospital a few days ago.

That's apparently not where the paperclip was suppose to be inserted.

Thank you for the response!

 

[chad_96]

Consumer antenna gain numbers are pretty much meaningless. They get overly inflated to impress those that don't understand that you can't cram 30dB of gain into an antenna that small.

If the antenna has a built in preamp, then it may be legit, but all it's going to do it amplify what little signal it gets by 30dB.

It's not going to damage your scanner unless you lived next door to a TV transmitter.

Thank you. I know nothing much of it other than it plugs in. Nothing more about pre-amps, or even how the HDTV antennas would work. Like I had mentioned I'm just really experimenting with it on my neighboring county site. The sds200 analyze function shows low signal strength and mid-high signal quality. Just seeing if I can get that signal strength up as I can eliminate the other site and be more efficient all around.

Thank you!

 

[wtp]

my mom used to tell the story of the lights going out in the house and found me with a fork in my hand and a black mark on the outlet.
we sold the house and the mark was still there.

 

[wtp]

this is not me and someone on here has it as an avatar.
but an incredible simulation.

 

[mmckenna]

Thank you. I know nothing much of it other than it plugs in. Nothing more about pre-amps, or even how the HDTV antennas would work. Like I had mentioned I'm just really experimenting with it on my neighboring county site. The sds200 analyze function shows low signal strength and mid-high signal quality. Just seeing if I can get that signal strength up as I can eliminate the other site and be more efficient all around.

Thank you!

Found the manual online.

The antenna has two cables coming out of it. One is a coaxial cable for connection to the TV. The other is a USB cord, for powering the amplifier.

https://manuals.plus/m/113b1368e771dd133b376b59dda060a2a7c873b7e267abdbfedc8b93ee970e38_optim.pdf

Try the antenna with the USB cord unplugged first and see if it does what you need. If not, try powering it up. Not going to damage the scanner, just like it wouldn't damage the TV set.

 

[chad_96]

my mom used to tell the story of the lights going out in the house and found me with a fork in my hand and a black mark on the outlet.
we sold the house and the mark was still there.

I hear you. When I was around 5 my parents owned a restaurant. One night after closing time my mother and father were shutting down and I decided to stick a fork in their new fancy industrial toaster to get a piece of bread out of the bottom.

And I still remember the feeling I got when that fork touched the inside of that toaster. I truly understood the meaning of Metallica's album Ride The Lightning.