Will an antenna tuner work on HDTV?

SWHouston

Moderator
Staff member
#2
Greetings Gary welcome to the Forum :welcome:

Are you saying that your HDTV does not have a built in Tuner ?

Take a look at the Spec Sheet or look for the following labels on it...
If it has a Digital Tuner in it, it will have a label like...
HDTV
DTV TUNER
SDTV TUNER
HD TUNER
DTV-READY

If it does not have a ATSC Tuner in it, then these may be seen...
HD-MONITOR
HDTV READY
HDTV CAPABLE

Should the latter be the case, then you can purchase a Digital Tuner, or, I believe there are resources where you could buy the parts, and assemble one yourself.

Just in case you'd like to test your TV, you can buy/borrow a simple set of RabitEars or other Antenna to temporarily connect to the set, do a scan, and see if you can receive any Digital station. If you can, then your set has an ATSC/Digital Tuner in it, and you then can arrange for a more perminent acceptable Antenna System for it.

Have a good Day ! :)
S.W.
 
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gary350

DTVUSA Member
#4
Greetings Gary welcome to the Forum :welcome:

Are you saying that your HDTV does not have a built in Tuner ?

Take a look at the Spec Sheet or look for the following labels on it...
If it has a Digital Tuner in it, it will have a label like...
HDTV
DTV TUNER
SDTV TUNER
HD TUNER
DTV-READY

If it does not have a ATSC Tuner in it, then these may be seen...
HD-MONITOR
HDTV READY
HDTV CAPABLE

Should the latter be the case, then you can purchase a Digital Tuner, or, I believe there are resources where you could buy the parts, and assemble one yourself.

Just in case you'd like to test your TV, you can buy/borrow a simple set of RabitEars or other Antenna to temporarily connect to the set, do a scan, and see if you can receive any Digital station. If you can, then your set has an ATSC/Digital Tuner in it, and you then can arrange for a more perminent acceptable Antenna System for it.

Have a good Day ! :)
S.W.
What I am says it, I am looking at a graph of the gain of the CM4228 antenna. Gain is low in the low frequency range and gain goes up and up about double in the high freq. range. Gain appears to peak about channel RF 42 then drop to RF 51.

The antenna CM4228 must be a better match for high freq. than low freq. I am thinking a variable capacitor and a choke coil could be used to tune the antenna to pick up better in the low freq. range.

Check out the link. http://www.aa5tb.com/tuner.html
 
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Fringe Reception

Super Moderator, Chief Content Editor
Staff member
#5
Gary, :welcome:
Thanks for the link but are you sure this antenna tuner actually works at UHF frequencies? In every way to me this looks like something for HF, perhaps as high as 6-meters and below.

Still, its pretty cool and being a packrat, I probably have what it takes to build a similar unit right now ... and I have better vintage knobs! Oh Lord, help me find a new home for the 'junk' I've collected over the years!
Jim
 
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serndipity

DTVUSA Jr. Member
#6
The purpose of an antenna tuner is to match the signal source and load impedances.

This is done because the maximum signal (i.e. power) transfer occurs when the signal source (i.e. antenna), load (i.e. TV) and any transmission line (i.e. coax) are all of the same characteristic impedance.

However, while the losses due to mismatches can be profound, an antenna tuner would not be an appropriate solution for TV reception.

First of all, the load impedance (i.e. TV) is fixed at 75 ohms. The variable is the impedance of the source (i.e. antenna). This means that the tuner must be located at this point and adjusted for each channel (e.g. typically not practical or convenient).

Because TV signals can be transmitted in 3 very different groups of frequencies (e.g. VHF-low, VHF-high and UHF) and antennas are frequency dependent, the design of a tuner to cover this range of frequencies would not likely be realizable (e.g. far be complex, challenging consruction and expensive).

Fortunately, antennas have been developed that will present a near constant source impedance and gain over a very wide range of frequencies. With a load/source mismatch of typically less than 2:1, the losses would be no more than 1/2 dB (i.e. insufficient).

The CM4228 is a UHF antenna. Initially, I thought you meant that you wanted to tune it to receive VHF channels. However, from the graphs in the link below, you may only be trying to improve it's gain within the UHF band.

Temporary page

It appears that there is an easier, practical solution

Another link that may be of interest is:

Channel Master 4228
 
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Fringe Reception

Super Moderator, Chief Content Editor
Staff member
#7
Above, what Serendipity said is spot on:

Saying it another way, your antenna system has to approach 75 ohms impedence (not a direct-current measurement as seen on an ohm-meter) for it to efficently pass RF signals to your TV set. That's what your receiver 'wants' to "see" because it was designed that way.

In specific situations anything is possible: an example from my LF Ham radio days: if you used an antenna tuner connected to a copper stake nailed into the stump of a long dead tree (1953 Radio Amateurs' Handbook) it could become a useable transmitting antenna (only because the antenna-matcher allows the transmitter to not self-destruct). NOT to say this would an efficent transmitting antenna and the receiving results on the same 'antenna' will be virtually non-existant! I think the 'concept' of an antenna matcher is a wrong choice for OTA HDTV, certainly wrong for UHF frequencies/channels.

Back to today: anything between your antenna and your receiver 'theoretically' attenuates the signal -- even joining two coaxial cables to each other to extend their length generates unexpected losses. If there is an A-B switch between antenna systems, there may be LOTS of loss (view my switch folder here).

I wish Piggy would chime-in and add to this post because his experience is beyond mine.
Jim
 
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gary350

DTVUSA Member
#8
I am not saying I want to connect this exact 6 meter tuner for a TV.

I am say will a tuner designed to work on TV frequencys work on a TV antenna?

I guess I forgot to mention I have a VHF antenna too.

The frequencies I want to receive are.

VHF channel 4 = RF-10 at 192-198 MHz

VHF channel 5 = RF-5 at 76-82 MHz

VHF channel 8 = RF-8 at 180-186 MHz

UHF channel 17 = RF-15 at 476-482 MHz

UHF channel 2 = RF-27 at 548-554 MHz

UHF channel 30 = RF-21 at 512-518 MHz

UHF channel 28 = RF-36 at 602-608 MHz

UHF channel 5 = RF-50 at 586-692 MHz


I plan to connect the CM4228 to the UHF connection of the preamp

I plan to connect the VHF antenna to the VHF connection of the preamp.

I plan to connect one 75 ohm coax cable form the preamp to the power supply.

I plan to connec one 75 ohm coax cable from PS to TV.

I hope that makes it clear now.

I thought an antenna tuner tuned the antenna to make a perfect match to the frequency that is trying to be received. Maybe I am wrong about that.

I am a builder and a pack rat. I use to have a lot more electronic parts than I have not. I cleaned out my shop got rid of lots of old parts I wish I have never done that. It is fun to build and experement. I could build 8 different antennas for all 8 frequencies I want to receive and use a switch to connect each antenna to the TV at the time I want to watch that channel. There are 100s of free TVs on craigslist I have been thinking about collecting 8 TVs then build an antenna for each TV and us each TV to watch a different channel. That might be fun to have a TV room in the house like a movie theater room if each TV has its own antenna there won't be any need to have an all band antenna so one TV will pick up all the channels. Probably a crazy idea but its fun to think and day dream up ideas even if I don't build them. For now I will stick with 1 TV, 1 VHF antenna, 1 UHF antenna and a preamp.
 
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Fringe Reception

Super Moderator, Chief Content Editor
Staff member
#9
Gary,
Take a look at this page: Temporary page It shows performance comparisons between different UHF antennas and the old-style 4228 (I use one) is an excellent choice for you to receive channels 27, 36 and 50, and its not bad for your channels 15 and 21.

Considering your channel 15 is only about 3-4db down from the antenna's peak gain, and the insertion of any device will cost you at least 3.5db, I don't see a reason to use any sort of antenna tuner with your 4228. Perhaps someone else here can respond about VHF and the use of some sort of antenna tuner.

To receive VHF 5,8, and 10 on one antenna, you will probably need an old-style low/high VHF Yagi and they can often be found free on Craigslist.

If you posted a hot-link to your TV Fool report here, it would be far easier for us to diagnose your situation and make better suggestions.
Jim
 
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#10
In the April 2009 QST there is an article on p 34 that would help you build a tuner:
Hairpin Tuners for Matching Balanced Antenna Systems; Balanced Transmatch designs for 28 to 450 MHz by John Stanley, K4ERO. If you built such a tuner you would need an instrument to adjust it for best match like a 75 ohm SWR bridge (the 50 ohm type is more common) or at least a signal strength indicator.

http://www.arrl.org/qst/?month=4&year=2009#toc table of contents, not article
 
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