Good (small) indoor antenna for DTV reception?
 

Can anyone suggest a good small indoor antenna for reception with a digital converter box?

I'm looking for something that can fit in a small bedroom without making it look like Frankenstein's lab.

Don't talk about bolting stuff on the roof, erecting towers in the yard, etc. Big outdoor antennas are not in the picture, and I can't poke any holes into this room.

So far, I have tried 3 antennas in this room: an old Rembrandt rabbit ear (poor), a modern Radio Shack amplified antenna (better), and a 4-foot long roof antenna that I harvested from an attic (best).

All suggestions are welcome. I'm able to bend & solder copper tubing and wire, so if there is a homebrew plan that would work, that might be fun (and more attractive than most commercial antennas).

Regards,

Phil Nelson

A lot will depend on what your walls are made of (plaster with metal lath indoors? brick outdoors? aluminum siding?), what sort of insulation you have (foil-backed fiberglas?), distance to the transmitter(s), houses in the way, trees, bushes; height above ground, etc. Heck, I have an amplified antenna on a 25 foot mast with a rotator, and because of all the trees, there are some DTV stations just 25 miles away that are now impossible to get. I'll have to wait until autumn and winter to be able to watch anything on CBS.

Basically, unless you have any DTV stations on VHF channels, a good regular UHF antenna is where you'd start. If you have a window where you'd be able to aim an antenna at the transmitter, with a minimum of obstructions, that would be a big help. Sensitivity of the DTV converter is also an issue.

If all the digital channels in your town are up on UHF and fairly strong, an old fashioned UHF hoop antenna will work fine.

---

The digital signal is different
 

Unlike it's analog counter-part digital signals are either on or off, I agree with oven-master that a lot depends upon what type of building you live in. The phase shift on the digital signal will cause it to totally drop out. I do think some of the amplified indoor antennas do work well like the terk models.

I just put up one of the Winegard models on the roof, it works very well

The best top of the set indoor UHF antennas for DTV I have found are the dual bow ties with rear reflector (gold type)...they perform better than the loop or rabbit ears.

I now use a 300-ohm uhf bowtie antenna mounted atop my set, with regular dipole rabbit ears. I route the vhf (dipole) into my Zenith balun under '2-13' and the bowtie into the '14-69' terminals. The signals are then mixed and sent 75-ohm into a male F-connector which i plug into my DTT900 converter. I average 90% reception on all channels found in the auto channel scan. I do live roughly 30 miles from the furthest transmitter, however.

I've been looking at some of the old Winegards for a more permanent solution.

Phil,

Check out: http://uhfhdtvantenna.blogspot.com/

I haven't tried it yet, but an antenna authority in our club says this method may be good, fast AND cheap!

--Dave

Screw my wacky setup! I'm building this tomorrow. Thanks Dave i'll come back with the pics.

I don't know about dtv, but I'm always trying to pull in a good clear picture and sound on ch 56, which is about 50 mi away from me, and I'm in a bottom floor apt. What works for me is 2 of those 'bow tie' antennas. Clip them on to a pair of rabbit ears, on the same rabbit ear, one on top of the other, have them both facing the same direction, whatever produces the best reception, but I only connect the top 'bow tie' to the uhf converter, I've tried several different arrangements of bow ties and that works the best. In my experience the bow ties outperform the loops. I've never tried one of those dual bow ties with the rear reflector, which is basically what I'm talking about here with the addition of the reflector, so that might work better.

Well, that does look cheap and easy. Pretty ugly to tack on the wall in my new "TV room," but maybe I could paint it to match the wall.

FWIW, here is the little antenna that I found in the attic. It had a little green connector labeled with KCPQ 13, a local station. Evidently a promotional item from the time when KCPQ introduced their new UFH channel. I see a little bowtie. Is the rest of it a VHF antenna, or a reflector of some sort? (I know nothing about antennas.

Phil

Dave that antenna is awesome. Thanks for the info and pics on how to build it.
Dan

http://www.audiokarma.org/forums/att...0&d=1213986130

Looks like a Yagi antenna, made for 200MHz) pointing straight up into space. Yagis usually have their booms horizontal, pointing towards the station transmitter tower. The elements can be vertical or horizontal, to match what the transmitter antenna is doing. I don't see the bow-tie (this the right picture?). Also, it may be missing some parts, hard to tell. Hard to tell what the antenna lead in is connecting to.

There is a single bowtie behind the main staff (hard to see in that photo).

It is riveted to the second-to-top pair of crossbar elements and insulated from the rest of the elements by the blue plastic supports. The lead-in comes past the lower blue insulator, next to the yellow caution sticker, and goes to my DTV converter box.

In the attic, it was mounted horizontally (longest staff facing the ground, not the horizon). I just stuck it up this way because it's a small room and I have a short lead-in.

The bowtie is 14 inches long. The crossbars are 24 inches, and the main staff is 50 inches.

Phil Nelson

The "bow tie" is a phased connector for the signal. This antenna is tuned for a specific UHF channel, and is normally used with the elements horizontal and the main boom pointed to the station. I think the end pointed to the station should be the lower end as you have it mounted.

The way you have it, you will get some reception from stations in the direction into or out of your wall.

Edit - you did say channel 13, so that's probably what it is tuned for

A lot of discussion of this very subject over on another forum - most of the antennas built by forum members look like the one shown. I built a similar one, and can say they work great in my area (Norfolk-Portsmouth-Suffolk VA).

Cheers,

Whoa, I got one of those from RatShack quite a few years ago at a clearance. $6. I replicated it with 12ga. aluminum grounding wire for the elements, and aluminum window screen for the reflector. Worked great.

Thanks for that link. I just may build another one of those my own self soon... my present combo VHF/UHF/FM RatShack antenna was their smallest available when I first got it, and it's just adequate, even with an amplifier.

Tom

That would make sense. The little green box connected to it advertised KCPQ and their new "Movie Channel." Coax from this antenna was connected to a much larger antenna in the attic.

Phil Nelson

Looks like a worthy project to me. Interesting that they compared their double-bay version to the Channel-Master 4-bay 4221. It raises the question, "Why not build a 4-bay Gray-Hoverman?". I think I might give that a try. Any thoughts on how best to connect them? An 8-bay? 16? Is bigger better? Does size matter?

Of course a multi-bay antenna probably won't work indoors, which the original topic stipulated. A single-bay ought to fit ok, for example the foil one given as an example that was wall-mounted. Sure looks easy to build.

Phil -

Another antenna that works quite well for DTV is the Philips (used to be Zenith) Silver Sensor. It's a UHF log-periodic that comes with its own tabletop stand and doesn't take up a lot of room. I was planning on building one of the antennas with the reflector when a co-worker loaned me his Silver Sensor, and from what I've read, it compares favorably with the reflector-style antenna.

I'm about 35 miles from the broadcast towers and have the antenna pointed out my front window. I get about 85-90% signal strength on all Chicago channels and can even pick up one out of Gary Indiana if I rotate the antenna 90 degrees.

-Jim

OK, here is what I built, using copper wire, screws, a precut piece of metal from the furnace section of Home Depot, and a stick from the garage.

The lead-in connects at the middle terminals, as per the plan.

It seems to be marginally better than the funky antenna that I found in the attic. With careful positioning, I can receive a couple of stations that had occasional dropouts before.

Not the miracle antenna I was hoping for, but maybe I'm already receiving much or all of what someone can reasonably expect in this location. Some stations come in just fine if you disconnect the antenna and touch your finger to one terminal of the lead-in.

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

Looks like your reflector could be out of phase. The Gray-hoverman has it 3.94 inches behind the plane of the active elements. The website you modeled after uses the wide dimension of a 2X4, which I think is around 3.75 inches. I bet someone out there can show us the math, but if I'm looking at your antenna correctly, it looks lke you used a 2x2. If the reflector is too close (or far), it's out of phase, and the reflected signal, instead of augmenting the incoming signal, will interfere with it instead -- do more harm than good. Don't know if this will help your antenna or not, but might be worth looking into.

Looks like the driven element is indeed too close to the reflector... and that's the first I've noticed the top and bottom bays with crossed feed lines.:scratch2: I would think that perhaps that would end up cancelling out incoming signals?
Tom

Also, the main 2x2 looks kind of metallic (gold). Might just be the photo, or maybe paint. If there's anything metallic about it, the whole antenna's one big short.

The crossed feed lines are curious, but correct. This channel-master looks to be the same design:

http://www.solidsignal.com/prod_disp...om=Large#xview

and the bays are cross-fed similarly. I don't know the math behind it, was hoping one of the experts would chime in...?

Yes, I used a 2x2 rather than a 2x4. Didn't realize that that dimension was important, but again, I know nothing about antennas.

I painted the stick with nonconductive brass-colored paint. Don't think that's an issue.

It's easy enough to rebuild it tomorrow with a 2x4 in place of the 2x2 stick. If the difference between (nominal) 3.75 and 3.94 inches is critical, I can probably find something -- like a strip of cardboard -- to shim it up, at least for testing purposes.

Thanks for the advice!

Phil Nelson

Here's version 2.0, built with a 2x4 shimmed up so that the bowties are just shy of 4 inches from the reflector.

It does work better. I pulled in 6 additional subchannels, compared to version 1.0.

Too bad it's so fugly. Not exactly what I had in mind for this small indoor TV room. Maybe I'll have throw caution to the winds, bore a hole in the wall, and weatherproof it to mount outside.

Phil Nelson

Son of a gun, you're absolutely right. Thank you for that.
Now I'm trying to figure out which is better: crossed or uncrossed. :scratch2:
Here's another call for experts to lend their knowledge on this, please!
Tom

If you are attempting to compare to the ChannelMaster, yours should be the same size. If it is smaller, it will be tuned to a higher frequency.

I've seen commercially made versions of this one http://www.audiokarma.org/forums/att...1&d=1214010356
with a few S shaped wire pieces for decoration attached to the reflector grill, with the entire thing gold colored. And the bow-ties made of stamped aluminium, with some decorative cutouts in the middle of the triangles. Looked briefly at eBay, but didn't see anything like this there right now.

:thmbsp: Looks good, Phil.

The only other thing I'd do is center and stand-off your 30-ohm twin-lead so that it can't press up against any metal of the antenna (as it is in your photo -- several places), which will cost you some gain. Otherwise I think you're gold.

Thanks, I rerouted the twin-lead as you suggested. Works like a champ now.

We were in Fry's electronics to get something else today, and on impulse I bought a Philips Silver Sensor tabletop antenna, which someone had mentioned earlier.

http://www.amazon.com/gp/product/B00..._cp_ob_title_0

The performance is much poorer than this homebrew antenna. Receives only 9 channels, as opposed to 32. Orientation didn't seem to change anything. I'll return it tomorrow.

Phil Nelson

One last footnote. I went to AntennaWeb

http://www.antennaweb.org/aw/Address.aspx

to get a list of digital stations broadcasting in this area. My homebrew antenna receives everything -- including a station 37 miles away. I even get one station that's not on their list.

Lucky for me, all of the transmitters are in the same general direction (southeast). Time to declare victory!

Phil Nelson

That is a sweet Double Bow Tie youve got there wa2ise.

Why is this message box so small?

Anyways, regarding indoor antennas. I have a big instrument measured shootout about to get under way with 20 or so commercially available units over at the AVSforum. And Im working on a guide as well. Its still a work in progress. But its getting there.

Check it out, everybody. Let me know what you think.

EV's Best Top Rated HDTV Indoor Antenna Review Test Round-Up Guide

Nice post over there. This part caught my eye:
"During the transition to digital TV, many stations are temporarily operating at reduced power levels. If you are not receiving certain digital TV stations, this does not necessarily mean there is a problem with your antenna or receiver."
I sure hope this is the case. I have an outdoor antenna 25 feet up. In the winter, everything was fine. But since the leaves sprouted on the 40-foot tall trees that surround my house, I've lost half my DTV channels. Not good.

I also saw that people who rely on indoor antennas for DTV are potentially in for a big hassle: http://www.centris.com/pages/viewnew...ID=34&SiteID=9

I know some people in this situation, and an outdoor antenna is simply not an option for them. Since they refuse to pay to watch TV, there's an excellent chance that they will simply stop watching TV after Februrary 2009.

Oh, and your message box is small because it's an issue of this forum's software and your IE browser. Firefox does not have this problem.

Tom

I use Opera, not IE.

Id use Firefox, but I have others using the same computer, and we(I) decided to use a different browser, just to keep things serparate. Im thinking about switching to seamonkey.

Dumb question here folks. I live 8 miles outside of Madison, and can make one of these homebrew antennas pretty easily. I have a roof mount standard unit now. Should I stick with the rooftop? Or put this beast in the attic? I really hate the look of the rooftop unit and would LOVE to get rid of it.

I have cable, but like having my options open!!

Evan

Post your tvfool.com info.

Depends on where the towers are that you are trying to reach. But Id say an attic mount would be fine.

Post the TVfool info and list the stations you are trying to get. Then I can give you some suggestions and perhaps some dimensions for an improved Home Brew Bow Tie antenna.