new to OTA DTV and have some questions

Your tvfool link doesn't give your results, just the form for entering your location. Save the results to your computer (it's a .png image), then post it as an attachment using the "Manage Attachments" button in the "Additional Options" section of the forum reply screen.

In the meantime, the black box is almost certainly the pre-amp. The power supply is the box by the TV. Try unplugging the power from the power supply module briefly. If you lose most of your signal, then the pre-amp is probably working. An unpowered pre-amp blocks most of the signal.

Assuming the pre-amp is OK, the first thing I'd do is replace the flat "twinlead" antenna cable with RG-6 coax, which doesn't have as much signal loss, and check or re-do the connections up at the antenna.

I was new at once to DTV, so here is what I've learned.

I also had a similar antenna on my house, but replaced it with a channel master 4228. A similar antenna is the antennas direct DB8. I used this antenna because everything I want to receive is either UHF, or high VHF (which does well with the 4228).

First, go back to tvfool.com and note the Real Channel stations, check before and after transition to see if you need a UHF antenna only, or if the UHF/VHF is best for you.

If you are still getting a good signal you may not need a new antenna and pre-amp.

I've read a single RG6 cable will have less loss compared to the 300 ohm wire you are using. I think it can be converted with a balun, my antenna came with one attached.

The link to TVfool you gave didn't go to any data, you can post the text from antennaweb.org, or you can post the picture after you save it from tvfool. (tvfool doesn't include the address you input, so you aren't giving away personal information).

In the ATSC tuner comparison forum, I think the zenith model fares slightly better with tuning.

Actually the twin lead you are using is very low loss. RG6 has greater loss but is less subject to interfearance and is often preferred for that reason. However RG6 quad shield has less loss than RG6. You might want to research antennas and preamps and see what improvements you could make there.

Rick R

Actually I believe "open air" twin lead has the least loss, followed by good quality regular twin lead. That said as Rick-R mentioned there is greater chance of interference with twin lead than coax. Twin lead is very prone to losses if ran without standoff's or near metal etc. So in theory twin lead is the way to go, but in real life stick with RG6. I used to use twin lead that had a metal shielding around it. It was quite stiff and hard to work with. It also had more loss than regular twin lead, but less than coax. Not sure if they still make it, but again in your case I would use Coax and a mast mount preamp to overcome cable loss.
I've also read that the Zenith/Insignia CECB fairs quite well for weaker signals.
For great UHF/HD reception I prefer the 8 bay bow tie (like the CM4228 that DrBri99 mentioned) over the combo w/yagi that you pictured.
Man with a 40' mast, you have potential for one hell of a system. You should be able to DX quite well with some minor improvements. Good luck!

As I see it, the job of an OTA antenna is to supply the tuner with the highest s/n ratio possible at a sufficient signal level.
- the antenna gathers the signal
- the pre-amp fixes a low noise floor and
- amplifies the signal so enough of it reachs the tuner
- the downlead transmits the signal from the pre-amp to the tuner.

Especially with ATSC, you'll get better signal quality to the extent that each of these elements does their job and ONLY their job! I like to start cheap ...

1) Replace the twin-lead with good, commercially-terminated RG-6 cable (Monoprice (above) has 100' of terminated RG-6 quad shielded for under $12). Transmission losses don't matter near as much as the spurious signals the twin-lead gathers. Waterproof all outdoor connections. Add a ground block before going indoors if there isn't one there already.

2) With a twin-lead downlead, I'll wager it's a twin-lead pre-amp - screw terminals instead of F-connectors and twin-lead to the antenna elements. Gains here come from a new, low noise pre-amp and using coax from it to the antenna. Waterproof these connections, too.

3) You have a monster of a VHF/UHF combo, but no VHF stations. There are better UHF antennas, among them the CM4228 already mentioned; I recommend it too.

4) If you can do this yourself, these steps are in order of increasing cost and complexity, and reduced payback. Twin-lead replacement may do the trick, but if you need a crane to do even that, it's cheaper to do it all at once - a CM4228 and pre-amp are only ~$100.

And lest you think this idle speculation, I'm building the second half of my CM4228 clone this weekend and I just ordered new baluns and a combiner to give the big boy a try against stations that are as weak as yours. I will never have your tower, though ...

Frank

Ah, now I see your situation more clearly. I think if you want to get more stations than you do now, you'll have to upgrade the antenna from the combination VHF/UHF job you have now, to at least a UHF-only antenna, or separate VHF and UHF antennas if you want to continue to receive the VHF analog stations until they shut down and/or you want to try to get KFVS-DT after analog shutdown. (It looks like it's the only CBS station in your area.) After analog shutdown they'll move their digital signal from channel 57 to channel 12. They can't keep it on 57 because that's one of the channels that are going to be sold off for other purposes by the government after analog shutdown. All your other digital stations will stay on UHF channels.

For UHF, the usual two suggestions here for deep fringe reception are the Channel Master 4228 that's already been mentioned, and the Antennas Direct / Terrestrial Digital 91XG. They're very different designs with somewhat different characteristics. I'm going to go with the 91XG myself when I upgrade my setup because it seems to deal with mulitpath interference better, and I have a lot of that from trees behind my house.

For VHF the choice depends on whether you want to keep getting 3 and 6 until analog shutdown, or just 12 (before and after). Good antennas for the full VHF range are big and heavy because the low-VHF channels (2-6) have longer wavelengths. On the other hand, good antennas for high-VHF only (7-13) are much narrower and lighter. An example is the Winegard YA-1713. It might be a good idea to go for an antenna that's cut specifically for channel 12, since that's the only VHF channel you'll need after analog shutdown, and it's pretty far away and weak where you are. (I think Wade makes those things.)

I have a large combination VHF/UHF antenna from Radio Shack, with a Channel Master 7777 pre-amp. My reception starts to deteriorate around -90dBm, and pretty much peters out below -100dBm except when I have good tropospheric conditions. That's consistent with what you report.

You've got a lot of good advice here. The only thing I didn't see mentioned is that you cannot simply replace the twin lead with RG-6 and two baluns because the baluns will not pass the DC voltage for the preamp. The baluns are DC shorts. You'll need to replace the preamp if you switch to RG-6.

Chuck

Actually, he'll just need the type of baluns that pass DC. Mast mounting pre-amps with coax is commonplace; there's no issue getting DC through.

Thirty years ago I lived in a difficult OTA area (as I do now but it was a different place then). I had a 100' run of twin lead using standoffs until it entered the house then ran it through the walls. I got all 8 OTA sataions but several were a little snowy. A salesman talked me into replacing the twin lead with coax (RG59 as that was what was used then). I completely lost all but two channels. Had to spend a second weekend snaking the twin lead through the house again. Had to argue with the salesman to accept the coax return.

Rick R

CM 4228 antenna, CM 7777 pre-amp, add rotator.

Also, do the grounding right. At my old house, which was a nightmare for reception (several large trees, a ridge 250 feet higher than the house in line of sight of the closest stations) I was able to pull in two more stations after I went through and cleaned up the grounding.

If it is a preamp, it needs power. There would need to be a separate cable to provide power to the preamp, or a power supply inline with your downlead.


No. I doubt the preamp you have is a modern good quality low noise preamp. Also, 300 ohm downlead hasn't been used in years and is probably old.


If it is in new condition, OK. But I expect it is old and corroded. You are better off with new low loss coax.


A new low noise amplifier. I am not using a preamp, but I am only 32 miles from my transmitters. I am using an amplifer to overcome loss from cable & splitters; as I have every room wired for TV.

Coax selection is critical. TV channel 51 (the highest used after the transition to digital) is at 698 MHz. You want to have the least amount of reasonable loss at that frequency for a run of 60+ feet of coax.


Well, he has no VHF stations NOW. But after the transition some stations will change where they are physically broadcasting. I did a quick search on some of the stations listed and found that KFVS, which is currently on 57 (12.1) will broadcast from 12 after the transition.

Note that we are currently using channels 2-69, but after the transition, not only will full power analog broadcasts be turned off, but all stations must be on channels 2-51. Therefore any station with a current (digital) broadcast on a channel between 52 and 69 must move it.

You're right that there will be VHF stations in the markets he's receiving, post-transition, but I didn't see any he'd be able to get. Newtothis2 posted a pre-transition listing, and I can get close to it using TVFool and his city and zip. Flipping to post-transition, his strongest VHF is Ch 5 in Nashville and at the limit of reception. We really need his address of lat/long to be sure, (or a TVFool chart, post-transition) but there may be no point to VHF reception beyond hobbyist DXing.

Yeah, the main reason I mentioned VHF was channel 12 which appears to be the only CBS station in his area. That one's a pretty long shot.