The Official AVS Antenna and Related Hardware Topic! - Page 500

Update on the Audiovox DT60CFTR "RCA in-line F-connector for RG6 coax" splice kit

Since my previous posts:

http://www.avsforum.com/t/381623/the-official-avs-antenna-and-related-hardware-topic/14760#post_21974161
http://www.avsforum.com/t/381623/the-official-avs-antenna-and-related-hardware-topic/14790#post_21982470

I sent my broken and defective DT60CFTR splice kit to Audiovox, and a month later I received a new replacement DT60CFTR. Unfortunately, it is from the same bad lot with a Date Code of "3107SE". The DT60CFTR was sent back to Audiovox because the center connector diameter was too loose for reliable and tight contact with a standard RG6, .040" diameter center conductor. Testing with a bare Channel Master RG6 coax .039" dia. center conductor sample, I found the replacement DT60CFTR center contact is also too loose, at least on one side. The other side is sufficiently tight.

However, using a pair of mini needle nose pliers, I could squeeze the tiny DT60CFTR split-tube gold-plated center contact so that it does fit tight and reliably onto a .039" RG6 center conductor.

Hopefully, Audiovox engineers have heeded my complaint letter, sent with RG6 coax conductor samples and the defective DT60CFTR, so that DT60CFTRs sold in the future will not have this defect. In the meantime, you can still use this product only if you first test a bare sample of your RG6 coax center conductor for fit and adjust the DT60CFTR center contact with mini needle nose pliers for a tight fit before installing it.



Edited by Smoke_signal - 6/7/12 at 3:22am

That seems like an awful lot of,trouble to go through... I think I'll stick with the old barrel connector, some di-electric grease, and wrap the heck out of it with electrical tape...

After posting in May about a store bought antenna, I decided to try a DIY coat hanger antenna. (Posts 14770, 14774 and 14778)

To my surprise, this is bringing in five channels just sitting in the room near the outside wall.

My question is, for green and yellow strength signals, how do I decide if adding a preamp or amplifier will bring in more channels? Also, which ones would fit a simple four bay coat hanger UHF design?

A reference that I could read and learn from is what I am primarily seeking, but if someone has a summary for dummies to post, I would appreciate it.

Steve

Antennae suggestions:

We just moved to a new house and are looking to put up an antennae. Here is the result from TVFool:



I'm not in an ideal location as the house is surrounded by trees and is down a slight hill. Here is a shot of my location; I'm more or less dead center, at the end of the cul de sac:



Any suggestions would be greatly appreciated.

@stevesr0 you were told in no uncertain terms that you should not use an amplifier of any sort. Your strongest signals are too strong - even if you ran 60 feet of coax first.

Second, I hope you used a design from this site for your antenna. Typical "coat hangar" antenna designs on YouTube and other web sites are too small for today's UHF band.

Third, read the Signal Analysis FAQ at TVFool to see how to relate predictions to required antenna gain. In summary, the equation you would use is: Noise Margin - environment losses + Antenna Gain - Cable Loss > or = 0.

Noise Margin: predicted by TVFool in dB over the minimum required for reception
Antenna Gain: greater or lesser sensitivity in dB compared to a dipole antenna. 0 dBd is equivalent to 2.2 dBi (sensitivity compared to an isotropic antenna)
Cable Loss: using RG-6 coax, that's 2.5 to 3 dB per 100 feet VHF and 5 or so dB per 100 feet UHF
Environment losses: the hard-to-predict losses encountered when an antenna is indoors. could easily be 20 dB or more

When a preamp is used, the equation becomes: Noise Margin - environmental losses + antenna gain - amplifier noise figure > or = 0. The preamp zeros out cable losses at the expense of adding noise. High quality preamps have noise figures of 3 dB or less. Cheap preamps have NFs of 8 or more dB.

@geddy76,

Your TVFool report is at the zip code level - not accurate enough for our use. Try the "Start Maps" option to place the receive location icon right over your house, then create the radar plot. Do not post the graphics from the report - post the URL.

Here you go:

http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3d13493da9c66c0d

geddy76,
Are you mainly just interested in the major networks that are closest to you?

Correct. The big 4 and PBS are all we really care about. CW and ION would make my wife and son happy, but aren't mandatory.

And I'm planning on mounting this on the roof, despite the chart showing that alot of my channels would be okay with an attic antennae. I'm thinking that with the trees and elevation (or lack thereof) that I'll need every inch I can get.

The pretty standard recommendation is a model from the Winegard HD769xP series. Without the trees, I would have suggested either the 7694 or 7696. Considering your surroundings, the 7696 is the smallest antenna I'd consider. The 7698 may be a better bet.

As far as the trees go, you may have better luck trying to look under the leaves. Your report at 10 feet suggests that there would be enough signal to work with.

You must be up in Charles Co., MD. I'm to your southwest with 2-edge paths to DC, but no trees. I get the entire market with an attic installation.

Close. I'm in Calvert County. When you say going under the trees, are you implying this shouldn't go on the roof?
Also, i couldn't tell from Winegard's site, but is this amplified? I'm hoping to split the signal at least once to feed two EyeTVs.

Thanks!

+1 on the suggested "under the trees" (as in nearer the ground), instead of the roof. You can easily try this with a temporary setup in the yard, before doing anything permanent. Placing the antenna on top of two wooden or fiberglass step ladders would make it possible for you to test the lower setup.

For your channels of interest, you should have enough signal to split to two TVs without adding any sort of amp, if using one of the antennas Dave Loudin suggested. You want to avoid amps if at all possible.

Awesome. Thanks to you both. So it looks like I have an initial plan.

Reply to Dave Loudin:

Thanks for comments.

Reassuring to know all I need worry about is antenna itself.

The DIY site you mentioned looks quite interesting.

I guess the message is if I want more channels than I can receive with this first DIY, to build a better one after scrutinizing the material from that site and elsewhere on this one.

Great forum.

Steve

@stevesr0, http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3D7fcf99c735cd96 is the TVFool report you posted earlier. For best results, you will need to use the 4-bay antenna design that favors channels 7, 8, and 9. A bit of history: that DIY site evolved from the "how to build a UHF antenna" thread at this site. If you want to try another bowtie project, there really is no reason to look anyplace else for ideas.

If you want to try another commercial antenna, an RCA ANT-751 would be a good choice.

The CW is usually hardest to receive full power DC station. ION should be a piece of cake. I suggest the Winegard 7698 at a minimum for reliable reception of the CW.
I agree. Attic installations are very unpredictable. I strongly suggest roof mounting to avoid frustration when conditions deteriorate due to weather & other factors.

I can't emphasize enough how your antenna needs to be above those trees. I've had my spectrum analyzer over to several locations where the antenna was looking through trees and the signals can be pretty ugly and vary dynamically with tree movement. Some signals make it through while others are destroyed. UHF is much more affected than VHF in most cases. With that many trees I'll be surprised if you get much trying to look under the trees. It should be a piece of cake with an antenna above the trees.

Chuck

I installed the antenna this weekend. Got to say that it works 100%. I am not looking for long range stations but just my local and network channels. Got them all and they are all coming in strong. The antenna is even pointing through some trees and doesnt seem to be affected.. Thanks for the advice

Has anyone ever used PVC pipe as an antenna mast? Are there any reasons not to do this? Just trying to save a couple of bucks.

Also, would someone recommend a static discharge unit that won't rob too much signal and is inexpensive?
Edited by RayGuy - 6/10/12 at 8:46pm

PVC is very flexible in the small diameter you'd need for a mast unless you only need a foot or two and are installing a small TV antenna. I wouldn't try 5' of it with a a moderate to large antenna. I've used fiberglass as a non-conducting cross mast when I needed that but I think it's more expensive than a metal mast.

Chuck

Dave,

Thanks for your comments.

I will review that thread and the RCA antenna you named.

Steve

I have, but I sealed in an old broom stick handle in it with polyurethane glue. Unless you already have the broom stick and polyurethane glue (which goes bad fairly quickly if not used) on hand, its cheaper to buy galvanized EMT pipe for a mast.

Well, I will get a chance to try the FM6 without the 7777 way sooner than I ever thought I would... Weekend before last I was listening to the HD receiver when a friend of mine knocked on the door. He came in and I turned the volume down while he was there. When he left, I increased the volume and heard only static noise. I tried stations all across the dial with the same result. Hhhhmmm. I hooked the TVs 7777 power supply up to the FM6 for a minute and I was back in business. I unhooked the TV PS and connected it back up to the TV antennas. I then went online to find a replacement PS and found one, an open box item, at the Channel Master web site for around $30 or so. I got it last Thursday and installed it on Saturday. It lasted about 3 minutes before it went kaput also... (Glad I disconnected the TV PS when I did!). So, apparently I've got a problem up top, so I am just going to hook the FM6 directly up to the receiver. I guess I will see how that does...
Edited by OTAhead - 6/15/12 at 4:42am

I have found that HD Radio reception locks in better without an amp, and that FM6 is a good FM antenna. But if you do use the amp, hopefully it is the older style CM7777, as the new version has a higher noise figure and reportably does not work as well.

The old 7777 wasn't all that quiet and I've yet to see independent technical measurements of the new one.

HD radio signals are much weaker than the main analog signal (-12 or -20 dB), so any amp that adds IMD would be particularly detrimental to the HD signal.

The FM6 is, indeed, a pretty good FM antenna.

Follow up. I put the antenna together yesterday (Winegard 7698). I tested it by setting it on my deck railing and bringing the laptop with EyeTV out to it. It received all the major channels us I few I wasnt expecting to receive. I then mounted it on the roof and tapped into the old DirectTV cable that was up there. Plugging the laptop into the other end of that cable in the basement I was still receiving the same channels. However, when I connected it to the end of the run the previous owner had laced out to the other end of the house ( where the living room is) all but 2 stations are gone.

Is this a cable-run issue? An amplifier issue? Any suggestions?

Also, the signal strength meter in EyeTV reflects a significant drop-off when plugged into the final destination.

Is there a splitter of some sort between the basement and living room? And if there is, is it a conventional 2 or 3 way splitter, or is it a splitter from the original DirectTV system?

There is no splitter. Only a few barrels.