The Official AVS Antenna and Related Hardware Topic! - Page 345

Yeah, I really dont know why it does that. Some have that zig zag at the bottom, while another piece right next to it is perfectly straight up and down.

I saw a tip on a bamboo website that tells you how to grow square bamboo (instead of round). Basically, you put a heavy square tube of appropriate size on it when it spouts up in the spring and it will follow that form. Ill think Ill try it when it starts to sprout up soon.

One of Confucius' sayings was "We can live without meat. We can live without rice. But if you take away our bamboo, we will die".

Oops, I was wrong. It was another GPX. (Coby, GPX and others are probably all made in the same factory in China anyway, heh) So I have 2 GPXs, and 1 International (made in Korea), heh.

Picture of the backs of them for comparison :


The left black one is the oldest, circa 1988 or so. The grey middle one is the newest, circa 2004 or so. And the dark gray right one is circa 1997. They all work, and are pretty much equally sensitive. On the black International one, I tried to put an F connector on it, but it doesnt work out too well for some reason, heh.

The GPXs take 10 "C" cells, while the black International one takes 10 "D" cells.

I paid $9 for the middle gray one new at a local department store on sale (bought about 5 of them for gifts, heh). I got the International one at a Goodwill store for $5 and just picked up the circa 1997 one, new and in original box, for $5 at the local flea market. They are excellent TV/AM/FM devices to have along while fishing, heh.

Heres a picture of a 2 element UHF corner reflector log-yagi growing out of my compost pile, heh.

Here is my comparison of the Apex DT502 vs the Sansonic FT300A when used as a signal level/BER meter, first in a strong signal area. The signal level readings in dBmV were made with a Sadelco DisplayMax 800 and a 719E SLM (Q=quality, S=strength):
And then in a weak signal area:
Note: The initial signal level readings are a little lower than last time because I needed to use a 4-way splitter instead of a 2-way splitter to feed 4 pieces of equipment. Because OTA signal levels are constantly changing, the attenuator settings don't exactly match the signal level meter readings, but this doesn't invalidate the general trend of readings.

Conclusions: The Apex box gives a wider range of readings than the Sansonic, and these readings are more consistent in that they are repeatable when given the same signal again. The Apex needs an inverter to run on battery power, which was necessary because I had to move to other test sites with my car because my CM4221 antenna at home is pointed across a well-traveled road which constantly changes the signal bar readings.

The Sansonic box works just a well as the Apex as a DTV converter box and it can run on battery power, but my main concern is its usefulness as a measurement tool. Its readings take a long time to settle (which I could live with), but they are not consistent from time-to-time which puts its accuracy in question. I can't recommend the Sansonic as a measurement tool. My results with the Sansonic confirm what the NAB-MSTV Converter Box Report says about it in this quote (they call it #7):

Their report is here:
http://www.nabfastroad.org/NAB-STV%2...y-report1.html
Click on Digital Converter Box Report which should take you to:
http://www.nabfastroad.org/NAB-STV%2...report.doc.pdf
The quote is on p22 of 53 of the pdf, which is p5 of 36 of the LABORATORY TEST REPORT under Signal Quality Indicator.

Edit: Added equivalent dBm values for 719E dBmV figures using conversion factor of -48.8 for people used to tvfool signal power values and to compare with NTIA sensitivity spec of -83.0 dBm for CECBs. The dBmV figures for the 719E are less accurate below -30 dBmV because the meter scale is crowded at that end. When using a very weak signal for comparisons, I add a preamp between the splitter and the SLM. Since it is not in line with the tuners its noise figure does not affect them:
http://www.avsforum.com/avs-vb/showp...ostcount=10649

Update: For some strange reason the Apex DT502 has trouble with ION network stations. I tried 3 different units. Also, the Apex does not allow you to add a channel after scan.

Thanks for the measurements rabbit73, they are still useful.


Yeah, consistancy and repeatability are important for any measurement tool. A yardstick that expanded and contracted would be pretty worthless, heh. (but would make a very good April Fools joke on any carpenter, he he)

I wonder what the malfunction could be ??

300ohm,

How well does that thing work? Do you have any measurements on it or Manf./Model #?

Do you mean the compost pile UHF corner reflector log-yagi ??

I believe it was a uhf front end to one of Radio Shacks highest gain combo antennas, (circa around 1985, dont know the model number but maybe could find it in an old RS catalog) which I believe were manufactured by AntennaCraft at the time. When I found it, the big VHF/FM section was so completely mangled up and most of the plastic pieces were broken, that I scrapped it for parts. (It probably came down in a big storm because the original owner didnt know the first thing about properly securing an antenna, or had followed the advice of a RS sales clerk, heh)
The UHF director boom was also mangled up pretty bad, but at least I had the first director in front of the driven elements, (the most important one) and after unbending what I could, put on a director boom with elements using typical UHF director spacing found on other similiar antennas.

I made a rough NEC model of it last September, but need to recheck my measurements before posting the file. With the 8 directors on it, in real life testing, it performs worse than a SBGH for channels below 51, but a little better on channels above 60. My DBGH blows it away on channels below say 55 and does about as well on the channels above 60, so I no longer use it.

Actually, some of the brownish spots you see on the booms are not rust stains, but rather whats left of the original gold anodizing, heh.

Thanks for replies. I got another 4' of mast and will play around with tilting and posistion when (and if) we get a nice sunny weekend. I see (using Google Earth) that I am in a shadow for CBS. Will rotate and scan for other stations also. Thanks again.

I originally posted this in my home area thread. But, I realized that it probably belongs here.
I am shopping for an antenna. I live less than 10 miles from the towers. Most channels are UHF. I do want to receive VHF channel 7.1, .2, .3.

TVFool is attached

Solid Signal suggested the Winegard HD7010. It is just barely in the budget. Actually a liitle outside once I consider the cable and stuff (from monoprice.com). I can swing it though. I saved some money on the TIVO box at Sears today. The $299 box was on sale for $189 and i got 5% off for floor model. I was planning on a refurb for $199.

I am also considering the Antenna Craft HBU22 which may be overkill, but is a few dollars cheaper for what appears to be more antenna.

I do like the price on the Winegard HD1080 $25.82 and free shipping. I don't know if it will meet my needs though. Solid signal says it will. I would hate to need to return it though.

Any suggestions?
Am I stressing too much about this and pretty much anything will work?

bcicocco,

Very well written and informative post! You have very strong signals in your area. It is very possible that you could receive all you locals with a **non**amplified indoor antenna such as the Radio shack 15-1874. See: http://www.radioshack.com/product/in...ductId=2103077

If you go outdoor antenna, the HBU22 is an excellent choice in your price range. Winegard 1080 has very poor reception for high vhf channel 7 and I would clearly avoid it in your situation.

HTH,

Rick

Yes, you are stressing too much.

All you probably need is a set-top antenna with both a loop and rabbit ears. You can probably find those at Big Lots for $10.

From Solid Signal's collection if you want to go outdoors: Antennacraft AC9 or Antennas Direct V10 are both adequate for your needs.

The AC9's price would work in your favor.

You don't need much antenna since you are so close.

So, after hitting the local Menards, Lowes and Home Depot I came up
empty handed for 300 ohm twin lead.

The only thing I could come up with was a wimpy 300 ohm FM antenna
from Magnavox.

The FM antenna wouldn't even pull in a signal.

So, I took your advice and bought some bare 16 gauge copper wire
and made a tuned antenna for VHF 7 out of masking tape, electrical tape,
some scrap plywood and a balun adapter, and guess what, it works great!

Total cost: $2.64 (copper wire)

Out of the Radio Shack UFO, and the Cornet F-645A indoor antennas, my homebrew was the only antenna that worked at all.

It's an ugly beta version, but it proves a nicer design will only work better.

I'm able to pick up VHF 7 indoors on my APEX DTV box with 68% signal strength and 100% quality (it has dual meters)

So, thanks again everyone!



I used the link below to make this beast.

I ordered the HBU22 from Solid Signal. I'll let you know how it goes.

In the meantime, I built the homemade antenna here. I tried it on my mom's TV (she lives a couple of blocks away) and got 9 channels in, all strong, including all three VHF 7channels. I am pretty sure the HUB22 will meet my needs now. I don't know that I will get any more channels. But I will get those 9.

BC

Using the 16 gauge copper wire for the driven element is better than using twinlead. However, the connection from the antenna to the TV should be 300ohm twin lead (or a balun and a length of 75ohm coax cable. )

if it receives or transmits the signals you want then it's not ugly, though some antennas might be better looking than others.

Yeah. I still wonder why they did that, it does have separate F connectors. Maybe it could be hacked so you could have a vhf and uhf input at the same time like on my CM0264. It would make a lot more sense then.

That masking tape on the wall however........................heh.

I'd like to offer you two suggestions you can try that may improve your reception.

1. To maintain the symmetry of your antenna, wrap electrical tape around the board every 6" or so.
2. Use screw terminals (wood screws and washers) at the feed point to maintain a 1" gap and attach a high quality balun (Channel Master 0089) there.

Thanks for the tips. Yes, the masking tape is just a temporary
solution. I actually have some paint leftover from that room,
and I'll be painting the wood that color and using those 3M
removable stick-ons to attach it to the wall.

I'll keep the element copper wire, and add some 300 ohm feedline
from somewhere. Heck, I'll even order that ladderline if I have to.

Would adding wood screws and washers alter the pattern?
Everything I read about antennas stresses keeping metal
away from the elements.

if you are feeding a device with a 75 ohm coax input then you could add a balun to the antenna feedpoint and use coax all the way. you may not need to buy the 300 ohm cable at all.

using the adhesive mounts would work. picture hanging devices (metal hooks) would work. having the wood backing extend a few inches longer than the antenna and putting screws in there would work. all these would keep metal away.

yes metal nearby (as in screws) does affect but so does the wall it is hanging on. make up the antenna and if it functions well then go with it even if it isn't optimum in all respects.

you've got good results with what you did. securing the elements a constant distance every six inches as was suggested will be a big improvement. using coax as a feed line or 300 ohm will be a big improvement. if those give a good signal then a screw or two may not matter.

Uh, the CM7777 already does accept VHF and UHF input at the same time. It has 2 75-ohm inputs and a 75-ohm output.

Just a tip about masking tape. You want to remove it as soon as possible. If not, it sets in and becomes harder to remove without wall damage.

You dont want to build a quick simple antenna and then have to spend many hours on a spackling and paint job for the wall. That kind of defeats the whole purpose, heh.

As an old saying goes, NEVER argue with success!
Heck if its ugly looking but it works, I doubt he would see any improvement going to 300 ohm flat lead....given the size of the wire, and the picture, he COULD be 300ohm now!! (remember, ladder line Z is dependant on wire size, distance, etc).

Masking tape is designed to be removed within 24 hours.

That could very well be true. But usually the odds are stacked way against it. If I were to place a bet, I would put my money that it wouldnt be 300ohm impedance, heh. (we have legalized gambling in Delaware, heh)


When I use it for painting a straight edge, I like to remove it within 30 minutes of finishing. Even then I sometimes get that nasty residue. (I know, I should break down and use that pricey blue tape, heh)

The use of two separate amplifiers, one for UHF and one for VHF, significantly reduces the possibility of overload.

Hey all, my inlaws have a vacation home upstate ny in the town of franklin. Its in the middle of no where. We have a radio shack indoor antenna which can be found here We get like 4 channels that come in somewhat clear but needs a bit of tweaking with the antenna. Last time i was up there i connected a digital converter box and got about 2 channels. Last week i built a homemade antenna which i followed the instructions according to this site. I connected it at my home on long island and get a decent amount of clear channels. I live somewhat close to where the signal is being emitted. Im wondering what type of antenna might be best for the house upstate based on this image i got from tv fool. I know its going to be tough but i was hoping to pick up some more channels for when we go up and visit.

With everything being MANY miles away, you WILL need an outside antenna and a decent amp like a Channel Master CM7777. I suggest you get 20ft of top rail post, slide them together and then use 3 screws (short sheet metal self tappers work fine!) 120 degrees apart to hold it together just above the joint..then a bracket from Radio Shack or similar to mount it to the eave or side of the house...put a decent outdoor antenna with the CM7777 right below it at the top of the mast, then walk it up, work the bottom into the ground at least 6in deep and clamp it in. I did that and it cost me MORE in the amp than the antenna (an older RS VU90) and mast, etc combined! Works like a champ and I get stations almost 90-100miles away from Houston a lot of the times (not ALL the time! 90+ is beyond the RF horizon..I DO get a station out of SE La ok all the time...your mileage may vary as they say)...forget the indoor stuff...especially with digital in the rural areas (we have a lot down in here in Texas like that; Outside of Houston, DFW, Austin, San Antonio, etc). With the arrangement above you can turn it by hand from the ground. not needing a rotor up top! Saves some cash...Looking at the printout, you may be able to point due north or slightly west and not have to turn it...

Wow, you are in a black hole of signals. I didnt think a place like that existed on the east coast.


You would be probably better off with this model here : http://www.radioshack.com/product/in...ductId=2062017

Like Dr Touchtone said, youre going to need a very high gain antenna, mounted outdoors way up high with a low noise preamp like the CM7777 to even have a chance at receiving some of those stations.
Some high gain do it yourself antennas can be found here http://www.digitalhome.ca/forum/forumdisplay.php?f=186 and here : http://www.avsforum.com/avs-vb/showt...798265&page=74

In a place like yours, I would seriously consider getting my home entertainment from a dvd player, heh.

so my best bet would prob be a "Grey Hoverman" type antenna with a amp
edit: i have an amp i found in my basement identical to this but just a different brand, would this work with the grey hoverman antenna?