Antenna recomendations and Construction Questions
Over the past several days I've been using Google and this site to learn about making my own TV antenna. It appears that you guys have done some fantastic work coming up with various designs that all seem to work very well. I'm a bit overwhelmed by all the information and don't really know which way to proceed. I need some guidance.
I have never seen the software you are using for the analysis, so I don't know how to use it (or if I can even run it, I'm using Debian 9), so I'm frustrated with trying to understand what I'm reading. I did finally find a .pdf with pictures and dimensions for building a GH antenna. I picked up some #6 AWG copper and bent it into the shape specified, to try and see what would happen.
At the moment, I've only used it with a short piece of RG-6 with the antenna sitting (vertically) on the floor next to the TV. It does not have a reflector on it. My floor is about 6ft AGL. So far, I haven't been able to pick up the only vhf channel (ch 9) in the area but I am receiving the stronger UHF channels. (I'd like to try and get as many channels as possible, naturally.) The performance is good enough that it makes me want to try and build a "real" antenna but I need some help.
This is my tvfool report
My physical location is out in the woods down a dirt road. I'm surrounded by trees all of which are much taller than the house. The ground (dirt) is relatively wet (I'm in a flood plane). The peak of the roof is approximately 25 ft above the ground and I'm guessing the best I'd be able to do is a mast along the side off the house, not much taller than the peak.
Based upon this info, which antenna would you all suggest I try to build?
Has anyone used the "L" shaped angle aluminum to make their antennas? Does the "L" shape have an adverse effect? I'm considering the 1/16th thick by 3/4 wide stock.
I've tried to solder pieces together but haven't been able to. I'm not set up to do this, so I expected that result.
I have joined pieces together using aluminum pop rivets. Along a 4ft piece, I'm seeing 0.01 ohms of resistance with my multi-meter. I assume this is negligible and won't affect performance, but correct me if I'm wrong.
Long term strength of the rivet connection I'm unsure of, so I'm considering something like the clear J-B Weld epoxy to reinforce the mechanical connection. I've never tried this before, would epoxy affect the electrical characteristics of the antenna?
I'd like to use some hardware cloth as a reflector to keep construction simpler; please advise if this is not a good idea.
Another nagging question I have (and don't know if its a good idea or not). Has anyone investigated using one reflector between two antennas? The idea being to improve reception in the "opposite" direction. Kinda sorta like an onmi antenna, but hoping for the gain of a directional antenna. I guess I'm envisioning folding a DBGH in half. Comments?
Anything else you want to add that you think I forgot to ask would also be helpful. I don't know what I don't know, so I wouldn't know to ask about it.
I can probably help to get ya going fairly quickly to at least be able to take a source file that someone else prepared, and be able to run the simulation locally...
Personally, I have never worked with angle. Here have only used copper wire, and in some application Copper Tape to 'draw' an antenna on to a plastic sheet that will fit inside a typical window. I am sure you'll wind up with something that works for you using what you have available... That is what makes it fun.
I'm running Debian Buster, which is the RC1 of Debian 9. I have found and installed Xnec2c from Debian's repositories, which is version 4.1.1. I have copied the above mentioned in-line files to use as input (under open file menu selection). This opens a 2nd window for me, but I'm presented with numerous errors, which I click OK to, to get through them all. (I have to assume that the files are correct, otherwise they wouldn't still be there, thus there's something wrong on my end.) I can then see a lot of stuff in a window, of which I haven't a clue as to what I'm looking at. I've come across some of your posts, where you display the results of the program, but what I'm seeing doesn't look anything like what you present.
If I remember, some of the errors I see say some type of Card error. I read that the nec program was originally written in FORTRAN. That a ham operator took it upon himself to convert nec to C language and put together the Xnec2c.
I no longer have any of my FORTRAN books. It has been around 30 years since I last saw an IBM punch card. Am I correct in assuming that each line of source file is equivalent to an individual punch card? That when I see references to cards, they are referring to an individual line of the file?
I've been trying to brush up on my antenna theory. I was never any good with Calculus and the last time I used that was prior to the punch cards, but I'm seeing formulas, which to me anyway, resemble Calculus. I'm assuming that these modelling programs take care of all the heavy lifting mathematics, so I don't need to relearn that stuff?
I'm also hoping that once I have the program operational, that all the variables will start making sense as to what they are?
Going back to my aluminum choice. I seem to remember learning about E and H fields, the electric and magnetic fields. I'm now coming across E and M fields as I read. Did labels change, like E to V did in Ohm's law equations?
If my memory is still working correctly, along a waveguide, the E fields would run along either the vertical or horizontal faces of the waveguide and the H field along the opposite faces (which on which depending upon polarization). With the "L" shape of the aluminum, being only half of the shape of waveguide, I was wondering what affect, if any, would be caused? If there is an effect, it might dictate which direction I need to orient the "L" shape. I'm making another assumption, that these programs can/will account for something like that?
I've also tried to use nikiml's plugin for Firefox, but still no joy.
Any help you can give me getting the programs running would be greatly appreciated. Doing all this remembering, so far back in time, especially since I haven't used it much, is really making my head hurt. I think I'll stop thinking now and go get something to eat.
Sure No problem...
Step 1, we have to get you the last version of the NEC2 program for linux that actually works with Nikiml's Python Optimization/Evaluation scripts.
As mentioned here in this post.
NEC2 is no longer supported/included in the modern Debian based Distros, so I had to download the source from debian and compile these .deb packages myself to get NEC2 going again. Note that 'NEC2' is not the same as 'NEC2C'. In order to run Nikiml's python Scripts we have to use the 'NEC2' engine.
These packages I've made available on my google drive. feel free to download them and install with 'dpkg'. When you get them installed, let me know and we'll point ya in the right direction to get Nikiml's python scripts installed, etc.
First two are the libf2c dependencies (fortran to c library). 3rd one is NEC2 itself.
I've used 4nec2 to analyze over 800 different Antenna Designs.....and have looked at a LOT of Antenna Builds....so I can help you chose an appropriate DIY Antenna....but I'm NOT in the Antenna Construction/Installation business....
I've looked at a LOT of user installation reports, but I do NOT recall ANYONE using Angle Extrusion rather than Circular Rods. Obviously, Angle Extrusions would have a MUCH higher wind resistance....and may or may NOT break sooner than Rods....it would depend a LOT on the inherent strength of the chosen metal formula....I would ALSO be worried about how it holds up to wind induced vibration.
Since an outdoor antenna needs to survive high winds [esp. in your location], I would highly recommend that you stick with what we know WORKS...namely 3/8-in Aluminum Rods.
Although very useful, TVFool isn't always being updated with latest changes....your area (Phase 2) finished the "Channel Repack" on 21Apr2019, and I'm pleased to see that TVFool shows the new Channels for WFSG (Ch28) and WBIF (Ch26)...but does NOT even show WJHG (Ch16). Hence, we also want to look at your www.rabbitears.info "TV STUDY" Report [post Repack at 30-ft height]:
[This is for the zipcode location (Post Office???) more than 5-mi from TVFool location....you can enter your address for a more accurate report]
First of all, FORGITABOUT receiving WDIQ (PBS) on weak Ch10....it's on Second Harmonic of Extremely Strong [-7.6 dBm] FM Station on 96.9 MHz....which would likely explain why it is NOT included in RabbitEars list.
Note that RabbitEars Report adds WFRW (IND) on strong Ch14 [NM=62.9 dB per R-E] and WJHG (NBC/CW) on strong Ch16 [NM=31.2 dB per R-E]....and for some reason I/we do not YET understand, calculates MUCH higher signal strength for WDHN (ABC) on Ch21 (NM=34.8 dB vs 18.3 dB per TVFool) and WDVX (FOX) on Ch33 (NM=17.1 dB vs 2.1 dB per TVFool)...and significantly LOWER signal strength for WFSG (PBS) on Ch28 (NM=5.6 dB vs 13.3 dB per TVFool).
You "should" receive (i.e. NM>10 dB) fol. NETWORKS: CBS on KTVY (Ch36), NBC/CW on WJHG (Ch16) ABC on WDHN (Ch21) [as well as WMBB (Ch13, Hi-VHF Band)] and FOX on WPGX (Ch9) [and MAYBE also WDVX (FOX) on Ch33]. So it is UNCLEAR whether you NEED a Hi-VHF Band Antenna [to receive FOX on Ch9 instead of Ch33], in addition to a UHF Band Antenna.
IF UHF-Only, a simple SBGH with 4 or 6 Pairs of Reflector Rods "should be adequate". You've probably seen Autofils's SBGH on-line drawings with 7.08-in=180-mm Zig-Zags at 45-deg Angles and 5.0-in=127-mm Horizontal "Spurs", which you will find for both with and w/o 6-Pairs of Reflectors in my fol. Analysis for the No Reflector Version:
https://imageevent.com/holl_ands/gra...bghnoreflector [Autofils's SBGH w/o Reflectors Analyzed]
OR nikiml's GH4 (4-Pairs of Equal Length Reflector Rods) with Optimized Dimensions for slightly improved performance:
nikiml's Antenna pages - GH4 UHF antenna [nikiml's Optimized GH4, Dimensions in figure]
OR nikiml's GH6 (6-Pair of Un-Equal Length Reflector Rods in a more complicated Array):
nikiml's Antenna pages - GH6 UHF antenna [dimensions in on-line Figure]
IF you want BOTH UHF+Hi-VHF, a G-H type Antenna COULD get more complicated, adding a Hi-VHF "Top Hat" (shown in Black) and possible a SECOND set of Longer Reflector Rods (shown in Blue color), such as Autofils version cited above....and (similar?) jed versions reported here:
nikiml's Antenna pages - GH*n3 jed mods [jed's GH4n3 WITH Hi-VHF mod]
OR even better, nikiml's GH4n, which "should be adequate" and is a bit simpler than the higher Hi-VHF Gain variations:
http://clients.teksavvy.com/~nickm/g..._6V9_13u1.html [In figures, select GH4n version]
Welcome to the forum, yankeeindixie.
You have channels in many directions. I suggest you concentrate on the UHF channels from the NE first since you are in the trees.
Later, you can add a separate VHF antenna aimed at Panama City, and combine the two antennas with a UVSJ UHF-VHF Combiner.
This is an image of your report:
These two reports from rabbitears.info should have an accurate list of channels:
As holl_ands mentioned, WDJR FM is strong enough, at -15.4 dBm, to possibly cause interference problems.
If you try to add a preamp for weaker channels, it probably will be overloaded by the very strong WTVY.
Guys, all of you, thanks for the help. I just got home and now have storms moving in; my internet (as well as TV) are satellite, so I'm libel to loose my connection soon, so I wanted to reply quickly. It appears I've got some studying to do.
I had not heard of the rabbit ears site, I'll have to look into that.
I know TVFool is slightly off, at least for me, because some of the stuff I am getting is not listed. At the moment, with the inside setup, I'm not getting any FOX channels.
holl_and. I don't care if you're a professional antenna guy or not, from what I've read so far, it seems you know your stuff. Don't sweat it. Any and all screw ups are mine, nobody else's. I'm just hoping you all will be around to help bail me out when the time comes.
I hadn't thought about wind loading on the L shaped aluminum. I thought of it because I have a small amount (not enough to make an antenna with) and its cheaper than the round solid stuff or square tube stuff that Lowe's carries and its lightweight. It also doesn't require me to do any straightening of the wire. I can cut it and be more precise than trying to bend the wire. I'm gonna have to think some more on that.
I'll need to take another look at the channel listings. I think the TVFool report I had seen only showed one FOX station and it was listed as being on Ch 9. If there is UHF FOX, then I might not need the VHF.
In the map that rabbit73 posted for my location, the nearby stations going slightly northeast, shown next to the Highway 2 indicator on the map, are the only channels I'm getting. But as I said before, the antenna is inside. I did use the top and bottom, I guess they're called NARODS, bent at 45 and separated by 1/2 inch. The drawing I had found has different dimensions and the feedpoint is separated by 100mm. Its a .pdf file I downloaded, from where I don't remember, but credit is given to onetransistor.blogspot. Its the variant 2 version I attempted.
major tom, I've downloaded those 3 packages, thanks. Are those completely what I need for the nec program or do I still need something else? Are they command line programs or will they run in X?
WOR. For some reason those call letters sound familiar, but I don't remember where they are located.
holl_and, here is a link to the RabbitEars report that I ran. It seems very much like what rabbit73 posted.
rabbit73 must've used some voodoo that I'm not aware of, to get a much more accurate location for where I'm at. The map he posted shows it just about dead nuts on. I'll guess that the discrepancy in the signal reports you were looking at are due to location differences. I'm not sure what a straight line distance from my house to the post office is, but driving distance is about 15 miles. Closest convenience store to me is 9 miles driving. There are literally more critters around me than people.
rabbit73. Is WOR that AM station that used to advertise serving X number of States and 3 Countries?
majortom. I read the posts you made about the packages. I'll try installing them tomorrow and see what happens. Regular Mint (not Mint DE) is built from Ubuntu, which is built from Debian testing. Although Debian testing is currently buster, which is what I've installed, because its so close to being the stable release, I'm guessing that the Mint (Ubuntu) you installed may still be newer than what I've got.
(as an aside, I'm still under the required number of posts needed to be able to post without review; sorry for the delay in responding.)
Back about 1956, many of us in my Mom's Cub Scout Den earned a Merit Badge by putting together a very crude Crystal [aka "Foxhole"] Radio following Cub Scout Handbook instructions using a DIY "Capacitor", a small piece of pencil lead held by a bent safety pin, which was rubbed around a rusty razor blade until some static was heard in a very sensitive earpiece. A bent piece of metal was rubbed against a coil of enamel coated wire until the enamel was worn off along it's length...and then I could search for local AM Stations:
https://www.google.com/url?sa=t&rct=...XwS7hDt-JpfnN6 [My Capacitor not included.]
https://bizarrelabs.com/crystalradio.htm [Shows various versions.]
The toilet paper roll the coil was wrapped around soon collapsed, so I rewound it onto something non-metallic....and more rigid. I also tried some garnet and quartz crystals we had gathered on earlier local hikes....ahhh, much better. Later, I upgraded to a store-bought Germanium Diode (probably 1N34)...which turned it into a "real" radio, rather than a fussy Science Project.
Several months later on my 9th Birthday, my Dad rewarded my obvious inquisitiveness with a Heathkit AR-3 All Band AM Radio....which meant I had to (trial & error) learn how to solder, how radio electronics work and a bit about HF Propagation. Followed by my 4-year older brother and I working together to learn enough Morse Code to pass a (slow speed) OTA test. [After 1st year of College, I completely rebuilt the aging AR-3 from a bare copper chassis, adding RF Pre-Amp, "Wideband" IF Transformers and wood front panel that matched my DIY 12-in Speakers. [Speaker Amp had to be eliminated to make room for upgrades.]
PS: Since my Dad was a Naval Aviator [PBY, TBM, AF Hunter/Killer, S2 ASW, E1 AWACS, et.al.], he taught us how to repair cars (incl. full engine rebuild), home construction/repairs, jungle survival, et. al., although the field of electronics was new to him as well, other than radio operation as the pilot....the guys in the other seat(s) had to be much more on top of the "state-of-the-art".
About the Aluminum
The online supplier indicates their 3/8 aluminum has poor characteristics when it comes to bending and forming.
I found this at Home Depot
The local store (45 miles away) shows it being in stock, but if not, I think shipping is free to the store.
With this square tube. I thought I could notch the end of one and slip it over the end of the other, then rivet it. It would probably be stronger than the "L" shape. I could still reinforce it with epoxy, but again don't know what effects epoxy would have.
The other consideration would then be the width. I guess spacing of the elements would be affected but I could center it on the specified dimension.
We've already established things will work even if it isn't the best choice (bed springs, toilet paper tubes, razor blades, etc.).
I've installed the three packages that you provided. What's next?
From a discussion about a Finco 400 clone antenna, I copied what I was calling the in-line file and used that as an input file to the nec2 program.
nec2 Finclone400-A.nec (the filename I made up myself)
this is the result of that command
GEOMETRY DATA CARD ERROR
CM Finco 400-ww with reflectors project in works
Then I'm returned to the promt.
The man page says if an output file is not specified, output goes to stdout. I was expecting something on the screen.
I still have a scar on the inside of my left ankle. Sometime, when I was in High School, I received a HeathKit, for an AM Shortwave receiver. It actually turned out pretty nice and I used it for years.
While building it, I was wearing a pair of hiking boots that were not laced up. A ball of solder feel off the iron and it landed on the inside of my boot. Did you know you can not remove molten solder from inside your shoe until it has cooled enough to become solid again?
It's not voodoo, it's practice.:smile I have been doing this for about ten years, with 7,494 posts on four forums, and consider it a challenge to solve the location puzzle. The more I know about the location, the better I'm able to help a poster with a reception problem.
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