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Old 20-Apr-2012, 3:46 PM   #21
GroundUrMast
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Here's a quick and simple Yagi design tool: http://forum.tvfool.com/showthread.php?t=1636

This thread, http://forum.tvfool.com/showthread.php?t=2865 deals with Rhombic designs which are going to be quite large when cut for the VHF band... But the 4NEC2 software used to evaluate the design is flexible and available for free, http://home.ict.nl/~arivoors/Home.htm. If you have an understanding of antenna theory, and a willingness to work through the learning curve, you can do a great deal with the software.
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Old 20-Apr-2012, 4:19 PM   #22
OberGeiss
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Thanks...that K7 MEM site seems very useful and starightforward.
Fascinating stuff.
I just need low band VHF for the moment and seems as if I can model something which should work pretty well. Appreciated!
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Old 20-Apr-2012, 5:25 PM   #23
MisterMe
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Quote:
Originally Posted by OberGeiss View Post
Does anyone know of a source of plans for building one's own low/high VHF antenna.....I searched the forum and could not find anything. JUst toying with the idea of using a separate carbon fiber mast and some wiring and parts I have laying about........my idea is to have an integrated short mast and VHF ant. Any ideas as to where I might consult for some basic design parameters?
Thanks!
A low/high VHF antenna is just a VHF-only antenna. There are several standard types of VHF-only antenna. The best such antenna is probably log-periodic. The log-periodic antenna design allows you to effectively "dial-in" the gain that you want. Be warned. Because it must cover the long-wavelength end of the TV frequencies (54-216 MHz), a full-spectrum VHF log-periodic TV antenna will be rather large.

You will need computer assistance to build the antenna. The RF Toolbox application from Black Cat Systems will give you the dimensions for a number of different types of antennas of interest to HAMs including the log-periodic type. The application is not free, but it can be used without paying the fee.

Having said all that, I have to wonder if you have really thought this out. Building an antenna is not the issue. Building a VHF-only antenna is. It is not 1957 anymore. Even before the digital transition, the majority of TV broadcasts were in the UHF band, not the VHF band. Today, there are metropolitan areas were there are no VHF transmissions at all. In others, all of the VHF transmissions are low-power. A VHF-only antenna makes sense if you want signals received from the best possible VHF-only antenna to be combined with signals from the best possible UHF-only antenna via UVSJ.

Now to your mast. There is a recent thread about using fiberglass masts. Like fiberglass, the rigidity of carbon fiber is provided by the hardened resin that holds the fibers in place. The fiber reinforces the hardened resin. There are several reasons that I recommend against a mast made of carbon fiber. They are they same reasons that I recommend against fiberglass:
  • Carbon fiber has no track record as a mast material. A galvanized or painted steel tube or tower will stand for decades with no appreciable loss of rigidity. Without maintenance, the resin holding the fibers together will deteriorate. Examine the body of an old Corvette. Examine a fiberglass boat that has not been maintained.
  • The resin that binds carbon fiber is non-conducting. This makes it impossible to ground your mast.
It might be helpful if you would explain what you are trying to accomplish by building your own VHF-only antenna. As for the carbon fiber mast, forget about it.
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Old 20-Apr-2012, 7:03 PM   #24
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Thanks MisterMe.....I have UHF covered already and yes it's critical here in 07083. There is one group of low vhf signals from NYC (virtual 42.1, et seq) broadcasting on RF 2. My thought is to essentially construct a set of rabbit ears for roof top mounting, splice it into my system with an Antenna Direct VHF/UHF combiner and give it a whirl.

I'm about 17 miles from where this signal is broadcasted and I can occasionally pull it in with my XG-91, pre-amped wit CPA 19. But I am after more of a rock solid signal. Likely, it's only a matter of time before this channel, assuming it survives, will go to some RF frequency in the UHF band, but until then, just want to play around a bit and see what I can grab.

On the mast issue, I need to read up admittedly on mast grounding. Currently I have the RG-6 cabling from the XG 91 grounded with a two part connector (to the earth, just prior to where the cabling enters the home). That's not grounding the mast I suppose so again I am admittedly in need of some reading on that.......

Best,
David
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Old 20-Apr-2012, 9:16 PM   #25
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With all of the channels available to you in the New York-Philadelphia area, you should not decide on an antenna based on one channel. WKOB broadcasts on RF-02. It is likely to continue to broadcast on RF-02 in perpetuity. However, between the Philadelphia and New York metropolitan areas, virtually every VHF channel is used. In the case of RF-12, it is used twice--by WPXU-LD (RF-12) and by WHYY-DT (RF-12). RF-09 and RF-06 are each used by two stations. Having neighboring stations on the same RF-channel is not limited to the VHF band. RF-43 is used by two stations.

With the proper antenna aimed properly, you may receive every station listed on your TV Fool Radar plot. In the case of WKOB, this should be one of your easiest stations to receive. A non-amplified set of rabbit ears should do the trick. You can pick-up one during a quick trip to your nearest drug store.

Antenna design is fascinating. Learning this skill will teach you a lot about practical physics and electrical engineering. However, as a means to pull-in WKOB, it is a waste of time. I recommend that you set as a goal to receive every channel on your TV Fool Radar plot.

Whether you buy your antenna or build your own, your task is directed by the actual channels that you are trying to receive and the environment in which you will receive them:
  • The data entry page for your TV Fool Radar plot is found here. Enter your exact address. For the height of your antenna, enter 20 ft or more if you have a choice. If you are limited for some reason, then enter that height. It might be useful to explain the antenna height constraint if you have one.
  • Create a new thread in the Help with Reception area of this forum. Post a link to the resulting web page that displays your TV Fool Radar plot in your original post of the new thread. Include information about your residence such as whether it is a single family dwelling, high-rise apartment building, etc. If there are obstructions that may interfere with your reception such as trees around your home or tall buildings, describe them and the location relative to your residence. If you are considering an indoor antenna, then describe the location within your residence and the nature of the materials used to construct your residence.
If you still want to design your own antenna, then examine the software that has been recommended to you. You may also find a plethora of books on the subject at the ARRL bookstore.

Last edited by MisterMe; 21-Apr-2012 at 3:00 PM.
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Old 21-Apr-2012, 5:11 AM   #26
GroundUrMast
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I don't want to discourage you from trying your hand at antenna construction. But I should point out that Antennacraft offers the CS600 for $29.99, which offers coverage of all VHF channels and the Y526 for $32.99, which covers real channels 2 through 6.

Re. grounding:

Grounding the mast and coax shield are prudent and relatively inexpensive steps that limit the buildup of static-electricity which can damage the tuner. When done correctly, grounding can also reduce the risk caused by a nearby lighting strike.

http://forum.tvfool.com/showthread.php?t=901

Grounding in a basic system is a two step process:

1) Connect a #10 gauge copper wire to the antenna mast (Presuming the mast is metallic. If not, the ground wire should connect to the metallic boom of the antenna.) A bronze ground clamp such as the Halex #36020 is well suited for 1.25" round mast. Run the wire directly to the electrical service ground. Avoid sharp bends in the wire. (Often you can use a 'split-bolt' electrical connector to clamp the #10 wire to the existing ground wire close to the ground rod outside the building. If possible, avoid running the new ground wire inside the building, energy from static or electrical storms is best directed to ground before it has any path into the building. The wire can be bare or insulated, your choice.)

2) Run the coax from the antenna to a location close to the electrical service ground. Install a ground block and with another peice of #10 wire, connect it to the electrical service ground at the same point you connected the mast ground.

I don't recommend short-cuts such as driving a new ground rod that is not connected to the existing electrical service ground. An isolated ground rod often has a high resistance that provides very limited ground connection. The goal is to connect to the same ground system that protects the rest of the home.

Surge protectors located inside outlet strips at the TV, computer or similar devises are worth consideration. A surge protector with a high joule rating is able to absorb more fault energy than a unit with a lower joule rating. Some surge protection units include phone jacks and F-connectors to enable protection of a phone line, coax cable and the power cable(s). However, in the case of an outdoor mounted antenna, this type of protection should not be considered a 'first-line of defense'.
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Last edited by GroundUrMast; 21-Apr-2012 at 5:18 AM.
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Old 21-Apr-2012, 11:31 AM   #27
OberGeiss
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Thanks Groundrurmast....greatly appreciated.
Will get it all properly grounded at the same time I put up the VHF antenna.
The you mention.....how can one beat that?
Do you think with an approx 60 run of RG6 to a 3 way balanced splitter, I will need to pre-amplify (given how close I am to NYC (07083)?

Also if that ant needs to pre ampified like my Yagi UHF, do I need to cable it separately (running a separate power injector) and then combine just prior to my indoor basement splitter?

Mant thanks!
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Old 21-Apr-2012, 3:23 PM   #28
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Antenna advice is properly based on your exact address rather than your ZIP Code. If your ZIP Code accurately represents your signal environment, then you do not need a pre-amp. If you are using an amplified UHF antenna, then I would say that you have the wrong UHF antenna. GroundUrMast recommended a good economy full-band VHF-only antenna in the CS600. This preserves your amplified UHF antenna. I recommend that you replace the amplified UHF antenna with the AntennaCraft 5884 for $42.99. This is a full-spectrum (2-69) economy VHF/UHF antenna.
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Old 21-Apr-2012, 3:26 PM   #29
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I doubt you'll need any amplification for reception of the local signals from the ESB. At the highest UHF frequencies, RG-6 loss is less than 6.5 dB/100'. The loss at lower frequencies is even less. If you use a preamp attempting to make WLIW stable, the power insertion block belongs indoors, between the splitter and antenna.

As others have pointed out, one all channel antenna would be the choice of most of your neighbors.

Most 3-way splitters have one output port that has half the loss of the other two. Use the lowest loss port on the longest distribution run.

Because this thread is related to your overall reception situation, I've taken the liberty to merge both this and your original 'Help With Reception' thread.

Cheers
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Last edited by GroundUrMast; 21-Apr-2012 at 3:39 PM.
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Old 23-May-2012, 1:25 AM   #30
Rumplestiltskin
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I live in Ridgewood, NJ 07450 Until recently I was able to receive WLIW with my roof antenna (on a rotor). Now there is absolutely no WLIW 21 signal. Any thoughts?
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Old 23-May-2012, 2:12 AM   #31
OberGeiss
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I have had some instances of complete drop out (like this past weekend one evening). Next morning all was back in stunning HD.
It's the best OTA content in the NYC area by far.

Best,
David

PS, have you by chance re-scanned or checked your cabling, connectors?
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Old 23-May-2012, 2:54 PM   #32
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Originally Posted by OberGeiss View Post
<SNIP> PS, have you by chance re-scanned or checked your cabling, connectors?
Yep, I re-scanned and checked my cabling, connectors...


Maybe I'll have them refund my membership pledge?
When I checked the coverage area, linked from this TV Fool site, my location showed up as very weak. I don't know how often that information is updated but I was getting a STRONG signal a while back. As far as I know there is no new construction blocking the signal and my reception on all other channels is still the same. I have contacted WLIW via their web site, if someone knows an email for their engineers that might result in better information.
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Old 23-May-2012, 3:29 PM   #33
Rumplestiltskin
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Smile Problem With WLIW Reception Solved!

I Solved MY Problem With WLIW Reception !

My almost 2 year old twin grandchildren like to push buttons and turn knobs!
My rotor was repositioned by them!
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Old 23-May-2012, 3:36 PM   #34
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Glad to hear that. Interested to know what other market you are pulling in via the rotor in your neck of the NJ wood!
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Old 23-May-2012, 7:52 PM   #35
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What I Receive From Zip 07450-4505

What I Receive From Zip 07450-4505

This list of 57 stations does not include over 10 stations that had no programs as I was going through the reception.

My antenna is tuned for 13.1 so that weak signals from other stations require either me or my two year old grand children to adjust the rotor.

I use FIOS to watch U of M sports, 99% of my tv time is from the antenna on my roof.


WXTV-DT 68.2
WFUT-DT 68.1
KCBN 63.9 (AUDIO ONLY)
WDNJ 63.8 (AUDIO ONLY)
ALIENTO 63.7
AZTECA 63.6
NDTTV 63.5
SINOVSN 63.4
CGNTV 63.3
WMBCDT 63.1
NJTV-AV 50.3 (AUDIO ONLY)
NJTV-HD 50.1
SOI 47.3
EXITOS 47.2
WNJU-HD 47.1
WKOB-LD 42.6
WKOB-LD 42.5
WIZEBUY 42.4
HOT 42.3
DAYSTAR 42.2
TELOS 42.1
WFUT-DT 41.2
WXTV-DT 41.1
WNYN-4 39.4 (WEAK SIGNAL WOULD HAVE TO ROTATE ANTENNA)
FOX 5 38.4
CCTV4 32.2
CCTVNE 32.1 (WEAK SIGNAL WOULD HAVE TO ROTATE ANTENNA)
IONLIFE 31.3
QUBO 31.2
ION 31.1
WNYE2 25.2
WNYE1 25.1
ICNTV 24.3
ICN CH 24.2
WASA 24.1
WORLD 21.3
CREATE 21.2
WLIW-SD 21.1
V-ME 13.3
KIDS 13.2
WNET-HD 13.1
ANTENNA 11.4
THISTV 11.3
ANTENNA 11.2
WPIX11 11.1
BOUNCE 9.3
WWOR-TV 9.2
WWOR-TV 9.1
LIVEWELL 7.3
LIVEWELL 7.2
WABC-DT 7.1
WNYW 5.2
WNYW 5.1
NONSTOP 4.2
WNBC 4.1
CBSNY+ 2.2
WCBS H-D 2.1
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