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Jim,


Looks kind of like some of the UHF designs I've seen in Europe. A lot more elements in the reflector and perhaps a bit more of a curve to the reflector. The bow elements look similar to the bow elements used on the Channelmaster 4248.


Over in Denmark and Germany most of the UHF antennas used X-shaped bows similar to the bowtie elements used in the Channelmaster 4221 and 4228. Is there any advantage or disadvantage to the solid bowties versus the X's?


Are most of the other antennas you designed going to be similar to this one? Please provide some more pictures and information on the other antennae.


Thank you,

Jim


P.S. how is the weight balance on that thing? It seems like the center of gravity would be way to the front. Maybe a counterweight or cantilever mount option?


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Let me get this straight, this show is hi-def and 5.1, but my local affiliate makes it crappy NTSC and mono?!


[This message has been edited by JimboG (edited 09-25-2001).]
 

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Interesting, kind of looks like the UHF portion of a CM-3021 with curved reflector supports. Does it use a standard matching transformer? How long before they go on sale?


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-Glenn
 

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Discussion Starter · #6 ·
That antenna is not quite the finished product. The finished product will have a mesh cylindrical parabolic back reflector. Also the driven element in the picture is just a simple di-pole. The actual driven element is a very unique design that we do not want to show until we have finished all of the patent applications. It will be fairly large in a three-dimensional shape for increased bandwidth, per channel, and across the UHF band with improved impedance. The back reflector also incorporates a shield for multi-path, this antenna was designed for a challenge I received from a now defunct dot com that was in the Manhattan Financial district. They had tried many, many different antenna designs and none worked, so I made this one for them. One of my other designs, which we will release later also worked there. There are some other special differences here that I don’t want to let out of the bag. There will be an official press release in TWICE on Thursday(?)


This antenna is good to 40 miles here in IL where it is flat. We are designing some pre-amps specifically for DTV they well have only from 5 to 10 db of gain with a larger bw for the DTV signal.


The other antennas are quit different than this one it is the closest to a traditional antenna design and therefore easier to manufacture in the current factory in NJ. There are indoor antenna designs also.


The bow ties that CM uses are better for UHF than a di-pole.





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Jim Burns
www.dtvconsultants.com
 

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Hmmm.. the $19.95 question is where and when can I buy one? I still haven't found a good solution to the OTA reception puzzle. Been trying a lot of different things, but nothing seems to work very well.
 

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'Tis true. Digital TV is actually transmitted as an analog signal, much like a modem transmission over a phone line.


I actually removed the VHF portion of my antenna; it's 1/3rd of the original size and it still works great.

 

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Jim,


Are you designing a combination UHF/VHF model for those of us in the Chicago area so that when CBS finally gets on the air we can pick up channel 3?


Ricardo
 

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Discussion Starter · #11 ·
Glenn_L & roman


Digital antenna is not marketing hype, given the broadcast signal is an analog waveform, the antenna is called “digital†because it is designed for the ATSC VSB system and the payload that system caries is digital. Calling the antenna digital is a lot easier calling it a fee space electromotive reception transducer up of analog waves caring a packetized MPEG digital signal on all of the product lit, not to mention the products box. This is the same as calling a DTV set top box digital when the input, radio waves and the output, Component or RGB are in fact analog. The name digital antenna refers to the design of the antenna for a specific system. The pre-amp situation is the same as the antenna. I hope that dots my “iâ€s and cross my “tâ€s.


Mongo,


I should know when they are shipping in about a week.


Cineramax,


One of the next antennas we release will work exceptionally well for that application. It is directional, about a 160 degree reception pattern, and it is better at multi-path reject than even a log P.


If you want, send an e-mail you could try just the driven element of the antenna mentioned and it may work at 180 degrees, might be practical for your application, but not the rest of the world.


RichardoD,


I have a very slick solution for the UHF VHF combo, I hopefully will be able to tell you about it soon. I just received some more patent applications to sign today, that one should be up soon.


JB





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Jim Burns
www.dtvconsultants.com
 

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Jim,


Thanks for the reply. I just created a separate post with questions about a "Chicago" solution when it may also be possible to pick up Milwaukee DTV stations as well.
http://www.avsforum.com/ubb/Forum11/HTML/016699.html


It's that stupid VHF channel 3 that that screws everything up! I look forward to reading more and seeing pictures of your UHF/VHF solution. Is this what you put in your mom's house?


All the best,

Ricardo




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All the best,

Ricardo
Sony KP-xxHS10 Zone
 

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Glad to hear someone is still designing antennas.


But digital city antennas are not enough:


I want a fringe UHF antenna with about 30 db gain and with

a polar pattern that is down 15 db or more from 30 degrees

off axis on around.


Then I'll believe it might work better than current antennas.

 

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Discussion Starter · #14 ·
Jhe,


Define fringe in distance and terrain please. I may have an answer.


The reason that these antennas are primarily designed for urban and suburban installations is two fold, I was challenged by the claims of 8 VSB not working well in urban areas, I knew ways to make the reception better so I implemented them for the area of most concern. Second reason is most people live closer to the city. An antenna design for what you want is certainly very possible, a manufacturer needs to see the volume for a product like that and I can have one for them.



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Jim Burns www.dtvconsultants.com


[This message has been edited by Jim Burns (edited 09-27-2001).]
 

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Discussion Starter · #16 ·
I do not want to give too much away. * VSB signals do not need a lot of signal amplitude to create a robust picture. Too much gain amplifies unwanted reception, overloads the receiver’s front end (harder to do than most people think) and confuses the receivers error correction and equalizer.


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Jim Burns
www.dtvconsultants.com
 

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Quote:
Originally posted by Jim Burns:


This antenna is good to 40 miles here in IL where it is flat.

I have found that ANY antenna is good for 40 miles in flat terrain.


I could maybe see a amp designed for a 8vsb, but a antenna is just picking up whatever it can. How can a antenna be designed to work better for digital? A digital only antenna is just marketing hype. If you put all the properties together such as high gain, low noise, narrow beamwidth and good F/B ratio, a good non-digital antenna will perform very well indeed.




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-Glenn
 

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Jim. I am very interested in your antennas. I live about 10 miles from the towers in Phladelphia, but live deep in a hole. I am able, with a CM 8 bow tie, to receive CBS, KYW on channel 6. The STB will lock on two others but generate only an intermittent picture, mostly in early AM or at night. Certainly not watchable. Do your attennas have more gain that the CM 8 bay? Thanks. I would love to be able to pull in the other channels rather than pay for cable which is coming in November.
 

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Discussion Starter · #19 ·
You do not need more gain. You need a better signal. My guess it that you have multi-path problems. Yes my antennas would work well there. I signed the patent materials today and I think I will have a ship date by the end of the day on Monday.


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Jim Burns
www.dtvconsultants.com
 

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Jim,


Would you like for me to see how your antenna stacks up against the others? I've done some extensive, conclusive comparison tests with the most popular top performing antennas out there. They are documented in this thread:
http://www.avsforum.com/ubb/Forum11/HTML/013407.html


I could either purchase one or you could send me one to try for evaluation.


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-Glenn
 
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