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Hondaman 10-16-2021 05:28 PM

Gray-Hoverman antenna
 
Hello all,

Recently I'm upgrading my Gray-Hoverman antenna. Original design. I cannot use a "double-stacked" antenna because of attic space. I do not wish to mount anything to my chimney.

I am using a separate antenna for WHAS Channel 11 (they are using RF Channel 11, 198-205 MHz). I replaced my 29-inch "T" antenna made out of #12 or #10 wire. I made a 58-inch "T" antenna out of 0.25-inch copper tubing. Hooked it up with a matching transformer to the 75-ohm coax going to my TV. I held the "T" antenna up against my ceiling, less than 12 inches below the old antenna in the attic (one-story ranch style home).

The new 58-inch monster didn't seem to do any better! When I replace the copper wire on the "bowtie" antenna (in the coming weeks) will the rest of the channels show no improvement? Will the signal never reach 100%, but will there be less degradation during wind and storms?

You can see the towers from my back yard, and I STILL have dropouts during wind and rain. I'm even using a reflective screen (reflective element) 4 inches behind the bowties (driven element).

Am I wasting my time with this upgrade?

stj 10-16-2021 07:49 PM

Re: Gray-Hoverman antenna
 
have you tried adding a grounded plate behind the elements?

Hondaman 10-16-2021 11:55 PM

Re: Gray-Hoverman antenna
 
A grounded plate? Well, yes and no. I have two pieces of wire mesh behind the two "bowties" that "reflect" and make the antenna more directional. I think one is 0.25 inch. The second antenna, that I am building, has 10mm by 10mm mesh. They are not grounded, but just mounted behind the "bowties" and not "hooked up" to anything.

(I am building a second Gray-Hoverman [and a rod for 201 MHz] that I would like to put on the other side of my attic, to feed the television set in my bedroom.)

Maybe I'll attach a picture of one of them.

NOTE: WBNA (Channel 8, 180-186 MHz) put their antenna near the airport in Louisville, a completely different direction than the rest of the TV stations in my area. I am not making any effort to receive their signal.

Further information: It looks like Channel 51 (692-698 MHz) is as high as modern ATSC television transmitters go nowadays. Soon, it looks like Channel 36 (602-608 MHz) will be the highest frequency for TV. At the dawn of US television (1947) Channel 1 was abolished, it interfered with two-way taxicab radios. Channel 37 (608 to 614 MHz) has always been used for radio astronomy, not television. And the US Federal Communications Commission never gave anyone permission to operate a TV transmitter above Channel 69 (800-806 MHz). Many of those old "television channel" frequencies were "re-purposed" and set aside for use by cell phones, a process that started in 1982/1983.

Hondaman 10-22-2021 01:18 AM

Re: Gray-Hoverman antenna
 
1 Attachment(s)
Okay, when I replaced the wire (10 or 12 gauge in the US system would be metric 4.0 or 6.0 square mm cross-section) on the main antenna with 0.25 inch copper pipe, the antenna did not give any better performance, but I put it back in my attic.

When I ask my TV to tell the "percent signal" (very un-scientific) on Channel 11 (198-205 MHz), the "T" antenna (29-inches, 10 or 12 gauge wire) DID outperform the 58-inch "T" made with copper pipe. So I put the 29-inch wire "T" back in the attic as well. This time I hung it up, and it is 30 inches higher than before.

So all TV stations are now at 97% signal except for WHAS Channel 11, which hovers around 90-92% in clear skies. This is as good as I will ever get.

EDIT: I made sure both the antenna and the "T" antenna had the same length of RG-6 going into the splitter/combiner to prevent signal from one antenna "backfeeding" into the other which would have hurt performance terribly.

(It also seems that the metal mesh reflector screen did not help things. I was using a temporary crude "bowtie" with no reflector screen and a 29-inch "T" for Channel 11 and got the very same results on all channels that I am seeing now.)

The attached picture shows the old wire version just after I finished building it at the end of March 2008.

stj 10-22-2021 04:22 AM

Re: Gray-Hoverman antenna
 
presuming your signal is DVB encoded and not analog,
strength is less important than quality.
the strength can be boosted in the tuner, but the BER (bit error rate) is what it is.

Topcat 10-22-2021 09:14 AM

Re: Gray-Hoverman antenna
 
Wow, Most plumbers can't put PVC together that nicely!


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