Mark P

EscapeVelocity

The numbers Ive seen from a NEC model is 7.5 dbd on Channel 7, slightly higher through the middle of VHF Hi and a dropoff on channel 12 and 13. However this dropoff is suspect, as the Winegard 10 element VHF Hi antenna also displayed this, and its great on 12 and 13.

So, the short answer is 7 to 9 dbd gain (over a reference dipole) on VHF High (Channel 7 to 9).

Ch 14 4dbd
Ch 30 5dbd
Ch 50 6dbd

or there abouts...

The UHF specs are from the front end of a Winegard 7000R. You can see that even it with the longer elements for VHF Low is only getting just above reference dipole gain. The 7000R is worth consideration if you need VHF Low as well and are within 25 miles of the towers. Its well built as well. My guess is that Winegard makes the RCA ANT751 too, which is also well built.

On VHF Low (Ch. 2-6), with the RCA ANT751, I would expect negative gain compared to reference dipole cut to channel....40" length telescoping Rabbit Ears will be better.

Don_M

Hi, Mark, and welcome to the forums here! If you plan to place the ANT751 outside at least several feet off the ground (higher being better) and point it directly at that station 22 miles away, it should be enough antenna to capture a full-power VHF signal on one TV 20 feet away without an amplifier. It should also do a reasonable job capturing UHF digital signals under similar circumstances.

An indoor installation is dicier if signal-blocking building materials (brick, stucco, aluminum siding, or foil-lined insulation or vapor barrier) stand in the way. That antenna should perform OK if the framing and siding are wood and/or the roof has asphalt shingles over a wooden deck and rafters.

Aaron62

What does negative gain do?

EscapeVelocity

Its just a relational figure to a reference antenna.

Piggie

I own two of those 10 element Winegards stacked 40 inches over each other. Winegard suggested 42 inches for channel 11. My calculations said 40 inches for the center of the band or channel 10 . I don't think 2 inches makes that much difference on VHF. 10 inches does. I experimented at 60 poor no better than one antenna, 50 no more gain but less drop outs, the at 40 inches I saw the gain pop alive.

I use my on channels 7,9,10, 13 and I don't think I agree with Ken's modeling that they don't have gain on Channel 13, it's one of my best channels. Though they pick up a 18 KW stations at 61 miles that is 2 edge from a 300 meter tower. Well unless there is tropo or impluse.

__________________
The more I understand, the less I know.

EscapeVelocity

That should read...

So, the short answer is 7 to 9 dbd gain (over a reference dipole) on VHF High (Channel 7 to 13)

Piggie

I missed that reading too fast.

Actually that seems too high of gain for that antenna from my "instinct" of seeing antennas for seems like forever at this point

If NEC software must have limitations. But don't get me wrong, not bad mouthing NEC software nor the RCA ANT751 both are good products in their niche. (I know almost nothing about the NEC software except the results of this antenna and the YA-1713).

Remember in the Lava thread, Boom Length is king. The RCA ANT751 is 35.16 and the boom to mast is ubolt is about 2 inches. So probably at best the boom length is 33 inches. Or shorter if you don't count the UHF section.

I can't see getting that much gain out of 0.55 wavelength boom (based on the middle of the band (195 MHz).

The Y5-7-13 has a boom length of 0.99 wavelengths and the YA-6713 has 0.85 wavelengths. Both have fairly well documented gain in the 7 dbd range.

I would lean toward the RCA ANT751 having closer to 3 to 5 dbd on high band.

Still for someone in a little too weak for indoor and needs VHF also, in suburban level signal ranges it is a niche filling antenna. If one doesn't need end mounting the same gain should be achieved at half the price with a Winegard HD7000R

__________________
The more I understand, the less I know.

EscapeVelocity

Makes sense.


Just playing Devil's Advocate, Winegard is claiming 5db on the 7000R, and the RCA ANT751 ditches the VHF Low elements and focuses on VHF High with a log-yagi design and 2 directors....which would back up claims that the RCA ANT751 is getting at least more then the 7000R. If we accept that Winegards posted figures are accurate, then the RCA has 6db or better gain on VHF High....but even their's dips at channel 13.

Interesting discussion.

EscapeVelocity

One more thing. Keep in mind the law of dimmishing returns.