Rca ant751

[stephenson]

Thought I had posted TVFool data, above ... should just be able use the url, right?

Short answer is 18-30 miles for the ones I really wanted.

http://www.tvfool.com/?option=com_wr...90389679234de3

[Nascarken]

Ok cool sounds good I have a suggestion for you that would work well for you it's the new channels master antenna
Cm-3011HD&amp,cm-7778,and use a Jpole mount.

[stephenson]

Thanks, but doing OK with the GE 29884 - just put it in the attic a few minutes ago - pointed 285T and all the signal strengths increased a bit ... got better WEIQ from Mobile so may be able to hold it, did lose Ch 19 from Pcola, but not a biggie - do ya think I could get it back by pointing 300T (120 + 180), instead of the 285? Would be backside of the antenna.

No preamp - doesn't look like one would help me much with current low cost approach?

Here's the numbers from floor to attic:
Update
ant floor ant attic
3 - 77/98/100 100/100/100
5 - 79/96/100 98/98/100
10 - 70/68/100 100/100/100
15 - 88/98/100 100/100/100
18 - 67/90/100 90/100/100
19 - 73/98/100 lost
21 - 82/98/100 100/100/100
23 - 94/98/100 100/100/100
33 - 72/90/100 100/100/100
35 - 76/98/100 92/98/100
42 - 38/48/none 73/90/100
44 - 91/98/100 100/100/100
55 - 72/98/100 91/98/100

[stephenson]

Checked pointing ... was a bit off - closer to 279, so repointed to 285 ... got 19 back with only noticeable thing being slight signal degradation on 42.

[JoeAZ]

Those GE antennas are quite sensitive to not only side to
side aiming but up/down aiming as well. You may want
to experiment and see if pointing skyward slightly gives you
better signals.....

[Nascarken]

You should try stacking them like 4 ANTENNAS in a square 3ft apart by 3ft apart
I bet it will be out of this world!!

[MikeBear]

The latest version of this RCA (VOXX) has out is labeled ANT752E.

The instruction manual and box photos to put it together shows a photo of the ANT751, and doesn't even quite match what the antenna is presently built like. Instructions are off, and it's hard to tell just exactly how they want you to put it together.

I've just picked one up for my dad, but I haven't installed it as of yet to see if it's any good. Hopefully it is, and works well for him.

Edit, 3:57pm:

Well, I decided to try out this antenna before taking it 50+ miles away and installing it at my dad's. I just put the J-mount on our outside raised deck railing (split level house), and screwed it down with two screws. I then mounted the antenna to it, and hooked it up to a 25' length of Walmart pre-packaged RG-6. So, it's about 9ft off ground level, and surrounded by trees. I then screwed the coax into the back of my 2013 LG tv set.

Works VERY well! Aimed towards WEYI-25 which is South-West, it picks up all my local channels, which are within a 35 to 47 miles radius. Including WJRT-12, which is on RF12 high vhf. It picks up but doesn't lock the two 10KW low powered stations (WFFC & WFKB) that are 32 miles away like my HDB91x does, but that antenna is mounted 15' higher up.

All in all, a good small low profile antenna for those that can only use a smaller unobtrusive one, and that the mud-flap antennas aren't quite good enough. As tiny as this antenna is, I'm AMAZED it works so well even without any sort of preamp, and only 8ft off the ground during this test.

[OTAFAN]

Hi MikeBear:

Thanks for the update on the latest version of this good work horse of an antenna. I don't know if this link to RCA is the same as you bought, but it's the only one labeled close to what you mentioned above:

https://www.rcaantennas.net/outdoor/?sku=ANT752Z

Probably due to monetary issues, RCA seems to "downsize" some of their antennas every time they "update" a model. Rabbit73 mentioned this earlier in this thread in post 16. The link above shows one less element and no Tetrapole. Is this the antenna you bought for your Dad?

http://forum.tvfool.com/showpost.php...8&postcount=16

However, the bottom line on any antenna is the reception it gives you at your location. Obviously you folks are happy with its performance, so congratulations and enjoy!

[MikeBear]

Originally Posted by OTAFAN

Hi MikeBear:

Thanks for the update on the latest version of this good work horse of an antenna. I don't know if this link to RCA is the same as you bought, but it's the only one labeled close to what you mentioned above:

https://www.rcaantennas.net/outdoor/?sku=ANT752Z

Probably due to monetary issues, RCA seems to "downsize" some of their antennas every time they "update" a model. @Rabbit73 mentioned this earlier in this thread in post 16. The link above shows one less element and no Tetrapole. Is this the antenna you bought for your Dad?

http://forum.tvfool.com/showpost.php...8&postcount=16

However, the bottom line on any antenna is the reception it gives you at your location. Obviously you folks are happy with its performance, so congratulations and enjoy!

Well, the Menard's store has the internet page ad labeled as ANT752Z, and that's what I thought I was getting. However in the store, the box is labeled ANT752E.

It's even slightly different than your link above, but real close. The only difference is that it has no complete Tetrapole, though it does have the top "wing" elements of the Tetrapole. Almost like it's now just an extra element (but thinner than the regular ones), and I swung them out and am using them as a element. There's nothing about that in the instructions, as the instructions don't even completely match the present antenna! So even though they update the antenna itself, they don't bother with updating the instructions.

The front half of the mast connects to the back half, and there's a separate set of aluminum phasing wires coming off of the single 1/2 Tetrapole sort of element, that screw down with nuts to the first elements of the back half.

Not having a Tetrapole really concerned me at first. However, it doesn't seem to make a whole lot of difference.

Edit: Whoops, looking at your link above again of the ANT7511, what I call the "top wing" elements of the Tetrapole, seems to be what @Rabbit73 shows screwed down to the rear section elements. He shows the aluminum wires he calls "shorting stubs" just hanging in the air alongside the boom. Is that the way it's meant to be installed? Can't tell from the instructions, as it doesn't show it.

I swung up the "top wing" elements, and stuck what Rabbit calls the "shorting stubs" under the nuts and tightened them down that way. I wonder if it'll work better the way Rabbit has it?

[rabbit73]

Originally Posted by MikeBear

Well, the Menard's store has the internet page ad labeled as ANT752Z, and that's what I thought I was getting. However in the store, the box is labeled ANT752E.

I really hate what RCA is doing with that antenna. The original 751 was a good design, but they have messed with it so many times it's difficult to know what version will be in the box you buy. It was originally introduced at the 2009 CES. AVS forum member holl_ands was there and he took some photos of it. I added some notes:





The design was based on a patent by John Winegard that shows a 3/4 wave folded dipole which he called a "Tetrapole," 1/4 wave shorting stubs, and director pairs:





The 751 is a combo antenna that receives UHF and VHF-High signals. The problem with a combo antenna is that the UHF section receives UHF signals and the VHF section receives VHF signals AND UHF signals. The UHF signals from the VHF section will interfere with the UHF signals from the UHF section, so they must be removed before the two sections are combined in one feedline. The conventional way to combine a UHF antenna and a VHF antenna is to use a UVSJ (UHF-VHF Separator-Joiner) which keeps the signals separated.

A UVSJ contains a low-pass filter and a high-pass filter. The low-pass filter passes VHF signals and blocks the UHF signals. The high-pass filter passes the UHF signals and blocks the VHF signals. It is an efficient low-loss device.



The Winegard Tetrapole and 1/4 wave shorting stubs act as a substitute UVSJ. The 1/4 wave shorting stubs at the top of the Tetrapole remove the UHF signals coming from the VHF section and the Tetrapole combines the VHF signals and UHF signals at the feedpoint on the bottom of the Tetrapole. Any VHF signals received by the UHF section are ignored because the UHF section isn't very good at receiving VHF signals; they will be very weak.

The function of the shorting stubs is based on transmission line theory which says that the open end of a 1/4 wave stub that is not connected is a high impedance point which makes the other end that is connected is a very low impedance point which shorts out any signals at the resonant frequency of the stub. The 751 has 4 stubs formed by two strips that are fastened off center. This makes two pairs of stubs, one long pair for the low end of UHF and one short pair for the high end of UHF.

[rabbit73]

Here is an illustration of the shorting stubs which M. J. Salvati calls an Isolation Network (see attachments):



The shorting stubs must be attached an odd number of 1/4 waves away from the UHF feedpoint. If they were attached to the feedpoint, they would short out the UHF signals. In the RCA ANT 751, they are attached to the top of the Tetrapole, which is 3/4 wavelength before the feedpoint through the Tetrapole.

In the RCA ANT7511, they are attached 1/4 wavelength away from the UHF feedpoint, B to C:



There are only two wire stubs on the 7511, which really isn't sufficient to cover the whole UHF band. The wires with one end not connected are a little longer because they aren't as wide as the flat strips. The 751 uses two sets of flat wide stubs to cover the UHF band; much more effective.

[rabbit73]

This is what the original RCA ANT751 looks like:



This is what the RCA ANT7511 looks like:

Differences between the original RCA ANT751 and the RCA ANT7511

                       751                    7511
 
UHF Driven Element   Tetrapole            Long Dipole
VHF Directors            2                      1
UHF Directors        1 Director Pair      3 Conventional
                     2 Conventional
Shorting Stubs       2 Pairs              1 Pair of thin wires
Mount                At rear              Between VHF elements

If you get the 7511, it will work, but not as well as the original 751. The 7511 has less gain, but you probably will not notice the difference in strong signal areas; it might make difference with weak marginal signals.



Maybe the only way left to get the original is to buy it from Denny.
http://dennysantennaservice.com/ez_hd_tv_Antenna.html

[MikeBear]

Thanks Rabbit, I appreciate the info.

Anyway, I hooked up that RCA ANT752E antenna inside my dads apt, and all UHF local channels come in fine with the antenna aimed sort of in the middle of his local towers to balance the signal as best I could (Flint-Saginaw-Bay City DMA). However, there's not even a HINT of signal for WJRT-12, which is high VHF RF12. Cement and steel bldg, must be blocking it, or some electrical device in the building might be jamming it. I couldn't believe there wasn't even a hint of signal, and I even tried an older PA19 preamp I had that's still good. Didn't help for WJRT-12, but did jack up the signals for the UHF channels. However, since I didn't need those jacked up, I removed the preamp.

They won't allow an outside antenna though. Oh well, he wanted MeTV on 12.2, but he'll have to do without it. This will pay for itself quickly, over a $100 a month Charter/Spectrum tv bill.

I wish there was a better combo UHF/VHF antenna about the same size as this one, and with the same width of reception that gets a higher signal level for high VHF. I guess though even at double the VHF db level of this one I installed, there's still no guarantee it could get WJRT, but it would be nice.

If I could find an original ANT751, is it really that much better at high VHF?

I do have a spare Stellar Labs 30-2475 antenna and a Radio Shack UVSJ to combine it that he could use, but I just don't have the room available to install it with the ANT752E already installed.