what is the best antenna for this location

[johnlvs2run]

[Bowties do not enjoy much in Front to Back rejection ratio.

This is why a single 4 bay pointed toward 333 degrees may be the best solution for your area. It won't reject the strong signals coming from the southeast, and has a wide beam angle. Of course a corner reflector on a rotor will give you the highest signal strength on all channels, but with digital what you want is a receivable, realitively interference free signal for all desired channels.

A 4 bay pointed at 333, with no preamp, no rotor, and no reflector could work well?

If so, that would be awesome.

Having no reflector would make it a bidirectional antenna, yes?

 

[dkreichen1968]

A 4 bay pointed at 333, with no preamp, no rotor, and no reflector could work well?

If so, that would be awesome.

Having no reflector would make it a bidirectional antenna, yes?

4 bays (or Gray Hovermans) without reflectors do work, but you lose gain. The reflector in effect reflects signal back toward the antenna elements. If the signal is reflected back in phase it adds gain. So yes, taking the reflector off makes it bi-directional, but you lose gain in the pointed direction. It may take some expermentation to get the right combo. You could also make a vertical stacked 8 bay (2 four bays wired in parallel) for added gain if needed.

 

[Fringe Reception]

4 bays (or Gray Hovermans) without reflectors do work, but you lose gain. The reflector in effect reflects signal back toward the antenna elements. If the signal is reflected back in phase it adds gain. So yes, taking the reflector off makes it bi-directional, but you lose gain in the pointed direction. It may take some expermentation to get the right combo. You could also make a vertical stacked 8 bay (2 four bays wired in parallel) for added gain if needed.

I experimented here with two old-style CM-4228s vertically stacked and I saw no improvement in signal "strengths" but then again, I do not have a genuine strength meter, only what my TV has for a diagnostic screen.

I also tested the antenna I decided to make permanent on my rear mast/system, an old style CM 4221 without its screen to see it it would capture signals from East and West at the same time. West was no problem but I lost my East channels. I reinstalled the reflector screen and bingo: Easterly stations were back. That's how I determined a rotor was necessary for this setup.

Jim

 

[johnlvs2run]

I also tested the antenna I decided to make permanent on my rear mast/system, an old style CM 4221 without its screen to see it it would capture signals from East and West at the same time. West was no problem but I lost my East channels. I reinstalled the reflector screen and bingo: Easterly stations were back. That's how I determined a rotor was necessary for this setup.

Do I understand correctly that you received only west without a screen, but both east and west with a screen?

 

[Fringe Reception]

Yes,

Stations to my West are LOS and although the ones to my East are physically closer to me, they are 1-edge. The screen is necessary for me to capture easterly stations.

Jim

 

[dkreichen1968]

When signals are strong in one direction and weak in the other, the reflector (i.e. screen) will help balance the signals. (Weaken the strong signals and strengthen the weak signals.)

 

[johnlvs2run]

The reflector in effect reflects signal back toward the antenna elements. If the signal is reflected back in phase it adds gain. So yes, taking the reflector off makes it bi-directional, but you lose gain in the pointed direction.

As long as this balances the gain between the two directions, that is fine.

When signals are strong in one direction and weak in the other, the reflector (i.e. screen) will help balance the signals. (Weaken the strong signals and strengthen the weak signals.)

The primary stations here in opposing directions have about the same signal strength.

 

[dkreichen1968]

As long as this balances the gain between the two directions, that is fine.
The primary stations here in opposing directions have about the same signal strength.

Based on your TV Fool the signals at 104 degrees are a lot stronger than the ones from 333 degrees. Two things to remember, the "signal strength meter" on most digital TV tuners are really signal quality meters, and the corner reflector on your current antenna is rejecting signals from 104 degrees when pointed toward 333 degrees.

 

[Fringe Reception]

When signals are strong in one direction and weak in the other, the reflector (i.e. screen) will help balance the signals. (Weaken the strong signals and strengthen the weak signals.)

That's not a dependible absolute per my experience here. With the screen reinstalled on my 4221 and with the antenna facing East, it completely blocks one UHF channel to my West and another pixelates and/or blocks: VHF 13 (also to my West) somehow 'sneaks thru' the reflector screen or I'm catching a solid echo from somewhere, far stronger than the direct signal hitting the screen from behind.

Jim

 

[Fringe Reception]

By the way, EV may be the best currently active Forum member to comment about your existing antenna, but I saw no comments from anyone regarding it.

I think it is an ultra-compromised low-high-band VHF periodic (version of a) Yagi with a (compromised) UHF stinger at its' front. Everything you could want and it makes coffee for you every morning as well. Not a bad choice when comparatively close to the transmitters ... definately directional to some extent ... but it is old school.

Jim

 

[johnlvs2run]

Based on your TV Fool the signals at 104 degrees are a lot stronger than the ones from 333 degrees.

The primary stations at 139 degrees (27/3.1) and 334 degrees (15/6.1) at 334 degrees are quite close in TF signal strength.
Those are the ones that I want to be balanced.

Two things to remember, the "signal strength meter" on most digital TV tuners are really signal quality meters, and the corner reflector on your current antenna is rejecting signals from 104 degrees when pointed toward 333 degrees.

It's okay with me that 19 is the only channel from 104 degrees.

 

[johnlvs2run]

By the way, EV may be the best currently active Forum member to comment about your existing antenna, but I saw no comments from anyone regarding it.

I think it is an ultra-compromised low-high-band VHF periodic (version of a) Yagi with a (compromised) UHF stinger at its' front. Everything you could want and it makes coffee for you every morning as well. Not a bad choice when comparatively close to the transmitters ... definately directional to some extent ... but it is old school.

I think it's a RS VU160 or similar and was on sale for $35 at the time. My first antenna was a long range VHF yagi from a neighbor who was moving and had never used it, free as long as I removed it from his roof.

The new tv picked up 5a+8d=13 channels a few days ago without a preamp, then 8a+9d=17 with. I just realized tonight the 13 were with NO antenna connection at all. Update: Wow, the antenna picks up 9a+14d=23 with no preamp and it's getting 16.1-4.

All I need now is an antenna with a little better reception overall, especially from 139 degrees.

 

[dkreichen1968]

That's not a dependible absolute per my experience here.

That's true Jim. I believe it is frequency dependant. Trying to get signals from opposite directions when the signals from one direction are weak is tough. Also, since TVfool isn't perfect, it's hard to predict what will happen until you try.

 

[Fringe Reception]

I went back and reread the PDF specifications sheet for the 'triple-boom' ANI-700 antenna and it says it is designed to receive channels 14-69. However, the same page also says 470-862 mHz, which covers channels 14-83. ANI-AV

Then I found the specifications sheet for the similar 'triple-boom' Televes DAT-75, and it's listed frequency coverage is 471.25-847.25 mHz, Channels 14-76. Televes DAT 75 TV Aerial (Televes 159702)

The 'triple-boom' design of these two antennas is quite unique and that makes me wonder about them. If this is a superior design, why haven't I ever seen even one remotely similar antenna used anywhere else for any other service?

There are 6 TV Towers within 5 miles of my home and they have dozens of secondary-service antennas all over them, primarily dishes and "true" Yagis. The old microwave telephone towers and new cell phone towers have secondary antenna services on them, but nothing like the two antennas mentioned above.

Seattle is a seaport and none of the Merchant Marine, Fishing Fleet, Coast Guard or Naval ships use anything similar. I have seen dozens of Ham radio towers and never seen a similar antenna used.

I conclude both of these antennas may work in Europe but they are a poor choice for TV reception in the Americas, considering all TV channels from 52-83 have been eliminated. I also suspect they are fancy-looking gimmics.

Jim

 

[johnlvs2run]

how to improve bidirectional reception with no rotor and no amp

I have some questions about my old antenna.
It is like the one below, except missing the 3 largest elements at the bottom right.

1) Would it be okay to cut off the 5 largest sets of elements?

2) The RG6 goes through the preamp on the roof, but straight to the tv inside, and there is no power to the amp. Is it okay to remove the amp from the antenna?

3) If the UHF section was duplicated on the opposite side of the antenna where the VHF elements are currently, would this work to pick up in both directions?

4) Which of, a 4 bay with no reflector, or the AD91xg, would be more likely to get better bidirectional reception than this antenna?

5) Would the AD91xg be more bidirectional if I used it with no reflector?

6) The cable is touching the ground just before it comes into the house. Is it better to have it entirely off the ground, especially when it rains?

 

[MrPogi]

1. probably ok, but you'll loose some VHF gain.

2. YES! Remove that preamp. In fact, without power, it's degrading your signal.

3. Yea, but it would be EASIER to use a separate antenna for the opposite direction

4. A 4 bay, 91xg is designed to be very directional with a high f/b ratio

5. 91xg is not really designed for more than 1 direction, narrow beam even without reflectors.

6. YES, get it off the ground, and DO put a drip loop in it before it goes into the house.

 

[Fringe Reception]

John,

Regarding giving your antenna a 'haircut', that's unexplored territory. There must have been many hours of genuine engineering, tons of math equations and who know what else that went in to your antenna's original design. All I can say is good luck and I hope you report your results back here.

Jim

 

[johnlvs2run]

I've been browsing through from the start of this thread which is helping me to digest all the great information.

The 91xg looks great but I'd need a rotor which drives up the price,
so I've decided to get a 4-bay antenna and experiment with and without the reflector.

Thank you to everyone for all the helpful responses.

 

[EscapeVelocity]

These 2 are worth a try.

The AntennaCraft G1483 Hoverman, which has good gain, some VHF High gain (although still in negative territory) and a low F/B Ratio over much of the UHF spectrum. Available exclusively at Summit Source.

The Channel Master 3021 4 Bay Bowtie (same exact design as the old discontinued version of the 4221) which can be found on eBay, and has been available by the same seller for over a year now(He sold at least 10 and relisted, as Ive been following this product). With this you can try it with the screen removed as it removed and is replaced relatively easily....to even out gain in both directions while losing about 3 dB from the Forward spec. With the screen on it has usuable gain (better than the G1483 but still in the negative territory) on VHF high towards the rear.

The possibility with both of these is to use them as deliveried, face them at your less strong signals (backside to the strong signals) and amp them.

 

[EscapeVelocity]

Here is information on the AntennaCraft G1483 Hoverman antenna.