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Old 29-Apr-2017, 12:22 AM   #1
Billiam
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Log Periodics vs. 4 and 8 Bays

I was just about ready to buy a 4 bay or 8 bay antenna for my current home after the Televes DAT 790 MIX that I just installed croaked. Worked great for a day and a half but then the pre amp bit the dust. I've decided I don't want to deal with the hassle of using such a proprietary pre amp and instead will go back to my Titan from Channel Master with the next antenna.

Anyhow, can anyone explain the advantages and disadvantages of the Log Periodic vs. the 4 and 8 bays?

I do know that 4 bay antennas have a wider beam width while the 8 bay's are narrower in that respect and require more precise aiming. Since I plan to use a rotor once I install a permanent installation that is not an issue.

I've read that the Log Periodic antennas have lower gain than the 4 or 8 bay's but somehow manage to do quite well at picking up and holding fringe channels. Read a number of reviews on the Antenna's Direct Log Periodic and people rave about it even in rural areas where they are more than 50 miles from some channels. I seem to believe the Log Periodic, like the 4 bay antennas has a wider beam width.

Anything else I need to know before I buy another antenna? Will be using a Delhi VIP 302SR for VHF and only need a UHF antenna.
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Old 29-Apr-2017, 12:42 AM   #2
ADTech
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The UHF portion of the Element is roughly on par with the DB2e. On high VHF, the C5 outperforms the Element by a small margin. IIRC, the modeled gain on high VHF was somewhere around 7 dBi (+/-) and on UHF was around 9-9.5 dBi.

I don't know of any technical reason that would support the claim of an LPDA doing better in fringe areas or with weak signals.

Yes, the Element is a modest gain antenna that does have a wide beamwidth, it's only about a meter long and it's a dual band design so there isn't a whole lot of space for multiple elements. I don't have the tech data handy ATM although I can get it on Monday.
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Last edited by ADTech; 29-Apr-2017 at 12:47 AM.
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Old 29-Apr-2017, 12:59 AM   #3
Billiam
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Thanks AD Tech. This antenna may work for my situation. I had a HBU22 up for a brief period and when coupled with the pre amp I was able to get some very weak UHF signals from Dayton. I am in northern KY near Cincinnati. The UHF gain for the HBU22, on average is reported as about 7 DB not DBI.

The 4 bay and 8 bays that I used here allowed for stronger signals and less multipath breakup. That was a real negative of the HBU22.
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Old 29-Apr-2017, 1:53 AM   #4
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If your Dehli does high VHF, for the money, I'd go with the DB4e.
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Old 29-Apr-2017, 1:07 PM   #5
JoeAZ
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You may also wish to consider the 4 or 8 bay UHF antennas
from MCM electronics..... In my experiences installing antennas,
I've rarely found any other design that can beat out the design
for gain, reliability and durability.
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Old 29-Apr-2017, 2:32 PM   #6
Billiam
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Quote:
Originally Posted by JoeAZ View Post
You may also wish to consider the 4 or 8 bay UHF antennas
from MCM electronics..... In my experiences installing antennas,
I've rarely found any other design that can beat out the design
for gain, reliability and durability.
OK. I will look into these as well.

Did another test this morning and swapped out the TV with another one. No question the DAT 790 is shot. Put in my U4000 4 bay and all channels are again received.

The DAT 790 gave me stronger gain than the U4000 but a little less than my Super G 1483. I don't want to use either antenna at this location since there are trees and limbs nearby that could easily damage the antenna. Want something currently in production that can easily be replaced with the identical antenna should it meet an untimely demise due to weather.
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Old 29-Apr-2017, 6:10 PM   #7
Billiam
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Potentially another flag on the play.

This morning before a very severe thunderstorm moved into the area I reinstalled the Antennacraft U4000 with the Titan pre amp. I did note that all my channels returned.

However, during the storm I lost several channels including local which I presume was due to the heavy rain and wind. I've never see this happen before except with really weak signals when I was living in a rural area.

Would a 8 bay or large Yagi help cure the problem or at least reduce the chance that I would lose local signals during storms? Since this is the first serious storm I've been through at my home I don't know what to expect in the future. No problems during the Winter or early Spring since I was not at home during these conditions if they existed since I was at work.

And just now I decided to do another test. Lost my real Ch. 51 but regained my real Ch. 50 when I raised the U4000 up another foot into the air. If I drop it back down I lose Ch. 50 again but regain Ch. 51. Ch. 26 is nowhere to be seen. May have been knocked off the air since I was receiving it during the early part of the storm.

This is by far the most perplexing situation I've had for receiving TV signals.
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Old 29-Apr-2017, 6:36 PM   #8
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Quote:
And just now I decided to do another test. Lost my real Ch. 51 but regained my real Ch. 50 when I raised the U4000 up another foot into the air. If I drop it back down I lose Ch. 50 again but regain Ch. 51. Ch. 26 is nowhere to be seen. May have been knocked off the air since I was receiving it during the early part of the storm.
I don't see a link to your tvfool report, so I don't know what those channel numbers mean.

Quote:
I don't want to use either antenna at this location since there are trees and limbs nearby that could easily damage the antenna.
Trees block TV signals; it's worse when the trees are wet.



http://www.hdtvprimer.com/ANTENNAS/siting.html

scroll down to Trees and UHF
Attached Images
File Type: jpg Trees and UHF4.jpg (183.5 KB, 2276 views)
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Last edited by rabbit73; 29-Apr-2017 at 6:45 PM.
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Old 29-Apr-2017, 7:17 PM   #9
rabbit73
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Is this your report?

There is only a 12 degree difference in azimuth between your weak signals and your extremely strong local signals.

http://www.tvfool.com/?option=com_wr...e6a4c725d89c82

You would need the two-antenna-trick to put the extremely strong local signals in a null.

Are the trees in your area still this bad?

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Last edited by rabbit73; 29-Apr-2017 at 7:22 PM.
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Old 29-Apr-2017, 8:05 PM   #10
Billiam
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http://www.tvfool.com/?option=com_wr...e6a4c725d89c82

It's gotten even weirder. I've now lost every single channel here. I tried the HBU22 with a different Balun. Nothing. Tried the U4000. Nothing. Tried both with and without the Titan pre amp. Still nothing. No channels. Unless every channel in Cincinnati is off the air somewhere I've got a major malfunction but I don't know where.

Is it possible for a Coax cable to go bad like this? I know that you will see a gradual weakening of channels over time but it is only about two years old. And just this morning I was receiving every channel I normally get until after the storm hit.
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Old 29-Apr-2017, 8:12 PM   #11
Billiam
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Well I now know the source of the signal loss. Just hooked up the U4000 inside the house and I am getting signals again. It appears something happened to my 50 foot run of coax outside possibly during the storm or during my swapping of antennas and pre amps. Off to find a new cable.
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Old 29-Apr-2017, 9:57 PM   #12
Billiam
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Replaced the coax. Problem solved at least in terms of getting reception again. Using the U4000 but have lost some signal on Ch. 26. Now borderline quality with a SNR of around 15. Previously it was around 20 to 22 SNR. Ch. 50 and 51 are right around 20 db SNR with this antenna just like previously when coupled with the Titan pre amp. Ch. 22 is fine.

Now I just have to find a suitable replacement for the DAT 790 MIX. That worked well here and I had virtually no multi path break up. That is a major issue at this location.

Wondering if the MCM Electronics clone of this antenna minus the pre amp would work as well as the DAT 790 if I used the Titan pre amp?
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Old 30-Apr-2017, 12:00 AM   #13
Billiam
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Rabbit. Yes, trees and buildings are a major issue at this spot. Thus I need a pre amp even for the local channels. Hard to believe but it really does help.

I am going to use a rotor because I've found that moving the antenna just a few inches from 15 degrees will give me a better signal for either Ch. 2 (virtual) or Ch. 7 (virtual). And I have also found that when I use either a 4 bay or 8 bay, (U4000 or Super G 1483 8 bay)moving the antenna up or down a few inches will mean the difference between getting 2 or 7 but not both at the same time unless I move the antenna a few degrees to the west of 15 degrees which also reduces the signal of Ch. 26. Ch. 22 is the strongest signal from Dayton and poses no issues.

I have noted with the MXU 59 and DAT 790 MIX that I do get more uniform signal strength on each of those Dayton signals and I don't have to worry about moving the antenna up or down a few inches to get better reception of Ch. 2 or Ch. 7 while worrying about Ch. 26. Ch. 26 is the least important signal at this time because once the Repack is in effect, it will be off the air.
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Old 30-Apr-2017, 2:10 AM   #14
rabbit73
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Well, at least you solved the loss of signal problem; good detective work!
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Old 30-Apr-2017, 3:04 AM   #15
Billiam
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Quote:
Originally Posted by rabbit73 View Post
Well, at least you solved the loss of signal problem; good detective work!
Naturally it was the very last option I had too. Did every other conceivable option beforehand.

I think the leaves on the trees are starting to impact the weaker signals on the TV Fool report. Have noted a bit of a drop in SS tonight though 2, 7 and 22 are still viewable. If this becomes a daily occurrence I will probably buy a larger Yagi or 8 Bay in lieu of the 4 bay.
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Old 30-Apr-2017, 3:15 AM   #16
JoeAZ
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Billiam, just a few things you may wish to consider. Bow tie antennas are pretty
sensitive to vertical tilt alignment, if you will. You mention that moving the antenna
up or down affects some channels with better signal and others with a worse signal.
It is probably the tilt of the antenna rather than moving it up or down a few inches.
Usually, I've found angling the antenna a few degrees above the horizon helps improve
signals across the spectrum. Now that we have your TV fool information, I think you
may wish to consider an alternative to a bow tie antenna. The broad beam width will
work against you. A high gain UHF antenna that is very directional might just be the
answer for you. You may wish to consider, MCM 30-2415 and 30-2370 antennas.
They usually are not my first choice but if you aim one of them at 20-25 degrees, it
may be enough to bring in the Dayton stations and not overload your locals....
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Old 30-Apr-2017, 12:45 PM   #17
Billiam
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Joe. Thankfully I have not had to worry about overload when using a pre amp at this location. Despite the fact I am very close to some very strong signals, I seem to be in a pit that repels signals which results in none of my local channels getting pegged on the SS meter without a pre amp even when using a Deep Fringe antenna like the Super G 1483 or MXU59.

I am going to do some research on the antennas you've suggested. I will be using a rotor which will make things easier. I like to DX and a rotor will allow me to pick up out of town signals far easier than a fixed antenna.
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Old 30-Apr-2017, 7:50 PM   #18
Billiam
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Potential Success

Today on a whim I decided to give the Televes DAT 790 MIX one more try. In the past when I've had a problem with a pre amp or sometimes another piece of electronic equipment that suddenly stopped working, I found if I left it unplugged for at least a couple of days and then plugged it back in, it would work. Not in all cases but in some.

Today I did a quick test of the DAT 790 at 5 feet off the ground and it seems to be working again. All the local stations are strong and even Ch. 22 from Dayton was watchable! Can't get 2 or 7 or 26 from Dayton at 5 feet but I think that will change if I remount the antenna up in the air.

Will do the next weekend. With luck I won't have to buy another antenna now.
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Old 6-May-2017, 2:45 PM   #19
KOGREN
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How did the DAT790 re-install work for you? Is that the Long Range version?
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Old 6-May-2017, 7:07 PM   #20
Billiam
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Originally Posted by KOGREN View Post
How did the DAT790 re-install work for you? Is that the Long Range version?
Should know on Sunday. Working late today. If I get home by 8 PM I should have time to install the DAT 790 tonight. Otherwise it will be on Sunday. Will let you know how it turns out. As long as the pre amp is working again it should be fine.
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