My bad, didn’t realize ABC was channel 6 (low VHF). I was just assuming that most VHF channels these days were hi VHF. In which case my loop scenario and measurements don’t apply here.
Holl_ands of course has interesting low VHF designs which I’ve been considering given the coming repack. Some stations across the US (like Ohio State U) have already ceded their UHF slot in the past week with the end of the auction and taken the money. Another one has indicated they will move to a vacant hi VHF slot and another said they would be going low VHF!!! In my area there are 5 UHF stations that will have to vacate their frequencies. One of them had broadcast on low VHF years ago and may revert to that again…
I would advise doing what you suggested at the beginning or maybe this one:
http://imageevent.com/holl_ands/loops/ch2ch3hourglassloopreflrods
If @Canons900 wants to avoid soldering, then perhaps alligator clips can be used to attach the balun to the dipole.
Thanks to @Canons900 and @MarkKindle for being so patient with me… I’ve been trying not to get too bogged down in the technical details, but I’ve also been a little sparse with information.
On my Tablo, my 66 inch long twin-lead folded-dipole in my attic gives me 5-green-dots of signal on channel 6 on a clear day. I lose some signal in the rain and snow, but very rarely lose the picture completely.
I looked up the calculations for circular antennas, and a full-wave loop antenna for 85 MHz should have 141.9 inches of wire length, making a circle that’s 45.2 inches in diameter. The rule-of-thumb formula for the length of wire in a loop antenna at VHF frequencies is Length-in-feet = 1005 / (Frequency-in-MHz). 1005/85 = 11.824 feet = 141.88 inches… Divide by PI to get 45.16 inches in diameter. These calculations are for a round antenna, the shape of the antenna will cause the lengths to work out differently. (Which is why the folded dipole using twin-lead wire is a shorter overall length.)
BTW my UHF antenna is a DIY DBGH (Double Bay Gray Hoverman). I’ve built 4 and 8 bay bowties in the past but the GH is my best performer thus far. Recommend the GH to any DIYers.
For hi VHF I have the loop mentioned above but a few weeks ago I decided to try the NAROD concept on my GH to see how well that would work in extending VHF to a UHF antenna. NARODs work wonderfully rivaling the loop for VHF performance on a basically UHF antenna.
This video shows marvelously the application, construction and testing of NARODs:
I may take down my hi VHF loop and replace it with a low VHF one if any channels migrate to low VHF in my area.
My UHF and VHF antennas are joined via an RCA TVPRAMP1R preamplifier since it has both UHF and VHF input ports. This preamp is also great for mitigating the effects of tuner overload when there is a mix of strong and weak stations.
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I use this online app to calculate frequency wavelengths:
http://www.wavelengthcalculator.com/
I get the station\channel frequencies from this table to supplement TVFool:
http://www.csgnetwork.com/tvfreqtable.html
Some websites mention placing a rod reflector behind the folded dipole which typically adds about 3 db in gain (about 30% increase). Have you tried a reflector to see whether it maintains stable reception with inclement weather?
I placed several 64 inch rods behind my hi VHF loop (16 inches away) and channel 11’s signal strength went up from 24 to 27. That added gain gave me a 6 db margin for when reception would dip during difficult days. Without the reflectors, there were times when channel 11 would dip as much as 6 db during the day and place it at 18 db which gave a shaky display. But at 27 db going down to 21 db, the display stayed good.
Interestingly enough, my LG TV works OK with 18 db signal strength (probably just high enough above its noise floor) but both my Samsung TV and Tablo croak at 18 db. I’ve found out by trial and error through experience that the Tablo works fine with a signal above 19 db but not below that level.
See I have the 4 tuner tablo and if I go right into the tv, abc seems very stable.
I am beginning to think that maybe the tablo tuners may be my culprit regarding this issue.
My buddy the next street over is using the same cv2 I am right into his basement, about 125’ run at most. And he is spot on all the time.
I don’t know if it’s the signal for me, the antenna or tuner in the tablo.
I am not saying the tablo is the issue, just conjecture at this point. If a 2 tuner was not another $200, I would pick one up and try just that one to see if there is a difference.
I am probably going to try one of the 2 options first. I’ll either make the one or purchase the other.
This has been an interesting read so far and I have learned a lot. And I have realized how much I don’t know regarding db, signal loss and everything else.
If@jberting is interested in meeting up, I’d love to build what you did and try it out. Your knowledge and experience would be a definite plus.
Both the dual tuner and quad tuner Tablo have the exact same internal amplified 1x4 splitter. The dual tuner just uses only 2 of the “outputs”. The signal loss is minimal but does exist and if you’re on the digital cliff, it can causes pixelation issues, etc.
As easy fix for this is to add a preamp at the antenna mast, such as the RCA preamp referenced by myself and others in this thread already. This should boost your signal enough from the VHF antenna on the Clearstream 2V. The 2V is a non-amplified antenna so adding a preamp may be a good fix before trying a separate new VHF antenna.
And then if you want to as well, put a distribution amplifier just before the Tablo to boost the signal one last time before it goes into the Tablo and split. A good distribution amplifier which I use is the Winegard HDA-200, see link below:
Basically, there are things you can try before jumping to a separate custom / larger VHF antenna.
Good strategy. I have both the RCA preamp and a CM distribution amp going to 6 devices\TVs and the Tablo benefits from the increased signal strength.
If that doesn’t work, @Canons900 could still try the low VHF antenna route since the Clearstream VHF addon is for hi VHF. Having a low VHF antenna on hand may be a benefit for when the channel repack fully arrives…
The problem for @Canons900 is that he has extremely powerful signals coming his way (LOS at only 17 miles away). The RCA preamp does work nicely with a mixture of strong and weak signals to avoid overdriving a tuner. BUT…if that happens, he may only need a distribution amp in front of the Tablo for lower gain. OR…solely drive up the channel 6 lo VHF signal through the preamp while leaving the UHF signals unamped.
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“Both the dual tuner and quad tuner Tablo have the exact same internal amplified 1x4 splitter. The dual tuner just uses only 2 of the outputs.”
Did it occur to Nuvyyo that a 4 way splitter loses 7 db per leg even if only two of the legs are used whereas a 2 way splitter loses 3.5 db per leg? What is the sense of putting in a 4 way splitter instead of a 2 way splitter into a two tuner Tablo? Saving on manufacturing costs by using the same part? The advice for the past 50 years has always been NEVER use a 4 way splitter when only a 2 way splitter is needed… Otherwise one is pissing away signal strength needlessly. There is a cost in signal reduction for each additional splitter leg.
Even having an amplifier in the box adds noise to the signal since any amplifier adds noise. One has to add Tablo’s amplifier’s noise to the noise generated by all other inline amps from the antenna. A tuner has a noise level it can tolerate.
If Tablo’s internal amplifier has a NF (noise factor) greater than 2 db that is not good. A good amplifier has to nowadays have a NF 1 db or less. Interestingly, has anyone ever discussed Tablo’s splitter-amplifier configuration? It may be that it is the combined NF that contributes to Tablo’s tuner’s performance and not just the actual signal strength. Tuners behave according to the NF because each tuner has a noise floor above which it cannot effectively perform decoding the signal.
Okay this make some more sense than going with a separate antenna. These are way to try and easily returnable if they don’t work for some reason.
That’s why I think signal strength does not mean much with the tablo. I think the tuner is somehow involved in this. Even with 5 green circles, abc exhibits poor performance.
That’s why I think thebtuner is part of the issue.
Then again, I am not qualified to make that statement. It was just a guess and discussion point.
I will try the rca preamp and the distribution amp.
It’s trial and error I guess before going a second antenna route…
I cannot begin to imagine how the channel repack is going to impact me at this point!
“That’s why I think signal strength does not mean much with the Tablo. I think the tuner is somehow involved in this. Even with 5 green circles, ABC exhibits poor performance.”
You’re absolutely right there! Tablo shows 5 green dots for a channel I know for certain is not that strong. On other tuners it shows at best as 60%. And when Tablo shows it at full strength, it pixelates nonetheless. One can’t trust the 5 green Martians… That’s why people say that OTA is a black magic art. Supposedly ATSC 3.0 is going to solve this quagmire.
Just be aware that amplifying the whole set of channels may result in you losing some channels. Hopefully the RCA preamp will not overdrive the tuner. Pete Higgins has a wonderful review of this preamp and its good handling of weak and strong channels - https://forum.tvfool.com/showthread.php?t=13530 He writes, “Based on one day of testing, I think this is a quality product that has shown good tolerance to overload.”
If the RCA does overdrive the tuner on some channels, you may need a selective preamp from Jan Jenca for just that one problematic channel thus leaving the other channels alone - http://www.antenne-komponenty.eu/english/main/product/zosilnovace.html Or try just a low gain distribution amp without the RCA. You’re going to have to play around with the possible combinations to get the right mix…
So with the clearstream 2,
I would plug in the VHF line from the antenna to the vhf separate input on the rca device, correct? Since I am trying to improve the vhf reception.
Do I need to use the uhf/combo input? and what do i do with the output power line? I may need to install in outlet in the attic.
The RCA preamp has a power injector that allows you to plug it into an electrical outlet near the TV\Tablo. The RCA comes in 2 pieces: amp placed near the antenna, power injector placed anywhere using the cable that eventually runs between the preamp and TV\Tablo. No electrical outlet needed in the attic. The RCA uses the same coax to send the signal down to the TV and send electrical power up to the amp.
I would first keep it simple by connecting the whole C2 into the preamp (not just the VHF portion) and trying it out. The preamp should prevent tuner overload on the UHF side.
If you lose UHF stations, then the next step would be to connect just the VHF portion to the preamp (VHF input side). However you would then have to join the C2’s cable with the cable coming out of the VHF preamp side using either a splitter-combiner or a UVSJ.
BTW is your antenna pointed directly 337 degrees where the majority of the stations are or is it pointed elsewhere (off the 337 axis) to capture other stations as well? That can also affect channel 6’s reception.
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I am as close to 337 as possible.
There are other VHF stations in your area - real channel 2 (KJWP 2.1), channel 12 (WHYY 12.1), channel 4 (WACP), channel 9 (WBPH 60.1). Are any of these coming in OK?
I pick up 12.1, but I dont know where that is coming from.
I do not get 2, 4 or 9.
The PBS station (12.1) comes in solid.