Combine UHF and VHF-Lo. DIY 4bay attic mount design

[milton]

Background Info
I am considering canceling COMCA$T for CATV service. Roku and AppleTV with OTA local stations in HD will replace.
I built a home-made 4-bay antenna (cat whisker style) with reflector and mounted it in the attic.
Construction: pvc vertical spine, #10 copper wire for whiskers and phase lines, aluminum foil over cardboard for reflector.
Configuration: 10" whisker length, 9.5" spacing between bays, 5" space between reflector and array.
All desired stations are 25miles away at 211 degrees, so antenna shall remain in a fixed position.

http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3d46ae9aa61c19b3


Current Status
I am able to receive all desired stations (UHF) including the one VHF-Lo station (WPVI - 85Mhz) when the antenna is connected directly to my TV over a 15' cable run. However the VHF-Lo station does pixelate from time-to-time.

I added a splitter resulting in a 15' and 40' run. TV's at the end of each. This caused me to lose the VHF-lo station and several of the UHF stations became weaker (pixelation). I added an amp that I had laying around (Leviton 48210-VA), before the splitter in the attic. This gave me back all of the UHF stations but the VHF-Lo station is still lost. FM-trap off worked best on the amp. I understand this amp is not meant to be used as an antenna pre-amp, and I plan to purchase the correct amp for my application.

Goal
I want to pull in that one VHF-Lo station along with the UHF stations, over a single coax cable in order to drive the rest of the TVs in my home.

The first step will be the following:
Antenna--->PreAmp---->split(A,B)
split(A)--->15' Coax ----> TV
split(B)---> 40' Coax ----> TV.

The final configuration will be the following:
Antenna--->PreAmp---->split(A,B)
split(A)--->15' Coax ----> TV
split(B)---> 40' Coax ----> DistributionAmp ---> 3 20' coax homeruns to 3 TVs.


Questions
1) I understand the 4-bay configuration is a UHF antenna and not designed to receive VHF-Lo. What type of antenna design should I use?
2) Assuming I build that VHF-Lo antenna, what is the best way to merge the signal with the UHF signal from the current 4-bay antenna? before or after the 300/70 ohm balun? And what device should I purchase (brand)?
3) The attic gets very hot in the summer. Do these preAmps handle that kind of heat? If so, what type/brand should I purchase (note my electrical outlet is also in the attic and subject to heat)? Or should I pull the coax line into an area that is room temperature?
4) Is there a better overall approach to meet the goal I stated above? I am ok with spending the $ for an antenna and solid preAmp considering it will drop my monthly cable bill by $120.

Thanks

[ADTech]

1. A big one. The physical size of the element(s) determines the resonant frequency. Lower frequency signals generally requires that the antenna elements be proportionately larger.

2. It depends on if you need to merge VHF-LO with a VHF-HI/UHF signal or if you are merging VHF-LO/VHF-HI with UHF only. The first uses an HLSJ, the second uses a UVSJ.

3. Most consumer pre-amps are rated for 140F.

4. Maybe.

How are your high-VHF (real ch 7-13) channels?

[milton]

Thanks for the fast reply.

RE: VHF-Hi (7-13).
I get channel 12 (WHYY-TV) in no problem with the 4bay antenna.

I assume the signal combiner would need to accept "vhf-hi/uhf" on one input, and "vhf-lo" on the other. Or some combination of combiners to achieve the equivalent.

I wonder if I can build a 1/2 or 1/4 wave antenna just for Channel 6. If there is a more "turn-key solution", off-the-shelf, I will consider that as well.

[ADTech]

Then you will need the HLSJ.

An FM antenna usually works pretty well on channel 6.

[milton]

Good idea for the FM antenna. I can put one up in the attic near the 4bay antenna.

If I use an HLSJ, will that allow my UHF to pass through over the Hi input. Sounds like these HLSJ's are only for VHF-Ho and VHF-Lo joins. Or perhaps I am looking at the wrong products. I was thinking there must be something out there that will allow me to join on the 300ohm side, like a multi-band outdoor antenna.

[ADTech]

If I use an HLSJ, will that allow my UHF to pass through over the Hi input.

Yes.

Sounds like these HLSJ's are only for VHF-Ho and VHF-Lo joins.

Nope. The "High" port passes everything above the crossover frequency which includes, of course, UHF frequencies.

join on the 300ohm side

Convert everything to 75 ohm coax/F-connectors using matching transformers, then do whatever is necessary.

[milton]

ahh! HLSJ's HI input acts as a hi-pass filter (not a band pass). I did not know that. The info on these devices do not indicate that. Do you recommend any particular HLSJ product?

Thanks

[ADTech]

I've used both Holland and Tru-Spec (Pico Macom). The difference is negligible.

[milton]

Excellent. They are inexpensive. Shipping is almost 10x more than the product unit price so I ordered 4. Any advice on a pre-amp to replace my temporary Leviton amp?

This sounds like it should meet my goals. There is so much tribal knowledge in this area. Thanks again. You've helped me take the next step in commoditizing [my relationship with] COMCA$T.

[ADTech]

Try the Leviton since you already have it. It's probably adequate. Experiment with the FM filter (may adversely affect ch 6) and the variable gain control looking for the best overall balance.

If you have to replace it, the two-port distribution amp from PCT/Channel Master should work fine in place of the amp and first splitter.

[milton]

RE: the Leviton amp; I will do that. I have a few other amps laying around that I can experiment with if needed.

Chan 6 station must increase their power during the day because now it comes through over my 4bay antenna just fine.

I can't find my old FM antenna so will need to build one. I'm thinking a simple dipole antenna for channel 6. Calculations suggest 5.7 feet for 1/2 wave (2.85' each element). Some sites suggest loop, cat whiskers, or straight horizontal configuration. Not sure which is best. Horizontal seems easiest because I can just tac each end to a truss using #10 solid wire.

[Tower Guy]

Try an Antennacraft CS600. It's in stock at solid signal for $16.99.

[milton]

With shipping the CS600 is still under $25. Good price, but wow is that a big antenna. I'll see what the homemade 1/2 wave will do for me and consider the CS600 a plan B.

[GroundUrMast]

The relatively low frequency of the signal you are trying to receive dictates long elements. Gain requires the use of multiple elements... That's the laws of physics.

Let us know how your DIY half wave performs.

[milton]

I built a simple dipole antenna and mounted it my attic just below my 4-bay antenna (2 sections of 2.85' #10 wire, configured horizontally). Since I have not received my HLSJ yet, I used a splitter/joiner to merge the vhf 1/2 wave with the uhf 4-bay. NOTE: yes I realize the HLSJ is what I need but this was an experiment.

Splitter and Joiners used are 5-1000Mhz sliptter/joiners made by Toner (yup had them for a while)

*Configuration:
4BayAnt(300/75 trans)-->Joiner(Input A -3.5db)
halfWaveVHFAnt(300/75 trans)-->Joiner(Input B -3.5db)

Joiner(Output)-->LevitonAmp(FM trap off)-->Splitter(Input)
Splitter(Output A -3.5db)-->15'Coax-->TV1
Splitter(Output B -3.5db)-->40'Coax-->TV2

*Results:
All UHF channels are between 70%-100% except Channel 34 (that one is at 45%)
Channel 6 is now at 100%.

[teleview]

+=>
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Are these VHF low band channels , 2 thru 6 , being received??

http://en.wikipedia.org/wiki/KJWP.

http://en.wikipedia.org/wiki/KVNV.

http://en.wikipedia.org/wiki/WACP.

http://en.wikipedia.org/wiki/WPVI-TV.

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The VHF low band channels are subject to more of a degree of disruption of reception by natural interference such as , sun shine , atmospheric conditions , atmospheric static , lightning , etc. .

And human made interference , electronic / electric.

Would you be so kind as to provide reports of the reliability of the VHF Digital low band reception.

Describe disruptions of reception and your evaluations of what you think the causes of disruptions are.

Many Thanks from teleview.