Time to re-think my strategy...

[johnodon]

Some of this has been discussed in my other threads but I want to consolidate and explain better where I would like to go.

TVfool Report
http://www.tvfool.com/?option=com_wr...d243843845a53e


Current Equipment
ANT751 (attic mounted) pointed at 123degT

V
V

~50ft quad shielded RG6 coax

V
V

8-Port Bi-Directional Cable TV HDTV Amplifier (MA28PN)

V
V

~25ft quad shielded RG6 coax to TV1
~25ft quad shielded RG6 coax to TV2
~10ft quad shielded RG6 coax to HDHOMERUN (HDHR3-US)


Current Results
With this setup, I can receive all of the Philly (122/123degT) channels that I care about with the following results:

UHF channels: 90% - 100% signal.
Hi-VHF channels: 90% - 100% signal
Lo-VHF channels: 60% - 85% signal

While this setup works very well, I would really like to boost the signal quality of the Lo-VHF Philly channels.


Aspirations

• I want to continue to receive all Philly channels (122/123degT) at the highest possible signal
• Keeping the attic installation is a must. I have a fair amount of room up there (especially horizontally) so we can be creative.
• I would like to also receive RC46 (VCHs 69.1, 69.2 and 69.3) @ 36degT (Allentown). I do not need to receive the VHF channels from those towers.

Questions/Thoughts

• Speaking specifically of the Philly channels, I was thinking that having separate antennas for UHF, Hi-VHF and Lo-VHF would be the way to go. However, I am limited vertically. Can I combine a UHF/Hi-VHF antenna (DB4.DB8) with a Lo-VHF Antenna?
• If the above is not possible, would I then need to have separate antennas for all 3 ranges...UHF, Hi-VHF and Lo-VHF? Honestly, I'm not even sure the a pure Hi-VHF antenna exists.
• Would a simple dipole FM antenna work for my Lo-VHF needs?
• RE: Allentown RC46 (36degT)...I assume that a normal DB4 or DB8 is all I would need to get this. I have about 25ft horizointally availbale in my attic so I could get this antenna away from the others.
• In another thread I was told that if I point the Philly antenna(s) @ 126degT, I could point the Allentown antenna @ 36degT and have a 90deg null...thus lett me using a simple combiner/splitter. Sound right?

TIA for the help guys...I really appreciate it!

John

[timgr]

The first obvious thing to do is remove the distribution amp and place an amplifier at the antenna mast. That should improve your SNR by 1-2 dB.

One VHF low antenna that I know of is the Antennacraft Y526. Or you could go with a 2-13 antenna like the CS600 and limit your ANT751 to UHF signals. http://www.antennacraft.net/Antennas/AntennasVHF.html

Not sure how you would keep the ANT751 for VHF high and UHF. Devices that I know of split VHF from UHF.

I'd use a RCA preamp http://www.amazon.com/RCA-TVPRAMP1R-...dp/B003P92D9Y# and connect the VHF antenna to the VHF port and the ANT751 to the UHF port. Replace the CM distribution amp with a passive splitter.

[ADTech]

The first obvious thing to do is remove the distribution amp and place an amplifier at the antenna mast. That should improve your SNR by 1-2 dB.

Probably closer to 3 dB since you'd be eliminating the 5.5-6 dB/100' insertion loss of RG6.


The device called the HLSJ will split/combine FM/low-V from high-V/UHF. They're getting harder to find, but they're out there. Look for Holland or Pico (Steren) names.

Can I combine a UHF/Hi-VHF antenna (DB4.DB8)

The DB4/DB8 antennas are UHF antennas. They are quite nearsighted on lower frequencies than they were designed for.

I'm not even sure the a pure Hi-VHF antenna exists.

Sure they do. We've been making and selling our ClearStream 5 for 5 years. It was purposely designed as a VHF high (7-13) antenna. There are others.

Would a simple dipole FM antenna work for my Lo-VHF needs?

It would likely work better than a 751 on low-VHF. However, since KJWP (http://www.rabbitears.info/market.ph...n=kjwp#station) is now on the air, you might want to consider the 5-element low-V antenna already suggested if you'd like to include that station combined with the 751 via an HLSJ or simply going to the CS600 for 2-13 coverage any using either a UVSJ or the input of the RCA pre-amp to combine.

RE: Allentown RC46 (36degT).

I'd suggest a simple UHF Yagi. Good, focused beam with extremely sharp nulls at 90°. Plus, they're long but not very tall, a good choice for a height-limited attic as compared to a 4 or 8 bay UHF antenna. Actually, I'd suggest getting two of the same model and make a proper 90° UHF-only array (two equal length cables plus a reversed splitter), then combine with the CS600 using the RCA amp. The 751 gets "re-gifted" to someone else.

.thus lett me using a simple combiner/splitter. Sound right?

When the angles are 90°, combining with a reversed simple splitter has about the best odds of working, but it's still a crap shoot, especially in an attic, due to signal reflections that still might make it into the undesired antenna. You will loose about 6 dB of signal from each antenna so keep that in mind. Worst case is that you'd need a custom, single channel combiner which would likely run $125-150 which would limit combining losses to less than a dB or so.

[johnodon]

Thanks guys...I'll have plenty more questions to come but I'll start with this one:

I'll definitely add the pre-amp to the mix but if I plan to eventually add 2 or 3 more TVs + another HDHOMERUN, should I leave the distribution amp in place? Or is it bad mojo to have two amps in the same path?

John

[ADTech]

It likely won't harm anything, your signals aren't very strong so there's no risk of overloading it. Only downside is a loss in system SNR due to the noise figure of the second amp, but, if you have adequate signal power levels and SNR coming off the antenna, it won't harm actual reception.

[johnodon]

OK...one more curveball that I forgot about...

I recently bought this for the sole purpose of receiving Allentown RCH46:

http://www.amazon.com/Eagle-Aspen-EA...ds=eagle+aspen

The only reason I decided on this was that the price was right and I figured it would be good enough for that sole purpose. Is this antenna best suited for :

1. Paired with a lo-VHF antenna to get Philly 2 - 69
2. Left by itself to get Allentown 46 and pair a Lo-VHF antenna with the ANT751 for Philly 2 - 69
3. Ditch it and come up with another plan (TBD)

All the above assume the proper UVSJ or HLSJ...I just didn't list them.

Please do not be afraid to say it is junk and don't mess with it.

John

[ADTech]

It's a 2-bay UHF design, expected to get stations that transmit on channels 14-69. It's basically a Chinese knock-off of our old DB2 antenna.

Try it in each direction and see what it might pull in.

[timgr]

Originally Posted by johnodon

OK...one more curveball that I forgot about...

I recently bought this for the sole purpose of receiving Allentown RCH46:

http://www.amazon.com/Eagle-Aspen-EA...ds=eagle+aspen

The only reason I decided on this was that the price was right and I figured it would be good enough for that sole purpose. Is this antenna best suited for :

1. Paired with a lo-VHF antenna to get Philly 2 - 69
2. Left by itself to get Allentown 46 and pair a Lo-VHF antenna with the ANT751 for Philly 2 - 69
3. Ditch it and come up with another plan (TBD)

All the above assume the proper UVSJ or HLSJ...I just didn't list them.

Please do not be afraid to say it is junk and don't mess with it.

John

I would not combine dissimilar antennas on the same band. Instead I would use an A/B switch, or a dedicated tuner like the Homerun HD for each antenna. A/B switch is cheap - http://www.solidsignal.com/pview.asp...h-%28pvab95%29

You've got the antenna - hook it up by itself and see if you get 46. I presume it's also for the attic, so you don't have to worry much about physical durability. Might be fine.

[johnodon]

Originally Posted by ADTech

I'd suggest a simple UHF Yagi. Good, focused beam with extremely sharp nulls at 90°. Plus, they're long but not very tall, a good choice for a height-limited attic as compared to a 4 or 8 bay UHF antenna. Actually, I'd suggest getting two of the same model and make a proper 90° UHF-only array (two equal length cables plus a reversed splitter), then combine with the CS600 using the RCA amp. The 751 gets "re-gifted" to someone else.



When the angles are 90°, combining with a reversed simple splitter has about the best odds of working, but it's still a crap shoot, especially in an attic, due to signal reflections that still might make it into the undesired antenna. You will loose about 6 dB of signal from each antenna so keep that in mind. Worst case is that you'd need a custom, single channel combiner which would likely run $125-150 which would limit combining losses to less than a dB or so.

I think this may be my best option...

I hooked up the cheap, little DB2 antenna to my bedroom TV. All I did was sit it on my bed and pointed it to 36degT and scanned. To my utter amazement, I pulled in everything that Allentown has to offer: RCH9, RCH38, RCH39 and RCH69. Better yet, I got the only channel I really cared about (RCH46) @ 100% signal.

However, I also was still able to receive a LOT of the Philly channels even though I was pointed directly at Allentown. I'm going to assume that this could cause me some issues. So, I think using 2x UHF YAGI's (one pointed at 36degT and one pointed at 123degT) + 1x CS600 (pointed at 123degT) is the way to go for me. This way I'm assuming I can combine the two UHF YAGIS with the reversed splitter and feed that single line + the single line from the CS600 into the pre-amp. Correct?

@ADTech...can you recommend a UHF YAGI I could pair with the CS600 and would best suit my needs? Maybe the AntennaCraft MXU47 or similar?

Thanks for all of the great advice!

John

[timgr]

Unless I'm mistaken, the ANT751 is a Yagi design.

There's no guarantee it will work, but I'd try combining the Eagle Aspen and ANT751 at 90 degrees with a reversed splitter (or splitter/combiner) and see what happens. Worth a try.

If those coexist happily on the UHF band (with no obvious station losses or multipath or lowered signal quality) then feed them through a UVSJ or preamp to discard any VHF, and add the CS600 to cover your VHF stations.

Since the Eagle-Aspen works so well here, you could try combining two of those at 90 degrees through the reversed splitter, as mentioned. I don't know how the bowties work in tandem, but I'd guess they would be ok. You could put them in an arrangement like the DB8e (ie on the same vertical plane) - basically you are building a mini-DB8e. There must be an optimum separation distance when they are combined like that; the DB8e panels are separated by 27.125".

http://www.amazon.com/CHANNEL-2512-P...KCQ64S18G7YRKQ

[johnodon]

Thx Tim. That is exactly what I was planning on doing when I get home from work...

Get the EA up in the attic and point it at 36degT.
Combine it with the ANT751 using a splitter/combiner. The one I actually have is teh same one you linked above.

Also, a couple questions about placement/runs...

1. RE: the DB8E panels....do I need to get the EA as far away from the ANT751 as possible, or, a specific distance away (like the DB8E panels), or, it doesn't matter?
2. I believe that the runs from each antenna to the combiner need to be the same length, correct?

If everything turns out hunky dory, I'll just leave it and add the CS600 to the mix with the RCA preamp. Heck, this would save me a nice chunk of change as I was starting to eyeball the DB8E and planned on asking about it.

Thx for the advice!

John

[timgr]

Re the EA-ANT751 optimal distance, I have no idea. I would guess that they will couple if close, and that would be bad. Sufficient distance should be a few feet, rather than many feet. Two wavelengths (ca 12 feet) is way away, but longer cables means more cable loss. I would say just far enough so they aren't coupled. This may give you some insight - http://www.ifwtech.co.uk/g3sek/stacking/stacking2.htm

(EDIT) Let me revise that - we are talking UHF here - typical wavelength at 500MHz RCH 19 is 2 feet. So separation by a few feet should be plenty.

Looking at the DB8e, they make the cable from the panel to the combiner as short as possible, and equal length. I'm sure the equal length is vital, and the cable length appears to be as short as possible and still allow the panels to pivot to 180 degrees opposed.

I'd expect that if equal lengths doesn't work with the EA-ANT751 combo, you should probably abandon that approach.

[johnodon]

OK...I'll keep them ~6ft away from each other and put the combiner in between so I'll have only 3ft runs from each.

I'll have a few beers before I go up there to make sure I numb the pain.

Stay tuned....

J

[johnodon]

Oh well...that experiment was a failure. When I combined the EA and the ANT751 (using equal 3ft lengths), I lost a few channels...namely RCH2. Also, I couldn't get any higher than 80% signal strength on RCH46.

So, I am back to one of the following combinations:

1. DB8E + CS600 --> TVPRAMP1R

or

2. 2x AntennaCraft MXU47 --> Combiner + CS600 --> TVPRAMP1R

What do you guys think is the best option?

John

[timgr]

How does the EA work by itself in the attic?

Sp. is it the attic or the combination that is costing you channels?

[johnodon]

Originally Posted by timgr

How does the EA work by itself in the attic?

Sp. is it the attic or the combination that is costing you channels?

By itself I was still getting only ~80% on RCH46. So, it was more the attic than the combo.

However, I must have done something stupid. I put the main coax line back on just the ANT751 and now I can't get RCH2 at all. Nothing changed other than disconnecting the main line from that ANT751 to connect it to the combiner. Now that everything is back to the way it was, I lost RCH2. I get 0% signal (typically ~60%).

I'll go back up tomorrow with my laptop (HDHOMERUN) and play around. Just seems weird to me. I didn't move the ANT751 at all and all other stations (including RCH6) are coming in at the same signal strength as before.

John

[johnodon]

I got all of my channels back but I can still do better with signal strength/quality. Where I have the EA mounted right now, it has a lot of a-frame beams in its way. I can move it to another part of the attic and that should help (although 10ft or so away).

I'm still torn if I want 2x directional UHF antennas or 2x multi-directional UHF antennas. I think the directional variety may pose a problem given the location where I am going to move the 36degT antenna to (a tighter spot...the boom length may be an issue).

John

[timgr]

First I would move the EA around in the attic to see if I could get as many channels there as in the bedroom. Sounds to me like you can get all the UHF channels that you want from the EA in the bedroom if you point it in different directions. I would be inclined to combine two of the EAs at 90 degrees in hopes of gathering all those stations. That appeals to me because it would more or less prove the principle behind the DB8e; that you can gang the UHF arrays mounted in the same horizontal plane and expect them to combine rather benignly.

It's a risk of buying another $20 antenna, but it would be an interesting result. Certainly you could outdo any result you get from that combo using a DB8e, but doing it on the cheap has some appeal.

Not sure what you mean by the 36degT antenna.

[johnodon]

Quick question about the RCATVPRAMP1R...

I will need to get power up to the attic (actually, there is a light so I just need to tie into that for an outlet). In the meantime, will the RCATVPRAMP1R act as a UVSJ if it does not have power?

John

[timgr]

No, not as far as I know. Amplifiers typically become near-100% attenuators when they are not powered.