I need some recommendations from the pros. Guys like Don M. :)

#1
Hey all -

Skulking around here has given me considerable insight on OTA stuff. I could really use some specific advice, if you'd be so kind.

I have a rooftop antenna, about 40' up. It's pointed directly at Philadelphia, and I'm 14 miles from the broadcast sites of all the major networks.

TV Fool stats are right here.

My old antenna (click for pic) is kinda falling apart (blew over, lost an element or two), but it immaculately receives all the major networks... with the exception of Fox29, which is only watchable when it feels like it. I'm told that the reason for that is that Fox's tower is less than HALF the height of the other major networks - 161 ft. as opposed to 377 at NBC. And there are some Lehigh Valley stations that would be nice to have in the opposite direction.

The antenna sends down an old 2 wire-type lead (not coax), and feeds a 4 channel amp in the basement (which dramatically increased signal to the 4 tvs it feeds once installed, but didn't help with our reception issues with Fox, obviously).

Fox is my major concern. Football season just started. :)

So here are my questions:

1) Do I stand to gain anything by upgrading my antenna?

2) What antenna (complete with a list of recommended preamp/accessories) would you recommend?

3) Would it make sense to recycle the old antenna in a 2 antenna setup, and face it toward the Lehigh Valley? How far apart should they be in that case, how would I mount them, etc?

4) What are the odds that the problem would be solved by just running coax from my current antenna instead of the old stuff that's up there now?

You guys are awesome. Thanks for reading.

-Liam
 
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Don_M

DTVUSA Member
#2
:welcome: Those are some mighty kind words, liam. Thank you.

The TVFool report is a big help. It shows rather strong Philly stations, but very weak signals from the Lehigh Valley, posing a challenge: The antenna and pre-amp you'd need to get those distant signals would likely overload your tuners on the local stations, causing loss of one or more of the locals (and probably "drowning out" the distant stations). There's a workaround, which I'll describe later.

Questions 1 and 4: If you're mostly happy with the local reception you get now, I'd definitely start by replacing the downlead from the antenna to the amp with RG-6 coaxial cable. Odds are good this alone might clear up the problem with Fox. Flat twinlead out in the elements provides trouble-free service for maybe a half-dozen years or so, then starts sliding downhill. This is needed regardless of whether you keep the old antenna or get a new one. You'll probably also need a coax transformer rated for use outdoors to connect the coax to the antenna terminals. While you're up on the roof, be sure to verify that the antenna is still aimed correctly.

Question 2:
If that doesn't help with the Fox station, I'd consider replacing your current antenna with a Winegard HD-7082P. This all-channel antenna has a built-in connector for coax cable.

This is where things get sticky: I'm assuming your amp is a distribution amp, and that it has 300-ohm input terminals for the twinlead. Is this correct? Does it have coax outputs for each of the TVs, or are those also connected with twinlead cable? If so, replacement may be in order as it doesn't make much sense to use a second transformer for connecting the coax to the existing amp. It may need replacing, or it may not. I'll need these details about your wiring to decide.

Question 3: Now, for the Lehigh Valley workaround (be warned, this won't come cheap!) -- Those stations will be tough to get reliably no matter what, thanks to the distance (greater than 70 miles) and numerous hills along the way. Practically speaking, the best way to avoid overload-related reception issues would be to put up a completely separate antenna, install a second pre-amp dedicated to those stations, and hook up this antenna system to one or two of your TVs, leaving the rest of the televisions for viewing local stations. (It's possible that some Philly signals on channels 12 and higher will come in on this antenna regardless of aim, thanks to their strength.) This would give you two discrete antenna systems in the house. The L.V. signals call for a Winegard HD-7698P antenna and a Winegard HDP-269 pre-amp. You'd want to put this antenna at the top of the mast, at least 6 feet higher than the local-stations antenna.

The alternative is to install a rotor to turn a single antenna. This doesn't work well when two people wish to watch something from each market on separate sets. It's one more thing needing attention when setting a recording on a DVR or DVD recorder. It's also one more component to fail and need replacement eventually.

BTW: The link pointing to the antenna photo comes back "access forbidden." Do you know how old it is? How old are the mount and masting?
 
#3
Hi Don,

Thanks for the quick reply. I greatly appreciate it.

The above link (for the antenna pic) is fixed. Here it is again for your convenience. As far as the age of the mount and masting, I'm guessing the Pleistocene. :) Was just on the roof, antenna is aimed correctly, though my sad duct tape repair effort on the two rear elements, as anticipated, failed rather quickly (they're both drooping pretty badly now). Just trying to dodge spending the cash :)

The amp: It's an Archer 75 OHM VHF/UHF/FM Amplifier with an FM trap (engaged). I have the twinlead attached to it with a balun. Coax to all the TVs.

Let's skip the Lehigh Valley bit. I'm reading that your recommendation would likely be (and correct me if I'm wrong):

1) Replace the twinlead with RG6 (using a transformer) and see if that works.
2) If not, replace antenna with Winegard HD7082P
3) If no luck, slam hand in car door. Poor reception doesn't seem like such a big deal now, huh? :)

Thanks again!
-Liam
 

Piggie

Super Moderator
#4
One thing that bothers me when replacing the 300 ohms with coax. There will be equal or more loss with the coax. Though everyone thinks amps were made to "boost range", the real reason they become popular was to over come the loss in coax. Coax lasts longer, less prone to interference and doesn't have to be routed exactly correctly like twin lead. But it has higher losses.

I would say buy a squareshooter amp and put it up at the mast. But the OP has several stations in the -25 dbm range, and a AP8700 can only stand about -22 dbm, so adding antenna gain will throw the OP just over the edge. Though this is the most tolerant amp they make with a built in FM trap. If he is that near TV towers, most likely he is near an FM tower or one even closer.

The HDP269 doesn't have a trap.

But I would proceed this way since I bring up mast mount amps. Hook it up the way Don says. New Balun transformer at the antenna, then coax down to the amp in the basement which will probably require another transformer (these double transformers alone before the amp are part of the loss I worry about).

Then see what happens. See if it's better.

I wonder how long the run is from the antenna to the amp in the basement?

If it's close to 60 ft , real world I would guess you will have about 5 to 6 db of loss at the bottom before the bottom transformer. That would be enough loss to not overload a AP8700, and may also be what is keeping you from overloading your Archer amp now.

If things get really tough getting enough signal from the roof inside, the OP could go with an HDP 269 up at the antenna, but put an FM trap before the amp. That would be the best of all worlds. One the FM trap would be right before the amp, an HDP can take up to -15 dbm or so and with an FM trap in front of it , things should be fine.
Then replace the 4 way amp at the bottom with a 4 way passive splitter.

Plus the OP would get mush lower noise figure than the Archer amp.
 

Piggie

Super Moderator
#5
but chances are I wasted my time as he will probably never come back to read it. I have to think before I type. seems I had something to do here.............
 

flcs3

DTVUSA Member
#6
I have a rooftop antenna, about 40' up. It's pointed directly at Philadelphia, and I'm 14 miles from the broadcast sites of all the major networks.

TV Fool stats are right here.
First observation is that all your "green" (NM > 40) stations except 6, 9 and 12, are UHF. Since your antenna is pointed away from it, I presume that you are not currently picking up 9 (nor 46 and 39). 6 (ABC) is a VHF-lo channel, so a VHF-hi only antenna won't suffice.

My old antenna (click for pic) is kinda falling apart (blew over, lost an element or two)
I do not know the exact model(s), but I have seen a Winegard patent for that zigzag VHF director near the front: US Patent 3392399, issued in 1968, and filed in 1965 by John R. Winegard, himself. The title is "Combined VHF-UHF Television Antenna with Serpentine Director".

it immaculately receives all the major networks... with the exception of Fox29, which is only watchable when it feels like it. I'm told that the reason for that is that Fox's tower is less than HALF the height of the other major networks - 161 ft. as opposed to 377 at NBC.
The tvfool data should account for that, and it still shows plenty of signal (NM 59). So, this poor reception is unexpected. This is your highest frequency UHF channel (real RF channel 42), other than 46 in the opposite direction, so I wonder about either high frequency attenuation in your signal path or lots of gain roll-off with this antenna (its UHF section appears small, but that may be an optical illusion, given the size of the rest of the antenna). For a new antenna you would replace your twinlead anyway, so I agree with Don_M and Piggie that ought to be the first to get your attention. Cleaning the electrical connections alone might help, but they are up the mast...

You might want to check with fmfool.com to look for strong FM stations that may be near by.

And there are some Lehigh Valley stations that would be nice to have in the opposite direction.
You ought to be able to pick up 39 and 46 with a bidirectional UHF panel antenna, say a 4 bay bowtie or Hoverman, with its reflector removed. Your signals are strong enough that the loss of gain going reflectorless should be tolerable. You could continue to use your existing antenna for the VHF-lo and VHF-hi bands, and connect the new UHF antenna with a UHF/VHF combiner (e.g. a Pico Macom UVSJ, ~$5) .

If you want to pick up 9 you may need a separate antenna for that, with a special combiner (e.g. a Channel Master Jointenna, ~$20). I don't know of any bidirectional VHF antennas, but since the signals are strong, you might be able to build a custom one, if you are into that sort of DIY project. Then you would need a High/Low combiner for the two VHF bands (e.g. a Pico Macom HLSJ, ~$5).

OTOH, if you are into DIY projects, you might be able to get a Hoverman panel to work well enough on VHF-hi in addition to UHF. I currently am using one indoors without a reflector to pull in a 43 NM ch 9, which is 4 dB weaker than your ch 9, according to tvfool. It may be a perfect match for your situation: bidirectional VHF!. It would be best installed above your existing antenna, connected with an HLSJ combiner. More details to follow, if you are interested.

You will have to be the judge of how much effort those Lehigh Valley stations are worth. :cool:

Good Luck!
 
#7
See, Piggie, this is why I worry about you. You need to have more FAITH in people... :)

More importantly, thanks for the time and consideration. I appreciate the insight.

If I read your post correctly, my steps toward troubleshooting this situation look kinda like this:

1) Replace twinlead with coax (might help, might not).
2) If not, install an FM trap and the HDP-269 (clean all connections while I'm up there - thanks flcs3).
3) Still no dice, purchase Winegard HD-7082P

Sound about right?

How is the HDp-269 powered? It looks from the product photos like it gets its juice from a second line of coax?

Thanks again, everyone!

-Liam
 

Don_M

DTVUSA Member
#8
1) Replace twinlead with coax (might help, might not).
2) If not, install an FM trap and the HDP-269 (clean all connections while I'm up there - thanks flcs3).
3) Still no dice, purchase Winegard HD-7082P

Sound about right?

How is the HDp-269 powered? It looks from the product photos like it gets its juice from a second line of coax?

Thanks again, everyone!

-Liam
That's right. Observations:

1. Forgot to mention earlier: Use black-jacketed coax for cables located outdoors. Seems kind of counter-intuitive to me, but black resists UV damage better than any other color, particularly white. There's little or no cost difference. You'll also want to use a sealant such as Coax-Seal and weather boots on each exposed connector. Moisture inside a connector will kill all signals; sealing greatly delays corrosion as well.

2. Attach the coax transformer after cleaning the terminals; connect a short coax cable between the transformer and the FM trap input; connect another short coax from the trap out to the HDP-269's input; then connect the downlead to the 269's output.

3. Yup. It'll be straightforward if it's necessary. After all, you will have already replaced much of the signal-distribution system already!

You will be replacing the Archer amp completely, so you will need a four-way splitter as Piggie mentioned. More on this in a sec.

About pre-amp power: HDP-269 has a power injector designed for indoor mounting near an AC outlet. The wall wart that powers the injector converts AC to DC power, which the injector sends up the coax cable even as signals travel in the other direction. That way, you only need a single cable running between pre-amp and injector, and you don't have line voltage running outdoors, either.

The most practical location for the injector is undoubtedly where your Archer amp is now. It's best to run one uninterrupted downlead cable from the pre-amp directly to the power injector so that nothing interferes with the pre-amp's power source. You then connect a short coax cable from the injector's output to the splitter input, and then distribute signals throughout the house using the splitter.

Tip for element repair: Get some solid aluminum rod stock at the hardware store, place a rod inside each broken element, and secure it in place with a dab of construction adhesive on both sides of the repair. I'm presuming the antenna is aluminum, so use only aluminum rod -- using any other metal may hasten corrosion in the presence of moisture and rain.
 

flcs3

DTVUSA Member
#9
1) Replace the twinlead with RG6 (using a transformer) and see if that works.
Be sure to use a good balun, e.g. outdoor Channel Master or Winegard. Many cheap ones can be lossy, much like cheap amps are likely to be noisy.

I neglected to mention last night that some FM traps may interfer with VHF channel 6, since they are immediately adjacent frequencies. Most good FM traps can be adjusted to spare channel 6, so be sure to get one of those. Hopefully you don't have a strong, low frequency FM (88-92) station nearby. At least your ch 6 signal is strong.
 

Piggie

Super Moderator
#10
See, Piggie, this is why I worry about you. You need to have more FAITH in people... :)

More importantly, thanks for the time and consideration. I appreciate the insight.

If I read your post correctly, my steps toward troubleshooting this situation look kinda like this:

1) Replace twinlead with coax (might help, might not).
2) If not, install an FM trap and the HDP-269 (clean all connections while I'm up there - thanks flcs3).
3) Still no dice, purchase Winegard HD-7082P

Sound about right?

How is the HDp-269 powered? It looks from the product photos like it gets its juice from a second line of coax?

Thanks again, everyone!

-Liam
1) Yes, still replace it with like Don says black. Quad shield if available. While quad shield RG6 was about double in price 5 years ago, it's now often the same price or cheaper.

Here is a hint that is important on a rotor but makes amps and traps easier. Use regular RG6 between the antenna and rotors and traps, as it's twice as flexible and easier to use in tight places. But with no rotor, if you buy bulk RG6 Quad Shield, no big deal, just make jumpers with it.

2) We are really "assuming" you need an FM Trap. Odds are you do, because you live in a metro area. Where as in a lot if not the majority of towns, the TV transmitters have centralized to a common location, FM towers are not. It's not unusual if you live in town or even suburb, there is a lower power FM station just down the street. The low power FMs tend to be scattered all over town. Biggest reason is cheaper tower space for them, as most are low budget. The best way to tell is do the same thing as with TVFool, but on the TVFool page click on FMFool

Here is your plot to the center of your zip code. It doesn't look bad, but there are some stations at the -30 dbm. They should not overload your amp, but may still end up "mixing" (means combining with other signals or creating 2nd harmonics) and harming any channels 7 - 13). If you don't mind double work, you could actually chance not needing a FM Trap with those FM signal levels, but a FMFool plot to your exact address might change that answer.

3) Yes. flcs suggested a bowtie for UHF up there to get the two stations off the back of your current antenna. (you might get them now). My reservations is while probably adding those two channels (if you don't get them now) you are opeing yourself up to all sorts of possible mulitpath, which could hurt the stations in the favored direction. The type of antenna you have now, the UHF part is intact and probably has decent front to side and front to back rejection, so I would be afraid to change that unless you really want 69.1 and 39.1 (virtual numbers).

8 bays have pretty good front to side because there is an element to the side for each element, narrowing the beam width. But all the 4 bays and 2 bays are not so good front to side rejection, though are often superior front to back. Trouble is, most multipath problems come from the front and sides, not the rear.

One last thought. If money is not an issue, but work is, changing the antenna would not be a waste of time.

I have no doubt people worry about me. :flypig:
 

Attachments

Piggie

Super Moderator
#11
Read this first!!!!!!!!! ****fmtrap****

The more I consider the FM trap, the more I wonder. The two cheaper untunable traps by Winegard suggest not using them with a Ch6.

The expensive really would require a spectrum analyzer to tune correctly.

I put a question into Winegard engineers with all the specs and waiting on an answer.

Piggie (so are you still worrying? you should).
 

Don_M

DTVUSA Member
#12
The more I consider the FM trap, the more I wonder.
This being Philly, the only other VHF TV station is on channel 12. Any strong FM station from 101.9 through 106.1 inclusive (just to be safe) might cause a harmonics issue. Otherwise, you're right to wonder since the trap's insertion loss would outweigh any benefits.

BTW, the FMFool report in that link is tiny, and it gets "Blurry Image Disease" when one tries to zoom it.
 

Piggie

Super Moderator
#13
This being Philly, the only other VHF TV station is on channel 12. Any strong FM station from 101.9 through 106.1 inclusive (just to be safe) might cause a harmonics issue. Otherwise, you're right to wonder since the trap's insertion loss would outweigh any benefits.

BTW, the FMFool report in that link is tiny, and it gets "Blurry Image Disease" when one tries to zoom it.
Jay has the image dimensions set too small for TVFool or FMFool. I have mentioned it to him.

Best to just go put in the zip code at FMFool and look. I can't fix it without posting the image elsewhere. I don't want to fill my server with images, and I guess to lazy to open one of those image service places accounts, which would fill quickly.

FMFool doesn't have a link like TVFool with the data to reproduce the radar plot later in the URL. TVFool has the same problem last year. You could post a link but withing a week or so the link didn't work.

=======

He has an FM trap now. But we know Archer FM traps are known not to be effective at all, maybe 6 db. Then we don't know if in the Archer amp is the trap before or after the amp?

Thought about putting the trap after the amp, but any mixing or harmonics in the amp would then already be outside the bandpass of the trap. It would block strong on frequency FM signals already amplified. But it might kill Ch6 also.

So that is why I went to those smarter than me (a lot to choose from), and asked Winegard engineering. Not sure how long it will take to get an answer. The boys there have been swamped lately, no recession at Winegard. Dang good thing to hear too! :cheers:
 

Piggie

Super Moderator
#15
Just go to: tinypic.com and upload as many pics as you want. No need to register or open an account. Just upload the pic, grab the code to post back here.[/QUOTE]

Thanks.

In this situation, we really really need the OP to put in his address and do a FMFool plot.

Just checked and no word back from Winegard, and they close at 7 eastern, so it's tomorrow now.
 

IDRick

DTVUSA Member
#16
Don M provides excellent advice and is always spot on. :applause: He is a "pro" in that regard! But, since we don't pay him, he's still an amateur!

:cheers: to a great guy!
 

Piggie

Super Moderator
#17
Ok, so far, in the last week two new posters asked for Don and Jay. hmmm.

Do you guys need me? There are things I could be doing. Like figuring out what I can do to raise $400 so to replace my broken TV. I don't even have OTA now. Guess that is were volunteer gets you.
 

O-O

DTVUSA Member
#18
Ok, so far, in the last week two new posters asked for Don and Jay. hmmm.

Do you guys need me? There are things I could be doing. Like figuring out what I can do to raise $400 so to replace my broken TV. I don't even have OTA now. Guess that is were volunteer gets you.
lol come on now Piggie, you've got your own cheering section too. ;)

Besides, I've never seen Jay answer a antenna question in details like you antenna gurus. :banplease:
 
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#20
Yes, Piggie. Still worried. Still grateful. :)

The update:

Found some coax at work - black, much more substanstial braid than what I'd used previously, with a foil shield, too. Also had a thin gauge, coated copper line running in tandem with it (ground?). It was supplied by DirecTV for an installation at our previous location, and it was just lying around, so I thought I'd give it a go.

Got a transformer with a weather boot, an aluminum rod, various tools, and hit the roof. Replaced the twinlead, sanded my connections with a fine grit sandpaper to bring the shine back, used the rod to repair a broken element, and sanded all the elements, too.

Hooked it all up, and poof - Fox29 is here with zero issues, so I got to watch the Eagles get pummeled yesterday in glorious HD. :-/

But upon scanning channels upstairs, I'd gained a few, and I'd lost a few. Took several rescans to get NBC (virtual number 10.1) and WHYY (12.1) on the TV with the shorter run. The one with the longer run had an easier time getting those in (amp overload?). And neither of them got ABC (6.1) - until I reread this thread and turned off the FM trap. Now I get 6.1 on the TV with the shorter run, but not on the one with the longer run.

But so far, so good! You guys are awesome. I greatly appreciate the help!

Thanks again!
-Liam
 
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