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Message |
    
Steve
New member
Username: Sagreer70
Post Number: 3
Registered: 04-2008
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, March 29, 2010 - 11:43 am: | 
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I live in Point Loma, near the corner of Willow and Xenophon.
http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3db7c8bbd70fbdd0
(this is not my actual address, but it is close).
Anyway, I live on a hill that basically faces west and a little south (looking at downtown). I can pick up NBC, PBS, Fox and the Mexican stations great with a bow tie, and with a small roof-mounted antenna. This one:
http://www.solidsignal.com/pview.asp?mc=03&p=DB2&d=Antennas-Direct-DB2-UHF-HDTV- Antenna-%28DB2%29&c=TV%20Antennas&sku=
But I cannot pick up channels 8 and 10 (CBS and ABC). It is because they are on the other side of the hill (broadcasting from La Jolla, I think).
Is there any hope of me getting the ABC and CBS over the air HDTV signal, either with this antenna (which was roof-mounted) or another antenna?
I want to dump cable, but can't give up CBS for football.
Thanks! |
holl_ands
Advanced Member
Username: Holl_ands
Post Number: 2319
Registered: 06-2004
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, March 29, 2010 - 01:25 pm: |
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There is plenty of signal strength for Ch8 + Ch10...
Indoor RabbitEars/Loop might even work...but if amplified could overload.
(Yes your TVFool calculated signal levels are that high.)
But the DB-2 is a UHF-Only antenna. You need to either replace the DB-2
with a UHF/Hi-VHF Combo antenna or add a Hi-VHF only antenna,
such as Antennacraft Y5-7-13 plus a UVSJ Combiner or
Antennas Direct C5 which comes with a Combiner.
RCA ANT751 (aka EZHD) is a small combo antenna (see amazon.com et.al.).
Fry's carries the larger W-G HD7694P and (too big) CM-3014/3016 combos.
Willy's Electronics carries W-G as well as Antennacraft HBU-22:
http://shop.willyselectronics.com/
You can also check Home Depot, Lowes, Radio Shack, Google, etc.
I wouldn't recommend the really small "combos" (e.g. W-G HD1080 & CM2016).
(Message edited by holl_ands on March 29, 2010) |
Mark
New member
Username: Sdmark
Post Number: 1
Registered: 08-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, August 15, 2010 - 06:17 pm: |
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Wow this is amazing to find a thread from someone only a couple blocks away. I'm on Quimby:
http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3d9fbe4b240d3c94
I've been testing OTA reception with a GE HD3 amplified indoor antenna. Have about 10 English-language channels, mostly with signal strength around 60-65%; 8-1 CBS and 10-1 ABC are over 80%. However, 39-1 (NBC) just isn't there, in spite of what TV Fool says. I assume that the issue is that I'm on the other side of the hill from the original poster. Pretty clear path up the coast, but I can't see downtown or points east. In fact I got a 50% signal from 4-01 KNBC from Los Angeles--not enough to use, but made me think I may have to rely on L.A. for my NBC.
The previous owner left an antenna mast, conveniently located right next to the Cox cable drop, so I can add an external antenna with little fuss (I hope).
I was all set to order the ChannelMastter CM-3016 from Amazon ($42, 45 miles) until I read holl_ands post. Why is the CM-3016 too big? Just unwieldy, or actually too strong? I'd be happy to go with the ANT751 ($45, 40 miles) if it will pull in the L.A. stations if I need them. I did figure out that I want a full VHF range if I need channel 4. Do I need to be concerned to find an omnidirectional antenna? These both look directional.
Also, should I hook up the amplifier and injector that Cox left there? The cable run is probably 60 feet.
Thanks for any advice!
Mark |
holl_ands
Advanced Member
Username: Holl_ands
Post Number: 2360
Registered: 06-2004
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, August 16, 2010 - 08:33 am: |
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CM-3016 is a BIG antenna (66"L x 84"W), which was designed
for Ch2-69....which is overkill, now that digital stations have
vacated Ch2-6.
Large antennas designed for the new, Ch7-52 band, are much
smaller, such as the Winegard HD7694P (65"L x 35"W).
And for some reason, new, Ch7-52+ Channel Master antennas
are still quite large, such as the CM-2016 (78"L x 60"W).
Unfortunately, if you used one of these monsters, you would also
need to rotate the antenna every time you changed channels between
Ch8/10 from Mt Soledad (LaJolla) and the remaining Local UHF
channels from Mt Miguel (Spring Valley) and Tijuana (XETV).
============================================
Local NBC (KNSD on Ch40) "should" be as easy to receive as
the other local UHF stations on Mt Miguel (KSWB, KUSI, KPBS).
However, your indoor antenna may need to be moved around to
find a "sweet spot", since the signal levels can vary quite a bit
due to multipath. An outdoor antenna would be much better.
============================================
Since you have VHF stations coming from Mt Soledad (Lajolla)
and UHF Stations coming from Mt Miguel (Spring Valley) and
potentially also Tijuana, I would recommend a wide beamwidth,
inexpensive, 4-Bay UHF Antenna. Try pointing it halfway between
Mt Miguel & Tijuana. Local Ch8 & Ch10 are so close, they "should"
come in just fine on the "back" of the 4-Bay.
[The old CM4221 actually has more Hi-VHF gain towards the "back".]
[This might also be the case for the new CM4221HD.]
Any commercial 4-Bay "should" do the job, although you should
avoid using the new DIY SUPER-SIZED 4-Bays (e.g. mclapp M4 and
& EV's Kosmic SuperQuad), since they are designed for more Hi-VHF
Gain in the FORWARD direction.
I don't think you'll need a separate VHF antenna, but if you
have multipath problems, you could use an ANT751 pointed
towards LaJolla for Ch8&10. Use a UVSJ VHF/UHF Combiner to
combine the 4-Bay UHF signals with VHF signals from the ANT751.
The strong signals from Ch8/10 will block reception of
Ch7/9/11 from L.A. If you truly want to receive UHF stations
from L.A., you would need a rotator for the 4-Bay...or better
yet a separate 8-Bay antenna pointed to L.A. on a separate
coax to an A/B RF Switch. Trying to combine both UHF antennas
will degrade reception from both directions....
An outdoor antenna should allow you to receive most L.A.
stations....BUT, K35DG (UCSD-TV) on Ch35 can prevent
reception of KNBC on Ch36 unless the antenna is carefully
positioned so that a null is directed towards K35DG.
[This might change in the future if/when Ch35 moves to Ch11.]
==============================================
You should try the outdoor (or attic) 4-Bay without a Preamp
first. If you have multiple drops and want to try a Preamp,
try a LOW-GAIN model (10-15 dB), although L.A. reception might
require a higher gain model. [Trial & Error.....]
(Message edited by holl_ands on August 16, 2010) |
Mark
New member
Username: Sdmark
Post Number: 2
Registered: 08-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, August 16, 2010 - 09:15 am: |
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holl_ands, thanks very much for taking the time to write that up.
Okay you talked me out of the CM-3016.
The only reason I mentioned L.A. stations is due to NBC. But if I want 4-1 KNBC from L.A., that's in the low VHF band, right? In which case I would need a full-spectrum antenna like the ANT751? The CM3010 looks similar but isn't as highly rated by Amazon users.
I'm looking for set-it-and-forget it simplicity. Really hope to avoid rotators, multiple antennas, multiple coax runs, etc. Solid reception of ABC, CBS, NBC, FOX, and PBS would be enough. I'll add a Netflix hookup for on-demand movies and TV.
Thanks again,
Mark |
holl_ands
Advanced Member
Username: Holl_ands
Post Number: 2361
Registered: 06-2004
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, August 16, 2010 - 09:23 am: |
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KNBC is VIRTUAL Ch4-1, the REAL Channel is Ch36...UHF.
Check the "REAL" column in your TVFool report.....
You really only need a relatively inexpensive 4-Bay Antenna.
The rest is fall-back & alternative discussions..... |
Gary S
Moderator
Username: Garys
Post Number: 567
Registered: 12-2002
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, August 16, 2010 - 10:03 am: |
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Mark, if it were me, I would install the Channel Master CM-2016 with a rotator, and here's why:
You can most likely aim NNW and receive all the channels you want, including 8 & 10 local, 13 from LA, and a bunch of UHFs from LA, including KNBC. You should have all the popular networks, including NBC, CBS, ABC, CW, PBS and even UCSD. You've already demonstrated that you get KNBC-36 even though K35DG (UCSD) is adjacent channel.
The rotator or second UHF-only antenna aimed ESE with switch will give you the option of local reception of NBC, CW, and PBS should the LA feeds fail on a dry, Santa Ana day. And they will fail occasionally.
I would not recommend a preamp to begin with because you may overload your set with signals from 8 & 10. Without the preamp, you may be lucky enough to get 9 & 11 (but don't count on it).
Like Holl_ands says, don't bother with a big VHF antenna because it will be wasted on 2-6 where there aren't any full-service digital TV stations.
Good luck,
Gary S.
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Mark
New member
Username: Sdmark
Post Number: 3
Registered: 08-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, August 16, 2010 - 12:15 pm: |
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Thanks guys. Seems there are multiple opinions and probably multiple solutions. I'll start with a 2016 and no rotator. I can always add a rotator and/or change to the CM4221HD.
Mark |
holl_ands
Advanced Member
Username: Holl_ands
Post Number: 2362
Registered: 06-2004
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, August 16, 2010 - 03:46 pm: |
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Specs for the CM-2016 says there is a narrowing of the beamwidth
to only 27-deg on Ch27 and only 19-deg on Ch35:
http://www.starkelectronic.com/cm2008.pdf
Although it is difficult to extrapolate for Ch23 (XETV), you might
have to tweak the direction more toward Tijuana, resulting in
Gain loss towards Ch30 (KPBS) and perhaps also Ch39 (KNSD).
A 4-Bay wouldn't have this loss of beamwidth problem, making
it more suitable to split the difference between Mt Miguel & Tijuana.
PS: Unfortunately C-M doesn't provide specs for the CM-4221HD....
But it's probably close to the other 4-Bays:
http://www.hdtvprimer.com/ANTENNAS/cm4221.html [Older model.]
http://www.hdtvprimer.com/ANTENNAS/DB4.html
http://www.hdtvprimer.com/ANTENNAS/w4400.html [Same as W-G HD4400.]
PS: Also check Willy's Electronics in Kearny Mesa & National City:
www.willyselectronics.com
DB-4 has a good price & Hi-VHF Gain is higher towards "back" than front.
(Message edited by holl_ands on August 16, 2010) |
Mark
Junior Member
Username: Sdmark
Post Number: 6
Registered: 08-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, August 18, 2010 - 04:38 pm: |
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Installed the CM-2016 today. Pointed NNW, I was missing KNSD 39.1 but I had some reception on a lot of yellow L.A. channels. The problem is the steep hill and house towards the east (Mt. Miguel, right?). After much fiddling, I wound up splitting the difference between L.A. and Mt. Miguel (20 degrees magnetic), and adding the 11 dB amp that Cox had installed at one point. With that I get these signal strengths:
KGTV 10.1 96%
KFMB 8.1 98%
KSWB 69.1 73%
KPBS 15.1 73%
KNSD 39.1 73%
KBEH 63.1 80%
KTLA 5.1 93%
KNBC 4.1 64%
KOCE 50.1 68%
KCBS 2.1 69%
KTTV 11 73%
KCOP 13.1 81%
KPXN 30.1 76%
There are probably others but that's what I was tracking.
Gary, you mentioned a risk of overloading the tuner with 8 and 10 if I use the amp. How would I know if that is happening? I'm using an external DTV Pal converter box and it sure gets hot, amp or no amp.
Mark |
HDTV@92120
Advanced Member
Username: Hdtv92120
Post Number: 201
Registered: 03-2004
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, August 18, 2010 - 10:58 pm: |
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I'm in La Mesa and I also cannot receive KNSD via OTA. Same reason. I'm on the wrong side of a hill and cannot see Mt Miguel.
I have cable so my antenna is pointed towards LA. If you get KNBC reliably then I'd say your all set. I wish I could get KCAL reliably though..
Samsung PN50B650 / Sony KP-57HW40 / Sony KDL-32SL130 / Panasonic TC-26LX20
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Gary S
Moderator
Username: Garys
Post Number: 568
Registered: 12-2002
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, August 19, 2010 - 07:49 am: |
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If you are getting KTTV, you are not overloading your amp.
This is a good looking list. Receive chips are so advanced these days, the multipath you are likely getting from not having your antenna aimed directly doesn't seem to matter.
One tip, though: You might try slowly turning your antenna back toward LA while watching reception of KNSD. There may be a point at which you can receive KNSD using a minor lobe off the back side of the antenna. At that point, make sure you haven't lost KSWB and KPBS.
KUSI (18) is likely lost to co-channel KSCI in LA.
Gary S.
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Mark
Junior Member
Username: Sdmark
Post Number: 7
Registered: 08-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, August 19, 2010 - 08:51 am: |
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Gary,
As part of my trial and error, I did try a couple other settings. At 15 degrees magnetic, KNSD was still 73%. At 0 degrees magnetic, it was down to 60%. The 20-degree orientation aims at the patch of sky between two houses uphill from me--does that matter if they are 150+ feet away?
Yes pretty much every channel marked with a "C" co-channel warning, I don't get.
I'm learning that the L.A. reception is flaky. Tried to watch a show on KPXN (ION) last night. Got 15-20 minutes in with reception around 60%, but finally lost the signal as it dipped to 50%.
Mark |
JoeM
Advanced Member
Username: Joem
Post Number: 169
Registered: 09-2005
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, August 19, 2010 - 11:59 am: |
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Mark wrote: ..."I'm learning that the L.A. reception is flaky. Tried to watch a show on KPXN (ION) last night. Got 15-20 minutes in with reception around 60%, but finally lost the signal as it dipped to 50%."
Actually the warm weather we've had last couple of days can enhance reception of distant signals. Don't be surprised come winter time that they vanish.
P.S. For those who considering the DB4, be advised that it has a "hole" in the graph for RF channels 18, 19 (51.1, 69.1). Also the ANT751 is not considered a fringe area antenna. |
jrgo43
Intermediate Member
Username: Jrgo43
Post Number: 34
Registered: 09-2003
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, August 19, 2010 - 01:34 pm: |
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i am in point loma, and my anecdotal evidence is contra. I lose 28 and 58 with the hot summer weather around 3pm to 6 or so then it seems to come back later in the evening. During the cold months got those channels pretty much all the time. No problem in any event with the other network LA stations regardless of weather
jose
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Mark
Junior Member
Username: Sdmark
Post Number: 8
Registered: 08-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, August 19, 2010 - 01:56 pm: |
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Jose,
What antenna are you using and which way is it pointed?
Mark |
jrgo43
Intermediate Member
Username: Jrgo43
Post Number: 35
Registered: 09-2003
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, August 19, 2010 - 02:30 pm: |
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i am not in the shadow so i have a direct line of sight to LA, plus i am at the top of the hill. I have the winegard 7968p with a rotator. I have also noted that the direction of the antenna varies and is not the setting that is given for the channel, thus for me the rotator is essential. I am set at 308 right now and i think tv fool indicates i should be at 323. I have no idea why this is local reflections or some other reason. btw, i claim no expertise just my undeducated observations.
jose
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Mark
Junior Member
Username: Sdmark
Post Number: 9
Registered: 08-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, August 19, 2010 - 03:21 pm: |
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Can I come watch TV at your house? LOL
The 7698P is a monster! 11 feet long. Does make me wonder if I should have gone for something bigger.
I have to remind myself that the other part of this "cancel cable" project is to set up Netflix on my TV (not done yet). I may use that on-demand service more than OTA anyway.
Your rotator numbers don't match either true or magnetic numbers from TVFool? Interesting...
Mark |
jrgo43
Intermediate Member
Username: Jrgo43
Post Number: 36
Registered: 09-2003
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, August 19, 2010 - 04:03 pm: |
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the numbers are magnetic. I too have gone the netflix streaming route. My antenna is mainly for PBS in LA and orange county. Plus the network sports. Sure you can come by and check it out. Probably won't get anything though if you came by.
jose
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JoeM
Advanced Member
Username: Joem
Post Number: 171
Registered: 09-2005
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, August 21, 2010 - 02:39 pm: |
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If you're in Point Loma, then the signal travels a longer distance over the water than if you are located more inland like I am. This can have quite an effect.
During the winter months, distant interferring signals may be reduced (enabling reception of certain stations). |
Mark
Junior Member
Username: Sdmark
Post Number: 10
Registered: 08-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, August 28, 2010 - 08:42 pm: |
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Well the CM-2016 has been doing alright but I wanted to try the other suggestion, the 4-bay commercial, so I picked up a CM-4221HD today at Fry's.
Notes:
- On the CM-2016, reception on the ever-tricky KNSD-DT 39.1 was down to 61 today from 73 last week. Don't know why.
- The CM-4221HD seemed to have a harder time pulling in KNSD. I pointed it 20, 90, 100, 110, 130, and 323 degrees magnetic with no reception on KNSD. I got 63% or 64% when pointed 35, 50, and 70 degrees.
- When pointed at 323 degrees to maximize L.A. stations, reception was better overall than the CM-2016. This makes sense as the CM-4221HD is rated for 45 miles vs. 35 for the CM-2016. (Come to think of it, my CM-2016 test at NNW was without the amp so I'm not sure about this.)
- When pointed at 35 degrees to get KNSD, reception of other stations was generally a bit lower than the CM-2016, losing three stations entirely. Comparison chart below.
| | | | CM-2016 | | CM-4221HD | | | | | With 11dB Amplifier | | With 11dB Amplifer | | Call Sign | Real | Virtual | Network | NNE | | NNE | | | | | 20 Magnetic | | 35 Magnetic | | KCBS-DT | 43 | 2.1 | CBS | 71 | | No | | KNBC-DT | 36 | 4.1 | NBC | 73 | | 74 | | KTLA-DT | 31 | 5.1 | CW | 85 | | 81 | | KFMB-DT | 8 | 8.1 | CBS | 98 | | 81 | | KGTV-DT | 10 | 10.1 | ABC | 98 | | 96 | | FOX-SD | 13 | 11.2 | Fox | 64 | | No | | KCOP-DT | 13 | 13.1 | MyN | 78 | | No | | KPBS-DT | 30 | 15.1 | PBS | 80 | | 73 | | KPXN-DT | 38 | 30.1 | ION | 54 | | 81 | | KNSD-DT | 40 | 39.1 | NBC | 61 | | 63 | | KOCE-DT | 48 | 50.1 | PBS | 73 | | 76 | | KLCS-DT | 41 | 58.1 | PBS | No | | No | | KBEH | 24 | 63.1 | Ind | 80 | | 88 | | KSWB-TV | 19 | 69.1 | Fox | 73 | | 76 | | K35DG | 35 | analog | UCSD | good | | good | |
At this point, it looks like the CM-2016 is slightly better for my location/terrain.
Question: I'd like to improve signal strength (and thus uninterrupted watch-ability) of L.A. stations while maintaining good local reception. Would the larger CM-2018 or even CM-2020 behave like the CM-2016 for local AND give me better long-distance?
I figure I'll be living with this choice for a long time so I'm willing to try one more ;).
Thanks for all the helpful discussion,
Mark
(Message edited by sdmark on August 28, 2010)
(Message edited by sdmark on August 29, 2010) |
Gary S
Moderator
Username: Garys
Post Number: 569
Registered: 12-2002
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, August 29, 2010 - 04:07 pm: |
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Good experimentation so far, Mark.
Unfortunately, at your location, convenience will be a cross purposes to the best reception. If you want more dependable reception of LA stations, you have to build a lot more gain into your antenna. This gives you fade margin, the extra bit of signal you can fade from and still receive the station. This requires a high gain antenna and rotator or switch.
If you were to use the Antennas Direct 91XG UHF antenna, you should get about 5 dB of extra signal over the CM-4221, which will allow you to keep the distant signal in a deep fade more of the time.
If you plan to continue receiving VHF, you would need an antenna switch or a UHF-VHF combiner and continue using the CM-2016 or the better Winegard YA 1713 or equivalent.
Gary S.
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Mark
Member
Username: Sdmark
Post Number: 11
Registered: 08-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, August 29, 2010 - 04:58 pm: |
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Thanks for your comments, Gary.
Why wouldn't a larger antenna in the same line (CM-2018 or CM-2020) give me the extra gain I need? I guess I'm thinking that this one is doing well enough for local stations, so why not go bigger in the same line to get better L.A. reception?
At this point the extra expense and installation effort of a rotator and/or splitter is not worth it to me. But if I could get KPXN, KOCE, and KLCS with some measure of confidence just by increasing the antenna size, I'm in. The CM-2016 does okay with at least two of those when pointed at L.A. (323). I just need something pick up as well when pointed off to the side a bit (e.g. 20) so I also get KNBC.
Mark |
Gary S
Moderator
Username: Garys
Post Number: 570
Registered: 12-2002
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, August 30, 2010 - 10:08 am: |
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The problem with the all-channel antennas like the CM-2018 and CM-2020 is that they have compromised performance on UHF. They are bigger because they have more elements for VHF.
The 91XG or 8-bay bowtie (like the Winegard PR-8800) can give you literally twice the UHF signal that the all-channel antennas give. The 8-bay bowtie has the advantage of additional cross-section area that helps a bit when signals fade. The 91XG is a superior antenna for eliminating interference from the back and sides.
Look at this comparison chart:
http://www.hdtvprimer.com/ANTENNAS/comparing.html
For every 6dB increase in gain, you are receiving DOUBLE the signal.
Expense is a very minor concern because you amortize over 20 years or so, and if you compare the cost to cable or satellite subscription TV, over-the-air reception is virtually free.
But if you are happy with your current set-up, you are good to go.
Gary S.
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jrgo43
Intermediate Member
Username: Jrgo43
Post Number: 37
Registered: 09-2003
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, August 30, 2010 - 10:23 am: |
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I was reluctant to spend the $ or time for a rotator, but went ahead anyway. The improvement in being able to get channels was dramatic. For whatever reason the direction is not always the same and even channels that are give the same direction i.e. 58 and 28 in reality there is about 10-20 degrees difference for optimum reception. Just a thought
jose
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Micawber
Advanced Member
Username: Micawber
Post Number: 249
Registered: 11-2005
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, August 30, 2010 - 04:07 pm: |
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Power=10xlog(base 10) of P1/P2 or 3 dB for double.
Voltage=20xlog (base 10) of V1/V2 or 6 dB for double.
99.5% Dark Matter
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Mark
Member
Username: Sdmark
Post Number: 12
Registered: 08-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, August 30, 2010 - 04:47 pm: |
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Thanks all for the clarifications and thoughts. This will take some time to digest.
Re. signal strength, "for every 6dB increase in gain, you are receiving DOUBLE the signal." So hypothetically: let's say channel 20 comes in with a 50% signal strength (according to my DTVPal converter) with my current antenna A. On the net gain chart, antenna A shows a strength of 10 dBi on channel 20, while antenna B show a strength of 16 dBi. If I change to antenna B, my set should show 100% signal?
Mark |
Micawber
Advanced Member
Username: Micawber
Post Number: 250
Registered: 11-2005
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, August 30, 2010 - 07:37 pm: |
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I don't know what the % signal on your device is measuring. But a 6 dB increase would be a x4 power increase. Definitely better at the expense of a much narrower beamwidth. Harder to point.
99.5% Dark Matter
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Gary S
Moderator
Username: Garys
Post Number: 571
Registered: 12-2002
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, August 30, 2010 - 09:12 pm: |
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By doubling, I mean signal strength, which is traditionally measured in uV/m. I'm talking here about voltage, not power. (Not that it can't be directly converted to watts--but that is not the convention used for TV broadcast signal strength, at least not in the 35 years I've been working with antennas.)
The signal strength indicator in your DTV receiver is usually related to the inverse of relative bit error ratio (BER). Although the 0-100 number is handy to compare signals, it's not directly related to signal strength, and it's not linear.
Many TV sets have in their menu structure a readout of carrier-to-noise ratio, which is more usable. It takes 15dB to make an ATSC picture. If you can bring the level up to 21dB, you will have 6dB of fade margin. You want that number to be as high as possible to avoid losing the signal during deep fades.
Gary S.
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Mark
Member
Username: Sdmark
Post Number: 13
Registered: 08-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, August 30, 2010 - 11:34 pm: |
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Gary,
hdtvprimer.com is interesting reading! I can see I could spend way too much time on this, and enjoy it. What does it say that I would rather be reading antenna specs than actually watching TV?
You mention the Winegard PR-8800. Any experience with its replacement, the HD-8800?
Interesting that all these antennas go up to 69 even though the highest U.S. channel is 51 (http://www.hdtvprimer.com/ISSUES/erecting_antenna.html). Maybe we are due for a new crop of antennas. IMHO a lot of people will soon drop cable because antenna reception is okay for networks and the much of the rest that they had with cable is available over the Internet.
Mark |
Gary S
Moderator
Username: Garys
Post Number: 572
Registered: 12-2002
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, August 31, 2010 - 09:52 am: |
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That chart on hdtvprimer.com is dated 2003, so channel 69 was relevant. Bowtie antennas are very broadband anyway.
I haven't done any research on the HD-8800, but I do know that some of the antenna makers made modifications that in some cases interfered with their performance, at least temporarily. You might have to nose around to find out what others think of the newer -8800 and its Channel Master equivalent.
Gary S.
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Mark
Member
Username: Sdmark
Post Number: 14
Registered: 08-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, August 31, 2010 - 10:11 am: |
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Yeah it was actually an hdtvprimer.com page that pointed out that channel 51 is highest: "Late news: Note that now is not a good time to buy a Yagi antenna. Present Yagi antennas are optimized for channel 69. But in the U.S. 51 is now the highest channel, and a new generation of Yagi antennas cut for channel 51 will be the most desirable. For the next few years Yagi buyers must pay close attention to the frequency specs."
He has some unflattering things to say about the 4228HD, which I assume it the CM equivalent:
http://www.hdtvprimer.com/ANTENNAS/TemporaryPage.html
"The bad news is that the new 4228HD and DB-8 are both wrecks."
"This [4228HD] is developed from the 4221HD, which is an excellent 4-bay. But the 4228HD engineer was some clown who knows a lot less about antennas than he thinks he does. The 'phasing harness' is awful. It looks like it was designed by a plumber."
Mark
(Message edited by sdmark on August 31, 2010) |
Andy
Advanced Member
Username: Andydrew
Post Number: 433
Registered: 04-2005
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, August 31, 2010 - 06:47 pm: |
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If you read more into the HDTV Primer where you are looking you will see that it is the author's opinion that it is better to combine two Channel Master 4221HD's vs. any 8-bay antenna currently on the market. You can combine with a regular 2-way splitter/combiner.
I had previously combined two 91XG's in an attempt to receive LA UHF television channels from the coastal area in Tijuana. My experience this far south is that sometimes the signal is great and you get a ton of channels, and other times it is not so great. So if you need the LA reception to be 100%, no loss of signal, likely you won't be able to achieve that.
In my opinion, concentrate on getting reception from the 3 broadcast locations in San Diego and don't spend too much effort trying to achieve reliable reception from LA. Likely you will be disappointed with your results in the long term.
Of course folks further North in San Diego have a different experience than me. |
Andy
Advanced Member
Username: Andydrew
Post Number: 434
Registered: 04-2005
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, August 31, 2010 - 06:49 pm: |
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Also, I had previously owned the Winegard HD-8800. I believe it is exactly the same as the previous model, PR-8800.
The Channel Master antennas seem to be better a better quality build than the Winegard 4 and 8 bays. In addition, they are lighter. |
Mark
Member
Username: Sdmark
Post Number: 15
Registered: 08-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, August 31, 2010 - 07:59 pm: |
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Andy,
Thanks very much for sharing your experiences. Maybe I will sit tight with what I have and see how the L.A. signals vary.
I did try the lauded CM-4221HD 4-bay but found it did not perform as well at my location as the CM-2016 (details in chart above).
I discovered today that I get a slightly stronger channel 39.1 if I aim the 2016 directly at a large house uphill. I assume the house is acting as a reflector. (There is a large hill in the direct path to Mt. Miguel.)
I wonder if the guy up the hill would notice if I put an antenna on his roof and strung the coax back to my house ;). Seems like there would be a business in community antennas ("my block's Cable TV") !
Mark |
Steve
New member
Username: Sagreer70
Post Number: 4
Registered: 04-2008
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, September 06, 2010 - 01:49 pm: |
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Mark -
Thanks for doing all this experimenting! I tried the small antenna suggested at the top of this thread, and still have had no luck picking up channels 8 and 10 (even though its a UHF antenna). I, like you, am too far down the hill to see La Jolla.
I don't care about the LA stations. All I want to be able to do is pick up CBS so I can watch the Chargers.
I got complacent, and am still ponying up for the DirecTV package. But now I'm feeling, again, that it's time to cut the monthly bill.
Did the CM-2016 work for you on CBS? Also, ABC, just in case they ever get their sports act together again (and I like Modern Family).
Thanks again! |
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