San Francisco, CA - OTA - Page 375 - AVS Forum
Forum Jump: 
 27Likes
Reply
 
Thread Tools
post #11221 of 11232 Old 09-21-2014, 12:33 AM
Senior Member
 
TonyB1966's Avatar
 
Join Date: Sep 2009
Posts: 382
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 156 Post(s)
Liked: 22
Quote:
Originally Posted by Larry Kenney View Post
Sorry to hear of your poor reception, Tony. Your Y10-7-13 should definitely do better than what you're getting. I receive channels 9 and 10 from the Walnut Grove transmitter site 62 miles away with an average of 17-20 dB SNR signals (don't know what that would be on the Tivo). You need 15.5 dB to produce a picture. I don't have any amplification due to the overload problem from Sutro stations, but the antenna is about 15 feet above the roof or 35 feet above the ground.

My TVFool shows the stations with these levels:
KXTV 10 8.2 NM with -82.6 power (dbM)
KVIE 9 7.1 NM with -83.8 power (dbM)

Your TVFool shows that KSBW is stronger than either of those with 17.7 NM and -73.2 power.
KNTV and KGO are in about the same range for you as KXTV and KVIE are for me:
KNTV 12 13.4 NM -77.4 power
KGO 7 7.5 NM -83.4 power
so I would suspect you to receive reliable signals from both of them.

Your signal strength for KCBA 13 is quite low, with -9.6 NM and -100.4 power. I don't have any VHF signals in that range for comparison, but I get a solid signal from KEMO 32 with a 10 element UHF yagi (an Antennas Direct S-15) and, according to TVFool it has a NM of -12.4 and 103.2 power. KQCA 46 from Walnut Grove has a NM of -7.0 and 97.8 dBM power and it comes in with a 18 to 21 db SNR signal from the CM4228, again without any amplification.

Good luck! I hope you can find where the problem is.

Larry
Thanks much Larry. Kids are in bed, wife soon... I'm working on this now.

I have KCBA! Just playing with direction every so slightly... Signal strength is not great, but a solid mid 40's to low 50's on the TiVo, which "grades" hard. Very strong SNR's on the Samsung TV of 30 show up as 65 on the TiVo, for perspective. Indeed, I found SNRs of 16 to be on the cliff...

From my viewing chair to the mast on the roof is less than one minute, so pretty slick.

I have no idea why I'm not getting KGO (ABC) and KNTV (NBC). That said, aiming south gets me NBC & ABC (KSBW 8) and now FOX (KCBA). Even I were to figure this out and get KGO and KNTV, I'd probably decide to go southward anyways. Getting KCBA is pretty big for me as KTVU FOX is one of my tougher UHF gets...

Larry, I appreciate the support.
TonyB1966 is offline  
Sponsored Links
Advertisement
 
post #11222 of 11232 Old 09-21-2014, 07:46 AM
AVS Special Member
 
Calaveras's Avatar
 
Join Date: Jan 2007
Location: Mountain Ranch
Posts: 2,931
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 96 Post(s)
Liked: 89
Quote:
Originally Posted by TonyB1966 View Post
Thanks much Larry. Kids are in bed, wife soon... I'm working on this now.

I have KCBA! Just playing with direction every so slightly... Signal strength is not great, but a solid mid 40's to low 50's on the TiVo, which "grades" hard. Very strong SNR's on the Samsung TV of 30 show up as 65 on the TiVo, for perspective. Indeed, I found SNRs of 16 to be on the cliff...

From my viewing chair to the mast on the roof is less than one minute, so pretty slick.

I have no idea why I'm not getting KGO (ABC) and KNTV (NBC). That said, aiming south gets me NBC & ABC (KSBW 8) and now FOX (KCBA). Even I were to figure this out and get KGO and KNTV, I'd probably decide to go southward anyways. Getting KCBA is pretty big for me as KTVU FOX is one of my tougher UHF gets...

Larry, I appreciate the support.

You're having a hard time with KCBA because its antenna pattern is unfavorable for you.

http://transition.fcc.gov/fcc-bin/po...78&p360=0.111&

You're heading on the above plot is 348 degrees. If you click on KCBA on your TV Fool report it shows the terrain between you and KCBA. It also says KCBA is 19.75 KW but to you it is 0.143 KW. If you try to read the field strength at 348 degrees it's about .09. To calculate the ERP in your direction you square the field strength and multiply by the transmitter power (.09 x .09 x 19750 = 160 watts). That's not much power. In order to get more reliable reception on KCBA you need a pair of VHF antennas like I have and a preamp.

I don't know what the problem with KGO and KNTV is. TV Fool says they should be plenty strong enough. Were you able to figure out the true signal strength of these stations? It could very well be vegetation issues are causing attenuation and multipath. TV Fool doesn't take into account vegetation. Larry doesn't have any trees to look through. Attached is a spectrum analyzer image showing KVIE and part of KXTV on 9 and 10 from a friend's house. He is 62 miles from the stations but is looking through a pine forest. The signals are supposed to be flat but the trees are causing the large variation in signal strength. The signal quality will be limited to what the weakest part of the signal is, and that doesn't include multipath issues.

Chuck
Attached Thumbnails
Click image for larger version

Name:	KVIE.gif
Views:	9
Size:	22.9 KB
ID:	273153  
TonyB1966 likes this.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
Calaveras is offline  
post #11223 of 11232 Old 09-21-2014, 09:43 AM
Senior Member
 
TonyB1966's Avatar
 
Join Date: Sep 2009
Posts: 382
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 156 Post(s)
Liked: 22
Great stuff Chuck. I'm actually understanding more and more of what I read, I'm happy to say.

Indeed, I have vegetation here, and terrain concerns, as stated. We drive up a hill, then downward toward the lake to get to the property. Beautiful here, but I knew it was not going to be easy reception-wise. The trees though are few, literally 3 to 5, both north (Sutro direction), and a few going south to get KSBW 8 and KCBA 13. The trees are closer when aiming south, like 50 feet away, but I'm not generally going through twigs and leaves, but lower more stationary branches and trunks. KCBA is looking solid and I got the best reception around 174 degrees, as I recall (was hard reading the compass on the roof at night, not wanting to shine the flashlight around too much. I have the antenna snugged-up to the mast.

In the bedroom here, the Samsung tuner is showing 7 to 8 bars (out of 10) for KCBA. While I get higher peaks with KTVU, that FOX on UHF seems to be less predictable as it fluctuates more, in both predictable and seemingly unpredictable patterns. I've only been experimenting with VHF a few hours, but it looks to be more solid thus far.

I am using a preamp, the VHF side of the RCA dual input amp. The UHF side is terminated as I'm not using it for the DB4e. I found that I was getting better results going through the CM 7777, so I'm using it, then combining the two antennas. Would be great if one preamp gave equal or better results, and I'm curious to try again. Removing the CM 7777 preamp and Winegard combiner, making things more simplistic would be nice... That said, I've had two RCA preamps fail on me over the course of weeks, and they keep sending me new ones.

KCBA is working like a champ thus far.

Last edited by TonyB1966; 09-21-2014 at 09:57 AM.
TonyB1966 is offline  
post #11224 of 11232 Old Yesterday, 01:05 AM
AVS Special Member
 
Larry Kenney's Avatar
 
Join Date: Nov 2001
Location: San Francisco, CA
Posts: 2,643
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 64 Post(s)
Liked: 33
Congratulations, Tony, on getting KCBA so well. As I mentioned yesterday, you're working with a weak signal, so it's great to hear that your Y10-7-13 is working well now. KSBW is probably really strong now, so you're all set for FOX, ABC and NBC using the new antenna. You really don't need to get KGO and KNTV for ABC and NBC.

If your conditions are anything like what I witness here, there will be times when signals get weak and drop below the cliff edge, so don't be surprised if KCBA disappears occasionally. At other times you might be surprised at how much stronger than usual the signal is. The Walnut Grove VHF signals vary as much as 10 dB SNR here.

Larry

My complete SF Bay Area DTV Station Lists:
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

Lots of Broadcasting links and information:
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

Check out photos and info on my antennas:
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
.
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

Larry Kenney is offline  
post #11225 of 11232 Old Yesterday, 07:58 AM
Senior Member
 
TonyB1966's Avatar
 
Join Date: Sep 2009
Posts: 382
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 156 Post(s)
Liked: 22
Quote:
Originally Posted by Larry Kenney View Post
Congratulations, Tony, on getting KCBA so well. As I mentioned yesterday, you're working with a weak signal, so it's great to hear that your Y10-7-13 is working well now. KSBW is probably really strong now, so you're all set for FOX, ABC and NBC using the new antenna. You really don't need to get KGO and KNTV for ABC and NBC.

If your conditions are anything like what I witness here, there will be times when signals get weak and drop below the cliff edge, so don't be surprised if KCBA disappears occasionally. At other times you might be surprised at how much stronger than usual the signal is. The Walnut Grove VHF signals vary as much as 10 dB SNR here.

Larry
Indeed Larry. I might have "spoken" a little too soon. Yesterday later in the afternoon I noticed darting horizontal breaks in KCBA's image. Very unique for me as I had not seen disruption like that previously on the UHF channels I've be working on... I wouldn't say it was unwatchable, but certainly not enjoyable during something like a football game.

I must admit that I'm not excited about having such a large antenna here in the first place. It's low, maybe two feet above the apex of the roof, so I probably won't get any grief from a neighbor. With the other antennas I experimented with, they all are max 1 meter in size (longest dimension). A 10' antenna for essentially one channel that already get 80% of the time (KTVU) is something that gives me internal strife, even more so now that it seems KCBA will not be as dependable as hoped, which I understand given its depth on my TV Fool report.

Just sharing my inner thoughts as a novice during this experimentation... I seem to get KSBW 8 equally well with the small RCA antenna as I do this Y10-7-13. I'm guessing that might not be the case during inclimate conditions though. I realize that there is no substitute for having more metal in the air.

Decisions, decisions...
TonyB1966 is offline  
post #11226 of 11232 Old Yesterday, 08:58 AM
Senior Member
 
ADTech's Avatar
 
Join Date: Jun 2010
Location: St Louis
Posts: 441
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 12 Post(s)
Liked: 30
Quote:
Originally Posted by 888CALLFCC View Post
I noticed those "Digital" gold plated husky splitters sold at home depot & electronic stores have HUGE losses. -7.5 or more per port.
Where as a simple 5-900 Mhz splitter is around 3.5 per port.
7.5 db loss is subtracted from the gain your antenna has (say 9+db) puts that cable wire system with splitter at + 1.5 or less.

I'd also be quite surprised to see such a splitter with that much loss.

I did an assessment of branded two-port splitters available in a variety of retail stores earlier this summer and found that the insertion loss varied from about 3.3 dB (best case) to 4.7 dB (worst case) at 700 MHz.

Tech support for Antennas Direct
ADTech is offline  
post #11227 of 11232 Old Yesterday, 09:25 AM
Newbie
 
Monte324's Avatar
 
Join Date: Feb 2005
Posts: 8
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 11 Post(s)
Liked: 1
KPIX signal info

Awhile back when asking about KRON people said they had issues with KPIX. When my directional antenna on the north side of the house pointed at KPIX I get about 75% strength with around 90% quality. While experimenting with different antennas on the south side of the house (big and small ones) I noticed KPIX had a stronger strength 90% or higher and quality ranged from 70%-100% depending on the direction. So if anyone is having issues with KPIX try seeing if this is the case for you too. I only noticed this because using combiners I was noticing the south direction signal was interfering with the north direction signal and it was bouncing back and forth until I aimed it just right to get the best signal. Not sure why the nearly LOS signal is weaker. Maybe the hills are bouncing back a better signal but only KPIX.
TonyB1966 likes this.
Monte324 is offline  
post #11228 of 11232 Old Yesterday, 02:13 PM
Senior Member
 
TonyB1966's Avatar
 
Join Date: Sep 2009
Posts: 382
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 156 Post(s)
Liked: 22
I put the RCA ANT751 back up, higher, much closer to the DB4e, like what I tried with the Y10-7-13, and I get KCBA, watchable, but not quite as good as with the Y10-7-13. I get KSBW, as noted earlier, at the same signal strength as the Y10-7-13, at least according to the TiVo. Either way, channel 8 is strong, as what might expect...

I'm inquiring with Solid Signal about a return, an RMA #, etc... Does anyone here want a Y10-7-13. 50 bucks? Figured I'd ask again. I'm actually heading up to Berkeley this weekend, so I can meet someone up there, which is probably more convenient for many.

That all said, given at that I am getting KCBA now with the small RCA ANT751, I wonder if the ClearStream 5 might even receive it better. ADTech, since you are here, any thoughts on KCBA 13 and the C5? Here is the TV Fool report again:

http://www.tvfool.com/?option=com_wr...d24344cdac3547
TonyB1966 is offline  
post #11229 of 11232 Old Yesterday, 05:04 PM
Advanced Member
 
888CALLFCC's Avatar
 
Join Date: Jul 2009
Location: Hayward, CA
Posts: 575
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 19 Post(s)
Liked: 24
Quote:
Originally Posted by TonyB1966 View Post
I put the RCA ANT751 back up, higher, much closer to the DB4e, like what I tried with the Y10-7-13, and I get KCBA, watchable, but not quite as good as with the Y10-7-13. I get KSBW, as noted earlier, at the same signal strength as the Y10-7-13, at least according to the TiVo. Either way, channel 8 is strong, as what might expect...

I'm inquiring with Solid Signal about a return, an RMA #, etc... Does anyone here want a Y10-7-13. 50 bucks? Figured I'd ask again. I'm actually heading up to Berkeley this weekend, so I can meet someone up there, which is probably more convenient for many.

That all said, given at that I am getting KCBA now with the small RCA ANT751, I wonder if the ClearStream 5 might even receive it better. ADTech, since you are here, any thoughts on KCBA 13 and the C5? Here is the TV Fool report again:

http://www.tvfool.com/?option=com_wr...d24344cdac3547
Given your location,... you need to probe for signals.
Generally you will find peaks every 2 to 3 feet on the mast (up or down) and nulls.
Usually any antenna will work in a signal peak elevation. And no antenna will work in a null.
Sometimes the signal is just as strong at ground level as on the roof.... Or with a big or small antenna.
Not an easy task,... but signal varies with elevation.
And windless rainy days are what "normal" signals are. The best time to do antenna work.
Windy days could wipe out some UHF stations altogether. but not VHF.
TonyB1966 likes this.
888CALLFCC is offline  
post #11230 of 11232 Old Yesterday, 05:16 PM
Senior Member
 
TonyB1966's Avatar
 
Join Date: Sep 2009
Posts: 382
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 156 Post(s)
Liked: 22
Quote:
Originally Posted by 888CALLFCC View Post
Given your location,... you need to probe for signals.
Generally you will find peaks every 2 to 3 feet on the mast (up or down) and nulls.
Usually any antenna will work in a signal peak elevation. And no antenna will work in a null.
Sometimes the signal is just as strong at ground level as on the roof.... Or with a big or small antenna.
Not an easy task,... but signal varies with elevation.
And windless rainy days are what "normal" signals are. The best time to do antenna work.
Windy days could wipe out some UHF stations altogether. but not VHF.
Thanks 888CALLFCC. I admit that I didn't experiment all that much vertically (up as well as down), but it sounds like I should.

Since Sears.com sells the C5, and confirmed that I can return it to their local store, should I find that desirable, I just ordered it. I had a bit of a credit with them and I couldn't find it cheaper elsewhere, so it was a no-brainer to try.

It actually comes with a combiner at the antennas, but I think I'll continue to use my Winegard one, which is after the preamps. Even the minimal insertion loss, before any amplification is something I'd like to avoid. It however means two RG6 cables going downward...
TonyB1966 is offline  
post #11231 of 11232 Old Yesterday, 05:22 PM
Advanced Member
 
888CALLFCC's Avatar
 
Join Date: Jul 2009
Location: Hayward, CA
Posts: 575
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 19 Post(s)
Liked: 24
Quote:
Originally Posted by TonyB1966 View Post
Thanks 888CALLFCC. I admit that I didn't experiment all that much vertically (up as well as down), but it sounds like I should.

Since Sears.com sells the C5, and confirmed that I can return it to their local store, should I find that desirable, I just ordered it. I had a bit of a credit with them and I couldn't find it cheaper elsewhere, so it was a no-brainer to try.

It actually comes with a combiner at the antennas, but I think I'll continue to use my Winegard one, which is after the preamps. Even the minimal insertion loss, before any amplification is something I'd like to avoid. It however means two RG6 cables going downward...
I own a C5, and here are some test sites and results.
Hayward, Mission Boulevard .....KSBW...yes .....KCBA.....no
Soledad, West Street .....KSBW....yes....KCBA ....no
Salinas, Home depot parking lot....KSBW....yes.....KCBA.....yes

Connected to a battery DTV with 4 feet of RG-6, standing at ground level, approx 6 feet

Last edited by 888CALLFCC; Yesterday at 05:33 PM.
888CALLFCC is offline  
post #11232 of 11232 Old Yesterday, 05:51 PM
Senior Member
 
TonyB1966's Avatar
 
Join Date: Sep 2009
Posts: 382
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 156 Post(s)
Liked: 22
Was thinking of getting a DC DTV for roof testing, but wow, the HD parking lot too.

Given that I'm getting KCBA now with the RCA antenna, and it's pretty decent, with these occasional darting horizontal interference... With TV Fool stating that KCBA is 9.6 dB in the hole, I'm pretty impressed that it's coming good as it is. Fingers crossed on the C5. Thanks 888.
TonyB1966 is offline  
Reply Local HDTV Info and Reception

User Tag List

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page


Forum Jump: 

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off