Sacramento, CA - OTA - Page 259

In their April 387 DTV TRANSITION STATUS REPORT it states that work requiring a tower crew was still needed to complete their transition in addition to getting and re-tuning the transmitter from 31 to 35. I just assumed it was the transmission line from the antenna.

The only thing I can think of at that distance is these stations actually transmit from a location near I-5 and Twin Cities Road, West of Galt. So they are Northwest and not the assumed due North. KXTV 10 should be easy. (should) Channel 6 KVIE is in a similar location.

Are you using an indoor or outdoor antenna?

Yes, that doesn't make much sense to me, unless, as I speculated in an earlier post, that they need to install new microwave antennas for the studio link and that's what the tower crews are for.

I thought I posted a picture of the KCRA/KMAX/KQCA combiner room before but I can't find it so I've attached it again. All that big copper tubing is coax and the black stuff is UHF waveguide. That flat thing in the upper left with what looks like 3 cans sitting on top is a coaxial switch.

Chuck

OK, I think I understand about half of that, but thanks for the information. It just seems like life would be a lot easier if all the stations were using a UHF signal.

Indoor. I was using this one.....

http://www.amazon.com/RCA-ANT1450B-M...7692987&sr=8-1

It worked good on every station other then 3.1 and 3.2 would brake up sometimes. But I could not at all get channel 6 and 10.

Today I tried using an older antenna (with rabbit ears)and could get channel 6 and channel 10 good but other stations like 31 and 40 would start braking up. This is really starting to get annoying!!

Anybody know if radio shack sells good indoor antennas?

Your question was answered by other posters but I would add that there is also a significant drop in in electricity costs. The power required between operating on their former high UHF band verses the high VHF band is staggering. Bob or Rory gave us an example of the savings involved some months back.

Anybody know if the WINEGARD SS-3000 is good? I've heard good reviews for it on other sites but I don't know if anybody locally here uses it.

http://cgi.ebay.com/WINEGARD-HDTV-AM...3%3A1|294%3A50

Ok, so they are doing it to save money then?

Lodi25,

Your RCA 1450B may still work for you, but you will need a longer cable in order to test it from a position further away from your television. VHF signals are more prone to electrical interference. Your television could be the culprit preventing reception of KXTV and KVIE. This solution worked for an amped indoor antenna here that was failing to receive VHF, while doing just fine with UHF.

I have one and it's good EXCEPT you won't be able to get Channel 6 or 10 due to the VHF frequency.

I had it away from the TV and put it on top of my subwoofer. The weird thing is that if I move or hold onto the amp (the little black box thing next to the power plug) channel 6 and 10 would come in. But as soon as I moved away and let go of it, both (channel 6 & 10) would be gone.

Another question, I live on a very busy and loud street. Dose that have any impact on the reception?

Lodi25,

What is the elevation of the RCA 1450B in the room you are using it? I would think you would get best results by mounting the antenna as high as possible. This also might help with nearby traffic. From my experience, UHF has been more prone to dropouts caused by passing vehicles. I've not seen any dropouts on VHF. Your subwoofer, is it always turned on? It might be causing problems.

The weird thing is, if I put the RCA ANT1450B on the top of the TV stand, I would only get about half of the channels. Putting it on the subwoofer gave me a good signal other then channel 3 braking up every other minute and not getting channel 10 or 6. I think I will try your suggestion and get a longer cable and trying putting the RCA ANT1450B in another location in the room.

Another weird thing is, the other "older" tv antenna (with rabbit ears) I was trying to use today, works 100% good in my bed room but not in my leaving room! Both of my TV's are the same 32 inch Sony Bravia's.

When I was in the Lodi area I had pretty good luck with this:

http://www.walmart.com/catalog/produ...ct_id=10542272

but I had to use an extension and hang it high on the wall. That was during the transition though, so I don't know how well it gets vhf-hi.

Chuck, thanks for sharing that pic.
That's some impressive RF plumbing!

Trip or someone else posted on how they ended up on VHF but as usual, I can't find the post so here's my best retelling.

KXTV was out of core pre-transition on 61 so the easy and obvious choice was to go back to 10. Same thing for KTXL out of core on 55 and going back to 40. KVIE was also out of core on 53 but low VHF 6 was not a good choice so they had to find something else which apparently was a problem. It's a story unto itself but they ended up on 9 after getting an interference agreement with KIXE also on 9.

Someone else can fix it if I've messed it up somehow.

Chuck

It's a room only an engineer can love.

Chuck

Couple questions...
1) Are those ERP figures for hpol which would be half of your total CP?
2) Do common TV receiver antennas (linear hpol & vpol) receive only half of the CP ERP because of the polarization loss factor?

No, you can't think of it like that. The transmitted wave goes through a full 360 degree rotation for every RF cycle. If the ERP is 22KW CP, that does not mean 11KW horizontal and 11 KW vertical.


Yes, in theory a uni-polarized antenna is down 3 dB when receiving a circular polarized signal.

I haven't researched how it is done, but in an elliptically polarized antenna there is typically less ERP in the vertical plane than in the horizontal plane but the wave polarization still rotates.

Chuck

Seems like KIXE signed off on that interference agreement without carefully considering it, considering the two are both PBS affiliates, I wonder just how many people can't receive either one now.

Ken

The antenna is, IMHO, the best UHF indoor antenna on the market. It does work on VHF, but our tests have found it to be inferior to rabbit ears.

For someone who absolutely must use an indoor antenna, a combination of amplified rabbit ears (for VHF) and the SS-3000 (for UHF), with a switch, might be a good way to go.

Bob

Well, you were really going good there until you brought up KSPX. Channel 29 digital was not an option due to KPIX on channel 29 in SF.

Bob

Thought I'd mention a couple of things...

For those of you who have been on the Forum for a while, you may recall all of the complaining about our microwave fading, primarily in the summer months. I am happy to say that KOVR has not had one microwave since we switched to the new system. I have declared this one fixed. Took long enough, but it was a complicated and very costly project.

Also, Angie, a ham operator, has been experimenting with antennas. She sent me some pictures and some funny text to go along with them. I am posting over several days on my blog.

I see some new folks here, using ham calls for their ID's. Mine is W1RH.

Bob
www.cbs13.com/blogs

No, at least not for KVIE and KXTV. As previously stated the upper tier UHF spectrum was taken back by the FCC and reassigned to other uses, (I believe cellular). The lower electricity costs is just a benefit they derived from the switch.

I dunno, Bob, my experience with an amplified rabbit ears (a Terk HDTVa) after June 13th has led me to avoid recommending any permutation of rabbit ears for anyone, unless they can see the Walnut Grove towers out their back window.

I like your idea of optimum VHF & UHF antennas for those who can't put one up outside, but I have to believe there's something else out there on VHF (indoor) that beats rabbit ears, amplified or not. I was impressed with the demo of the Terk TV5 at KVIE's seminar last month--their TV5 pulled in their ch. 9 signal solid, while a rabbit ears (albeit unamplified) in the same room was no good. Maybe an SS3000 paired with a TV5 would be optimum, but you're talking about two large footprints in a living room. Might not be practical.

VHF indoors with any antenna is a challenge. I tried checking the many Internet reviews of the TV5 and others, but 99% of those reviewers don't know VHF/UHF from Citizens Band, so objective evaluations of VHF performance mainly can't be found.

Footnote: I had to give up on KVIE & KXTV in my Mom's apartment. It just wasn't going to happen without maybe a 5-element yagi slung from the ceiling. She's now happy as a clam with Comcast HD, and I'm out 40 bucks a month (more after a year).

--Ron

I'll buy a TV5. One of the few we have not tried here.

Thanks, Ron.

Bob

TV5 is a takeoff of an antenna called a biquad, and a biduad is a known good antenna design.

http://martybugs.net/wireless/biquad/

I used to sell an older version years ago when I worked at Radio Shack and it worked pretty good in the store, it seems to fall off more and more at higher frequencies though. Good luck with it.

Ken

I'm farther away from Walnut Grove than the KVIE studios and have received it and KXTV flawlessly for over a month now with rabbit ears and a bowtie w/converter box to an old CRT. The old standard equipment still works.

Last time I looked at the KRCR website, their recommendation for digital reception was, NO RABBIT EARS. What is one to use for indoor reception of RF 7?

You're supposed to use the Magic Antenna. Pardon my sarcasm but I've been pondering this post for sometime. I've experimented with antennas for many years, mostly in ham radio, and I've seen the search for the magic antenna as a recurring theme. I'm not making fun of any person here, just the concept of the magic antenna as almost everyone who has played with antennas has embarked on this search.

What is a Magic Antenna? That is the antenna that is smaller and mounted much lower than a traditional and higher mounted antenna, often of an unconventional design, but performs as well or nearly as well as the latter.

In the ham radio world the search is often for a reduced sized antenna for 7 Mhz, 3.5 MHz, or 1.8 MHz, ground mounted that will work like a full sized antenna 100' or more in the air. The designs are endless and the mythology that grows up around some of them is vast. But under computer modeling, none of them show performance anywhere near the old standards.

The same thing is going on today for indoor antennas for DTV. Reports run the gambit from useless to great for just about any antenna. Why is this so?

If we assume that enough signal is getting inside a building for it to at least be possible to receive a DTV signal, then the problem we're left with is reflections - multipath.

Try imagining a signal entering a room from a couple different places and then bouncing off the walls and everything else inside. The room is full of crisscrossing signals from every direction. Further imagine that the reflections are not necessarily equal in amplitude at all points across the 5.4 MHz bandwidth occupied by the signal.

Now you have a room filled with weak spots and hot spots for all those reflections that are slightly out of time sync with each other.

Your mission, if you decide to accept it, is to position your antenna in the room where just one reflection reaches it, is strong enough across the entire 5.4 MHz bandwidth and where all the other reflections are weak enough so that the signal-to-noise ratio of the main signal is high enough so that your TV can decode the signal. Then try to find one position for all the other stations you wish to receive. This indeed can be Mission Impossible.

It's no surprise then that just about any antenna will work in some locations on some channels and not in other locations on other channels. It's also no surprise that antennas contorted into all sorts of positions that break all the rules of antenna design sometimes work. After all, what you're doing is not much different from moving your cell phone to find the hot spot with the most bars but that DTV is more sensitive to multipath so it makes the job even harder.

I'm sure some of these indoor antennas are worse than others, but none are the magic antenna that is as good or nearly as good as a traditional antenna on your roof above the trees and buildings. Beyond eliminating the truly bad ones, I don't think there is any indoor antenna that can be recommended with any certainty of success.

Chuck

I would agree with Calaveras in that for indoor antennas location is often the key. Unfortunately on top of the TV may be far from the best location signal strength wise. It would seem that you need to find a location where you are not at or near a signal strength minimum for all of the stations you want to watch. You can add to that the problem that people moving around will also change where the signal strength nulls are. The location of signal nulls will also change when the trees loose their leaves in the fall. I think there will be lots of problems when we get back to wet weather and trees moving around in the wind. On top of that the materials used in home construction may be effective RF shields as for example the wire mesh used with stucco siding. It would be very interesting to observe the TV spectrum with a spectrum analyzer using an indoor antenna as you move the antenna around the room.

A final issue is how good does a TV antenna need to work for VHF with reference to UHF to be considered a U/V antenna. I was looking at the specs on an antenna a few days ago the said it had zero dB gain for UHF and a 10dB loss for VHF but was being sold as a U/V antenna. It would seem there is no regulation of this. Most indoor antennas have no published specs at all.