San Francisco, CA - OTA - Page 159

ERP is Effective Radiated Power... the power that is equal to the transmitter output, minus line loss, times antenna gain and height advantage. That is the standard used by the FCC for all stations. I have no idea what the KGO transmitter is putting out, but their authorized power is 24,000 watts ERP. That's all the FCC would approve for them at their antenna height.

Remember, High VHF takes a lot less power to cover the same area as a UHF station. KGO at 24 kW digital is equivalent to their 316 kW analog on channel 7, since digital is measured as average power, analog was measured as peak power.

Stations on Low VHF needed even less power to cover the same area.

Unless you've studied electronics, this is all difficult to understand, but it all has to do with the frequency characteristics.

Larry
SF

That's exactly the same combination I'm using, minus the preamp. I use a simple coupler instead. I'm too close to Sutro and all of the signals overpower any preamp I've tried. It would be nice to have one to help pull in the Sacramento stations.

I think you'll find that you've got a winning combination there, Dave.

Larry
SF

Actually it was your recommendation in the Yahoo group that helped me decide to buy this antenna, so thanks for the recommendation. If Fry's had any high-band UHF antennas, I would have purchased what they had, but they only had UHF and UHF/VHF antennas, so I ordered the Y10-7-13 from Solid Signal.

I did try turning off the FM trap on the CM7777 figuring that it might be nice to connect the antenna to my AVR for FM, but turning off the FM trap did have a negative effect on signal strength. Even though FM is not close to high-band VHF, some of the FM stations must have harmonics that are interfering with KGO.

-Dave

DTV signal levels in Milpitas. Photos could be better, I just used an old digital camera pointed at the spectrum analyzer.

Channel 7, 11 (analog) and 12 (the strongest at 40 dB above the analyzer noise floor)



Channel 19 and 22 (analog)



Channel 27, 28 (analog), 29, 30 and 33



Channel 34, 36, 38, 39, 40 (analog) and 41



Channel 43, 44, 45, 49 and 50



Channel 51 and 55 (MediaFLO)



Close-up of the multipath on Channel 36, KICU-DT



Ron

Nice pics, dr1394.

I'm amused with the wide variation in the San Jose signals (I can't remember the name of the mountain). KICU-36 has a ton of multipath resulting in some really serious distortion, 50 and 51 look equally tilted but in opposite directions, but 49 looks okay.

- Trip

KTVU (44) will be at 1000kW by late September or mid-October, when the work on Sutro is finished; according to their engineering dept.; and this pdf doesn't show the 1000kW plot.

I'm enthusiastic about the Sutro antenna work. I think our reception is going to be
very good on most stations.

If we're lucky, maybe we'll get KCSM (43) PBS up here in SR.

- DFGY

KICU (also 30 on digital) and KTEH (50) are on Monument Peak; KSTS (49) and KDTV (51) are right next door on Mount Allison. I wouldn't expect you to remember those mountain names!


Patty

http://www.broadcastingcable.com/art..._DTV_World.php

"In the race to sign up station partners, RTV, which marks its fourth anniversary next week, has 88 affiliates currently on-air (it recently inked deals with Multicultural Broadcasting stations in New York, Los Angeles and San Francisco), while This TV has 70 on air since it launched in November."

That would be KCNS 38. Dunno when they plan to start airing Retro TV. You can get a sneak preview of the programming on the Retro TV website.


Patty

Hmm...then I wonder why their website lists KRON?

I checked the programming for KRON4 through the retrotv website and KRON4 is definitedly not retro. Perhaps the website error is due to KRON4 broadcasting on RF38 while KCNS38 broadcasts on RF39.

Their website is out of date. KRON dropped Retro TV some time ago.


Patty

I'll consider myself very lucky if I get all the major network channels including any PBS channel in HD. Channel 22 from Cotati seems to be only transmitting SD on programs which I want in HD like the Operas from time to time.

I'm curious about where you live. I'm in the flats adjacent to the WF Arts center and wish we would have bought on top of one of the hills when we moved here 9 years ago. Seems I would have better reception from Sutro if we had done so. But of course, maybe I couldn't afford one on top of the hill anyway.

The picture I get from ch2 OTA now seems to be a bit better than that supplied by Dish. I haven't compared it to Comcast yet.

I'm in south-east Santa Rosa; and I'm up about 800ft above sea-level.

I do pretty well with OTA. I can't really complain. I'm getting more stations than I
did with analog and my older antenna rig. Much more when Sutro is finished.
I get KNTV very well here; it's one of my best stations; watching U.S. Open in HD is
nice. I get the more powerful Sac. stations; KSPX, KQCA, KMAX in the mornings; but, I lost KVIE when they went to VHF. Might need to go up a little higher...

It's because Milpitas is pretty much underneath the Monument Peak and Mount Allison stations and at the same time, the antenna is (probably) pointed at Sutro/Mount Bruno (putting the San Jose stations almost exactly 90 degrees off axis).

The pics are from the distribution system at my place of work. I'm not sure what kind of antenna is on the roof, but I guess it's some VHF/UHF combo that came with the building. There's a big 38 dB distribution amp and then a huge patch panel with dozens of splitters. Every cubicle and lab in the building has a drop. I'm also not sure how many splitters my particular drop goes through, it's too much of a rats nest to trace the cable.

The system was installed when we were developing ATSC tuner DVD recorders. It's hardly used now.

BTW, the multipath on KICU is a good tuner benchmark. The old Samsung SIR-T165 has a lot of trouble, but my AMD/ATI T316 (6th generation) ATSC tuner/demod evaluation board has no problem at all decoding the signal.

Ron

So I'm wondering how long stations like KTVU, KRON and KPIX are going to continue identifying with their non-existent low-VHF channel? Shouldn't CBS5 now be CBS29?

No. Won't happen.

Under the FCC rules, any station that had a full power analog station will continue using that identifier regardless of the actual channel used to carry their broadcast.

That's what the rule is and it probably will never change.

Double the FM frequency and it falls right into the 7-13 channel range.

An FM trap should help anyone who has both high-VHF channels and an FM-rich environment. It's especially important if there is an inexpensive amplifier in use.

Thanks, Ron, for the very interesting display of signals across the band.

I appreciate you taking the time to photograph and upload the pics for us.

Larry
SF

Dave, glad to hear that it was my recommendation for the new antenna. I've been very happy with its performance.

When KNTV was transmitting from Loma Prieta we couldn't get it, so the "Antenna Doctor" (my he rest in peace) suggested adding an FM trap. After that KNTV was perfect all the time from 55 miles away. The trap is still in the circuit even though KNTV is now transmitting from only 5 miles away, and I'm glad that it is. It's probably the reason I'm able to get KVIE on 9 and KXTV on 10.

There are five FM stations transmitting from Sutro, so those second harmonic signals are real strong here.

Larry
SF

N.B.: The FM trap can't filter out the second harmonics after they exist. It can however prevent them from coming into existence if they're actually created locally from the fundamental frequencies by harmonic distortions in non-passive electronic components. (Hence ProjectSHO89's comment above about "inexpensive amplifiers")

Dave's setup may well have reduced FM harmonics in his high-VHF spectrum by using a trap to keep those FM stations out of his mast-mounted broadband amplifier where they would otherwise generate at least some harmonics. But Larry's amp-less antenna setup should be more nearly immune--unless the FM stations actually overload the (non-broadband) first-stage amplifiers of his TV tuners.

That may be so, but evidence suggests that FM traps are very helpful in upper-VHF reception, whatever the reason.

- Trip

i lost KTVU and KGO after the transition. WTF?

Did you do a rescan? They both changed channels, KTVU to channel 44 and KGO to channel 7.

What's a FM trap??

Are they cheap for DTV

Ask Google and ye shall receive.

thanks..I will check

How far does KFTL-CA go in San Francisco?? I'm in Vallejo..I just want to know how far can it reach with only 90 KW power..I got that for the Wiki

and the other 2 Translators Channels..How can I look them up without knowing the Station's

K02OA 2
K15ET 11

An FM trap is a band reject filter that typically has at least 20dB of rejection in the FM band (88 - 108MHz). They used to be very common and stocked by B&M electronics parts houses and Rat Shack. Rat Shack has discontinued them but they are still available from online sources for less than $10.

It seems that I now have a watchable KGO signal off my UHF based DB2 clone. Any idea what have changed? Could the aux antenna turns out to be better than the main?

Reporting from Sunnyvale.

hm...speaking of KGO, I was just watching a junk science summer drama ("Impact") on 7, and I noticed these moving rose-colored dots - or probably longer than dots - that I at first thought were part of the particular scene. Then I noticed them later, and realized they were some kind of mess-up, usually appearing in almost vertical lines...I've never seen that before...

didn't noticed them in the second hour of the program...Tony

My bet is that they looked a lot like the artifacts that toast0 mentioned a couple of pages ago.