Sutro Tower Woes

[hardware1197]

Hi.

I just moved to within 1500 feet west of the base of Sutro Tower in San Francisco. I'm wondering if my scanning days are over. You know, that crazy ugly tower on the skyline of San Fran. Sutro is the main FM transmitter for about 10 TV stations, as well as the HD
TV transmitter for the greater bay area. I'm not sure the frequency range of HDTV, but we all know the others.

For those of you not familiar, it is also within about 1000 feet of the City and County's main radio site for their 800 Mhz system and the backup low band system.

I have noticed the following:

With the setup in my car, I enjoyed great Low band reception, good 800mhz reception, and excellent VHF. I also enjoyed relatively good AM Aircraft and Military air band reception

Now, as you can imagine, I'm almost wiped out but for good 800 MHz reception on the County site (it's close enough to hit with a baseball)

I cannot get a single AM aircraft band transmission, and I have a route overhead from SFO. If sat on 120.5 with 0 squelch and get nothing but noise from the adjecent TV stuff.

My Car's GPS receiver goes blank within 1000 feet of that thing......what's that, like 3.4 Ghz!?

Cell phone is near impossible except for static "good" spots.

My question is this:

Do I bother trying an outdoor antenna for my home monitoring? Can I make or buy a filter/attenuator for the TV BANDS? How do I find out exactly what transmitters are up there and what band they are on?

I listen to the Marin MERA (UHF-Trunked) , CHP Low band, San Mateo Trunked (UHF), CCSF (800 MHZ, Oakland PD (EDACS 800 Mhz), West County (800 MHZ EDACS) and civilian aircraft.

And no I'm not close enough to run an rg-8 cable up the tower! It was my first plan, to place my discone at the top.

And please don't tell me I'll get brain cancer from the transmitters. The kooks in the nieghboorhood have covered that topic.

Thanks!

 

[n0doz]

Sounds like your radio days are over. Sorry. Keep your stuff for when you leave the neighborhood.

 

[radio10-8]

You have the best views in the city. Ok so your scanning days are over? Maybe not? Being that close you could start to listen to who's really up there. Hows reception in Noe Valley? Maybe you could scan via internet streaming?

 

[radio10-8]

You have the best views in the city. Ok so your scanning days are over? Maybe not? Being that close you could start to listen to who's really up there. Hows reception in Noe Valley? Maybe you could scan via internet streaming? set up your own antenna and block out TV signals, see what happenns.

 

[Sac916]

There are various band filters out there, you'll just have to try and buy a few.
You just may end up having quite the scanner outpost with lots of couplers, switches and filters to deal with. Also look into directional antennas.

www.scannermaster.com
www.grove-ent.com


I've been in your neighborhood many, many times. Trade my house for your home.

good luck from an ex-east bay resident.

 

[zz0468]

I think if the commercial and government operators actually ON the Sutro tower can make their receivers work, you can too. You may wind up with multiple window filters feeding multiple receivers. A scanner on a broadband antenna will just roll over and quit working under those conditions. In fact, even WITH the filters, that could prove too much for a scanner. You might have to upgrade to commercial radios.

GPS is on around 1.5 GHz, so if that's getting slammed, figure that's a lost cause when you're close to home. Low pass filters for low band might do the trick, along with notch filters for the fm band.

The HDTV transmitters are worrisome. It's a 6 mhz wide chunk of rf that gets into everything. Just hope that it's not causing intermod with anything, because it's absolutely miserable to figure out the mix components when an HDTV transmitter is involved. BTW, it's going to be in the usual tv spectrum, most likely on the UHF channels. If you're really serious about improving your reception, talk to Angle Linear. They make about the best filters out there.

It's an interesting situation... your house is now located in what amounts to a mountaintop site rf environment - and probably the worst possible situation. Yet, there are countless receivers working just fine in those environments. It ain't easy, but it CAN be fun figuring out how to make things play. Good luck!

 

[Don_Burke]

I'm wondering if my scanning days are over.

It appears your days of using wideband antennas are on hold.

GPS is on 1575.42 MHz and 1227.60 MHz. The best I can tell you on that is now you know that when your GPS is belly up you are near home.

HDTV is in the UHF TV band.

You may be able to salvage some monitoring with antennas with some selectivity. Folded dipoles, loops, j-poles, and the like would be my first try. They would give the filters mentioned above a fighting chance.

If there are particular frequencies you are interested in, a commercial radio programmed for receive only would be an option, although pretty pricey.

Good luck.

 

[trooperdude]

Money

Nothing that a LOT of money can't cure.

Filters, notches, stubs and the like can get expensive rather quickly.

First thing I would dump is the scanner and go to commercial radios.

There is always remote control at a friend's house far away via internet
with something like Butel's software.

 

[prcguy]

With enough filters you might be able to keep the hobby going but being that close to that tower there will be a lot of intermodulation products that fall right in the bands you want to hear. I don’t think Angle Linear will make a wide enough filter to cover a complete scanner band like 144-174MHz, etc. Chip usually concentrates his filters on receive input bands for repeater use. His filters are very well made but you really pay for the quality. You might shop Ebay for surplus filters like item # 330055075054. This will keep out the UHF HDTV and everything below about 420MHz and might help with UHF mil air reception. The seller is also near you in SF. Lots of other useful filters show up on Ebay cheap like 88-108MHz notch, 174MHZ low pass, etc. Good luck with your new location.
prcguy

 

[OpSec]

To the OP:

I hope the new view is worth living the that RF hellhole. At least your not one of the morons that wants it taken down. I love reading those websites...chock full of mis-information.

 

[gmclam]

I'd love to live up there! What a view. And certainly a good place to pick up radio transmissions. BUT, you can NOT use "garbage" receivers. You need to use receivers which have GREAT SELECTIVITY and image rejection.

Also using something like a rubber duckie antenna will just be a "barn door" and let everything in. You need GREAT shielding from an antenna, with filters in-line. You want to get as much "desired signal" as you can, without letting in too much undesired signal.... I started a post here recently looking for a filter, and someone from RR pointed me to a filter from ScannerMaster than filters everything below 25 MHz and the FM band (88-108 MHz). That did wonders for me! It is a good start for you. It will reduce the FM band by at least 30dB, hopefully that's enough.

TV stations on Sutro are on channels 2,4,5,7,9,20,44 ... and the ATSC broadcasts (I do not have the list in front of me, but they are CURRENTLY on UHF channels). Keep in mind that near/after 2/17/2009 the NTSC broadcasts will cease and many of the current digital TV broadcasters will move to their current VHF slot. For example, I believe KGO-TV will resume digitally on VHF 7 after they turn off NTSC. I have the complete chart at home and can comment precisely, but I am not there at the moment.

SO, another thing you might do now is add filters for some or all TV channels. 2, 4 & 5 are one filter; 7 & 9 another (I do not believe 11 is on Sutro but I am not 100% sure). The UHF channels would require other filters; assuming they can be filtered being so close.

Another approach is to determine which frequencies are giving you trouble, and start by filtering them (after you've clearly rid AM & FM broadcasts from your receiver).

Bottom line, your scanner days are only over if you want them to be.

Good luck.

 

[gcgrotz]

Wow, I feel for you. Was it your wife that said "what a lovely view, let's buy this one"?

 

[hardware1197]

All,

Thanks for the great feedback. I do note that if I drive up to the South peak of twin peaks, and tuck the car next to the hill, I get some absolutely subperb reception on the CHP freqs throught the bay area and beyond....I got Auburn on the green until Santa Cruz clobbered it. I also got the White from Stockton very clear.

Anyway I am experimenting with some filters and I have narrowed the main culprit in terms of intermod as being PBS. (Channel 9) Now I like a good nature show and political commentary now and again, but I might be able to cook a hot dog off the levels it's hitting the back of the house.

It seems to be the only thing I hear when there is bleedover or crosstalk.

Anyway I'll be experimenting. The real unexpected casualty was the cvil aircraft band. It seems to be totally missing....

Thanks for the comments. And no I don't want it removed! First new art for the house: detailed Sutro Tower antenna blueprint diagram.

 

[jimvm]

Sutro Tower

Here is an Antenna diagram of Sutro Tower.

jim

 

[gcgrotz]

Maybe you should ask PBS for a copy of their RF exposure study to see if you are safe. Seriously. I've seen mountaintop sites where even on the ground it is hot enough that you shouldn't linger in those spots very long.

 

[sholt]

I live facing south towards Sutro tower from the north (lower Pac Heights between Lafayette park and Alta Plaza).

I am particularly interested in listening to VHF airband however the noise floor is very high. I am not sure if I need a better antenna (I am in an apartment so have nowhere to mount on a roof, etc) or if an fm filter will do the job.

I have never scanned in a city like San Francisco so I have no experience with hills or potential interference from things that might require to stalling an inline fm notch filter.

Any tips from people who might also be having trouble on the VHF band in the city?

 

[kma371]

......

 

[mdulrich]

HDTV is in the UHF TV band.

Not all HDTV is UHF.

Mike

 

[ridgescan]

I live facing south towards Sutro tower from the north (lower Pac Heights between Lafayette park and Alta Plaza).

I am particularly interested in listening to VHF airband however the noise floor is very high. I am not sure if I need a better antenna (I am in an apartment so have nowhere to mount on a roof, etc) or if an fm filter will do the job.

I have never scanned in a city like San Francisco so I have no experience with hills or potential interference from things that might require to stalling an inline fm notch filter.

Any tips from people who might also be having trouble on the VHF band in the city?

Go to Radio Shack and get their $7 FM trap. This little thing put me from hearing only aircraft on the approach'departure frequencies-to hearing everything down to ground at Oakland and even an ATIS out 49 miles at Travis. Hardware, it may even help you.
I live 1.72 miles west of Sutro and I know it's the cause of flattening the airband as well as vhf-hi and some uhf.
Even after the trap, transmissions on the marine band 156-157, and the rails on 160-161 still get cut up by something intermittent. Probably pagers.
Hardware, do you have a handheld you can walk around the premises for locating clear spots?
BTW every now and then I go up there just for the views towards downtown, and to take in the sheer awesomness of that tower.

 

[sholt]

Hi ridgescan,

It's great to hear an actual case study from someone in the area, especially if it means I can try something out for $7 instead of $80!

I am 2.6 miles from Sutro and in direct line of sight so hopefully in a similar situation to you, where a filter will help.

Thanks again!

sholt