While the choices below are quite an optimal solution, you are probably
making this too complicated.
In Palo Alto, there's enough signal that a U-75 will pick up the
Monument/Allison stations even from the side or back of the antenna, if
it's mounted outside and up high. It also does a fair job of picking up
ch. 12 from Mt. Bruno I have yet to see how ch. 7 from Sutro will work.

A little experimentation goes a long way...

- Don


Larry Kenney wrote:
> Hi Baumgrenze...
>
> Before seeing your post here, I answered the one you posted on the SF
> OTA thread on the AVS Forum. You provide more information here, so
> let me post what I posted there, for the benefit of others reading
> this group, and then I'll add a few more comments.
>
> [QUOTE]
> For the moment I have the antenna mast lashed to an 8' stepladder with
> 4 parachute cord guy wires. By chance I oriented the UHF antenna so
> that with a new 300-75 ohm balun and coax I get a 'just like in the
> store' picture OTA for KQED 9.1 on my new 32” Sony 1080p Bravia. I
> hope I remain so lucky once I’ve permanently remounted the mast.[/QUOTE]
>
> If you can get KQED, you should be able to get all of the other
> digital stations transmitting from Sutro Tower, and probably Mt. San
> Bruno, except for the VHF stations. KNTV digital transmits on channel
> 12 and KGO will be moving its digital transmission to channel 7 in
> February. You might need to add a small VHF antenna to receive those
> two stations.
>
> [QUOTE]I have a 'simple' (no rotor) solution I would like to have
> critiqued.
>
> 1) The FM antenna does not need to be on a rotor. I propose buying
> chimney hardware and mounting its mast on a nearby chimney. I have
> almost 5' of straight 22" x 26" brick chimney atop an indoor barbecue.
> I trust that I can use a pair of Ronard 2212 Y mounts, well spaced,
> and get away without guy wires for a ~10’ FM mast.
>
> 2) I propose leaving the U-75R on top of the TV mast and pointing it
> north to Mt. Sutro. Below it I would place something like a
> non-directional DB-4, pointed midway between Mission Peak and Mt.
> Hamilton to pick up the two broadcast towers "in San Jose." I copied
> the online TV coverage maps from tvfool.com and pasted them into
> Autosketch. I drew transmitter-to-house lines and copied them onto one
> drawing with their local ends connected. This sketch tells me that the
> former is 114.5° and the latter 151.26° relative to the line to San
> Francisco. That makes the average relative antenna orientations ~133°
> apart. The San Jose transmitters are ~15 and ~22 miles away, whereas
> San Francisco is ~28 miles.
>
> a) Is it reasonable to expect that if I orient a DB-4 this way I will
> get an acceptable signal from both of these transmitters on a
> non-rotated antenna, or will multi-path reflections just mess things
> up so that the investment in a DB-4 is not worth it in my location?
>
> b) Are there commercial switches with F-connectors that will allow me
> to switch from one antenna to the other in the house?
>
> c) How much vertical clearance must I allow in such a 2-antenna stack?
>
> This configuration will place the FM antenna 'behind' the U-75R UHF
> antenna relative to the San Francisco transmitter, and side-on to the
> DB-4 non-directional UHF antenna pointed towards San Jose. The
> plan-view separation is of the order of 12 - 15" but I can provide
> vertical separation, within reason. Think of it as though all the
> antennas were stacked on one mast.
>
> Does anyone have practical experience or a theoretical opinion
> regarding this proposal?
>
> Thanks,
>
> baumgrenze[/QUOTE]
>
> First, as Falcon pointed out, there are no stations on Mt. Hamilton or
> Mission Peak. There are four stations, all within a mile of each
> other, on Monument Peak and Mt. Allison, located up above Fremont.
> You should be able to get all of them with a UHF antenna pointed in
> that direction. A DB-4 should work fine.
>
> You might want to consider a new rotor so that you can use one antenna
> instead of two. Don't spend a lot of money fixing that old rotor.
> Channel Master makes a good one (I got mine at Fryes) that even has
> channel memory. You set the antenna for best reception for a station
> and then store the channel number. After that, just type in the
> channel number on the remote keypad and the rotor will turn your
> antenna to the right direction for that station.
>
> You'll find that stations that come from the same tower often come in
> best at different directions, due to multipath reflections. Where you
> are, you shouldn't have much problem with an antenna set in one fixed
> direction, but it's nice to have the rotor for the stations that can
> give you problems. Often a turn of a few degrees one way or the other
> can make the difference between a solid signal and one that breaks up
> occasionally. So if the fixed antenna doesn't work out, try a rotor.
>
> You'll find A-B switches with F-connectors at Radio Shack or Fye's
> Electronics.
>
> I've been told that the vertical clearance between antennas should be
> a minimum of two feet, but three feet or more is better if you have
> room on the mast. Two identical antennas have to be separated by a
> specific distance, if used together, so that they combine and not
> subtract from each other, but you're not combining the outputs so 2 to
> 3 feet should be fine.
>
> Go to TVFool.com, put in your address and you'll get a complete list
> of stations showing the strongest to weakest for your location, along
> with the heading for your antenna to the various transmitters.
>
> For a complete list of all the digital stations within 100 miles of
> San Francisco, check out the list I put together, included in Falcon's
> post:
> http://www.choisser.com/sfonair.html
>
> Larry
> SF
>
> Added comments, based on your post here:
>
> What I would do is to mount one mast with the following combination of
> antennas:
>
> A:
> 1-Your U-75R UHF antenna at the top pointed toward Sutro/Mt. San Bruno
> 2-A new VHF antenna for channels 7 and 12 below it also pointed toward
> Sutro/Mt. San Bruno
> 3-The DB4 pointed at the East Bay hills for 14, 36, 48 and 54.
> 4-Your FM antenna
> Mounted so that the FM antenna is about 6 feet off your roof, you'd
> need about a 15 foot mast for this combination, so you'd need to guy
> it well.
> -OR-
> B: On a 10 foot mast
> 1-A new combination high VHF/UHF antenna, such as the AntennaCraft HBU-22
> (http://www.warrenelectronics.com/antennas/hbu22.htm) at the top
> 2-The DB4 pointed at the East Bay hills for 14, 36, 48 and 54 below it
> 3-Your FM antenna
> -OR-
> C:
> 1-Your U-75R UHF antenna at the top above a new rotor, as mentioned in
> my post above
> 2-A new VHF antenna for channels 7 and 12 below the rotor pointed
> toward Sutro/Mt. San Bruno
> 3-Your FM antenna
>
> There's lots of possibilities, so you'll have to decide what route you
> want to take. Note that there will be no TV stations in the channel
> 2-6 range, so an antenna covering low VHF will not be needed. That
> eliminates the long elements seen on older VHF antennas.
>
> Larry
> SF
>
> - - -
>
> On Nov 23, 2008, at 5:26 PM, baumgrenze wrote:
>
>> Hello,
>>
>> I'm the new kid on the block. Here are my current questions.
>>
>> I am in Palo Alto. A search on www.batchgeocode
>> <http://www.batchgeocode>.com puts me at
>> Latitude: 37.442104 / Longitude: -122.129052.
>>
>> I am currently reworking my antenna system for OTA reception on a Sony
>> Model #: KDL-32XBR6.
>>
>> The current state of affairs is as follows.
>>
>> I removed the VHF antenna from the top of my 1.25" x 9.5' tubular
>> mast. I moved my Archer Model U-75R directional UHF antenna, purchased
>> in 1989, to the top of the mast. I attached a 300 ohm to 75 ohm balun
>> and 50' of RG6U cable and connected it to the TV and ran the setup.
>> The mast is currently leaning against a ladder, guyed to 4 points with
>> parachute cord. The antenna is roughly pointed at Mt. Sutro. The
>> reception on KQED 9.1 is great. I should be so lucky once I have set
>> and guyed the mast properly. I recognize that to pull in signals from
>> Mission Peak and Mt. Hamilton I must reorient this antenna towards the
>> transmitter towers.
>>
>> I am considering replacing the U-75R with a Terrestrial DB-4
>> non-directional antenna. Can I expect to receive good signals from
>> broadcast antennae that are 114.5° (Mission Peak) and 151.26° (Mt.
>> Hamilton) relative to a line-of-sight bearing on Mt. Sutro? Do I need
>> to worry about signals being reflected from the local mountain ranges?
>> Do I need to worry about Palo Alto's many trees? I have some very tall
>> ones near my house.
>>
>> In my rework, I removed about 6' of 1.5" tubular mast from between the
>> swivel base mount and a 1960's rotor. I discovered that it came with
>> only 8 ball bearings running in an upper race and another 8 in a lower
>> race. Needless to say, the aluminum bearing race is severely by years
>> of wind rocking of the antenna system. I think I could get it to run
>> again, but it hardly seems worth the effort.
>>
>> The mast still carries a large FM antenna, too. It is ~148" long and
>> ~138" wide on its rear-most, longest element. I would like to get this
>> a bit more than 6' from my flat Eichler roof for safety reasons. I can
>> see two possible solutions:
>>
>> 1) Purchase 6' of schedule 40 or heavier galvanized iron pipe threaded
>> on one end. Install a pipe flange on the upper end and use this as a
>> lower extension, running guy wires from holes drilled in the flange.
>> The mounting end would be in a Universal Swivel Base Mount (9013)
>> mounted on a 4" x 7.5" x 0.25" thick steel plate lag screwed to the
>> fascia board of the upper roof. This should give me room to put my FM
>> antenna at 4' below even a DB-4 mounted on the top of the mast. It
>> would allow a slip fit of 18" between the pipe and the tubular mast.
>> If the pipe does not fit the swivel base, I could bore hole through it
>> an appropriate distance from the bottom to fit the swivel bolt.
>>
>> 2) To keep both antennae lower, I could purchase a chimney mount kit
>> and mount an 8' long mast on it. The chimney in question extends up
>> ~4.5' above the lower roof (~18" lower,) so roughly half of the mast
>> would be between the upper and lower mounting brackets. Wouldn't this
>> make for a pretty secure mount without guy wires? I would use this to
>> mount the FM antenna. Should I be concerned that the forward-most
>> element of the FM antenna would be ~18" from the mast carrying the UHF
>> antenna? It would be `behind' the UHF with respect to Mt. Sutro, off
>> to the side with respect to Mission Peak, and in front with respect to
>> Mt. Hamilton. Would this make a difference?
>>
>> 3) The entire tar-and-gravel roof has urethane foam sheet insulation
>> with an aluminum foil facing. Is this significant?
>>
>> Thanks,
>>
>> baumgrenze
>>
>
>