To all those interested listeners:

The debate at city council about the pager antennas on the Palomar roof has been postponed due to the fact that notices were not posted on the Palomar premises.

I did a little digging at the library and on the Internet and tried out Marylin Garrett's beeper. Here is what I found:

First, I looked at the documents from the FCC:

www.fcc.gov/Bureaus/Engineering_Technology/Documents/bulletins/oet65/oet65a.pdf

and

www.fcc.gov/Bureaus/Engineering_Technology/Documents/bulletins/oet65/oet65.pdf

to get a feel for what radio stations are required to comply with. It looks like the frequency range of 88Mhz to 108 MHz is more readily absorbed by the human body than the radiation from AM or cell phone frequencies, so the limits on FM are more stringent.
A 60 watt antenna that is 10 ft tall could produce a field of 162 microwatts per square cm at its base, if one stretches the figures in the FCC documents to cover low power smaller antennas. A 30 ft high antenna would generate 18 microwatts per square cm at its base. The Maximum Permissible Exposure limit for the general public for FM transmitters is 200 microwatts per square cm. Note that this is an exposure that is averaged over a period of 30 minutes. It is not clear if the FCC requires longer exposures to be less intense, but they have an equation which seems to imply as much.

I don't know if the SCRAM/FRSC folks have considered using a portion of the AM band. That may address some of the concern here. A 10,000 watt AM station is FCC compliant
some 6 meters from the base of the antenna. I guess KSCO messes up phone lines effectively, but does not do much tissue heating. KSCO does set off Marylin's detector, if one is right in front of the station. The instructions for the detector say that it is only off by a factor of 2 for frequencies at or below 6 MHz and a factor of 20 for frequencies at or below 1 MHz. KSCO broadcasts at 1MHz. So that means that KSCO could be emitting 20 microwatts per square cm right in front of the station.


The detector:

I got the Microalert detector for just one day. I started by replacing the battery. Then I drove to Davenport (which if I had read the directions was unnecessary. I could have simply cupped the detector inside of my hands to zero it) and “zeroed� the detector. This consisted of adjusting a pot on the side until it just barely stops beeping in a zero RF field. Then I drove to downtown Santa Cruz and walked around in and out of the Palomar. I found that the detector does not beep inside of the Palomar. But as soon as you are away from the front door on the outside, then it starts beeping. On the North side it stops beeping at O'Niels. On the South side it continues beeping until you reach the Del Mar Theater or even 1010 Pacific Avenue. It can beep strongly as far away as in front of the Library on Church st.

The instructions claim that the detector can be adjusted to detect anywhere from 0.1 to 15 microwatts per sq cm. The adjustment pot was some distance from the maximum sensitivity setting at Davenport, so I would guess a field of 0.5 to 1.0 microwatts per square cm was making it beep as observed during these tests. By comparison, an analog cell phone or cordless phone emits about 1000 microwatts per square cm at the antenna, when it is held right up to your head. This is about the same intensity as putting your head against the closed door of a microwave oven while it is operating. These figures square with the earlier guesstimate that I made that the radiation outside of the Palomar was equivalent to using an analog cell phone for a couple of minutes per day. I ran one test at 10PM Monday and another test at 1PM Tuesday, with similar results.

I attempted to double check the beeper against the tri-field meter using a 900 MHz cordless phone and a microwave oven. Neither device gave a reliable enough output to be much use. But it did seem that the beeper could detect radiation from at least twice as far away as the tri-field meter. (14 feet away in the case of the microwave). The cordless phone radiated power seemed to behave as 1/r up to a distance of 40� horizontally from the antenna but then it dropped off too fast after that to get a reliable picture of what it meant to have the beeper go off as far away as 84�. The beeper does go off about 1�-4� from a compact fluorescent light bulb.

Finally, I located the reports on the Palomar antennas at the library on Church st. The secretary at the city council office had to show me exactly where they were since the library clerk could not find them last night. One is in a green binder labeled “City Council Agenda Packet�. This is available at the reference desk or in unbound form on the shelves behind the reference desk where they keep the tapes. Look for the Feb 8th agenda packet. The other binder available from the reference desk is a white binder labeled “ Palomar Hotel Cell Towers.�

The reports go into some detail about what measurements and calculations show concerning the radiation levels from the antennas on the roof of the Palomar. First, it should be pointed out that of the 20 antennas on the roof, 17 of them are pager antennas, which broadcast up to a total of 1900 Watts, while the rest are Satellite TV and GPS antennas that receive but do not broadcast.

Although they were able to measure levels on the roof that were 200% of the Maximum Exposure limit for the general public, they were not able to detect any radiation inside of the hotel. The meters that they were using were only sensitive to 2.5% of the Maximum exposure limit for the general public, or about 25 microwatts per square cm.

The reports do tend to contradict each other a little bit. One report (Antenna Site RF Emissions Evaluation Report by Richard A. Tell, Jan 3, 2005) calculated that the Maximum theoretical exposure from all of the antennas on the roof operating simultaneously was a factor of 4 times less than what was actually measured in the other report. Tell's report also stated that the maximum possible exposure on the top floor of the hotel would be about 2% of the maximum exposure limit for the general public. The same report stated that the maximum possible exposure on the sidewalk 50 ft from the hotel would be about 2% of the maximum exposure limit for the general public (20 microwatts per square cm). Another source, Peter Gruchawka, stated in a letter that he thought the reinforced concrete roof would attenuate the radiation by a factor of 100 for the people on the top floor.

The reports also contain some reference materials put out by the anti-cell towers crowd, detailing the biological effects of microwaves. Some studies only show effects on the blood brain barrier when the brains are actually heated to 40-43 degrees C. While other studies show effects at much lower levels, such as SAR's of 2.5 and lower (cell phones are supposed to have SAR's of 1.6 W/kg or less). Digital phones are hypothesized to be more dangerous per unit of power than analog phones, based on what the studies have found for pulsed RF.