APRIL 2004
San Francisco
Roy Trumbull - Editor
Bill Dempster - Artist
Advertisers for this month's newsletter are:

Santucci Video Systems - Sandra Santucci - (818) 704-6324
Belden - Steve Lampen - (415) 440-8393
Media Technical Consulting - Paul T. Black - (925) 827-9511
MARCOM - Martin Jackson - (408) 768-8668
William F. Ruck, Jr. Broadcast Engineer - (415) 564-1450
Ross Marketing Associates - Kevin Frost - (408) 988-8111
Kathrein (Scala Division) - Michael Wm. Bach - (541) 779-6500
Hammett & Edison, Inc. - Dane E. Ericksen, P.E. - (707) 996-5200
Howell Communications - Mike Howell - (559) 674-8989
Econco - George Badger - 650-327-7599
Improbable Missions Fource - Mike Schweizer - (888) 4-ISDN4U
Digi-Gear / Cancomm - Eric Lane - (818) 980-9188
West Penn Wire/CDT - Michael J. La Porte - (650) 652-9080
Microwave Radio Communications - Clark Rhoads - (909) 246-1602

Babes/SBE Luncheon on Wednesday April 28th.

This month we'll do our NAB wrap-up with contributions from all those who visited the place where a double latte means double the normal price of a single latte, Los Gouge-em, NV. The place were almost all equipment question can be answered if you work for a huge group and come to a vendor's booth 6 or 8 at a time.

Larry Bloomfield will join us with his post NAB road show. Last year he was in 31 cities and looks to make it to over 50 this year. This show tends to last a little long, but it is worth sticking around for.

As usual, our luncheon will be at Sinbad's just south of the Ferry Building on the Embarcadero near the foot of Mission St. We meet at 11:30 and are seated at 12:30. To make reservations call Paul Black at 925-827-9511 and leave a message on his machine.

Tax-Exempt At Last

Prior to NAB, Dane was in touch with various State offices that had questions regarding our Articles of Incorporation and our application for tax-exempt status. To make an all too long story a bit shorter, it looks like we may finally get tax-exempt status. We are a non-profit corporation but that doesn't exempt us from a minimum levy of $800/year. Tax-exempt takes care of that.

Paul Black's Wheels

Last month Paul came to the meeting in a wheelchair. He had a stepladder to garage floor re-entry and took a real beating. He expects to be in the chair for some months. So give him a call and some good cheer. It's the sort of thing that eventually happens to us all.

Longley-Rice Fun

At NAB, a friend told me of running some radials using Longley Rice and finding that the predicted field went up when the transmitting center of radiation was lowered. There were also some counterintuitive results when the receive antenna height was lowered. I once thought that the height of optimism was predicting contours using the Part 73 method. Then I tried Longley-Rice and found just how conservative Part 73 actually was. All programs of this sort have certain limits and the results are often impacted by user specified parameters. Beware Garbage In to Gospel Out.

MPEG Gargle

The current chapter 48 newsletter from Denver describes an effect produced by too many Mpeg encode and decode cycles of the same radio program. The clue is that the local break sounds just fine. Check it out at

And The Bandwidth Played On

I was reminded of an experience I had with a T1 line by a friend who ran into the same thing with much more bandwidth. The terminal gear that lies between point A and point B is generally out of your control and there is no reason to believe that it has been optimized for your application. A T1 can be used for 24 telephone voice channels and, as such, the distribution of usage channel to channel is fairly soft. If you send MPEG video and audio using the entire bandwidth, the stress is considerably higher than it is for voice. The result might be that a very high error rate develops because one piece of gear in the chain can't handle the stress. The test for this is to seed a random number in one channel and cycle the number. Then do it to another channel and continue adding channels with this kind of activity until the error rate goes bad. None of the classic telco data circuit tests work as well. In fact the bad circuit will likely pass them all but this test it will flunk big time. Now let's try this with a much larger bandwidth circuit and stack a bunch of 4.4 MHz Mpeg signals into it and see what happens. If it's a dedicated circuit and there is access to the equipment in each leg, we can make it work. But if it goes onto the Internet, we may find that it works part of the time and fails most of the time.

Bob & Don

Here is another story from my collection of the adventures of Don Lincoln and Bob Morrison Don liked to "do lunch" with a short list of longtime friends and one time they were in Berkeley. Don had read an article to the effect that the Coop stores in Berkeley were selling ladybugs to control garden pests. Don and friends went to a Coop store. A young man from Berkeley central casting waited upon them. That is to say he was thin, wore sandals and wire rims, and had his hair in a ponytail. Don asked about the ladybugs and the young man told him they didn't have them at that store but they could be found at the one on University. He then launched into an organic gardening lecture to the effect that more than ladybugs were needed to restore balance and harmony and environmental soundness to a garden. He went on for a good ten minutes and other shoppers gathered around to hear these words of wisdom. When he was done, Don's next interlocution was, "You say the store on University has them?"

Help Wanted

KBLX/KVTO/KVVN is looking for a maintenance engineer. Please contact Paul Marks at 415-284-1029 for further information.

High School Low Power Looking For Equipment

KSRH (San Rafael High School LPFM) is a LPFM High School radio station located at San Rafael High School in San Rafael in the North SF Bay. They are in dire need of a replacement console in their main broadcast studio. A production size board (12-14 channels) would be ideal. KSRH is still using carts for the present, and if any ITC stereo units are gathering dust they would be put to good use at the station. Also, if a spare EAS unit needs to find a good home, they would appreciate. If you can help, please call Bill Smith at 415-456-4481 or Marianne Melnick at the station 415-457-5314.

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Web Page

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Roy also posts the current newsletter at but the posting is without links.