Xpertek Electronics

5312 ERNEST ROAD, LOCKPORT, NY 14094

(716) 434-6380

(NY residents add appropriate safes lax}

The first 100 customers mentioning this ad will receive $5 off the purchase price,

Figure 2, Chart of attenuation vs. frequency for the 7-pote fitter,

/Wtte Stone WB0QCD PO Box H

Lowden Iowa 52255

Advancing the State of the Art

73 Magazine is taking a more technically-oriented tack now, and so shall the ATV column! For [he past two years, many of you have followed this column each month to enhance your knowledge of fast and slow scan TV operation- Many of you have also bought or built your own ham TV gear, and now you're on the air, sending live black and white, or even color, amateur TV pictures across town or within the county. Some of you have become really serious about ATV DXing, even out of stale Great going!

Stay with us in 1969, and we'll take you even further into the mystical world of the video waveform in future columns, we will cover easy-to-build receive downcon-verters, transmitters, synch signal-stretchers, antennas, preamplifiers, bandpass fitters, simple video switchers, and much more. We II look in depth at computer programs designed for ATV graphic applications, and explain how to mix SSTVt FAX, FtTTY, packet radio and other modes with FSTV. We'll compare AM and FM TV signals based on the results of studies, and explore ham TV on the 900, 1200, and 2300 MHz bands.

I've received many tetters

Ham Television asking about how to form an ATV club, write a constitution, and build a group ATV repeater or remote transmitter. Keep those cards and letters coming. We ll cover these and other facets of ham TV in comtng ATV columns.

AEA Unveils New Fast Scan Rig

Those active in fast scan TV are well aware that Advanced Electronics Applications has added a new UHF ham TV transmitter to their tine of amateur specially equipment. The FSTV-430 ATV rig was unveiled late last year The introduction of AEA into the ATV marketplace shows one major manufacturer's belief in a yet-to-be exploited visual mode of communications. Other manufac* turers are rumored to be close behind. At the Dayton Hamven-tion )ast year, several manufacturers were asking hams, "Do you own a camera or a VCR?" Getting major manufacturers involved in the ham TV marketplace, which has yet to peak, would boost all aspects of FSTV activity everywhere. For a comparison of the three most popular 1-watt ATV transceivers on the amateur market today, see Table 1. The results were based on rigs tested locally by the BRATS ATV Club in Iowa.

To decide which ATV transceiver is right for your study the features that attract you the most. Ask other hams in your local ATV group what ihey are running. Wy-

man Research and PC Electronics also offer partial kits.

70 Cm Alert

In most parts of the country, there is still plenty of room for wideband television transmissions on UHF in the 70 cm band. In other parts, hams are moving into the 900 and 1200 MHz region. A QRM-free verbal battle is raging to keep ATV mode operations on the 420-440 MHz, or 70 cm band. Loss of the 70 cm band for ATV operation would be a disaster An estimated eighty-five percent of hams now on the 70 cm FSTV band in the US. doubt whether they would continue operating ham TV on higher bands, I feel it's worth fighting for. Others may disagree. but the important thing is for motivated hams to build or buy some equipment and start having some of the FU N that the rest of us are enjoying!

ATV Workbench Projects

Many fast scanners continue to build their own equipment. Merle

Reynolds W9DMT in Illinois, Gerald Cromer K4NHN of South Carolina, "Captain Video" Ron Cohen K3ZKO of Pennsylvania, Dave Williams WB0ZJP of Missouri. Mel Dunbrack W1 BHD of Massachusetts, Robert Jett W7KPW of Texas. Don Miller W9NTP of tndiana, and many others have built some of the neatest looking gear for ham TV I ve ever seen.

The Line Sampler and 7-Pole Filter

Here are a couple of easy*lo* buiid projects for the ATVer, to take your mind off of shoveling snow or worrying about whether your XYL left your car lights on at the grocery store. The Transmission Line Sampler was sent to me by Bill Parker W8DMR, Mr. ATV of The ATCO Ohio ATV Group (see Figure 1). W8DMR writes: "Sampling the RF field flowing in a transmission line is fairly easy tt is just a matter of inserting a short

Continued on page 73

0 0

Post a comment