KDX Expansion Plans
Since starting KDX in 2007 it has provided excellent programming for my personal enjoyment everyday using AM radio for outdoor listening and FM inside. This means a lot since programming by local area stations tends to provide nothing of interest to me. KDX-AM occupies very clear real estate up in the extended band between 1610 and 1700, but one of my favorite radios is a Zenith Transoceanic from the 1970s, with its AM band cutting off at 1600 kHz. But there's no shortage of open frequencies these days since five local AM stations have gone dark, leaving lots of room for me to open plenty of part 15 transmitters. That's why I will be launching a second AM channel anywhere between 1500 and 1550 kHz employing one of the SSTran Transmitters that are ready for service. Also, both AM stations will be upgraded with the installation of antenna top hats as we've been discussing in a neighboring thread. And although there's no real need for it, we can't ignore the possibility of restoring carrier current service in the middle of the band.
There're two different version of SStran ,one is for inside short range and the other for long range broadcast. Simple difference between the two makes a major difference with range . The capacitance hat shouldn't be connected directly to the feed wire , it won't tune up if connected . I used a thin pvc pipe with a home made inductor, wire wrapped tightly around the pipe . To make the capacitance hat I used a high voltage line , shave the insulation of most of it and bent the aluminum windings inside outward. The unshaven end fits into the pvc inductor. It creates a energy field inside the pvc and the unshaven part of the inductor is energized that is inside the pipe . Use thin telephone wire and connect the outer ends of the spokes together, more efficient that way. . I wish I had enough ferrite bars to fill my inductor , it would work better . You should be able to get 2 to 3 miles range at 1520 . I was able to get that much with one of my talking house transmitters at 1530.
You are right, Mark, that SSTran produced two transmitters. The original one was the AMT3000 which, when built according to the basic instructions, sent a signal round the house but was not hefty enough for outdoor range. BUT, and here is what many do not realize, the inventor, PhilB, provides an alternate set of instructions for beefing the AMT3000 up to a serious transmitter with heavy-duty loading coil and outdoor installation. The website is still online, so let's go there now. Scroll down to where it says "VIEW ANTENNA CONSTRUCTION PLANS".
CORRECTION to my last entry: I addressed Mark but it was Diablo who made the remark about the two versions of the SSTran transmitters.
The other sstran is called the 5000. The 5000 was for outdoor long distance broadcasting. I saw on another site that it has a couple of internal differences from the 3000 , resistor and capacitor. The two transmitters are out of production. I think the owner was getting overwhelmed by too many orders and had a huge backlog. I added two more capacitance hats on my antenna ,one below he inductor and another at the bottom before the roof . It did remove an unwanted harmonic, so something I was experimenting with will stay . The two other antennas on the tower are for experimental use . Last weekend I hung a loop antenna on one of the ...It worked very well.
A few words about the AMT5000 Transmitter, by far the most sophisticated part 15 AM transmitter kit ever available. Seeing it removed from the market marks an unfortunate setback for the radio hobby. Several features make it special: The RF output stage operates in Class E mode, making it 98% efficient! Much greater than any other part 15 AM transmitter. It had a built-in low-loss toroid tuning coil with numerous taps that allowed tuning the antenna for maximum efficiency. A power-adjustment control allowed tweaking for perfect 100mW operation, or could be turned way down for very low power or turned high up to about 400mW. And it had a choice of two audio inputs: the usual unbalanced input together with a pro-balanced audio input. If you spot one on the used market you would be wise to buy it.
i just bought station8 / Jeff's sstran amt5000. think i paid about 250.00 shipped for it from him. all professionally assembled by him i believe and i believe he was the original owner.
i have a schlockwood sw300 mod monitor and spec an as well as a fluke dmm to tune it up with along with my choice of a crl smp950 or schlockwood sw200 processors in my stash.
i also have a couple barix boxes and henry matchboxes to setup a couple more remote sites in town. this in addition to my 4 frequency main/remote sites (2 for main building and 2 for remote building) covering my entire apartment complex under part 15.239, 15.219, 15.221.
using decade, sstran, procaster, and rangemaster transmitters as well as avalan 900 mhz fhss part 15 ip link between the two buildings.
i have a pretty advanced and professionally run part 15 am/fm cluster.
and i hope to expand the part 15 am operations to downtown in the future.