Hello my name is Matt and I have a SStran Amt3000. I'm a little confused because I want to use a whip or vertical pipe antenna on it but unsure how to mod it for that. The article for their baseloaded antenna shows flipping all the switches up on the 4-position dip switch but I'm pretty sure this is not needed if there is no coil. Also unsure if the jumper needs to be installed or not along with the other resistors. I've tried a couple combos and the performance has been pretty poor.
Thanks,
Matt
the internal loading on a SST3k in a word...
SUCKS.
even with a 3m copper pipe over a ground plane you won't get very far.
the sst3k is what it is. if you bypass internal loading and build your own base loaded vertical outdoor over a ground plane you will get much much better performance
i had a sst3k and while it's audio was great i was not impressed by it's internal loading coil system. the sst5k's toroid loading and class e finals improve greatly over the 3k while continuing to have a great on air sound.
I run three SSTran transmitters, and here is what I find.
One AMT3000 is set with the internal loading and a vertical wire antenna, which could be changed to a pipe. It only serves the indoors but does so very well.
The second AMT3000 has a loading coil I made myself and loads up a metal window frame with vertical wires at the top and bottom to make up the full 10-feet, and this transmitter bellows out a strong signal for two blocks each direction.
The AMT5000 is also tuned into a window-type-antenna, but gets out about twice as far as the loaded-coil AMT3000 because of its higher efficiency.
The maker himself explains that the internal loading coils on the AMT3000 are "lossy", and the design is for those who want a plain home transmitter, but with the option of making their own loaded-coil antenna for serious use.
The key to the AMT3000 is to build a loading coil.
The AMT5000 offers the advantage of a loading-coil already built in.
It's a beautiful set of choices.
The internal coils in the AMT-3000 are
for covering something like your house
and yard - maybe further - but the deal
is that you won't have to fool around with
a base loaded vertical - which is a big
project, I think. You can just put the
transmitter on the air that way.
I had a different approach. I took out
an internal coil (the one that covers
the lowest frequencies in the AM BCB.
I ran wires from those connections
to the outside of the transmitter - and
I made my own coil, which was
pretty large. So electrically - there
was still a coil in that empty space -
it was just a big one that was external
to the transmitter.
It worked well, but was hard to tune.
I had to use a "ferrite" rod to get it
to resonance, along with the appropriate
coil tap. As far as I know, I am the only
person to try this. And this was with
the 3 meter ant/gnd lead approach in
the middle of the backyard on the ground.
Bruce, The DOGRADIO Group