Cats in bags
I should probably let her out or i may already have.
I will explain and I hope Phil of SStran Fame won't scald me too badly over this.
Someone tipped me off that that chip that controls what frequencies the SSTRAN 3000 and 5000 can cover is capable of going as low as 20 khz and as high as 2560 khz BUT with some minor modifications. The chip is not confined to just 530 to 1700 khz and this knowledge is actually public if we do some digging around on Google Search for the PLL. The serial number of that chip escapes me right now and i cannot find the manual, if anyone wants to chime in on that chip number i wouldn't be upset in the least bit.
So here is how i confirmed that the transmitter will go "out of band" after someone and honestly i cannot remember who told me, tipped me off that the transmitter will indeed transmit lower or higher than the AM BCB, i sent Phil at SSTran an email and asked if this was true and if i could have a list of frequencies the AMT3000 would broadcast on. He eventually sent a reply along with a pdf and a brief but clear explanation how to go about transmitting either above or below 530 to 1700 khz.
Here is the
PDF Extended 10 Khz Frequency Chart
Now to the mods needed to make this happen, a quote from the email.
" The PLL won't lock below about 350 kHz unless cap C30 is changed from 180pF to a somewhat higher value. This would be at the expense of reducing the highest frequency lock range. C30 essentially determines a frequency range "window" which is smaller than the entire switch coverage range of 20 kHz to 2,560 kHz.
The output tuning should cover the entire range from ~350 kHz and up for a 3 meter long antenna. If you use a longer antenna, the LF frequency range will go lower, so if you can't tune a particular LF frequency, you can lengthen the antenna until it tunes, or increase the output tuning inductance. If the output tuning won't tune to the highest frequencies you may need to reduce the output tuning inductance. See the graph "Frequency Range Graph for 3 Meter Antenna" on page 34 of the manual. "
Note: I mentioned the AMT5000 above in the first couple of lines, i could be wrong about that considering i asked only about the AMT3000 and I have no idea what it would do for the 9 khz version used overseas, but i imagine it would do the same thing only in 9 khz increments.
Disclaimer: Keep in mind, the frequencies above 1710 Khz are still considered the medium wave band BUT in America and other countries those frequencies are set aside for both HAM radio and Maritime Radio so i don't want to read about one of you fine folks getting a NOUO for broadcasting in those bands although you can technically experiment there as long as you keep your transmission on a very short leash or you hold a valid amateur radio license.
My parts box is looking pretty sparse and I may have to start scrounging for parts off of old radio's and tv sets (pre-hd) to restock.
For this mod i used a 190 pf capacitor, a coil that i mentioned previously that was wound for or close to 1620 Khz coupled with 50 foot of 12 ga wire and was able to tune as low as 100 khz with little to no effort. My frequency of choice is 170 khz which seems to be dead here according to some online Websdr radio's i use a lot for remote dx'ing. The
websdr from Twente University the Netherlands is my favorite receiver but the remaining Longwave stations are nearly in their backyards so i have to tune into Websdrs that are in the United States, my second favorite radio online is the one in
Reston Virginia The radio in Virginia is the closest I will get to a real world reception of Longwave broadcasts without the noise I have to deal with here at home so I am able to see or rather hear that 170 khz is indeed clear for me to transmit on.
Power input is i guess still 100 mW no matter where you choose to broadcast and i imagine it could be more or less coming out of the antenna depending of course on how resonant your antenna is.
I wonder if the transmitter would do better with a directional array? Trouble is we are still confined to 50 foot, including feed line, ground and radiator so a directional antenna probably won't work. And as Carl said, I could add a 1 watt linear amplifier to bring the transmitter up to the full legal power.
Still thinking on that antenna though.
So as I said, i hope i don't cause any trouble letting this information get out to the public but i also look at it this way, by posting the link to the pdf i am probably doing Phil a favor, he is a busy guy and can't always answer emails as quickly as he'd like, by putting this up on Google Drive it saves him the trouble of answering emails or at least reduces the amount of emails he has to answer.
And to repeat what i said in the beginning, we could easily look this information up online and see that the PLL used in the AMT3000 indeed covers a wide area.
Hope this helps someone, back to the drawing board.
Barry of BBR World Wide
