Where is that oscillator going to come from? The other design I posted has an oscillator, but then why would the PLL thing be needed?
"Where is that oscillator going to come from? The other design I posted has an oscillator, but then why would the PLL thing be needed?"
Weeelllll the oscillator can come from the one you already have in V1.0 of that unit.
And the reason for the PLL....hrmmm...well now that one will require a bit of simple "OR" function logic to solve for x.
You can go with V1.0 and mess with finding specific crystals which most likely will have to be special cut...equals higher cost...."OR"
...use the PLL to control the oscillator that would otherwise be controlled by the crystal. !!!!!!!!
Neat how that fuzzy logic works eh?! 😀
RFB
I am seeing spirals in my eyes because of the confusion now being experienced as more details are added to what I thought was said back when it seemed like I was told there was no need for the original V 1.0 oscillator by simply using the PLL thing.
But that's not what I guess was said when I thought the other thing was being said, because what you meant was that those rare crystals weren't needed.......
Does it make sense now?
"But that's not what I guess was said when I thought the other thing was being said, because what you meant was that those rare crystals weren't needed"
What was said was there was no need for the crystals.
Nothing was ever said that the v1's oscillator would be omitted. Not by me anyway. Nor have I ever said the current oscillator couldn't be the oscillator that is needed for the PLL unit.
Did I just cause more confusion? LOL!!!
RFB
The problem with being smart is that the rest of us, who also think we are smart, think we know what a smarter person is talking about, only to find out that we don't know what we're talking about, even though you knew what you were talking about when we thought we knew.
That explains it.
Maybe that's why the government is opening confusion centers all over the country.
Just sub out the crystal with an LC circuit and a varactor diode. The manual that came with the PLL board has examples of oscillators for reference.
Once its ready, set the oscillator to free run at or near 180khz. Then fire up the PLL, punch in the numbers, and it should lock to the frequency entered.
I have found that setting the oscillator's free run state frequency above the frequencies I want to use, the PLL locks the oscillator very quickly and prevents motor-boating, which can happen if the oscillator is running too far away from the intended frequencies you want to work with.
RFB
I just scrolled through the many interesting comments from everybody on this long wave thread, and would like to roundup a few ideas....
This thread has morphed into a part 15 long wave transmitter design and building project under the name "Deep Voice"
The frequency range allowed per 15.217 is 160 to 190kHz.
The specific frequencies of a typical long wave digital radio are 162, 171, 180 and 189kHz, which are 9kHz apart, based on the European standard, where long wave is used for broadcasting.
The U.S. has not set a spacing standard for long wave, therefore any spacing choice is available for experimentation.
The Crow has proposed primary frequency: 162kHz and secondary frequency: 180kHz for this project, and of those, 180kHz is in line with either the 9kHz normal receiver settings or a 10kHz approach.
Version 1.0.0 utilizes a crystal driven oscillator with a multiplier circuit so that the crystal can be a higher value than the base operating frequency.
RFB has proposed use of a PLL circuit in place of a crystal, but this will not work with the multiplier chip used in V 1.0.0, and requires a different oscillator design.
There are sample oscillators shown in the lit for the PLL board, but those are specified as operating in the near FM VHF range and may not be appropriate for LW use.
The use of the PLL requires selection of a suitable varactor diode, but the lit does not address LW and we are in the dark as to how to make this choice.
Therefore I am requesting from RFB or other project participant a detailed sketch of a proposed LW oscillator/varactor diode for use with the PLL.
Also, the PLL is supplied for 10M-crystal operation, which will not allow 9kHz use, thus the question, should we use a 9M crystal?
"Version 1.0.0 utilizes a crystal driven oscillator with a multiplier circuit so that the crystal can be a higher value than the base operating frequency."
BZZZZTT!! The V1 does NOT use a frequency multiplier, it uses a divider IC taking the higher crystal frequency and dividing it down to the operating frequency.
"RFB has proposed use of a PLL circuit in place of a crystal, but this will not work with the multiplier chip used in V 1.0.0, and requires a different oscillator design."
Which is what I have been saying all along..the PLL needs an oscillator. The V1 has no oscillator..never did. Thus an oscillator will have to be built. I'm surprised you did not catch this 2 pages back. Tests come in many different forms!
"There are sample oscillators shown in the lit for the PLL board, but those are specified as operating in the near FM VHF range and may not be appropriate for LW use."
Tell me something...do you always throw in the towel so quickly when running into a wee problem?
Simply build an oscillator for the frequency range...those within the manual are good "REFERENCE" designs. Naturally component values will be different for the frequency range of oscillation, but just because those reference schematics of oscillators mostly deal with VHF does NOT mean the PLL board is useless for this LW project.
How do I know..because right now at this very moment my LW TX is running from this exact PLL board as I type this. And it covers the entire band we are interested in, and above it and below it with no issues at all.
"The use of the PLL requires selection of a suitable varactor diode, but the lit does not address LW and we are in the dark as to how to make this choice."
The choice of varactor diode is determined by the circuit specifics...ie the oscillator's LC network parameters. Part of designing electronic circuits is to calculate component values necessary to make the circuit design work. But things can be even more simpler than that. Got a HF circuit handbook handy? Well then reference to those oscillators with varactors and work from there. Chances are the varactors used for HF work will do just fine for our LW oscillator. Any tolerances too far out of range can be compensated with the LC circuit tank...a larger coil...a heavier capacitor...or a tweak or two of an inductor coil if used.
"Also, the PLL is supplied for 10M-crystal operation, which will not allow 9kHz use, thus the question, should we use a 9M crystal?"
Why would you need a 9Mhz crystal for? The PLL's 10Mhz crystal will do everything needed for this project. As I posted before, you punch in 000016 for 160Khz, then use the up button to step to 162Khz...simple. For 180, simply punch in 000018 and bada bing. Why muck with a perfectly good working PLL already set up to do what we need it to do for the project? Just more added work that is unnecessary.
The PLL crystal has nothing to do with what our oscillator will do, nor does it do anything about frequency selection when punched in on the keyboard. The crystal is the PLL's reference to lock the oscillator to and operate the clock internal to the PLL chip. Replacing it with a 9Mhz crystal will have no effect on selecting the frequency via the keypad. You merely changed the PLL IC's clock frequency and reference frequency which is used to match the phase of the oscillator frequency..thus it locks. In other words, a 9Mhz crystal wont give you 9Khz channel spacing from the PLL OR oscillator. What gives you channel spacing is what frequency you punch in into the keypad!
One step at a time and cross the bridges one at a time will lead to project completion and happy LW broadcasters.
RFB
Dear RFB:
You are a good college teacher, but you are no grade school teacher.
Metaphorically, you are telling me, "Learn algebra."
And here I am with a pencil, paper, and a tongue hanging out.
"Pick a varactor diode for the frequency range." Oh, that'll be easy. Here's one on the floor.
You have an oscillator and varactor already in operation. They must be proprietary information, it hasn't been sent over in the form of a diagram.
"Just set it on the keyboard." What is the setting for 162kHz?
I can't throw in the towel. I don't have a towel.
Well I have been told once I should have been a professor of electronic and electrical engineering...but I like to get my hands dirty!
I will draw up the schematic with part values/numbers and when completed, post a link within this thread for the PLL oscillator.
Be patient...at the moment I am dealing with some terrible developments and news just learned regarding a family member.
RFB
There has been a loss. I will be out of pocket for some time..not sure how long. Station is on full auto pilot set to also download the newest episodes of the programs it airs and will place them into the daily lineups, but will be monitored via remote pc software.
Until then...hold the fort.
RFB
RFB, you have my best wishes.
Whatever it is, I'm very sorry for the news - and we will
all be thinking of you.
Carl, I will probably have some comments for you,
as soon as I get my act together and reread some
of your posts.
Best Wishes,
Bruce, DOGRADIO STUDIO 2
Bruce, with your love of part 15 and radio, and now RFB, with so many creative ideas and always a solution or answer for whatever we ask about, it is saddening to see troubles come into the picture.
Loss and health are time stealers and I hope the resolutions and cures come in a very short time.
We'll keep the conversation going while we wait for your return.
Just checking in via wi-fi and laptop across free wi-fi access at hotel and through remote pc to machines back home.
Wife's mom passed yesterday. We are about to get back on the road...long way to Georgia from Wyoming.
Will check in again at earliest chance.
RFB
The death of a family member comes in many forms. The worst are sudden and unexpected. Abrupt losses are crippling and shocking.
Less traumatic but still dread is the expected loss, as with someone who has been expected to go because of age or health.
One thing is always true of a loss. We all and always stop what we're doing and gather for the goodbye memorial. We, the survivors, pool all our thoughts and memories about the departed.
RFB, I extend to your wife my regrets over the loss of her good mother.
The evolution of our species has put all its refinement into the beginning of life and done very little to improve the end of life.
Religions manage to create little distraction ceremonies to help keep our mind off of the sorrow.
Thanks for checking in along the way.