Re: AE7EU Top Level PCB Mod
Regarding putting diodes near the front end of the uBitx, this post is worth reviewing: ? ?? /g/BITX20/message/35656And this thread, which continues the discussion: ? ?? /g/BITX20/message/37330So that ADE-1 attenuator might work better if placed after the 45mhz roofing filter, or somewhere beyond that. But up front where we have the whole world of RF coming in, the diodes may create harmonics of a 50kW AM broadcast station across town, harmonics that will show up in the ham bands. Vince wrote: " Before smoothing, at moderately high RF fields the RF was setting off the Halon alarm!"
Exactly what do you mean by "smoothing"?
Do you figure the diode ring mixer was creating harmonics?
Jerry, KE7ER
On Fri, Jan 12, 2018 at 10:38 pm, Diver Martin wrote:
This is one of those "We'll see how this works" things I think.? The guy who I've been talking to knows his stuff pretty well when it comes to building radios, so I trust his advice.? He's got some cool stuff on his webpage, though he doesn't sell any of the kits anymore I think.... .
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Re: Bitx40/Raduino no power - help
Yes, thanks Raj. I was confusing the pot numbers...I was adjusting RV1 not RV136. Found the problem to be a dead Q13, which seems to happen a lot!
=Vic=
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Re: Sotabeams CW filter problem
I tried the 90.1 uF cap in series with the AF filter output but it didn't help.
My filter is always on, but there is no noise from it when it is bypassed, so I don't think it is generating noise on the power line.
??? Bob?? KD8CGH
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Re: Micro-BITX ... Lost in post ? Possibly
Apparently that number is the board number as tested from the run or #71 of Run 1.? Yours ordered on Dec 9th while mine ordered on Dec 10th was something like #322/1.?? They were certainly cranking them out like that for just a few days before using up the entire first run.??
Congrats and keep the soldering iron warm.
Dave Wi6R
On Thu, Jan 11, 2018 at 11:55 AM, G1KQH via Groups.Io <g1kqh@...> wrote: Mine arrived today too!
You just got to find the inner strength to wait!
73 Steve
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Re: AE7EU Top Level PCB Mod
Ok - found a circuit on this group that removes my confusion.?
?You have it wired correctly Martin!
The data sheet is not very clear with nomenclature - if the PIN numbers were indicated on the circuit diagram then it would be far less confusing!
Mike
On Sat, 13 Jan 2018 at 8:42 PM, Mike Woods < mhwoods@...> wrote: We agree that we need to inject the DC into pin I in the circuit (the centre tap on the transformer).? I believe this is pin 6 (LO) for port I and not pin 2 (IF).? In your circuit diagram you have LO pin 6 connected to the antenna and not to the DC input.? Sorry I wasn¡¯t clear, ?but I think there may be an error.? The data sheet confuses the matter because different nomenclature is used in the circuit diagram from the pinout on the chip.? I believe the labels correspond as follows: L = RF, I=LO, and R=IF.? But I may be wrong!? I have not used this package before.
Mike Hi Mike,
Check out the datasheet for the ADE-1 here:? .? Page 1, bottom right side for the electrical schematic, you'll see the "I" pin has a DC connection to the diodes and then to ground.? This will forward-bias two of the diodes, and reverse-bias the other two.? A current limiting resistor (R14 in this case) limits the current going through the diodes.? I picked 1.2k randomly, it might be 1k-100k, I'll have to play with it I'm sure.
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Re: AE7EU Top Level PCB Mod
We agree that we need to inject the DC into pin I in the circuit (the centre tap on the transformer).? I believe this is pin 6 (LO) for port I and not pin 2 (IF).? In your circuit diagram you have LO pin 6 connected to the antenna and not to the DC input.? Sorry I wasn¡¯t clear, ?but I think there may be an error.? The data sheet confuses the matter because different nomenclature is used in the circuit diagram from the pinout on the chip.? I believe the labels correspond as follows: L = RF, I=LO, and R=IF.? But I may be wrong!? I have not used this package before.
Mike
Hi Mike,
Check out the datasheet for the ADE-1 here:? .? Page 1, bottom right side for the electrical schematic, you'll see the "I" pin has a DC connection to the diodes and then to ground.? This will forward-bias two of the diodes, and reverse-bias the other two.? A current limiting resistor (R14 in this case) limits the current going through the diodes.? I picked 1.2k randomly, it might be 1k-100k, I'll have to play with it I'm sure.
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Re: AE7EU Top Level PCB Mod
This is one of those "We'll see how this works" things I think.? The guy who I've been talking to knows his stuff pretty well when it comes to building radios, so I trust his advice.? He's got some cool stuff on his webpage, though he doesn't sell any of the kits anymore I think.... .
On Fri, Jan 12, 2018 at 10:26 PM, Vince Vielhaber <vev@...> wrote:
On 01/13/2018 12:56 AM, Jerry Gaffke via Groups.Io wrote:
A neat trick, I've never seen a mixer used as an attenuator.
Though might be cheaper ways than using an ADE-1
And I'm curious how linear this would be for incoming high level RF signals
when partially attenuated.
Amplifier Research Model 777 is an RF leveling preamp.? It uses a mini-circuits mixer as an attenuator.? First time I saw one used for that. I had to modify one to smooth the output.? It was in the chain between an RF generator and an amplifier putting RF into an anechoic chamber.? Before smoothing, at moderately high RF fields the RF was setting off the Halon alarm!
Vince.
--
? Michigan VHF Corp.? ?? ?
? ? ? ? ? ? ? ? ? ? ? ? ?
-- Martin Held - AE7EU
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If there aren't any questions, then what is there to learn?
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Re: AE7EU Top Level PCB Mod
On 01/13/2018 12:56 AM, Jerry Gaffke via Groups.Io wrote: A neat trick, I've never seen a mixer used as an attenuator.
Though might be cheaper ways than using an ADE-1
And I'm curious how linear this would be for incoming high level RF signals
when partially attenuated. Amplifier Research Model 777 is an RF leveling preamp. It uses a mini-circuits mixer as an attenuator. First time I saw one used for that. I had to modify one to smooth the output. It was in the chain between an RF generator and an amplifier putting RF into an anechoic chamber. Before smoothing, at moderately high RF fields the RF was setting off the Halon alarm! Vince. -- Michigan VHF Corp.
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Re: MAX9814 integration to uBitX
Dave,
toggle quoted message
Show quoted text
just received my Max9814 and was waiting for someone smarter than me to figure out the wiring to the uBITX. I did download the 9814 tutorial from Adafruit but haven¡¯t read it yet.?
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Re: AE7EU Top Level PCB Mod
Here's his board design, ADE-1 is bottom-right of the first sheet: ? ?? /g/BITX20/attachment/38900/1/uBitx_top.pdfHere's the ADE-1 datasheet:?? ? ?? ADE-1 pins are as follows: L=LO? ? ? ?(local oscillator, or vfo) R=RFIN? ?(input from antenna, we assume this is a receiver) I=RFOUT (intermediate frequency) A current source on the I pin (RFOUT) will flow through the top-left and bottom-right diodes, With those two diodes conducting, the tops of the two transformers are connected together, and the bottoms are also. So the L and R windings are effectively coupled through the two back-to-back transformers. Signals pass freely from ATT-IN to ATT-OUT when the diodes are conducting. A neat trick, I've never seen a mixer used as an attenuator. Though might be cheaper ways than using an ADE-1 And I'm curious how linear this would be for incoming high level RF signals when partially attenuated. Jerry, KE7ER
On Fri, Jan 12, 2018 at 09:21 pm, Mike Woods wrote:
Ok - I understand how it works now.? The one remaining question is how injecting DC into the output side (IF pin) of the mixer (as you have it drawn) would unbalance the mixer? Doesn¡¯t this look like a short circuit to the DC? I would have thought you would connect the DC to the LO input to have current flowing through the diodes?
?
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Re: AE7EU Top Level PCB Mod
Also, why not a whole kit option? would that not cut cost?
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Re: AE7EU Top Level PCB Mod
I say make a Kickstarter or indigogo. I think more people might be interested in this. I for one would be happy to have all this in one board solving many mods at once. Not to mention an ATU in the bitx just sounds fun!
?
?73
?? David
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Re: AE7EU Top Level PCB Mod
A reasonable idea. Main thing will be to have both pads close enough together for the 0603, but large enough to accommodate the 1206.? I've done 0603's across a 1206 pad, but it's a PITA, and not easy for fabrication certainly.? I'm sure many fab houses won't like putting an 0603 onto a universal pad though, it'll probably have a greater tendency to tombstone.
On Fri, Jan 12, 2018 at 9:19 PM, Glenn <glennp@...> wrote: Maybe consider a 'special' footprint that will take any smd size from 0603 to 1206. Seems there is plenty of room, in the main, to do this.
glenn
vk3pe
-- Martin Held - AE7EU
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If there aren't any questions, then what is there to learn?
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Re: AE7EU Top Level PCB Mod
Hi Mike,
Check out the datasheet for the ADE-1 here:? .? Page 1, bottom right side for the electrical schematic, you'll see the "I" pin has a DC connection to the diodes and then to ground.? This will forward-bias two of the diodes, and reverse-bias the other two.? A current limiting resistor (R14 in this case) limits the current going through the diodes.? I picked 1.2k randomly, it might be 1k-100k, I'll have to play with it I'm sure.
On Fri, Jan 12, 2018 at 9:21 PM, Mike Woods <mhwoods@...> wrote: Ok - I understand how it works now.? The one remaining question is how injecting DC into the output side (IF pin) of the mixer (as you have it drawn) would unbalance the mixer? Doesn¡¯t this look like a short circuit to the DC? I would have thought you would connect the DC to the LO input to have current flowing through the diodes?
Mike?
-- Martin Held - AE7EU
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If there aren't any questions, then what is there to learn?
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Re: AE7EU Top Level PCB Mod
Ok - I understand how it works now.? The one remaining question is how injecting DC into the output side (IF pin) of the mixer (as you have it drawn) would unbalance the mixer? Doesn¡¯t this look like a short circuit to the DC? I would have thought you would connect the DC to the LO input to have current flowing through the diodes?
Mike?
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Re: AE7EU Top Level PCB Mod
Maybe consider a 'special' footprint that will take any smd size from 0603 to 1206. Seems there is plenty of room, in the main, to do this.
glenn
vk3pe
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I ordered mine on Dec12 as a preorder. ?I just recieved an email that mine has shipped via DHL and to expect it on Tuesday?
Aug
AG5AT
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while Im impatiently waiting
I ordered a hand full of nano boards to learn more about programming the part and set up my development project..I got it all up and running in a few minutes. I ordered 3 boards for under $10 on ebay and got them in a couple of days.
I also have an SI5351A board from a previuos project..maybe I'll make my own radiouino while Im waiting.
Brian K9WIS
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Re: AE7EU Top Level PCB Mod
So, without any major modifications to the pick structure of my design, here's what I got back from Macrofab (US based in TX).
As you can see in the attached, the raw PCB cost is about $95 a pop, in qty 100.? In qty 1000, this goes down to about $75.? This doesn't include any of the Through-hole components though, things like the Teensy32, potentiometers, inductors (in a kit like this, it'd be you-wind), power connectors, and they couldn't quote me the ADE-1 ($2.55).? In total, about $45 in parts not included in that.? This makes the overall PCB $140, not including shipping, or about $150 if you assume about $10 for shipping within the USA, $130 if there were preorders for 1000 (Sorry, I don't have $10k to lose in advance, let alone $100k)
Is it even still reasonable?
On Fri, Jan 12, 2018 at 2:43 PM, Martin Held <diver.martin@...> wrote: I used a lot of 0603's and such.? Those are a large percent of the assembly cost.? I could go to 1206's pretty easily I think....? A lot of people don't like assembling 0603's.? The other option then might be change a bunch of the resistors to through hole, same for the caps.
A coworker who's used the same assembly house got $0.40 a part for 25 PCB's, at about 180 parts per PCB he said.? That would make the assembly cost about $60.
There are a few places where resistor/capacitor arrays might be applicable in this design, which can significantly reduce costs.
-- Martin Held - AE7EU
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If there aren't any questions, then what is there to learn?
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Re: Bitx40/Raduino - no power out
Another group member Bill found his Q13 dead.. so seems like something is
killing them!
Raj
At 13/01/2018, you wrote:
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Show quoted text
Probably ok as is, though a bit
of copper could make it happier.
Most failed q13's? here saw a nearby QRO transmitter, and that's
only fixed by the back-to-back diodes.
I'm not aware of many that burn out due to too much power dissipation,
and we may be under the wire on the spec.
But if it did burn out, I'd replace it with the leaded TO92 2n3904, as
that can dissipate considerably more.
As an alternative, I think Raj once suggested soldering a second mmbt3904
on top of it.
Or I suppose you could solder a leaded 2n3904 in parallel.
The ubitx uses paralled 2n3904's in that position.
Your choice.
On Fri, Jan 12, 2018 at 02:59 pm, Gordon Gibby wrote:
- should we glue some sort of small bit of copper on top of that
hurtin' puppy?
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Vic WA4THR
Bob Benedict, KD8CGH
N8DAH
Raj vu2zap