Re: ND6T AGC implementation for uBIT-X
You can change the value of C7 to 1.0uF. X7R material, 0805 size, there are some nice Kemet with low ESL/ESR ( 73, Ion
VA3NOI
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Jack, Thanks for that example to the group on how com with the USB port will need to be handled differently.
Yes there are going to be a few quirks and software tweaks, but I still don't see any major roadblocks, yet.
It's also a total disappointment that hardware supported I2C SDA/SCL are pinned out differently.
Ron, Thanks for pointing that out.?
Right now, I think that's a mistake on the part of Protoneer.? They may have their reasons, but ???
Thankfully, I2C is pretty easy to bit bang out for com with the SI5351.? We shouldn¡¯t be scared either, someone has already done that for us.
I shouldn't assume anything here, but is seems logical that those who want to add I2C for other peripherals are going to convert?the display first.
If you want a hardware I2C, You can pick up:
SERCOM1 PAD_0? on PA16 = "D11"
SERCOM1 PAD_1 on PA17 = "D13"
You can check my work fromthe SAMD21 datasheet.? I picked my version up from:
https://cdn.sparkfun.com/datasheets/Dev/Arduino/Boards/Atmel-42181-SAM-D21_Datasheet.pdf
The Protoneer board has a 3.3V voltage regulator, so feeding 5V from the Raduino regulator should work fine.
Like Jack said, you can¡¯t drive 5V directly into the I/O pads.?
I haven't built and testing anything.? Just ideas towards a project to serve a lower budget incremental upgrade.
My?Protoneer?board is on the slow boat from ZK land.? Where evidently shipping to the US is much cheaper than the other way.
Regards,
Gary
Ag5TX
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Re: ND6T AGC implementation for uBIT-X
Got the "OK" from Don and Ion so let me see what I can come up with and the schematics and board layout look fine to me. The only thing I would change is make C7 a 1uF cap. This will be a SMT board
73 Kees K5BCQ
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Re: ND6T AGC implementation for uBIT-X
Mike,
I had no idea about the non-machinable letter stamp. Thanks !!
73 Kees K5BCQ
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Re: mono band 2 meters rig based on the micro BITx circuit
#ubitx
#2meters
for Ken and Steve, if you want compact antenni you really need to look into loop antenni, it's amazing what you can accomplish with some old Cable TV coax and an adjustable vacuum capacitor.? or soft copper tubing for that matter, some people have even managed to pass them off as "Lawn Art". I've even seen at least one example of a loop hidden under the table top of a plastic outdoor set.? with limited success there is the old standby of the rail gutters, and even the holiday lights for the creative!?
-Justin N2TOH?
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Re: ND6T AGC implementation for uBIT-X
Here is the link to the files. https://app.box.com/s/qf4jubi8942dhwdc8lhivctycnue4f12 They are on my cloud storage. Let me know if it is not working and I will upload here. 73,? Ion
VA3NOI
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Re: ND6T AGC implementation for uBIT-X
The USPS has a special stamp for mailing non-machine able letters.? Costs 70 cents. ? 
Mike K5ESS ?
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From: [email protected] [mailto:[email protected]] On Behalf Of Jerry Gaffke via Groups.Io
Sent: Thursday, April 26, 2018 1:59 PM
To: [email protected]
Subject: Re: [BITX20] ND6T AGC implementation for uBIT-X ? That sounds great!
I for one would be happy enough at $10 if it saves me a day of messing around
with Mouser orders and Xacto knife emergency room visits.
Maybe send it out in an envelope with all parts mounted to a piece of card stock,
holes punched in the card to accommodate any thicker parts.
Machine jams are likely their primary concern when determining what's a letter.
Well, that and the obvious height, width, depth and weight measurements.
A 31 mil thick board might be less likely to jam their letter sorting (and shredding) machines
than a standard 62 mil board.? With that and 0201 surface mount parts, we should be just fine.? ?;-)
Here's a FAQ from the USPS, note the 12 hits when searching for the word "machinable".
? ?
Jerry, KE7ER
On Thu, Apr 26, 2018 at 10:30 am, Kees T wrote: I figure a bare PC board could be sent in the USA for $1. postpaid....... and a complete kit of parts for $3. postpaid as long as it can be mailed in a letter envelope and we avoid PayPal fees.??
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Re: mono band 2 meters rig based on the micro BITx circuit
#ubitx
#2meters
I wouldn't even care about AM. AM operation greatly increases the complexity of thermal design. SSB would be all I would want - especially with a good receiver! tim ab0wr On Thu, 26 Apr 2018 16:00:38 -0500 "Ken Hansen" <ken@...> wrote: I understand the motivation, but the Chinese are mass-producing dual
band HTs for less than $30 delivered to your door, and the Japanese
are producing higher-quality units starting at about $120, how much
of a premium over these off-the-shelf solutions are you willing to
pay to build your own VHF radio? Are you hoping for SSB operation or
FM?
Personally, I'd love to see an extremely simple version of the old
Heathkit Two'er lunchbox that handles either SSB or AM on 2 Meters
for under $40 all-in, as a fun club build, but I suspect I'm alone on
that desire...
I think it would be fun to have a local net based on low-cost radios
and antennas so small no HOA could object to.
Ken, N2VIP
On Apr 26, 2018, at 3:44 PM, freefuel@... wrote:
my attention has turned to building a single band rig for 2 meters
and I am curious who might also be interested in such a device. my
initial plan is to build the main circuit board the identical size
of the uBITX and later reduce it to within the confines of the
common 20 by 4 line LCD character display. in an attempt to build
this as a Handi Talkie rig.
-Justin N2TOH
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Re: ND6T AGC implementation for uBIT-X
I am interested in 2 surface mount boards
Paul K0ZYV
On Thursday, April 26, 2018, 6:44:15 PM CDT, William R Maxwell <wrmaxwell@...> wrote:
Yes Ion, please post
the files.
Bill, VK7MX
On 27/04/2018 9:16 AM, Ion Petroianu,
VA3NOI wrote:
Hi Guys!
I have both versions of the board designed.
Through hole with a size of 17X38 mm, single side.
SMT with a size of 18X31 mm. SMT components are 0805. 1 uF cap is
tantalum or niobium polarized.
In terms of performance I am expecting better results with the SMT
board.
I have ordered through hole version for experimenting with some
values (AGC release time minimum resistor and coupling capacitors
on RF line) at PCBway and they are in route to Canada.
The PCBs have provision for adding a pot to adjust AGC release
time and a switch to disable the AGC.
If interested let me know and I will post the files (schematic,
board layout and Gerbers).
Feel free to use the files as you can see fit. If anyone wants to
put kits together just do it.
73
Ion
VA3NOI
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Re: minimum supply voltage
When I simulate the PA at 6VDC I get about 750 mW from it¡ ? ? Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch ¨C K9ZC Staunton, Illinois ? Owner ¨C Operator Villa Grand Piton ¨C J68HZ Soufriere, St. Lucia W.I. Rent it: Like us on Facebook! ? Moderator ¨C North American QRO Group at Groups.IO. ? email:? bill@... ? ?
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From: [email protected] [mailto:[email protected]] On Behalf Of Jerry Gaffke via Groups.Io
Sent: Thursday, April 26, 2018 1:00 PM
To: [email protected]
Subject: Re: [BITX20] minimum supply voltage ? The board is designed to operate at 12v.
I doubt it will work very well at 6v.
That said, in answer to your question, an LM2940-5 has a lower dropout voltage than the LM7805:
??
?
The "Dropout Voltage" at the bottom of page 5 of the LM2940c datasheet says worst case at 1 Amp is 1 Volt.
But the Raduino pulls far less than 1 Amp, likely well under a half volt.? So would work with 5.5v going in.
Near the bottom of page 6 of the second datasheet above (covers both LM340 and LM7805)
it says the "Dropout Voltage" is "typically" 2 volts at 1 Amp, they don't give a worst case.
Will probably be less than 2v since the Raduino is not pulling much current, but you'd be on very
shaky ground if trying to feed it only 6v.
Jerry, KE7ER
On Thu, Apr 26, 2018 at 09:35 am, vajra guru wrote: Have received my uBITx but haven't started assembling yet... I was thinking along similar lines, using 6V to power the board, and using 24V for the PA... Does it make sense to change out the 7805 voltage regulator for something different to make this work? Thx, Calvin VE3EIT
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Re: minimum supply voltage
Depends upon the regulator, but the general rule is about 2v¡ ? ? Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch ¨C K9ZC Staunton, Illinois ? Owner ¨C Operator Villa Grand Piton ¨C J68HZ Soufriere, St. Lucia W.I. Rent it: Like us on Facebook! ? Moderator ¨C North American QRO Group at Groups.IO. ? email:? bill@... ? ?
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From: [email protected] [mailto:[email protected]] On Behalf Of Jack Purdum via Groups.Io
Sent: Thursday, April 26, 2018 12:21 PM
To: [email protected]
Subject: Re: [BITX20] minimum supply voltage? I thought the input voltage (e.g., 7V) had to be at least 2V greater than the output voltage (5V), or is that only for buck converters. (Software guy here...not hardware.) On Thursday, April 26, 2018, 12:35:48 PM EDT, vajra guru <vajraguru99@...> wrote: Have received my uBITx but haven't started assembling yet... I was thinking along similar lines, using 6V to power the board, and using 24V for the PA... Does it make sense to change out the 7805 voltage regulator for something different to make this work? Thx, Calvin VE3EIT
On Thursday, April 26, 2018, Skip Davis via Groups.Io <skipnc9o=[email protected]> wrote: Sarma, if we look at setting up the uBITX for a minimal supply voltage operation we will need to also include minimal dropout regulators to the RF amplifier stages too. Then the resistors values will need to be recalculate for all stages to maintain the gain throughout the bidirectional RF amplifiers. This sounds like an interesting idea try. We need to study the minimum voltage needed for relay operation. If we can change the relays to5V type, and use a LDO regulator on raduino, we can work at 6V battery for the rig except that we may have to provide higher voltage for the HF linear? final section. May be, the bias arrangements of the pre-amp, driver and power amp need to be tweaked. regards ?sarma ?vu3zmv
? On Thu, Apr 26, 2018 at 12:24 AM, Matthew Stevens <matthew@...> wrote: Apologies if this has been answered before, but I can't find it anywhere. I know the max recommended supply voltage is 15v. But, what is the minimum recommended? I have a 9.9v lithium pack I was thinking about re-purposing for a /p power supply.
73
--
- Matthew nj4y
?
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Re: ND6T AGC implementation for uBIT-X
Yes please post the files.
73
Ken VA3ABN
On Thu, Apr 26, 2018 at 7:44 PM, William R Maxwell <wrmaxwell@...> wrote:
Yes Ion, please post
the files.
Bill, VK7MX
On 27/04/2018 9:16 AM, Ion Petroianu,
VA3NOI wrote:
Hi Guys!
I have both versions of the board designed.
Through hole with a size of 17X38 mm, single side.
SMT with a size of 18X31 mm. SMT components are 0805. 1 uF cap is
tantalum or niobium polarized.
In terms of performance I am expecting better results with the SMT
board.
I have ordered through hole version for experimenting with some
values (AGC release time minimum resistor and coupling capacitors
on RF line) at PCBway and they are in route to Canada.
The PCBs have provision for adding a pot to adjust AGC release
time and a switch to disable the AGC.
If interested let me know and I will post the files (schematic,
board layout and Gerbers).
Feel free to use the files as you can see fit. If anyone wants to
put kits together just do it.
73
Ion
VA3NOI
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Re: ND6T AGC implementation for uBIT-X
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Re: ND6T AGC implementation for uBIT-X
Yes Ion, please post
the files.
Bill, VK7MX
On 27/04/2018 9:16 AM, Ion Petroianu,
VA3NOI wrote:
toggle quoted message
Show quoted text
Hi Guys!
I have both versions of the board designed.
Through hole with a size of 17X38 mm, single side.
SMT with a size of 18X31 mm. SMT components are 0805. 1 uF cap is
tantalum or niobium polarized.
In terms of performance I am expecting better results with the SMT
board.
I have ordered through hole version for experimenting with some
values (AGC release time minimum resistor and coupling capacitors
on RF line) at PCBway and they are in route to Canada.
The PCBs have provision for adding a pot to adjust AGC release
time and a switch to disable the AGC.
If interested let me know and I will post the files (schematic,
board layout and Gerbers).
Feel free to use the files as you can see fit. If anyone wants to
put kits together just do it.
73
Ion
VA3NOI
|
Re: ND6T AGC implementation for uBIT-X
Hi Guys! I have both versions of the board designed. Through hole with a size of 17X38 mm, single side. SMT with a size of 18X31 mm. SMT components are 0805. 1 uF cap is tantalum or niobium polarized. In terms of performance I am expecting better results with the SMT board. I have ordered through hole version for experimenting with some values (AGC release time minimum resistor and coupling capacitors on RF line) at PCBway and they are in route to Canada. The PCBs have provision for adding a pot to adjust AGC release time and a switch to disable the AGC. If interested let me know and I will post the files (schematic, board layout and Gerbers). Feel free to use the files as you can see fit. If anyone wants to put kits together just do it. 73 Ion
VA3NOI
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Re: ND6T AGC implementation for uBIT-X
Sign me up for 2 kits.
73,
Alan N4AYE
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Re: ND6T AGC implementation for uBIT-X
Hello All
? ? I would be interested in getting 4 kits. 2 for myself and 2 for others in Calgary, Canada (since I know they are around)?
Thank You in Advance
73?
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Re: ND6T AGC implementation for uBIT-X
I would order 2 kits, with parts.?? Prefer larger 1206 parts but 0805s are okay.
-Jonathan
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Re: minimum supply voltage
Thanks folks, great info... 73 de VE3EIT
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On Thursday, April 26, 2018, Jerry Gaffke via Groups.Io <jgaffke= [email protected]> wrote: Good to know.
The discussion thus far is mostly about the LM7805 linear regulator on the Raduino.
The TDA2822 and LM7805 set definite max and min voltages, but nobody
really knows over what range of supply voltages the remainder of the
analog circuits in the rig will operate properly.
On Thu, Apr 26, 2018 at 01:18 pm, Tim Gorman wrote:
My ubitx main board pulls about .6amp in transmit when the PA is fed
from a separate power supply.
tim ab0wr
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Ion Petroianu, VA3NOI
K9HZ
Jonathan