Re: Amplifier chain design - best practices
If there was ever an appropriate comparison, the now overused phrase ¡°like herding cats¡± fits the bill with regard to keeping these group posts on topic. Mike K5ESS ?
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From: [email protected] [mailto:[email protected]] On Behalf Of ajparent1/KB1GMX
Sent: Saturday, September 22, 2018 2:21 PM
To: [email protected]
Subject: Re: [BITX20] Amplifier chain design - best practices ? Did a count and nearly 50% of the posts in thsi string have nothing to do with:
amplifier chain design - best practices.
About DBMs,
DBM drive levels
Low pass filters
Spectrum analyzer and probes.
K2 and its price.
SSD
QUCS
I might have forgotten a few.
Someone change the title to "WHATEVER/"
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Re: Amplifier chain design best practices
Maybe not written stone, but rather silicon ...All diodes need a minimum threshold voltage to "turn on" ie start conducting ...Silicon happens to be about .7 volts, schottky about .3 volts ...Level "7" mixers have one diode per leg in the bridge,? Level "14" have 2 diodes in series per leg ..etc.?? You can build your own out of 1n914's if you wish ...Still gonna take X amount of volts to turn em on...If you don't meet "x" then your problems start ..
Jim
On Saturday, September 22, 2018, 4:46:11 PM PDT, Timothy Fidler <engstr@...> wrote:
st
Amplifier chain design - best practices? WHATEVER.
For whom it may concern : The 7 dBm/50Z? figure comes from a requirement which was common for the Minicircuits series of? DBMs? viz the ADE-01 and SBL-1 which used to be very common in ARRL Imprimatur designs.? It is not written in stone.? Some other? Minicircuits Dbms require other input power to meet the mafr's datasheets.?
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Low pass filter kits can be had from QRPLabs or you can build your own. The QRPLabs instruction documents have all the values they use...it would be easy to roll your own on a piece of perf board. Or some of the members here offer circuit boards. The components are not expensive or hard to find (altho it might be more cost effective to order them from QRPLabs). Lots of info online or in the ARRL Handbook on design.
Or see the wiki for details on how to hack the existing filters on the uBitX (thanks to Allison, et al.).
See for more info on the kits (disclaimer...I have no financial interest in QRPLAbs, just a customer).
73... Mark AA7TA
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On 9/22/18 7:41 PM, ajparent1/KB1GMX wrote: ...
Spurs are less an issue for 20M and below.
External low pass or transmitting band pass filters are responsible way to go.
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Dave, I can only speak with some authority about 20 meters.? I don¡¯t have antennas for the other bands so I haven¡¯t characterized my uBitx on those bands yet. ?I verified that my unmodified uBitx passed muster (by 1.6 dB third harmonic) for harmonics and spurs with my spectrum analyzer.? I¡¯m only doing FT8 not voice.? uBitx is running with about 7watts out on 20.? 298 confirmed QSOs since July which include Australia, New Zealand, Brazil, Alaska and Hawaii.? All with a fantastic dipole in the attic (see my QRZ page).? Go for it. Mike K5ESS ?
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From: [email protected] [mailto:[email protected]] On Behalf Of davedt1e@...
Sent: Saturday, September 22, 2018 7:57 PM
To: [email protected]
Subject: Re: [BITX20] Ubitx evolving fixes updated to wiki? #ubitx #ubitx-help ? Sorry if I'm asking you all to beat a dead horse here, but I need to ask a few questions.
I've just passed my General, and would really like to get on the air.? Very much a neophyte.? ?
The "Simple Spurs Fix"? Looks easy enough for me to handle.? But not entirely clear as to whether this is required for 20 or 40 meter ssb.
For harmonics, would you all consider it responsible to use external filters in the coax?? Seems there's been some debate as to whether that is acceptable.? Are there suitable filters available for those bands? (low pass right?)? ?If not how does one go about building one?
I have read thru all of the posts repeatedly,? but there always seems to be a few things that stump me so sorry if I'm asking questions that have already been answered.
Any input would be much appreciated.
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Doc sees horse,
? ? ? ? ? ? ? ? He's dead Jim!
Spurs are less an issue for 20M and below.
External low pass or transmitting band pass filters are responsible way to go.
Allison
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Sorry if I'm asking you all to beat a dead horse here, but I need to ask a few questions.
I've just passed my General, and would really like to get on the air.? Very much a neophyte.? ?
The "Simple Spurs Fix"? Looks easy enough for me to handle.? But not entirely clear as to whether this is required for 20 or 40 meter ssb.
For harmonics, would you all consider it responsible to use external filters in the coax?? Seems there's been some debate as to whether that is acceptable.? Are there suitable filters available for those bands? (low pass right?)? ?If not how does one go about building one?
I have read thru all of the posts repeatedly,? but there always seems to be a few things that stump me so sorry if I'm asking questions that have already been answered.
Any input would be much appreciated.
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Re: Ubitx - using Amateurradiokits.in AGC
#ubitx
Sunil says to wire it just like the instructions for a Bitx20.? Still a little sketchy for me.? I need a schematic !!????
--
John
NQ3RP
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Re: I find This Shorted Circuit on Raduino, here the pics..plz Help?
#ubitx-help
Hi Skip,
yes I know that the v3 schematic is wrong an it was corrected in v4. Just wanted to show Fabian that the connection between these two pins is OK and has nothing to do with his reception problem, and he could concentrate on the alignment process.
I think your more detailed description will help Fabian.?
Armin, DJ2AG
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Re: Amplifier chain design - best practices
Amplifier chain design - best practices? WHATEVER.
For whom it may concern : The 7 dBm/50Z? figure comes from a requirement which was common for the Minicircuits series of? DBMs? viz the ADE-01 and SBL-1 which used to be very common in ARRL Imprimatur designs.? It is not written in stone.? Some other? Minicircuits Dbms require other input power to meet the mafr's datasheets.?
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Re: I find This Shorted Circuit on Raduino, here the pics..plz Help?
#ubitx-help
Armin, both those are connected under that solder there is a tiny bridge connecting them. The schematic of the Raduino board showed pins 15 and 16 connected (on connector P3) which the clearly are if you measure the board removed from the UBitx. The connector Conn_01X16 on the UBITX schematic first of all has the pin numbers reversed, pin 1 should be pin 16. Also if you look carefully at that pin 16 you will see that it is floating and not connected to anything not ground like the schematic. Unplug the Raduino board and turn the board over and measure between pin 15 and 16 you will measure open circuit and measuring from 16 to ground should be the same. If now you plug-in the Raduino and measure between 15 and 16 you should read zero ohms or a short.?
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On Sep 22, 2018, at 15:41, DJ2AG < ya_duck@...> wrote: Hi Fabian,
sure I used my multi-meter to test connectivity before I sent my message and I also have? the FCI chip.
Please have a look onto attached picture, which shows my Raduino board. You can clearly see that both pins are connected (under solder mask). As far as I remember this was also the case with the first Raduino for BITX40. It may be confusing, but for sure it has nothing to do with your problem.
Are you using Memory Manager?
Regards
Armin
<2018_09_22_Shorted_Pins.jpg>
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Lyn
Just to clarify. My uBITX still has the original Raduino in it. The DIY pcb I made was fitted to a VK4PLN Raduino just fopr testing? but is not in the rig itself.
The new 'buffer' board will fit directly onto the main uBITX board as shown? further down this thread. Once i actually make it.
glenn
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Hi Lyn,
Not had time to make up the PCB for it, as yet.? Hopefully in coming week.
glenn
vk3pe
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On Sat, Sep 22, 2018 at 07:43 PM, <lynatmts@...> wrote:
Hey Glenn, So what were the results of adding the buffer stages??
Thanks
Lyn
--
"You see, wire telegraph is a kind of a very, very long cat. You pull his tail in New York and his head is meowing in Los Angeles. Do you understand this? And radio operates exactly the same way: you send signals here, they receive them there. The only difference is that there is no cat."
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Re: Ubitx - using Amateurradiokits.in AGC
#ubitx
Thanks, Richie.? The mystery is part of the fun, and frustration.
Eddie
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I don¡¯t have your reference at my disposal. Do we need a BCI to transmit through? The BCI mid for the ubitx puts a BCI filter in the RX path only. So my question was is will the one I provided work from a tech spec point of view.?
W3NQN has some nice filters. ?RX only and TX. A bit pricey though. ?
Joe
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On Sep 22, 2018, at 5:40 PM, ohwenzelph via Groups.Io < Ohwenzelph@...> wrote: QST Feb ¡®78 p22 BC-Band Energy ¡ª A Rejection Filter W3NQN
does this look one could transmit thru it?
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QST Feb ¡®78 p22 BC-Band Energy ¡ª A Rejection Filter W3NQN
does this look one could transmit thru it?
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Re: Amplifier chain design - best practices
Ah good to know ...Since I'm the only one that mentioned "in? passing" that I modeled Q90 circuitry (part of the PA chain last I looked) in the hopes that "someone else" might to choose to model it also as a comparison ...I mentioned QUCS only because I use it and it is "not spice" ,,,just another tool in the toolbox
Jim (not imho whatever, or not)
On Saturday, September 22, 2018, 12:20:45 PM PDT, ajparent1/KB1GMX <kb1gmx@...> wrote:
Did a count and nearly 50% of the posts in thsi string have nothing to do with:
amplifier chain design - best practices.
About DBMs,
DBM drive levels
Low pass filters
Spectrum analyzer and probes.
K2 and its price.
SSD
QUCS
I might have forgotten a few.
Someone change the title to "WHATEVER/"
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Re: Amplifier chain design - best practices
tek p6100 > extended bandwidth 2215a scope
Jim
On Saturday, September 22, 2018, 6:35:54 AM PDT, Raj vu2zap <rajendrakumargg@...> wrote:
What probe are you using? Raj
At 22/09/2018, you wrote: >This ...I measured 0.6 volts P-P on the junction or R102/R103 ...thats about 0 dbm ...Not enough for a 'level? 7 ' mixer? (more nearly a sine wave than a square wave? or kinda a sineish square wave) > >Jim > >On Friday, September 21, 2018, 9:21:53 PM PDT, Jerry Gaffke via Groups.Io <jgaffke= [email protected]> wrote: > > >Howard, > > > > >The Si5351 is having a hard time dealing with the 50 ohm 6dB pads it's trying to drive, >but otherwise doing pretty good. >Jerry, KE7ER
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Re: RTTY a small device ...... and a bit QRP
Hi,
It's easily used field portable with the BitX20 or the uBitX or other small field portable radios. Can you see that these radios are not intended to be assembled and then sit on a shelf someplace. Using them is actually on-topic.
73,
Bill KU8H
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On 09/22/2018 03:42 PM, Jim Wennblom wrote: What does this have to do with BITX20?
Thanks,
Jim
K0HW
On Sat, Sep 22, 2018 at 9:28 AM Johan Holstein <j.g.holstein@...
<mailto:j.g.holstein@...>> wrote:
The small units .......
Best,
Johan
--
bark less - wag more
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Re: I find This Shorted Circuit on Raduino, here the pics..plz Help?
#ubitx-help
Hi Fabian,
sure I used my multi-meter to test connectivity before I sent my message and I also have? the FCI chip.
Please have a look onto attached picture, which shows my Raduino board. You can clearly see that both pins are connected (under solder mask). As far as I remember this was also the case with the first Raduino for BITX40. It may be confusing, but for sure it has nothing to do with your problem.
Are you using Memory Manager?
Regards
Armin
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John McClun
Skip Davis
