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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Show quoted text
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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Re: 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/"
|
Re: Amplifier chain design - best practices
RCBG/Carl,
R.E. has an opinion.? Venders supply fact. Home brew is speculation and requires testing.
uBitx uses the latter, until tested its all a guess.? WHile patterned after many the transformers
are part of the picture and no commercial packaged design I've seen do those transformers.
However its widely copied and almost never tested.
The LO should be at least 5dbm and can be as high as 10.? Higher is better to a point.
The ubitx has maybe a 3dbm or less LO.? LEast that what I get with O'scope, SA, and
calibrated RF power meter.? Its not enough!
The suggested level is for a level 7 (7dbm nominal) DBM the input power should be -10dbm or less.
that is actually 17db below the LO.? ?So -20DBM is only 3db away and likely to make no
easily measured difference.
But if we peruse that at 3dbm we need to be at not more than -17dbm and the output signal
then is less than -22dbm.
Allison
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Re: I find This Shorted Circuit on Raduino, here the pics..plz Help?
#ubitx-help
Ok yes it was the one post i have write an when load up was deleten i have forget to write it again.. Here re the information from the lost posting
Power supply is 12v 3amp or batterypack of 8x1,5v for sometimes or when testing outdoors
AM station till today only received in version like seems to be an AM radio station bu never a clear sound rceive of this, but the bad thing that since an other ham tried to play at 'calibration' and 'bfo' is going more to negative receive...
HAM in my town i contacted they have no knowledge for other things like finish buying tansceeiver this is no joke no one from many have any knowledge with homebrew and they have licence A and not new... I thought that is an way but the only way till now is to ask here.. One only HAM in my town make homebrew but i such for contact next month at first week when the club meets.till that day only i have you all here for help no joke
I have make at RV2 and RV3 the 100milliamps pro so 200 toghether just want like in fasctory set..
I think the solderpoint which i have described on picture here at first posting can not be ok when look shematic for first batch v3 ubitx , you have ubitx3 with the Fci tda? And have you test with multimeter an contact tone on these 2 solder points are have conctact? Please can you say me these things are like so by your ubitx raduino??
The Software is CEC 1.08 and which you have??
I think the calibration of menu points "Calibration" and "BFO" setting is important for me but how should make this when its totaly distored and every post i found not find a way for this to bring it right or even to factory set...
I hope you? can help
AM station to hear was an begin but first the calibrating to make it right...that is mostly my issue with the wrong calibration and bfo i think....
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RTTY a small device ...... and a bit QRP
The small units .......
?
?
Best,
Johan
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Re: Amplifier chain design - best practices
As I recall, several here have posted that the LO input to the DBM should be about 7 dBm.? That agrees with the following DBM tutorial I found online:
However, I also recall someone here mentioning that they measured the LO input as only a little over 10dB higher than the RF input during transmit.? The above tutorial recommends that the LO be about 20 dBm higher than the RF input.
What is the consensus here?? Is having the LO input to the dBM only 10 dBm higher than the RF input during transmit OK, or is the tutorial correct about needing a 20 dBM delta between the two for the best results?
73,
Carl, K0MWC
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Re: NEXTION DISPLAY UPDATES For KD8CEC ver 1.094 up
KD8CEC? 3.2 files
Download this file
Extract Ubitx_32.tft for just the tft or Ubitx_32.him for the him file.
Marty
--
N5KBP
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Prototype for the MMIC based bi-directional amplifier replacement. That is not the actual MMIC.... still awaiting delivery. But the transmission line boards are here and the isolation caps, bias choke, and zero ohm place holder for the attenuator are set. The device in the center is just for modeling purposes to be ready when the semiconductors get here.
There will be a 3 week hiatus on this project though unless the devices arrive today as I am headed overseas until mid-October. Will report on the results on my return.
WA8TOD
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Look at KD8CEC firmware updates, they do work with your display, and do fix the keyer subroutine. But if you stay with the straight key, it won't matter much.
Ed KC8SBV
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Re: Amplifier chain design - best practices
What probe are you using?
Raj
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Show quoted text
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@...> 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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100% agree Sarma. Almost any microphone will give satisfactory performance across the 300 - 2700 Hz passband used for SSB. Instead of spending huge dollars on high performance microphones, SSB operators would do well to spend any extra audio money for microphone processing. Equalization for leveling out or emphasizing critical portions of the SSB passband, noise-gating to remove ambient low level noise, and compression to raise the average talk power. "Thumping" bass response and crystal clear highs are both thrown away by the SSB filter anyway. So the smart money would be spent limiting dynamic range and emphasizing intelligibility within the remaining response.
WA8TOD
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You might check on the New England qrp club site for their ?switched capacitor filter kit. It has good reviews and is about $35 I think
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Re: Amplifier chain design - best practices
Ha, well, you indeed may be correct ..Since I didn't save my invoices, (maybe I didn't want to remember) and bought pieces and bits as they arrived I never kept track of exactly how much I spent ( SN 19xx ..Late-comer)
Jim
On Saturday, September 22, 2018, 4:36:38 AM PDT, Michael Maiorana <zfreak@...> wrote:
Jim, Your post made me curious. I have an early K2 that I bought and built in 1999. Looking at my invoice, and adjusting for inflation, the K2 is about $100 cheaper today (100 2018 US dollars).? Inflation is a thief.? Mike M. KU4QO
On Fri, Sep 21, 2018 at 2:55 PM, jim via Groups.Io <ab7vf@...> wrote: I also too have the K2 manual for my unit ...Looking a "little further in front" you will notice 5 ea. band-pass filters ...Not dc to daylight transmit path ... if you want K2 performance, buy a K2 @ $800 to $1200 ...(glad I got mine when they were cheap) elsewise work with whacha got
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Re: Amplifier chain design - best practices
Jim, Your post made me curious. I have an early K2 that I bought and built in 1999. Looking at my invoice, and adjusting for inflation, the K2 is about $100 cheaper today (100 2018 US dollars).? Inflation is a thief.? Mike M. KU4QO
On Fri, Sep 21, 2018 at 2:55 PM, jim via Groups.Io <ab7vf@...> wrote: I also too have the K2 manual for my unit ...Looking a "little further in front" you will notice 5 ea. band-pass filters ...Not dc to daylight transmit path ... if you want K2 performance, buy a K2 @ $800 to $1200 ...(glad I got mine when they were cheap) elsewise work with whacha got
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Re: Amplifier chain design - best practices
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@...> 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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Your quote is Thomas Edison ??? Timothy E. Fidler : Engineer BE Mech(1) Auckland , NDT specialist AINDT UT /RT3 , MT2 CB #2885,?
Telephone Whangarei?? 022? 691 8405
e: Engstr@...
----- Original Message -----
To: <[email protected]>
Cc:
Sent: Sat, 22 Sep 2018 02:50:11 -0700
Subject: Re: [BITX20] si5351 crosstalk #radiuno
Re 78 Fairchild Diode Data Book
In the old days the manufacturers really went all out with their data books.? They wanted the designer to know exactly what he was buying and how to use the thing.? In fact most data books had many application notes where they would lead the designer down the garden path to show how their part could be used in other ways, sometimes unexpected ways.
National Semi was famous for this approach.? Their Op Amp data book was better than a graduate level course in Op Amp theory.? I still have my early 80's copy...dog eared...probably has 10 lbs of highlighter ink in it.
--
"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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