On Wed, Sep 5, 2018 at 05:54 PM, Nick VK4PP wrote:
Would it not be even better to then implement the complete 45mhz filter prior to the mixer?
See the device on he board labeled Y1, that is a complete crystal filter.? That is what Raj and
Farhan as well as myself have been reffing to.? The mod is to add another one at the other
end of the 45mhz IF amp which is before the mixer.
So the answer is yes, it is.? Remove R27 and place it there.
Allison
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The way I am understanding what I've read on it so far, it would seem the simplest solution to the worst of the issues would be just to tear out the pcb traces between the relays and the ends of the filters and bodge in some shielded cable in their place??
This fix reduced the spurs by up to 10 db? and requires ONLY ONE
part to be added.
There is big change above 10MHz in the board. There is some improvement
below also.
The way I did it, CW may not work anymore will
need some more mods for CW:
1. T2 - desolder the transformer wires that go to pin 3 and 5. Pin 1
has a square pad.
2. Bring out the two wires above board and join them together and
solder.
3. Take a 45Mhz filter- 45M15 or? similar 2 pole - one xtal only.
Solder one end of filter
to the wires of T2 pulled out. The center filter wire to ground at one
end of R26. You will
see a ground via there.
4. Solder the third wire of filter to C10/R27 junction.
Thats it! This prevents the leaked TX signal that gets amplified by the
1st BiDi from getting into
the first mixer and creating havoc.
Farhan method of the same..much simpler and CW will work.
1. Remove R27
2. Solder the 45Mhz filter two extreme ends to the pads of the
resistor.
3. Solder the center lead of the filter to the nearest ground. R13 is
very near with a ground via.
The first method the extra filter will work in RX mode also and may help!
In the second the
filter is only in the TX path..
Folks with DSA815 or better please share your feed back. The filter may
work better properly
terminated etc.
Have fun!
--
Raj, vu2zap
Bengaluru, South India.
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On Thu, Sep 6, 2018 at 10:35 AM, ajparent1/KB1GMX wrote:
Seriously?? ?The easy way is remove the part.? To put it inline you have to cut a trace, no?? Sure you could?
but why?
That's what I am asking: would leaving in the R and C disrupt the circuit less?
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I suggest looking at these:
--Ron? ?N7FTZ
Hi Allison.
Thanks for the explanation, I see where I was confused now...
So is a?TOYOCOM 612S07? just a crystal, a filter, an oscillator? can find much on that part...
Would it not be even better to then implement the complete 45mhz filter prior to the mixer?
73
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Hi Allison.
Thanks for the explanation, I see where I was confused now...
So is a?TOYOCOM 612S07? just a crystal, a filter, an oscillator? can find much on that part...
Would it not be even better to then implement the complete 45mhz filter prior to the mixer?
73
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Farhan,
Testing says buffers work The SN74AUP1T04 inverter one per package
(4 pins like the mmbt3904s) or the 74LVT04 (6 per)work well.
I can do that with transistor or Fet but then I need bias and other parts
as both have thresholds to hit and we want them to work at 80mhz
or higher.
That alone makes it harder to use just cheap devices.
Allison
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Nick,
>>Which is better R27 or C22? or neither and just put it in-line with R27/C22 leaving those components un-touched?
Seriously?? ?The easy way is remove the part.? To put it inline you have to cut a trace, no?? Sure you could?
but why?
>>Also, just thinking a bit her out of the square, Does it have to be 45mhz crystal? could something else close, but easier to get hold of work too?
Could someone with some technical understanding give us a quick rundown as to what this is doing under TX conditions? I assume, its to block the 45mhz IF from making it back to the previous stage?
First you going the wrong way!? Your not out of the box you are flailing. The direction is toward the power amplifier.? No its not blocking
anything at 45mhz, its to allow only 45mhz through and not other stuff that is not 45mhz and catching a free ride.? A crystal might work
if implemented right it still has to be 45mhz (good luck finding one)?and if you asking these questions you do not understand filters and
their use.? ? Based on a suggested oscillator you have less concept of crystal filter and a complete package oscillator.? They are sorta
different.
For you:
Oscillators generate signals.? An active device.
Filter allow or disallow the passage of certain signals based on frequency.? Usually but not always a passive device.
Allison
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Gee, I grew up with Lafayette radio and Harrison radio so that goes well back over a half century.
Never mind other places like that.
Pretty much post WWII the industry for parts and radios existed.? Either that or the late 50s
Hallicrafters HT37 and S110 were only sold mail order and hams had them along with
Collins, Drake, Ameco, and a list longer than my arm.
That said there were always kits and kit sources and howto books and magazines.? ?My Eico 710
grid dipper from then confirms that and a few others like the 680 multimeter/transistor tester I
depend on still.??
However with Arduino and SI570 and 5351, cheap transistors and parts I can say its
never been better.? The internet has improved on the magazines QST, HamRadio,
73 magazine, Popular Electronics, and Radio Electronics.? More information and
?readily available often free.? I remember the library when that was the only place for
information and it was free..
?So ubitx, it has warts.? Fix them, its not impossible nor is it that hard.? Many solutions
have been offered.? ?
Allison
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Du machts einer Witz ??? ?Perhaps a stone in a a settled pond.. and interference patterns will radiate..
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Re: Ubitx V3 Please Help, ANTENNA Pins on PCB have SHORTED no Receive
#ubitx
#ubitx-help
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a 45mhz crystal is a stone....
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All may not be lost. The spurs start as you start to draw power. So, don't draw power. A source/emitter follower will lightly load the si5351 outputs. Buffering helps. There are other ways to use multiple si5351s. A simply solution is to use analog muliplexers to switch the i2c lines between multiple devices.?
On Thu, 6 Sep 2018, 05:36 ajparent1/KB1GMX, < kb1gmx@...> wrote: There are a raft of bidirectional switches that would work for two or 3.
Allison
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On Wednesday, September 5, 2018, 11:21:48 AM PDT, ajparent1/KB1GMX <kb1gmx@...> wrote:
On Wed, Sep 5, 2018 at 11:09 AM, Lev likely copied: 4. RF transistors (BFS17P) Yes, we could use something better than 2n3904's in places. Though using buckets of $0.02 2n3904's/mmbt3904's (at lower gain where appropriate) has a cost and stocking advantage. If used right but they are not good at high currents. The BFS17P? is a really weak device.? Max collector current of 25ma, FT of 1.4ghz, 15V mac collector voltage.? Good enough for q90 only! I suspect very few have an idea of how amplifiers in RF power chains work. Bingo! ...I got some 2sc9018's I am going to try after I finish sorting out some of the other stuff ..Look like a reasonable direct replacement for the 3904's
Jim
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I'm sure you missed the question from the person asking for the
same thing of the V3 board.?
The answer is does not exist or has not been published.
Allison
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Re: Personal Best Distance, SSB Phone
#ubitx
Thanks! ? David A Posthuma, President E-Church Essentials, LLC
Author: Author: 1-800-724-1159 1 (616) 283-7703 ?
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From: [email protected] <[email protected]> On Behalf Of Don, ND6T via Groups.Io
Sent: Wednesday, September 05, 2018 7:56 PM
To: [email protected]
Subject: Re: [BITX20] Personal Best Distance, SSB Phone #ubitx ? David,
I don't spend much time on line but my email is good on QRZ (yours isn't posted there) and on my web site, too! I try to check my mail at least once a day.
Anyway, if you put the AGC or the RF gain control in backward it is no big deal. Maybe a couple of dB difference.
Like in wiring the encoder, if you find that you have it backward then just reverse it. Unlike wiring up a whole new circuit, this is just two connections.
Don't worry, just have fun! -Don
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There are a raft of bidirectional switches that would work for two or 3.
Allison
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Where can I find a drawing of the current version 4 PCB without parts overlaid?
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Use this I2C MUX.? I¡¯ve used it before with great success¡ ?
? MRM ?
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From: [email protected] [mailto:[email protected]] On Behalf Of Glenn
Sent: Wednesday, September 5, 2018 5:11 PM
To: [email protected]
Subject: Re: [BITX20] si5351 crosstalk #radiuno ? It's a shame the manufacturers didn't put 2 more pins on the chip and use them as I2C address select lines.
Right now, the only way i can see to use multiple (10pin) Si5351's in a rig is to have say, an ATtiny or similar 8 pin uP to program it on power up. Or as commanded by the master uP.
glenn -- ¡_. _._
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Re: Personal Best Distance, SSB Phone
#ubitx
David,
I don't spend much time on line but my email is good on QRZ (yours isn't posted there) and on my web site, too! I try to check my mail at least once a day.
Anyway, if you put the AGC or the RF gain control in backward it is no big deal. Maybe a couple of dB difference.
Like in wiring the encoder, if you find that you have it backward then just reverse it. Unlike wiring up a whole new circuit, this is just two connections.
Don't worry, just have fun! -Don
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Ver good response and I agree with the sentiment. ?? Amateur Radio is just that Amateur.? In the past there were no places like Yaesu, Kenwood, Icom, Alinco,? making specialty Ham radios.? There were not places like HRO, AES, or other places to go "Buy" the
nice ready made radios.
In the old days Hams built, modified, or repurposed old commercial grade gear to use on the Ham bands.? We are blessed today to have all the ready made equipment built to commercial standards.? However there are still some Hams who want the challenge of building
their own. ? I think that this and projects like it are a wonderful thing for these hams.? Its not perfect and maybe some modifications can be utilized to make it better but please don't condemn those who do the old time construction and experimentation.?
Especially when they are courteous enough to know to operate in such a way as they do the least to interfere with those around them.
All the best to you all
Chuck
WA5ZTD ?? (Just an old time extra)
All the best to you
Charles T Dennis?
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He didn't say "it'sOK to violate FCC regulations, if you do not annoy anybody," he reasonably said:
1) the conversation on spurious emissions went over his head
2) he's only using the radio when the band seems quiet, so if he is spewing spurious emissions he isn't likely to bother anyone
Amateur transceivers are not held to the same signal purity standards as say a broadcast transmitter, and it is unreasonable to expect every ham to invest in sophisticated testing apparatus to constantly monitor their radio's emissions in real-time.
The vast majority of hams buy their radios from major manufacturers and rely on them to build s quality, properly designed radio that meets all spectral purity requirements.
A smaller, but not insignificant, number of hams refurbish older radios and put them on the air and make good faith efforts to ensure the radios operate within present regulations to the best of their inherent design limitations.
And then there are a number of hams that take a pile of parts and solder and conjure up a radio that they believe complied with all applicable regulations, but most lack the training/resources to prove their creations comply with all regulations.
The one thing all three broad groups have in common, is that if made aware of a spectral issue with their equipment, they make every effort to correct the issue. Every ham I know, and I feel I know a pretty wide cross section of hams, take pride in their radios
and wants them to perform to the best of their abilities - I've never heard anyone say, for example, "I don't care about the second and third harmonics of my Chinese HT - as long as I can hit the local repeater I'm happy!"
The OP said nothing wrong, and shame on you for distorting what he said to give you an excuse to question him.
Ken, N2VIP
> On Sep 5, 2018, at 10:20 AM, RICHARD <k6kwq@...> wrote:
>
> So it¡¯s OK to violate FCC regulations , if you do not annoy anybody? How do you know?
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Nick VK4PP
David Posthuma
MadRadioModder
Don, ND6T
Chuck Dennis W5CTD