Kees,
With what HFsignals used it would left to the transformer symmetry.
The testing was part of the what int he world is going on after spurs were spotted.
Allison
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Allison,
If the old reliable standby SBL-1 mixers didn't make any difference (thanks for testing), I would guess the HSMS-282R would not do any better, ......although I've had luck with the HP "die matched" pairs/quads before.
73 Kees K5BCQ
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Hello Nick,
When the boards are received and you are ready to take orders how would you like to be compensated, PayPal.
Thank you? Ripley KD8UYQ The words are mine but this iPad does what it will with them.
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On Sep 12, 2018, at 6:17 PM, Nick VK4PP < nickpullen@...> wrote: On Wed, Sep 12, 2018 at 11:39 PM, Michael wrote:
Would also like to order 4 of the filter boards. Let me know how
HI Everyone, Boards should be around 2 weeks, i took the cheap option for shipping... 73 Nick
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Re: K5BCQ uBITX Relay Switched LPF/BPF board
Hello Kees,
Will your proposed mods here change the case requirements for the uBitX.? I have a? case?I was planning on using.? Its a great case for portability and the stock uBitx?fits - just ;-).
-John
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Re: uBITX Firmware CEC Version 1.1 Release
#ubitx
Your accomplishments are massive when viewed in one big list.
Basically you have changed our little Chevy into a nice big Caddy! ?
My little ubitx is making contacts with my mag loop INDOORS!
Take a break before you start into more mods.
73, Bo W4GHV?
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As far as the firmware is concerned, for monoband operation you could use the latest Raduino sketch v1.28.1.
This includes the latest enhancements such as spurious prevention, CW keyer, capacitive touch keyer, improved calibration, etc.
To modify it for 80m, just change the defines for MIN_FREQ and MAX_FREQ at lines 36 and 37.
And set Region to 0 at line 47.
73 Allard PE1NWL
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How about replacing the 2N3904 in the Bi-di amp with BFR106? as with Q60 pre-driver?
Would that help in making them more linear?
73 Nick VK4PP
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On Wed, Sep 12, 2018 at 11:39 PM, Michael wrote:
Would also like to order 4 of the filter boards. Let me know how
HI Everyone, Boards should be around 2 weeks, i took the cheap option for shipping... 73 Nick
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I just checked?? ?
covers 80 40 20 15 10? so in fact the code is already there and supposedly tested and contains all the ALLARD Brillig enhancements too.. which is a bonus. CW etc etc.
but? how you do the band switch in ferrite and copper? is up to you - nb a couple of LPF boards are in? the works.? Because the Raduino is already packed,? a rotary switch for band select is the/a? sensible and crude option.? It makes sense to try to retain 40 as well as 80mtrs in? a switchable form.
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Kees,
The mixers are already using monolithic diode pairs.? Going to diode quads might help balance
but I can say replacing the mixers with packaged Tuf-1 or SBL-1 made not one bit of difference.
However having an amp that by 20M can barely apply 150mw(clean) to the finals and is
struggling to do that because its prior stages are also gain impaired has a lot to do with that.
So then people people harder to get the 10W they "paid for" which is mostly IMD and splatter.
Allison
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It would be better to put all of this on the main board as close to its landed destination as possible.? Just send the I2C to the main board. ? ?
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From: [email protected] [mailto:[email protected]] On Behalf Of Kees T
Sent: Wednesday, September 12, 2018 9:52 AM
To: [email protected]
Subject: Re: [BITX20] si5351 crosstalk #radiuno ? Jerry,
Would you suggest mounting those three 74LVC1G04GW parts on the Raduino board, close to the Si5351? ?
73 Kees K5BCQ -- ¡_. _._
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Since homebuilt diode DBMs are quite "touchy" what about using a better matched diode ring quad mixer like the HSMS-282R.?
Maybe this should be in the "spurs" thread
73 Kees K5BCQ
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Does he have a true 3.5 version available for download? I notice the link has the tft only. Is the hmi available?
--
N5KBP
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100% agreed.
--Ron? ? n7FTZ
On Wed, Sep 12, 2018 at 10:13 AM Lawrence Macionski via Groups.Io <am_fm_radio= [email protected]> wrote: Daniel-
I've been studying and building antenna's for 52 years.. Here's some things I've concluded:
With regard to uBITX (under 300 watts) operation:
#1. The guy that tells you, you need a balun for a dipole, Usually is the guy that is selling them. They can be made for $5 or less. Markup is huge.
#2. You need no better than RG-8X coax... Unless:
?????? A. Your coax run is over 75 feet? and used to 148Mhz. (27ft per dB loss -under 3dB which is 1/2 power) negligible loss.
?????? B. Your coax run is? 150 feet or less? under 30Mhz. (63ft per dB @28.4Mhz- under 3dB or less on lower bands) negligible loss.
?????? C. You are not running over 650 watts (approximate)
#3. There is no "secret sauce" when? buying a manufactured antenna.
?????? A. One manufacture makes antenna's in colors and that is their #1 selling point.
?????? B. Virtually none come assembled, so you have to put them together anyhow and tune them.
?????? C. Markup on materials is 4-10x, so you get a "kit of parts" they put together for you. (and pay for the "secret Sauce"
#4. If you can't afford Antenna books, your local public library will get you any Antenna Book with an Library of Congress number.
????? A. My antenna books stacked on the floor are Knee high.. 20+ years ago I paid $52 for John Krause's Antenna Theory.
????? B. Authors such as Lew McCoy, John Krause, R.L Cibek, Joe Carr, anything sold by ARRL are authoritative. This is a start, there are others.
#5. Regarding coax in #1... Reference QST October 2017 page 72.
#6. Remember? 3dB loss can be measured with instruments but never detected by ear.
#7. An antenna constructed with sound engineering plans will get you on the air.? Having the test equipment/ tuners is optional (OCD frankly)
#8. Watch them bash my sound advice.. Yet some will also agree with me.
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Gordon,
1. ?Fixed external filters, changed manually (no software change)
2. ?Replace the right-hand side of the relays with a daughter board as I did. (no software change in the way I implemented it)
3. ?Replace all the relays & filters ?with an external daughter board (May or may not require software change). Hey or may not use the existing components, might use all new components
4. ?There was even a commercially available multiple relay system that could be pressed into service.?
5!
Rip up the relays.? Remove all the traces under them. Install the relays from the underside of the board
and rewire with short direct wires to revised hook up.? Sounds nasty but I've tested and it fixes the problem.
It was the spaghetti wiring you do not see under the relays doing bad things.? ?This is not the full procedure
and details but a solid outline.? The relays get wired up so only one is in use at a time and the DC feed
under them gets rerouted as wires but there are a few hidden fixes to other things that comes from that.
Allison
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HI all,
I've started on that in the wiki and its not a small task.
Also some of the fixes are not "settled" with conflicting approaches.
Right now the best and most complete is Ubitx.net.
Allison
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Farhan,
Yes, Si5351 crosstalk may not be a problem worth chasing for most.
Though a hack to the 6dB pads would be quite easy to do, if that does help.
In addition to RX birdies, I can believe si5351 crosstalk might contribute to spurs on TX.
Though Raj's extra 45mhz filter seems to bring down all spurs well enough, and that occurs
before clk2 enters the mixer.?
Having 12mhz get into clk1 will contribute to carrier leakage on TX.
But residual carrier is not a deal breaker for most of us.
I'm thinking of you and your parents.
I know from experience that these health issues can be all consuming.?
Wishing all of you the best.
Jerry, KE7ER
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On Wed, Sep 12, 2018 at 11:16 AM, Ashhar Farhan wrote:
the si5351 cross talk is not causing either distortions or harmonics. it can result in the birdies, but that's about all.
?
the spurs in the 57 MHz and the 12 Mhz clocks are confined by the following filters at 12 Mhs and 45 Mhz. The only spurs that you have to actually bother about (only on the rx side) are those in the first mixer's oscillators.
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On Wed, Sep 12, 2018 at 10:50 AM, <terryhugheskirkcudbright@...> wrote:
hi
i am still waiting for the delivery of my bitx40 but while waiting i am pondering
i have 40 and 20 using my trio ft520 and dipoles.
but i do not have enough room for an 80 m dipole so i have built a qrp atu and erected an end fed long wire for 80.
there is no way to reduce the 200w from the trio to use a qrp atu so the answer is the bitx40. 200 wats would be like a pan galactic gargle blaster to my atu !!
but i need to hack the bitx40 for 80
nd6t has published a hack for 60 m which involves adding parallel caps to c2, c4, c6 and across l7
so i modeled the bpf and lpf using aade program with 560 pf across c2,c4,c6 and 390 across l7 and the plots look good for 80 m . the sketch also has to be hacked but that is not a problem as i am a retired computer programmer.
What do people think about the? thoughts of an idle fellow.
73 de terry gm4dso
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the si5351 cross talk is not causing either distortions or harmonics. it can result in the birdies, but that's about all.
the spurs in the 57 MHz and the 12 Mhz clocks are confined by the following filters at 12 Mhs and 45 Mhz. The only spurs that you have to actually bother about (only on the rx side) are those in the first mixer's oscillators.
On Wed, Sep 12, 2018 at 11:19 PM, Vince Vielhaber <vev@...> wrote: I've always used an ADA-4789 for DDS buffering.? 50 ohm in and out, single supply and good to 2.5 GHz.
Vince - K8ZW.
On 09/12/2018 10:40 AM, Jerry Gaffke via Groups.Io wrote:
I suspect it is more critical that we have sufficient drive into the
mixer LO port
than to have that 6dB 50 ohm pad.
This sort of thing is best evaluated by somebody with a spectrum analyzer.
A series cap plus series resistor between the si5351 and the mixer may
be sufficient,
the resistor value is a compromise between sufficient drive to the mixer
and minimizing how much power we demand from si5351.
Could also add a resistor from mixer port to ground to bring source
impedance there down,
though that further reduces drive available to the mixer
? ? /g/BITX20/message/35206
The CMOS buffers previously mentioned are good down to about a 100 ohm load,
? ?/g/BITX20/message/59200
Use separate devices for each clock to avoid crosstalk, and filter Vcc
well.
If you insist on driving 50 ohms with CMOS buffers you might put two
such gates in parallel:
Often you see an MMIC in that position, but we don't have to be linear here.
The diode mixers work well with a square wave.
Jerry, KE7ER
On Wed, Sep 12, 2018 at 12:08 AM, Tom, wb6b wrote:
? ? How critical is the impedance the mixer sees?
? ? Possibly another good reason for a buffer where you can control the
? ? impedance better.
? Michigan VHF Corp.? ?? ?
? ? ? ? ? ? ? ? ? ? ? ? ?
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Distorted audio is easy enough for us to be aware of,
even if we cannot all measure it accurately.??
Spurs and harmonics are more apt to slip by unnoticed,
and can wreak havoc outside the ham bands.
Most of the reports in the forum about bad audio seem to come down to
a BFO not placed correctly with respect to the 12mhz filter,
or a poorly shaped 12mhz filter passband.?
Perhaps some are due to IMD, and we simply have not been aware of that aspect.?
But many here report good sounding audio.
In most cases, distortion due to IMD will go down with lower audio levels into the mike.
This will not help if the issue has to do with the 12mhz filter shape or BFO placement.
These levels of IMD should not be ignored.
I'm hoping there will be a v5 with much improved IMD specs.
We may eventually come to some easy partial fixes on v3 and v4,
but a complete fix may require a significant redesign.
Jerry, KE7ER
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On Wed, Sep 12, 2018 at 10:22 AM, Warren Allgyer wrote:
There is is nothing illegal about putting distorted audio in the air. But I would not do it.?
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Ripley
John Scherer
Allard PE1NWL
Nick VK4PP
MadRadioModder