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Re: VK4PP uBitx LPF BANK add-on Board
Timothy Fidler
MRModder it is not so much a a mess. If they realise they cannot safely add an amp and they spin the dice as far as a letter from the FCC/SMA then the sun rises each morning much the same.? The issues for them will be overtaxed components,? vias not fully plated through and needing a soldered in copper stub? and such like.? I guess they did nto figure on getting component removal and SMD soldering skills when they signed up. Bit like the Army or Marines. have to Man up? and tool up? ?:-))? Perhaps? A F could put something like that in his advertising Spiel .. So saith Don Draper... Perhaps not.
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Timothy E. Fidler : Engineer BE Mech(1) Auckland , NDT specialist AINDT UT /RT3 , MT2?
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Re: KD8CEC v.1.095 CW Issue
#ubitx
#ubitxcw
#ubitx-help
¿ªÔÆÌåÓýI have a 3.5 and am patiently waiting on Alan Merrill to update the 3.5 lcd. You can load the released Hmi/tft but will only fill out 3/4 of the larger lcdsOn Sep 2, 2018, at 5:00 PM, Art Olson <olson339@...> wrote:
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Re: KD8CEC v.1.095 CW Issue
#ubitx
#ubitxcw
#ubitx-help
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On Sep 2, 2018, at 5:00 PM, Art Olson <olson339@...> wrote:
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Re: VK4PP uBitx LPF BANK add-on Board
RICHARD
¿ªÔÆÌåÓýNot surprised at all, the number of hams that ignore the problem and operate any way Bring back the wofhong ? Sent from for Windows 10 ? From: [email protected] <[email protected]> on behalf of dfine100@... <dfine100@...>
Sent: Sunday, September 2, 2018 12:38:34 PM To: [email protected] Subject: Re: [BITX20] VK4PP uBitx LPF BANK add-on Board ?
I would think that Farhan should put a disclaimer on the hfsigs website stating that the ubitx does not meet some countries (i.e. USA) specifications for legal operation and that it will take a considerable
amount of modification to make it meet those specs.? I agree that most new hams buy it thinking all they have to do is connect a few cables and the have a legal ready to go transceiver, when in fact they could buy a used 100 watt transceiver for not much more
money that would meet specs.? That's my $.02 opinion.
W0DF
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Re: UBITX TX level diagramme
MRM,
An example of a DBM radio and oldie is the Atlas180 and friends (210, 215 210x...). a really simple radio once you cut to the bone. They use band pass filters for RX and TX pre-power amp and low pass post amp to take out harmonics.? It was the standard of the day and still is.?? So is the case for bitx20V1, Bitx17, bitx40 and other variations and flavors. Filter using band pass you get clean, low pass is not adequate filtering save for harmonics. Allison |
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Re: UBITX TX level diagramme
On Sun, Sep 2, 2018 at 12:45 PM, Henning Weddig wrote:
The result is intersting: als Allison already stated the gain of the TX stage after the first mixer is 48 dB under these assumptions. My guess is that "normally" a lower level (-10 dBm) will do better in respect of IMD resulting in nearly 60 dB of gain!Doesn't sound at all correct.? Since the mixer output is in the near -20dbm you need 60db of gain to achieve +40DBm (10W).? ?I believe I've been saying at least 60db is the target for some time.? What we get is far less but that an amplifier design issue. FYI most that get maybe 1.7w at 10M are getting far less maybe 48-50db at 10M. Most level 7 mixers for "clean" (quoted as they are never pure or clean) output need an input 10db less than the LO drive minus the insertion loss of the mixer.? So we start at 7dbm (or up to 10 dbM) of LO and that means input max is -3dbm -another 7db for the mixer loss or minus 10dbm (-10).? Than another 2-4db loss for a bandpass filter if done right so you at -14.? So you can if lucky get away with 54 db of gain but you need a tiny bit more for losses and errors.? That is idealized sometimes? you can push the mixer harder, but you get more unwanted products. uBitx case is more complicated as you have ground currents inducing signals where they should not be and a lack of filters to scrub the output.? Now add to that a output low pas filter system that is compromised by layout.? Now you have a mix of signals that should not be there at all mixing with those that should be plus excess gain in the IF to overdrive the RF starved ( I measured not more than 3dbm at the mixer) mixer, output contains a lot of not mathematically predicted outputs because there are inputs not recognized like a sample of what the power amp is putting out ( coupling though incidental and current loops). So for a simple 3.5mhz output the mixer may have 45mhx, 48mhz, 3.5mhz, 7mhz, 14mhz, and on with unpredictable levels and those are the likely inputs the output products are .[...]? many! Now I did try a 45mhz low pass and it helped a little, less than 6db.? Reason was simple you have unpredictable paths (ground currents, DC supply lines with RF...) you cannot stop.? But some are also the nature of the?DBM and cannot be filtered with a low pass filter.? An example of that is the 2IF (90mhz) mixing with the LO (we will use 28Mhz) of 73mhz to get both 28mhz output and 90-73 or 17mhz.? A low pass cannot prevent the 17mhz if it is to pass 28mhz.? Also the existing 33mhz low pass reflects sum products back the mixer so figure all the possible sums returning to the mixer. Remember a DBM is both a 4 quadrant multiplier and a chopped sampling system the products out suggest both as its linear and no linear.? With clean 45mhz you still get diode limited and squared 45mhz with harmonics circulating internally. In short you have to map all the possible signals that may exist and their unwanted return paths and then do the matrix of sums and differences for the fundamentals and their harmonics. IT made my head hurt and spurtune went nuts listing all of them though the 11th order. By then levels are no longer an issue. Allison |
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Re: KD8CEC v.1.095 CW Issue
#ubitx
#ubitxcw
#ubitx-help
¿ªÔÆÌåÓýVery good. Is version 1.097 stable yet? Are you using it personally? ? David A Posthuma, WD8PUO 1 (616) 283-7703 ? From: [email protected] <[email protected]> On Behalf Of Art Olson
Sent: Sunday, September 02, 2018 5:01 PM To: [email protected] Subject: Re: [BITX20] KD8CEC v.1.095 CW Issue #ubitx #ubitxcw #ubitx-help ? It¡¯s in version 1.097
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Re: KD8CEC v.1.095 CW Issue
#ubitx
#ubitxcw
#ubitx-help
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On Sep 2, 2018, at 4:53 PM, David Posthuma <davep@...> wrote:
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Re: KD8CEC v.1.095 CW Issue
#ubitx
#ubitxcw
#ubitx-help
¿ªÔÆÌåÓýBelieve you can push the tune button and dial to setup? ?The deselect until you get to change key. The menu is still there. I am not sure but think you can change it via the screen using 1.097Art On Sep 2, 2018, at 4:39 PM, David Posthuma <davep@...> wrote:
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Re: KD8CEC v.1.095 CW Issue
#ubitx
#ubitxcw
#ubitx-help
¿ªÔÆÌåÓýKD8CEC ?V.1.095 FEATURE REQUEST ¨C RE: CW Settings. Overall, I love what you have done with version 1.095. However, I wish the CW settings could be managed better. It appears that the only way to change key-type and speed is to push the main encoder, make sure Setup is On, and then find the CW type menu item. In the next firmware revision, can we have the table in the bottom left corner of the display that communicates CW information be selectable and bring us right into a large on-screen menu to make these menu selections one level deep instead of 4-5 levels deep in the menu structure? As it is, CW settings are not intuitive and it¡¯s a bit cumbersome to work with. ? Please forgive my critique, your work is truly incredible, ? David A Posthuma, WD8PUO 1 (616) 283-7703 ? From: [email protected] <[email protected]> On Behalf Of David Posthuma
Sent: Sunday, September 02, 2018 4:39 PM To: [email protected] Subject: Re: [BITX20] KD8CEC v.1.095 CW Issue #ubitx #ubitxcw #ubitx-help ? Mike: ? The 1.095 firmware screen reads ¡°straight¡± for key setting, but when I go into the menu, I cannot find anywhere to change that setting. Nor is the screen label on the screen selectable to change it????? I would think selecting Key-type and keying speed should be a very easy change right from the touchscreen main screen. But I am unable to change any of these settings. ? David A Posthuma, WD8PUO 1 (616) 283-7703 ? From: [email protected] <[email protected]> On Behalf Of Mike Woods ? David
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Re: KD8CEC v.1.095 CW Issue
#ubitx
#ubitxcw
#ubitx-help
¿ªÔÆÌåÓýMike: ? The 1.095 firmware screen reads ¡°straight¡± for key setting, but when I go into the menu, I cannot find anywhere to change that setting. Nor is the screen label on the screen selectable to change it????? I would think selecting Key-type and keying speed should be a very easy change right from the touchscreen main screen. But I am unable to change any of these settings. ? David A Posthuma, WD8PUO 1 (616) 283-7703 ? From: [email protected] <[email protected]> On Behalf Of Mike Woods
Sent: Sunday, September 02, 2018 2:45 AM To: [email protected] Subject: Re: [BITX20] KD8CEC v.1.095 CW Issue #ubitx #ubitxcw #ubitx-help ? David
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Re: VK4PP uBitx LPF BANK add-on Board
¿ªÔÆÌåÓýNice and simple.? Why don¡¯t you give us the OSHPark link and we can just order some of these instead of designing our own¡? ? ? From: [email protected] [mailto:[email protected]] On Behalf Of James Lynes ? Received my version of an external LPF board from OSHPark. To second Jerry's comments, OSHPark has a very nice front end process. ? This board is 1.5in by 3in sized for T68 cores and 1206 caps to provide flexibility for use in future projects. Footprints are provided for both BNC connectors and header pins for input and output. ? Get a copy of "Make Your Own PCBs with Eagle" by Simon Monk and you can make your own boards for the investment of a small learning curve. ? James KEMIQ ? -- ¡_. _._ |
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Re: VK4PP uBitx LPF BANK add-on Board
James Lynes
Received my version of an external LPF board from OSHPark. To second Jerry's comments, OSHPark has a very nice front end process. This board is 1.5in by 3in sized for T68 cores and 1206 caps to provide flexibility for use in future projects. Footprints are provided for both BNC connectors and header pins for input and output. Get a copy of "Make Your Own PCBs with Eagle" by Simon Monk and you can make your own boards for the investment of a small learning curve. James KEMIQ |
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Re: UBITX TX level diagramme
Thanks for doing this. The diagram is very informative (need this diagram for the uBITx too). You are correct but a BPF (not LPF) after the mixer is probably better since the mixer is where most of the real nasty harmonics originate...
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-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Henning Weddig via Groups.Io Sent: Sunday, September 2, 2018 2:46 PM To: [email protected] Subject: [BITX20] UBITX TX level diagramme All, in preparing my talk to be held at the "UKW-Tagung" in Weinheim Germany next Saturday about my UBITX I prepared a level diagramme with some assumptions: the maximum powe rlevel at the input of a mixer is in the range of -1 dBm (near the 1 dB compression point?) The result is intersting: als Allison already stated the gain of the TX stage after the first mixer is 48 dB under these assumptions. My guess is that "normally" a lower level (-10 dBm) will do better in respect of IMD resulting in nearly 60 dB of gain! Another guess for the resultant spurs observed at higher output frequencies: the bidi amp (45 MHz) is not free of harmonics, i.e. also can and will produce harmonics! If true, these harmonics could be easily removed by introducing a low pass filter between the mixer ("45 MHz port") and the mixer itself. Who can and will try this mod? Henning Weddig DK5LV --- This email has been checked for viruses by AVG. -- ¡_. _._ |
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Re: Perspex Case
¿ªÔÆÌåÓýBoom Box uBITx¡ ? ? From: [email protected] [mailto:[email protected]] On Behalf Of george.ellis@... ? Just couldn¡¯t hide the beautiful electronics ? -- ¡_. _._ |
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UBITX TX level diagramme
All,
in preparing my talk to be held at the "UKW-Tagung" in Weinheim Germany next Saturday about my UBITX I prepared a level diagramme with some assumptions: the maximum powe rlevel at the input of a mixer is in the range of -1 dBm (near the 1 dB compression point?) The result is intersting: als Allison already stated the gain of the TX stage after the first mixer is 48 dB under these assumptions. My guess is that "normally" a lower level (-10 dBm) will do better in respect of IMD resulting in nearly 60 dB of gain! Another guess for the resultant spurs observed at higher output frequencies: the bidi amp (45 MHz) is not free of harmonics, i.e. also can and will produce harmonics! If true, these harmonics could be easily removed by introducing a low pass filter between the mixer ("45 MHz port") and the mixer itself. Who can and will try this mod? Henning Weddig DK5LV |
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Re: VK4PP uBitx LPF BANK add-on Board
I would think that Farhan should put a disclaimer on the hfsigs website stating that the ubitx does not meet some countries (i.e. USA) specifications for legal operation and that it will take a considerable amount of modification to make it meet those specs.? I agree that most new hams buy it thinking all they have to do is connect a few cables and the have a legal ready to go transceiver, when in fact they could buy a used 100 watt transceiver for not much more money that would meet specs.? That's my $.02 opinion. W0DF |
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