Just one step at a time ....Did replace R97 and R98 (47 ohm) on the mosfets gates with 10K resistors ...Improved drive and output Now Q90 is going into limiting at -17 dbm...Gotta check/redo the bias there (limits on + side so R81 is too small probably ..Get it to limit symmetrically and then see whats what
Pulled Q912 and Q's 92,92,96.97?? Can always put em back
Jim
On Sunday, September 9, 2018, 8:06:54 AM PDT, ajparent1/KB1GMX <kb1gmx@...> wrote:
Jim, The problem was I was peeling a very pungent onion. Allison
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Re: Right-sided relay harmonic attempted fix for v3/4 ubitx
Hello Gordon,
Good to hear. I am looking forward to purchasing a few.
Ripley The words are mine but this iPad does what it will with them.
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On Sep 9, 2018, at 4:58 PM, Gordon Gibby < ggibby@...> wrote: Hi folks....
25 new blank boards for the simple-minded right-sided relay board fix are supposed to arrive from China on Tuesday.? ?If so, I'll re-enable? the Ebay advertisement and up the "count" (a learning experience) on Wednesday.? ?Was able to mail out five boards on Friday before leaving on a camping trip.? ?Hope they arrive OK!!!? ?I figured out how to mark them as "shipped" and send a note to each purchaser through Ebay.? ?With all the SPUR FIXES now being discovered, things are really shaping up around this little transceiver to make it have much fewer spurious responses.? ?Delighted to see the group progress.? ?Each person proceeds at? their own pace, but the group moves forward huge amounts.
Cheers,
gordon KX4Z
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Warren,
Impressive plots and visually shows the effect of better filter matching, including what happens to the filter skirts. Now what to do about further gain reduction which also helped reduce the spurs.? ?
73 Kees K5BCQ
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Just eyeballing the schematic, it looks to me like the source impedance for a filter replacing R27 would be about 400 ohms. I have no idea how to calculate the output impedance made up of the bifilar winding on T2 and it is likely to be different based on frequency. The best bet in this circumstance would be to assume a low impedance for the output of the filter transformer and probably no transformer would be needed for the input (the Q21 side). The two effects if it is a wrong assumption will be too low gain and a tilted passband. Too low gain is probably not a problem since we are trying to take some out. Tilted passband can be checked by sweeping a tone input from 300 - 2700 Hz and watching the output power. Variation more than 3 dB is probably unacceptable and both USB and LSB should be checked.
WA8TOD
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Re: M1 and M2 tied together effect.
Kees,
I have done this with success, I will send a picture soon of how.
But basically, remove R70, bridge the front pad to the adjacent track, cut the adjacent track and short the relay sides of both tracks to ground...
I attach the pop fix the this point too.
73 Nick VK4PP
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Great John! Just be aware, I do not know what the true interstage impedances really are. Maybe that has been calculated or stated in the past but I have not seen it that I remember. The actual impedances should be used and not just assume it is 50 ohms. I assumed that only for this proof of concept. It is pretty clear from the traces if you assume 600 ohms for the filter though, you will be close enough.
WA8TOD
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Re: Right-sided relay harmonic attempted fix for v3/4 ubitx
Hi folks....
25 new blank boards for the simple-minded right-sided relay board fix are supposed to arrive from China on Tuesday.? ?If so, I'll re-enable? the Ebay advertisement and up the "count" (a learning experience) on Wednesday.? ?Was able to mail out five boards on Friday before leaving on a camping trip.? ?Hope they arrive OK!!!? ?I figured out how to mark them as "shipped" and send a note to each purchaser through Ebay.? ?With all the SPUR FIXES now being discovered, things are really shaping up around this little transceiver to make it have much fewer spurious responses.? ?Delighted to see the group progress.? ?Each person proceeds at? their own pace, but the group moves forward huge amounts.
Cheers,
gordon KX4Z
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Hi All
Really sorry to ask this, but I'd appreciate your help setting up my uBitx. I've read countless ways of calibration, from KD8CEC and others on here, but cannot fathom how to get it right. What exactly is 'zero beat', do I select LSB or USB when setting it up? When I htink I've got it set I find out the sidebands are swapped (compared with a websdr site)
I've borrowed a 10.7MHz crystal marker that transmits a 1khz sine wave. I can pick this up with the box off. An app on my phone can generate a 1khz sound too. I've also got a picoscope 2105 with 25Mhz bandwidth if that helps. I'd appreciate some pointers what to do, what to look out for.
Many thanks
Graham
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Per Warren's suggestion I build a pcb with impedance transformers and I checked before and after and the spurs are very low now relative to pre-filter. I'll post a photo of my installation.
John
KC9OJV
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Pretty impressive differences!
On Sep 9, 2018, at 15:23, Warren Allgyer < allgyer@...> wrote:
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Here we have the eBay filter between a pair of 12:1 transformers (purple) wound 7:2 on a BN-43-2402 core, compared to a pair of 9:1 transformers (blue) wound 3:1, and a pair of 9:1 transformers (yellow) wound 6:2.
<9903.jpg>
WA8TOD
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Here we have the eBay filter between a pair of 12:1 transformers (purple) wound 7:2 on a BN-43-2402 core, compared to a pair of 9:1 transformers (blue) wound 3:1, and a pair of 9:1 transformers (yellow) wound 6:2.  WA8TOD
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Hiya guys, HELP!? UBITX Ver4.3 Built..Wiring triple checked. My problem on CW, I press the key and just get a repeat of dot dash and sometimes it takes several stokes of the hand key to repeat the same. Any idea's
of a sulution?
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The only cb ones I have tried on 2 m are the long parallel rod pick up type, they were quite in accurate
For VHF/UHF I use ham products made for the purpose
Cheers
Gordon kx4z
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On Sep 9, 2018, at 13:59, Bill Cromwell <wrcromwell@...> wrote:
Hi,
It might start to be a little shaky on the two meter band. And maybe will work there too.
73,
Bill KU8H
On 09/09/2018 05:37 AM, gonewiththeego@... wrote:
I was thinking about an Albrecht SWR 20 which I can see that is used
only for CB. Do you think it should work for 20/40m band ? --
bark less - wag more
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Hi,
It might start to be a little shaky on the two meter band. And maybe will work there too.
73,
Bill KU8H
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On 09/09/2018 05:37 AM, gonewiththeego@... wrote: I was thinking about an Albrecht SWR 20 which I can see that is used
only for CB. Do you think it should work for 20/40m band ?
--
bark less - wag more
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Hi There,
Labels are one thing. What will happen of you insist on using that CB SWR bridge and meter is that you have an SWR meter:) many SWR meters in ham service are ecpected to handle several hundred watts to the legal limit. Here in the USA that is 1500 watts. A ubitx is never going to hurt a CB SWR meter. I have used a couple of them at the 100 watt level over the years.
I don't have your name. It is good on the mail lists to sign with your name and your ham call sign if you are licensed. Some list members are not licensed so no call sign. In the USA it is not illegal for an unlicensed person to own transmitter. Just illegal to put it on the air without a license. Most of us acquired our first radio before the license arrived. Some members are SWLs
73,
Bill KU8H
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On 09/09/2018 03:12 AM, gonewiththeego@... wrote: Thank you very much for your nice "Welcome aboard", indeed I appreciate
all of the answers above and I'm pretty sure that this topic will have
some "echo" throughout community. These are maybe the most common
questions asked by those with just the license of operation in hand and
a few basic knowledge of electronics. I can't wait to see the uBitx on
my desk. Meanwhile, I can't find some genuine information about the
output impedance of the uBitx itself. Is it 50 ohms ? Gordon Gibby
previously sugested that a CB SWR-Meter will do the job on HF also. I
found one but it's rated to 11m band only, or at least that's what on
the label. Can someone tell me what can go wrong it I start using it ?
And by experiment, does anyone know how much SWR can uBitx handle
without permanent damage?
--
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With the heathkits , we’ve already done that, on the surface it seems to work well. ?
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Hi Allison,?
would you be willing to try your load testing again, with the Si5351a driving a set of high impedance loads? say something perhaps 10k Ohms or higher.?
-Justin N2TOH?
P.S. I'd like to see what the Si5351a would do driving the crystal tube oscillators in the Heathkit SB/HW101 series rigs.?
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Sorry. ? David A Posthuma, WD8PUO 1 (616) 283-7703 ?
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From: [email protected] <[email protected]> On Behalf Of Arv Evans
Sent: Sunday, September 09, 2018 1:14 PM
To: [email protected]
Subject: Re: [BITX20] Antenna Loops #ubitx-help #ubitx #antennas #loops ? David
A copy of your post to the uBITX group has been forwarded to the [email protected]?discussion group.??
This group was formed to move the long and multiple off-topic posts, mostly about EFHW antennas,? to a
place where antennas would be?more on-topic.? If not already on that group you can join at
and post to [email protected]?.
Arv? K7HKL
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Hi Allison,?
would you be willing to try your load testing again, with the Si5351a driving a set of high impedance loads? say something perhaps 10k Ohms or higher.?
-Justin N2TOH?
P.S. I'd like to see what the Si5351a would do driving the crystal tube oscillators in the Heathkit SB/HW101 series rigs.?
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David A copy of your post to the uBITX group has been forwarded to the [email protected]?discussion group.?? This group was formed to move the long and multiple off-topic posts, mostly about EFHW antennas,? to a place where antennas would be?more on-topic.? If not already on that group you can join at and post to [email protected]?. Arv? K7HKL _._
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I’m using one there is almost identical to the one he suggested. ?Works fine all bands as far as I can tell. ?I have used boatloads of different ones throughout the years
Those that use toroids (instead of the old parallel lines) probably use this basic circuit:
You can tell the ones that use the parallel transmission line pick ups: they are longer. ? Those with a toroids ?can be more square shaped boxes
I’ve used them both, they all work
Cheers?
Gordon
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Output of the uBITX is 50 ohms.? Your CB SWR meter should work for the upper end of?
HF range (20M through 10M) and maybe acceptably good for 80M through 10M.? Many?
of those old CB SWR meters were just copies of ham radio SWR meters of the era.??
If the CB SWR meter is not performing well, it does provide a case, meter, and knob to?
use in building a more modern bridge type SWR and power meter.
Arv
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Ripley
Nick VK4PP
David Posthuma