Re: End Fed antennas w/ uBITX
#ubitx
I trust you Allison. Up to now I followed two rules of thumbs: 1) check the SWR with a proper load. 2) if and only if SWR was found close to 1 at a frequency, check the SWR without any load. If and only if in this case SWR is very high, at least greater than 10, losses are acceptable. If SWR is around 5 half power is lost into heat. If SWR is close to 1 everything goes into heat.
Il 25/ago/2018 23:32, "ajparent1/KB1GMX" < kb1gmx@...> ha scritto: Iz oos,
Depending on a few things self resonance is a bad thing.? For that transformer its
likely the core would absorb a lot of power as a side effect of the circulating currents
in the wire.? After all it showed a good SWR so the power is going somewhere.
As to SWR and wide band transformers.? I disagree, however I do that knowing full
well SWR (S11) is only a partial measurement.? ?It speaks to the source being
reflections or?not but not one clue if the power (all of it) makes it to the desired
load. A through measurement (S21) will provide a better idea of if the SWR is
good because its? delivered or absorbed and to what extent.? You must do both
or the image is incomplete.??
So at best the SWR is a suggestion of some level of merit but also incomplete.
Allison
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Re: Need New Raduino Board
Timothy,
DO NOT PRIVATE EMAIL ME.? You are plonked, Clear!
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Re: Lead-free solder, regular solder
On 25/08/2018 19:06, Jon Titus, KZ1G
wrote:
As a youngster I wondered why the tips on my Weller soldering gun
broke after intense use.? I wired large relay terminals, switches,
and small light bulbs for projects.? Turns out the solder
dissolves copper, so little by little the tip would get eaten
away.? Copper or alloys might also dissolve in lead-free solders,
which leads to soldering-iron degradation.?
Some time ago a company in the UK sold solder
with a small amount of copper in it, which stopped or reduced
the decay of iron tips.
I think choice of solder manufacture is a
personal just like the style of iron.
What works for one doesn't for another, I just don't get along
with (genuine) HAKO.
It's possibly the Multicore Solder,? SAVBIT product you are
referring to. Now owned by Loctite / Henkel.
It's being in the product catalogue since the early 1980's, a long
before leadfree...
We had commercial contracts that specified by name it was to be
used, personally I didn't note much difference compared to the
normal brew.
Leaded Solder is still freely used in UK / EU.? Automotive,
Military, Telco, Aviation, Medical electronics are all exempt from
the green laws, basically anything that needs to work
is exempt,
and is the choice of a particular manufacture.
It's only consumer electronics, that's legislated as being lead
free.
To compound the problem the common practice is the dross gets
skimmed off the solder bath,
Returned to the supplier for refining & reuse in the next
batch of solder pellets for cheapness.....
If it's not a dry joint, swap the panel. Still doesn't work? then
it's for recycling....
It always a laugh when at Hamfests to see people selling the "last
few rolls of leaded solder, for double or triple the price of what
it costs from a trade supplier.
Where do they keep finding this new "old stock" that was banned in
2006?? ;-)
Alan
?
For an interesting
article about copper dissolving in lead-free solders, see:
--
Jon Titus, KZ1G
Herriman, UT USA
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Re: New build uBITX wont run
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Re: Need New Raduino Board
Timothy,
You should check the site first.? No such reference.? They may sell them
but there was no reference on the page I could find.
of course one can email them and ask...
Allison
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Re: UBITX won't key--- solved
Could someone walk me through the menu to turn on the keyer?? I get dots, but no dahs, just out of the installation of the correct resistors.? And get straight key working fine.
Some where in the setup menu I do recall seeing a keyer page, but I'll be darned if I can find it. Checked all resistances and they are spot on for both dots and dahs.? And I'm at duh.
Thanks. 73.? All this assumes I still remember the code.
Eddie
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Re: End Fed antennas w/ uBITX
#ubitx
Iz oos,
Depending on a few things self resonance is a bad thing.? For that transformer its
likely the core would absorb a lot of power as a side effect of the circulating currents
in the wire.? After all it showed a good SWR so the power is going somewhere.
As to SWR and wide band transformers.? I disagree, however I do that knowing full
well SWR (S11) is only a partial measurement.? ?It speaks to the source being
reflections or?not but not one clue if the power (all of it) makes it to the desired
load. A through measurement (S21) will provide a better idea of if the SWR is
good because its? delivered or absorbed and to what extent.? You must do both
or the image is incomplete.??
So at best the SWR is a suggestion of some level of merit but also incomplete.
Allison
|
Re: End Fed antennas w/ uBITX
#ubitx
Yes Warren also a long run of unterminated RG174 shows an acceptable SWR.
Il 25/ago/2018 22:29, "Warren Allgyer" < allgyer@...> ha scritto: Iz
VSWR measurements as a means of evaluating the performance of wide band transformers are almost meaningless. In order for the VSWR to mean anything one must first know how much power is actually being transformed versus how much power is being turned in to heat by transformer losses. A transformer with 100% loss will show an SWR of 1:1. A 49:1 transformer with no loss, perfectly terminated in a 2450 ohm resistive load will also show a VSWR of 1:1. A transformer with 90% loss, terminated with a 10:1 mismatch, will show a VSWR of very nearly 1:1.
The only effective way to measure the performance of an impedance ratio transformer is to build 2 and place them back to back and measure how much power gets through.
?
WA8TOD
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Re: Need New Raduino Board
Allison... it must be a Millennial thing !!.? (the lack of memory /IT)
Seriously-? there have been other posts that HF signals will sell new Raduinos at USD 35 plus courier charges (however my guess is they do them as only a small extra production run so you takes yer chances on how many they have to sell at any given time ).? Look at HF Signals pages for any email addresses ....
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Re: End Fed antennas w/ uBITX
#ubitx
Hi Allison, yes the small binocular core must be a material similar if not 43, which for the low bands such as 160 and 80m has its use. What happens to the self resonant frequency? Is RF all converted into heat? May it be dangerous to transmit in there?
Il 25/ago/2018 20:19, "ajparent1/KB1GMX" < kb1gmx@...> ha scritto: Iz oos,
The amount of wire interacts as well.? for example the white toroid with lots of
wire runs into self resonance at 20.8 so any frequency close to that will be impaired.
At low frequencies there is not enough inductance. Over all also the mutual inductance
and coupling looks to be poor (coupling factor of less than 1).
The choice of the 150pf cap may even be wrong I've tried a mica trimmer?
on some of the published designs and the 150pf value was not what I
arrived at.??
The smaller core sounds like 43 material and not always a good choice.
Winding transformers for any use is not a random thing there is science to it but in
the end how the windings are organized, conductor size, and transformer material
all interact.
Allison
|
Re: New build uBITX wont run
Am 25.08.2018 um 20:23 schrieb ajparent1/KB1GMX: Make sure you not in transmit mode!
Check the switched 12V line to see if its 12V-T or 12V-R Hi Allison and tnx for your help to find the bug. It was a contact problem in the socket between Raduino and uBITX. Now the uBITX is up and running. 73 Matthias, DD7NT Two most common problems is forgot the resistor for the key (4.7K) so its in CW tx mode.
And the TX (transmit line, orange) is grounded due to wrong pin on mic socket or even mic plus.
Allison
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Re: End Fed antennas w/ uBITX
#ubitx
Iz
VSWR measurements as a means of evaluating the performance of wide band transformers are almost meaningless. In order for the VSWR to mean anything one must first know how much power is actually being transformed versus how much power is being turned in to heat by transformer losses. A transformer with 100% loss will show an SWR of 1:1. A 49:1 transformer with no loss, perfectly terminated in a 2450 ohm resistive load will also show a VSWR of 1:1. A transformer with 90% loss, terminated with a 10:1 mismatch, will show a VSWR of very nearly 1:1.
The only effective way to measure the performance of an impedance ratio transformer is to build 2 and place them back to back and measure how much power gets through.
?
WA8TOD
|
This is from my friend Konstantinos SV1ONW please open it with LibreOffice Writer .
|
Re: New build uBITX wont run
Make sure you not in transmit mode!
Check the switched 12V line to see if its 12V-T or 12V-R
Two most common problems is forgot the resistor for the key (4.7K) so its in CW tx mode.
And the TX (transmit line, orange) is grounded due to wrong pin on mic socket or even mic plus.
Allison
|
Re: End Fed antennas w/ uBITX
#ubitx
Iz oos,
The amount of wire interacts as well.? for example the white toroid with lots of
wire runs into self resonance at 20.8 so any frequency close to that will be impaired.
At low frequencies there is not enough inductance. Over all also the mutual inductance
and coupling looks to be poor (coupling factor of less than 1).
The choice of the 150pf cap may even be wrong I've tried a mica trimmer?
on some of the published designs and the 150pf value was not what I
arrived at.??
The smaller core sounds like 43 material and not always a good choice.
Winding transformers for any use is not a random thing there is science to it but in
the end how the windings are organized, conductor size, and transformer material
all interact.
Allison
|
Re: Lead-free solder, regular solder
As a youngster I wondered why the tips on my Weller soldering gun broke after intense use.? I wired large relay terminals, switches, and small light bulbs for projects.? Turns out the solder dissolves copper, so little by little the tip would get eaten away.? Copper or alloys might also dissolve in lead-free solders, which leads to soldering-iron degradation.? Some time ago a company in the UK sold solder with a small amount of copper in it, which stopped or reduced the decay of iron tips.
For an interesting article about copper dissolving in lead-free solders, see:
--
Jon Titus, KZ1G
Herriman, UT USA
|
Found now time to wire up my uBITX V4.3. After that I switched it on and measured the current. It took 370mA - too much. No magic smoke, nothing warmed up except the 5V regulator on the Raduino board after some time.
The display came up with uBITX V 4.3 and frequency, could walk to the menues and tune. No reception at all. To get the reason why it consumes 390 mA I tried to get the current of the several function blocks:
uBITX board without Arduino, Raduino and display: 84mA
uBITX board with Arduino, Raduino and no display: 350mA so dispylay and backligth take 20mA
uBITX board and Raduino only 294mA (-84mA Board ) = 210 mA only for the raduino board (?). Both connectors were plugged off.
Had a look at the Si531 BQPC 729. It gets 3,68V when the Arduino is in.
The I can see between 2.4 and 2,5V at C4,C5 and C6. But no wave out at the 50MHz scope. It has no voltage at Pin1,C4,C5,C6 if the Arduino is away. But in both cases (!) the power consumption is 294mA.
Has ayone an advice where to look next?
73 Matthias, DD7NT
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Re: Need New Raduino Board
Since the group using mail have no memory.
Check here.
Allison
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Re: Fried irf510s replaced but
Jeff,
K2, nice.? Not always noted but it was a simple radio that made the top of
Bob Sherwood's receiver list for performance.? It was that good.
As to the ubitx I knew of I suspect some of the 20m coils got put in where
the 40M coils should be.? They were the same and as a result short on wire.
Rewound with wire on hand and 40M had less power than 80 and more than
20M which is normal.
Alliosn
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Hi in izq Danilo, the 2822 was used up to ver. 3. Then as the failure rate was high it had been replaced by a different circuit. The 2822 by the way was able to produce a pretty loud volume. In your case check whether the volume pot was properly wired.
Il 25/ago/2018 18:51, "danilo datres" < in3izq@...> ha scritto: hello guys, i'm? in3izq danilo? and? just? have? finish my? ubitx ver. 4.3 .
have? some problem : audio? is very loud ? its because tda 2822 is broken ? on? mother board have not found 2822.? maybe is next version ?
sorry? for my? english,? hope you understand. ? have read? more message , but are now
in high sea.....best '73? and tnx in advance? for? help ? in3izq danilo
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Alan de G1FXB
SV9CVJ Nikos