Re: Antenna System Multi-band
I did simulations on a 44 foot doublet recommended by Cebik (SK), good for 40M-10M.? Used EZNEC to generate a "last Z" file which I fed into SimSmith. This doublet has some advantages. I found, with simulations in SimSmith, that you could make the 44 foot doublet at 35 feet high? with 300 ohm ladder-line such as DX Engineering DXE-LL300-1C, 59 feet, 1 inch long fed with a 1:1 balun. My goal was to get VSWR low enough to be able to use the 3:1 capable tuner built into many modern rigs.? I succeeded in this for the 30M, 20M, 15M, and 10M bands. 40M needs an external tuner.? For QRP rigs, you would need an external tuner but no critical tuning. A simple L-network would do the job. See referenced article. Tune the electrical length of the ladderline by terminating it with a 2K resistor (not critical)? and look for a dip in VSWR at 4.273 MHz.?
30M: VSWR=2.5
20M: VSWR=1.5
15M: VSWR=2.2
10M: VSWR= 1.6
-Steve K1RF
------ Original Message ------
Sent: 5/29/2022 7:52:24 AM
Subject: Re: [QRPLabs] Antenna System Multi-band
I have also been using a classic Cebik doublet for 40-10 meters for years with good results. I use 300 ohm window line to a 1:1 balun to a remote antenna tuner. It's paired with a wire up to tree top vertical that I use for 160-40 with the remote tuner antenna switch selecting between them.
At a previous QTH I had tall trees and ran the doublet oriented vertically.
--
? 73
??? KD8CGH
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IT'S WORKING!
After some rest, I tried again this morning and noticed that if I held the USB cable juuuuuuuust right I would get a connection.
I looked under the microscope and it looks like three of the USB connector pins are not completely soldered, so I touched them up and it's all fine now. They are sort of soldered underneath the pin, but it's not real great. My other UB4 connector soldering looks even worse, so I'll touch that up also. MAN, the pins on that connector do NOT want to take solder even with flux. #supplychain
Anyway, I'm back up and running and won't power with two supplies at the same time again just for safety.
Thanks Dave,
Alan KC1QHV
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Re: Difference in behavior between the key jacks of my original QCX-17 and original QCX-80
Bill, it sounds like the contacts inside the key Jack of the QCX 80 are bad and the Jack needs to be replaced.?
Ron
On Sun, May 29, 2022 at 05:38 n4qa < n4qa@...> wrote: The key jack of my QCX-17 allows the stereo ( tip, ring, sleeve ) key plug to be completely plugged in for normal operation.
However, proper? keying of my QCX-80 requires that the same key plug be plugged in only part way.
I suspect that the internal connections of the two key jacks in question are somewhat different.
I would like for the action of the key jack of my QCX-80 to mimic that of the QCX-17.
Any guidance in this regard would be greatly appreciated.
Thank you and 72 / 73,
Bill, N4QA
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Re: Antenna System Multi-band
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Difference in behavior between the key jacks of my original QCX-17 and original QCX-80
The key jack of my QCX-17 allows the stereo ( tip, ring, sleeve ) key plug to be completely plugged in for normal operation.
However, proper? keying of my QCX-80 requires that the same key plug be plugged in only part way.
I suspect that the internal connections of the two key jacks in question are somewhat different.
I would like for the action of the key jack of my QCX-80 to mimic that of the QCX-17.
Any guidance in this regard would be greatly appreciated.
Thank you and 72 / 73,
Bill, N4QA
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Re: QDX no transmit on 20/30m
I figured someone might want those values.
I took the liberty of checking Q3, Q4, and Q5. I see the pattern. Q5's drain is 5.4 volts when the gate is 3.3 while on 20 meters. See chart below:
20 meters selected with audio sweep (values rounded to nearest 1/10):
Q3 - Gate: 0.0? ?Drain: 5.8? ?Source: 0.0
Q5 - Gate: 0.0? ?Drain: 5.8? ?Source: 0.0
Q5 - Gate: 3.3? ?Drain: 5.4? ?Source: 0.0
40 meters selected with audio sweep (values rounded to nearest 1/10):
Q3 - Gate: 0.0? ?Drain: 5.8? ?Source: 0.0
Q5 - Gate: 3.3? ?Drain: 0.0? ?Source: 0.0
Q5 - Gate: 0.0? ?Drain: 5.4? ?Source: 0.0
80 meters selected with audio sweep (values rounded to nearest 1/10):
Q3 - Gate: 3.3? ?Drain: 0.0? ?Source: 0.0
Q5 - Gate: 0.0? ?Drain: 5.7? ?Source: 0.0
Q5 - Gate: 0.0? ?Drain: 5.3? ?Source: 0.0
Q5 bad???
Rick
K4LX
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Hi Colin
It may not be advisable to run 2 power sources at the same time.( the solar input is protected by a blocking diode but the battery input is not and can cause trouble)
When connected to the USB the U4B senses this and I believe runs the processor at a higher clock speed to generate the USB connection throwing off the? power consumption values.?
Also when running from the USB power, the STM32 has to do a lot work updating the monitor etc. and hence the timing is a bit slower... you could be misled by the results.
For instance Transmitting the QRSS glyph and ident takes 56 seconds on battery power and 62 seconds on usb power ... this could cause a problem, if the next wspr tx is supposed to start at the top of the minute and now it is 2 seconds late.?
What I do to evaluate solar cells for the U4B is simply use a series ma meter and a volt meter in the solar circuit on earth into a fixed resistor load and then adjust the numbers for the cold at float which will produce as much as 20% more power.
You need about? 56ma for high power tx mode and as high as 40ma to lock the gps and transmit low power ... If you have those numbers @ >3.3v the solar cells should work fine.
Dave VE3KCL
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Re: Remote "bottom of the garden" QDX...
Very nice, One of the few YouTube videos worth watching all the way through, and then re-watching sections of!
Can you tell us more about the reflectometer? William Smith ComputerSmiths Consulting, Inc.? w_smith@...
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On May 28, 2022, at 4:24 PM, Linus <linus.peter.sweers@...> wrote:
?On Sat, May 28, 2022 at 01:07 PM, G3SPL wrote:
https://youtu.be/GPlvy_8QNrw
Peter. Your video is amazing. Thank you for sharing.
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Re: Sources for hydrogen/helium in small quantities? #u4b Thermite
#u4b
I just checked ¡°thermite¡± on wiki¡¡ disaster waiting to happen. ?Even the Germans (the greatest scientists of the pre WWII day, at least in chemistry) made mistakes or compromises due to unavailability of helium.?
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On May 28, 2022, at 3:05 PM, Jim Strohm <jim.strohm@...> wrote:
? Hydrogen would have the CHEAPEST lift. ?
FWIW, the reason that the Hindenburg was full of hydrogen was that the US wouldn¡¯t sell helium to Nazi Germany.?
The Hindenburg made multiple trips across the Atlantic using hydrogen without any issues. ? However, part of the disaster was that the coating on the outer envelope was thermite. ?
Looked nice, repelled UV very nicely, but was more flammable than hydro. ?
73 Jim N6OTQ?
Sent from my quenched-gap spark transmitter.? On May 28, 2022, at 1:57 PM, Colin Kaminski <colinskaminski@...> wrote:
?Hydrogen is lighter but also a bigger molecule so it is less likely to leak.?
Colin K6JTH?
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Re: Antenna System Multi-band
I have also been using a classic Cebik doublet for 40-10 meters for years with good results. I use 300 ohm window line to a 1:1 balun to a remote antenna tuner. It's paired with a wire up to tree top vertical that I use for 160-40 with the remote tuner antenna switch selecting between them.
At a previous QTH I had tall trees and ran the doublet oriented vertically.
--
? 73
??? KD8CGH
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Re: Antenna System Multi-band
I have used an open wire doublet for years here. It works very well on all bands from 80 to 10 including warc. It is 110' end to end, fed in the middle with 4 inch open wire into the shack to an old Decca kw107 tuner. The wire is aluminum#17 electric fence wire from the farm store. The open wire is made from more of the same wire with 4 inch plastic spacers every couple feet.? I started with the antenna at 130' long but it didn't like 40 metres. 110' is much better. The materials are very inexpensive, both the wire and fence insulators were less than $30 at the local TSC farm store. It would be cumbersome to use as a portable antenna though. It is fairly stealthy at home with the aluminum wire.? I am impressed with the performance of it. It seems better than fan dipoles that I have used to try and get multi band operation.?
73 Don ve3ids
All,
Good comments and opinions so far. Ron you reaffirmed my thoughts?
Any open ladder line users with performance details? I might put one in use in my base station and use the segmented dipole for portable use.?
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Re: 60m QCX mini unusable with EHFW during SOTA
#qcxmini
Morning Richard.? My 60m Mini has no problems with my full length 60m EFHW and homebrew 49:1 transformer.? I've had it out on a number of SOTA activations using about 20 feet of feedline.? I've always found it curious that the QRP Guys unit requires an odd length of wire for each band that is not a half wave???
Ken,
W4KAC
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Re: 12V to 9V Converter : QDX ?
On Sun, May 29, 2022 at 10:53 AM, David Wilcox K8WPE wrote:
A ham in the UK sent me this one he has sued successfully. I may order one.
I thought it looked too good " Output current: 200mA" OK if you do not TX. I should use your typo on the UK ham:-) 73 Alan G4ZFQ
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Re: K6JTH's versatile stand for the QCX-mini
Got it today, and will try to get it out Tues or Wed on to Jim W4QE.? Jim, your QRZ info accurate?
Bob
KG5GTE
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Re: 12V to 9V Converter : QDX ?
A ham in the UK sent me this one he has sued successfully. I may order one.
Dave K8WPE David J. Wilcox¡¯s iPad
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On May 29, 2022, at 3:30 AM, Alan G4ZFQ <alan4alan@...> wrote:
? On 29/05/2022 01:18, Linus wrote: ???The wires are different colours, if the input/output is completely
???isolated then it would probably be OK but needs checking.
I have one at my desk and a multimeter. What is the method to test isolation?
Measure the resistance between the output wires and the input wires.Most converters of this type have the input and output ?grounds common. Maybe they are although they are different colours.If you see zero Ohms between them makes sure it is zero, there is a remote possibility there could be a low value resistor between them. My usual approach on an unknown like this is to look.You probably will not find an infinite resistance between input/output. It is possible they may be completely isolated but I've never seen this on such converters.73 Alan G4ZFQ
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Re: Antenna System Multi-band
41 m EFHW and a 1: 41 transformer plus a chocke at 4 from the feedpoint and off you are on all bands. Tunes easily by folding back the far end and no tuners needed.
Martin DK3UW
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Re: no Conection to Linux Mint and Windows 8.1
On 28/05/2022 12:14, mweidle@... via groups.io wrote: Thanks,
where is the picture ? I was looking for my full text description, here Windows 7/8 serial driver and attach the two pictures here. You may have to dismiss Windows warnings that it is the wrong driver. 73 Alan G4ZFQ
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Re: 12V to 9V Converter : QDX ?
On 29/05/2022 01:18, Linus wrote: The wires are different colours, if the input/output is completely
isolated then it would probably be OK but needs checking.
I have one at my desk and a multimeter. What is the method to test isolation? Measure the resistance between the output wires and the input wires. Most converters of this type have the input and output grounds common. Maybe they are although they are different colours. If you see zero Ohms between them makes sure it is zero, there is a remote possibility there could be a low value resistor between them. My usual approach on an unknown like this is to look. You probably will not find an infinite resistance between input/output. It is possible they may be completely isolated but I've never seen this on such converters. 73 Alan G4ZFQ
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Re: QDX no transmit on 20/30m
What are the voltages at Q5 when in 20M mode?
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Ronald Taylor
VE3KCL
David Wilcox K8WPE
Bob Benedict, KD8CGH
Don VE3IDS
Richard Robbins
Colin Kaminski