Filter values for 160m QDX?
I've seen discussion about the possibility of building a 160M QDX-M... But haven't found anyone that's documented doing it, other than Hans saying he ran some WSPR on one?
I see filter values for
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Nate Reik N8BTR
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#116842
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Re: QMX power out measument concerns
Nate: yes and yes.
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Larry VE7EA
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#116841
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Re: QMX power out measument concerns
When you say your scope is calibrated.....what do you mean? Were you using a x10 probe with the scope? Was the probe properly compensated first?
-Nate
N8BTR
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Nate Reik N8BTR
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#116840
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Re: BS170 Killer?
I used the 47-volt version from this Amazon assortment (I always buy assortments to build my parts bin).
https://www.amazon.com/gp/product/B099F24G22/
73
Evan
AC9TU
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Evan Hand
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#116839
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Re: QMX power out measument concerns
Probably T507 has one unmade connection (on the thin wire).
I would believe the scope reading, assuming a good 50 Ohm dummy load.
Most of my other power readings disagree!
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Chris KB1NLW
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#116838
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Re: #qmx PCB Rev 2 recommended modification
#qmx
Hi Stefan,
" lower IR" should be no problem, lower IR is better for reverse operation.
Look here ( https://html.alldatasheet.com/html-pdf/15021/PHILIPS/1N4148/745/3/1N4148.html ). The worst value for
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@Ludwig_DH8WN
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#116837
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QMX power out measument concerns
My QMX hi-band build is great so far. Am currently measuring power output. However, I have two concerns:
*
The terminal emulator Diagnostics power output indicator always reads 0 watts out, even
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Larry VE7EA
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#116836
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Re: BS170 Killer?
Evan
What zener do you recommend?
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Chris KB1NLW
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#116835
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Re: Qcx Mini as a 6 Meter CW Beacon
Hi Giuseppe,
Thanks for the information about the T37-6 yellow toroid. I seem to remember reading something about that while researching toroids. I'm only getting about 1/2 watt RF power out using the
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John Olsavicky
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#116834
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Re: QMX Rev2 80m RF sweep good enough?
#bpf
#filter
#qmx
#80m
Hello Stefan,
In all honesty, I don't think there's any noticeable improvement... or my ears don't hear it, at least. I did the mod because the pacient was already on the table for the recommended
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Adrian YO3GFH
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#116833
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Re: QMX Rev2 80m RF sweep good enough?
#bpf
#filter
#qmx
#80m
Hi Adrian, Lun, Jim & Paul,
I'm fascinated by your efforts to optimize the sweeps, however, I wonder, whether this will really have a recognizable effect in day-to-day operation.
From what I got now
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Stefan U. Hegner
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#116832
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Re: #qmx PCB Rev 2 recommended modification
#qmx
Hi folks,
now that I got my filter sweeps fine after replacing Q508, I want to do the Diode mod.
However, I have no 1N4148 lying around.
What I got at hand that comes closest is a BAW76, specs (and
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Stefan U. Hegner
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#116831
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Re: QMX: Filter issues [solved]
Hi John & Evan,
Am 15.01.24 um 22:00 schrieb Stefan U. Hegner:
Replaced my Q508 and now all the sweeps look good to me. - I think I maybe post them later for reference.
Thanks a lot for you help,
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Stefan U. Hegner
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#116830
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Re: BS170 Killer?
Hi Peter Li,
I think the Zeners will provide some protection against SWR that results in high voltage, not in SWR that causes excessive current.? A bad SWR can cause either, depending on the
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Evan Hand
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#116829
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Re: BS170 Killer?
Thanks (again) Evan! For voltage, don't the Zeners give SWR protection that the L14 diode does not give??Do you think doing both Zeners and TN0110/TN0106 is also perhaps belt-and-suspenders?
For
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Peter Li
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#116828
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Re: QDX Rev 3 using firmware v1_10 issue
I've just checked my V3..Firmware 1.10. I guess I fixed the audio short if that was relevant It has a clock buffer like the V4, .I do not think that will make a difference.
I did audio and RF scans
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Alan G4ZFQ
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#116827
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Re: QMX and MAT-705 Plus Tuner?
Simon & Randy - thanks for the replies to my post. I understand the dangers of auto-tuners with the QMX/QDX rigs. And it is unfortunate that the little PA units aren¡¯t robust enough to withstand the
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Jim Bennett / K7TXA
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#116826
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Re: clock contrast mod
#clock
Hi Bob. thanks for the idea.
Its called contrast <improvement> in the manual but either way it certainly effects brightness at extreme settings.
I'm okay with it as is. I found a 220k in the junk box
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Bryan Curl
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#116825
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Re: QDX Rev 3 using firmware v1_10 issue
Lynx,
Have you tried returning to 1_05 to verify it is a software issue?? It could be that the Si5351 has failed.? If you return to 1_05, please post a screenshot of the oscilloscope trace.
Of
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Evan Hand
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#116824
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Re: QDX Rev 3 using firmware v1_10 issue
Today I use firmware v1_10 do some test again. I use a?oscilloscope watching R41 and R40(CLK0 and CLK1), and found something strange.?In theory, CLK0 and CLK1 should have the same frequency but be
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Lynx BG7JAF
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#116823
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