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Re: QCX-mini update
namerati@...
Edge mount would be quite alright, though the edge mount SMA connectors I have used were designed for slightly thinner microwave boards and did not fit standard FR4.
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I also notice that you managed to match the dimensions of the MTR3b almost down to the millimetre :)
On Fri, Sep 11, 2020 at 10:35:51PM +0300, Hans Summers wrote:
Good point, I forgot that. Thanks for fhe reminder. I must see if I can put
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Re: QCX-mini update
The Crunchbird
Hans, we have no mountains in Florida but I would love to take one to the beach, Dave. N2SN
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Re: QCX Mini Upgrde ...
Hans Summers
Hi Andy Get well soon OM, all my best wishes...
There are no more QCXs here. Only QCX+. We have some assembled QCX+ (i think this is what you're asking) in the shop, see http://shop.qrp-labs.com/assembled If you need a particular band that you don't see available then if you email me, I can help arrange it. 73 Hans G0UPL
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Viktors Miske KC8CKZ
KE9UW, give this chart a shot..
https://kitsandparts.com/xtoroids.html
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Re: QCX-mini update
Hans Summers
Almost, but not quite small enough to fit in an Altoids tin... There's not much point going to 0402. It has to be big enough to hold the LCD and have space for the controls below that. Or do something much more radical which would be an out-of-scope redesign. If we could have a 5W radio the size of a postage stamp, would it be all that practical to squint at the tiny screen and operate it? 73 Hans G0UPL
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Re: BPF 80m
Hello group,
well... not wanting to stay theoretical, I implemented the thoughts in the message above #43560 and cascaded the Low Pass Filters (LP) sitting on the filter switch board of the U3S with static, non-switchable HighPass FIlters sticking into the Rx PinHeaders where a BandPass is supposed to go to. What I was curious to see is what the difference is between this combo and the standard, official BandPassFIlter (BP). From these I only built one for 80, but it is enough for the question here. This is what I got: The picture below should be self explaining. Important are the red (BP) and the green (LP&HP) curves. The other two curves are the "root" of the LP&HP combo, the individual frequency responses of the original LowPass from qrp-labs and my own HighPass based on the same idea, but with nervous coefficients (Cheby instead Butterworth). Cascading the filters yields the green curve. Compared to the red BandPass filter.... well there is no free lunch. I could have pulled the skirts of the two filters nearer to each-other, but the combo depicted here perfectly fits my needs, for a while... About the -5dB insertion loss of the original BandPass.... there is somewhere in this net an ongoing discussion. Some said that you might need "heavy" groundplanes below the filter when measuring it. I did the experiment, with and without "heavy" groundplanes and must say that I do not subscribe to this oppinion, without wanting to start a chest-beating discussion here (the coupling cap used is thea standard one prescribed by the manual.. I recall 47pF). This is what I got, your mileage might vary. I need this configuration of cascaded filters NOT as a big improvement (because it is obviously not a betterment), but because this is what I need at the moment. For dedicated setups on single bands I will probably build other and other U3S and corresponding Rx'es. It is so much fun! Yours friendly, Razvan DL2ARL
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Re: BPF 80m
...and because it was so much fun, I did almost the same for 40m. A bang of a band here, full qrm. But for this band, I lacked a BandPass from qrp-Labs and feeling no desperate need for one at the moment, I thought I give it a try my way, by cascading the original LowPassFilter sitting in the U3S Filtershotgun and a High Pass Filter I rolled myself with somewhat more nervous coefficients, not caring about the resultig ripple.
This is what I got: the picture should be as self explaining as the one in the former message. It is only weird that the I measured the HighPass as low as 1MHz whereas the original qrpLabs LowPass is only measured 5MHz and above. This is my way of thinking qrp which has become a state of the mind. Why should I be interested in the behavior of a LowPass way down below? What I got perfectly suits my needs. The QRM I have at my location comes mainly from below and getting rid of those ugly ones below 3MHz helps a lot. "whach out for the chimneys" Yours friendly, Razvan DL2ARL
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Re: QCX-mini update
ohwenzelph
Almost, but not quite small enough to fit in an Altoids tin...
Have you considered 402 parts??? But, the hard part is getting the height thin enough....
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ke9uw
I meant the large winding only...not the additional 5 turn windings and the big loops described in the manual. I wound them all separately.
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QCX Mini Upgrde ...
Andrew Cunningham
Hans ... Loved the video ... will watch it over & over I know Can we have a “ Micro CW Key “ from Brass or Alu ... maybe to go along with the radios ( Use & Love My KK5PY Micro Te-Ne-Ke ) http://g0mwt.org.uk/skills/cars-skills-aug2015.htm?LMCL=H7gKGd Dunno if you’ve implemented “ Continuous Drive Control “ Yet with the aid of a Linear Pot Switch or Flick Switches But I still think this a great, neat idea ... particularly for folks wanting to really push the challenge both in & outdoors Up The Mountains Of Our World-Audience with this “ Easy To Achieve dB Cut-Back “ Feature would be a great selling point I’m a REAL QRPp Freak As well as QRP who hasn’t tried QRPp yet but is dyin to go - Just can't find “ An easy minimalist way of achieving this “ From the confines of my Bed ! Due to health issues Before I go Hans - What QCX’s On HF Bands as selling point are still available I have few Bands I’d love to fill Thanks Man For All The Years Of Excellent Work Sent From Andy - GM0NWI’s iPhone
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Re: QCX-mini update
Kees T
Hans,
Amazing, you did it !! ...not that I had any doubts. Excellent Human Factors testing with the LCD, sunglasses, etc. I like those much better than the blue ones. Very impressed with the overall QCX-Mini ....and the small uSDX daughter card is the icing on the cake. Yes. please include it with the kit. Great work !! Can't wait to order. 73 Kees K5BCQ
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ke9uw
The wire supplied is 28 ga and the length for the 80M T1 T50 large winding is 48 inches. You can scale with that for the other bands. The toroids are T37 instead of T50 so I’m going to guess that the wire required is about 37/50 ths of what they would have been if they were T50s.
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Re: QCX-mini update
Hans Summers
Hi Michael Shout out to the Norcal 40A in the background of the QCX Mini video :) I had an original back when they came out. Never finished it and it was lost to the turmoils of a tumultuous life. For the memory I bought another from Wilderness at Ozarcon 2007. I built it but the frequency annunciation didn't work and I didn't have time at that moment to investigate that... so put it on the shelf. Where it still sits 13 years later. Different continent (twice), different shelf (thrice). Same concept. I'll fix it one day... 73 Hans G0UPL
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Re: QCX-mini update
Hans Summers
Good point, I forgot that. Thanks for fhe reminder. I must see if I can put them in. Edge mount? How can that work... the edge is up against the enclosure wall. 73 Hans G0UPL
On Fri, Sep 11, 2020, 22:31 <namerati@...> wrote: No alternate pads for an SMA connector?
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Re: QCX-mini update
Michael N6MST
Shout out to the Norcal 40A in the background of the QCX Mini video :)
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Re: QCX-mini update
namerati@...
No alternate pads for an SMA connector?
toggle quoted messageShow quoted text
On Fri, Sep 11, 2020 at 07:23:16PM +0300, Hans Summers wrote:
Hi all
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Re: QCX-mini update
Hans Summers
Hi Bob It's a different pot. Smaller size and green. The pins stick out of the plastic body. More pricey but I needed the small size. See attached. 73 Hans G0UPL
On Fri, Sep 11, 2020, 22:11 Bob M. <wa1mik@...> wrote: Looks like a bunch of nice improvements.
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Re: QCX+ mechanical problem
Jim Manley
I haven't found it necessary to drill/file/sand any nuts, but I do occasionally find that scratching them to be beneficial during extended build sessions. Scratching a line on a nut and the PC board helps identify their correct orientation when adequately tightened if I have to disassemble and reassemble boards - what was your mind-in-the-gutter thinking? I will now return to my hidey-hole to avoid massive incoming flak anyway!
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Re: QCX-mini update
Looks like a bunch of nice improvements.
From reading lots of posts here, it does seem as if a lot of people had problems with the 5k volume control lugs either disconnecting from the phenolic or losing contact elsewhere. Does your new design address this problem at all, either by a different wiring method or a different pot? Bob M.
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Re: QCX-mini update
Ben
Wow, that is a good looking transceiver! For you not a major effort, but man, I am amazed ^_^ Even the alignment pots are reachable. I also like the CAT and PTT ports for when using the rig at home.
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