Date
1 - 20 of 32
Multi band QCX plus Party time...
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Nigel ZS6RN
Hello again from ZS land :-) |
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Richard Tomlinson G4TGJ
There are 3 parts of the QCX that are band specific: input tuned circuit, output low pas filter and class E amplifier.
I also have a 30m QCX. We should have QCX activity that isn't a contest so that we aren't left out. -- 73 Richard G4TGJ |
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John Kirby
Niger,
Of course T1 is prime but not as critical as one thinks :>) This pcb with 30m T1 is a four band xcvr Parallel C1 and Outboard LPF and Bypass onboard audio filter and Add variable (tunable) audio filter This HB loop es set up 'WHISPERED' to Antarctic, Auz es NZ before XYL said "%$flkx 345 , ## ■ x" rough xlation "get it OUT here!!! 72 73 John N3AAZ FM19 |
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n4qa at_hotmail.com
Hey there, Nigel.
Not having a stock QCX-30, I can't speak to its performance on other bands. But, as for my stock QCX-17, I have enjoyed more QSOs with it on 30m than on any other band...would love to QSO ZS6RN on 30m ! I was informed yesterday by Alan, G1FXB of the 6-band QCX rig by Andreas, DM5MU, found near the bottom of the page at: https://www.qrp-labs.com/qcx/qcxgallery.html Very interesting rig ! 72 / 73, Bill, N4QA |
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John Kirby
OOPS image ? N3AAZ SETUP |
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n4qa at_hotmail.com
Hey, John, N3AAZ,
Many thanks for the hint about the "variable (tunable)" audio filter. I've been wanting to improve on my 7-band QCX rig's performance while receiving, for example, CHU on USB on its three freqs, as well as AM SWBC, JS8, FT8 etc on all my QCX-17's freqs ! 72 / 73, Bill, N4QA |
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John Kirby
N3AAZ
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John Kirby
RE T1 and pcb de solder / re solder
As we all know T1 is prime RX ... If u can't hear-em can't QSO-EM Solved my problem N3AAZ |
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jjpurdum
Somebody is a bachelor or has a really understanding XYL. Jack, W8TEE
On Tuesday, April 16, 2019, 7:31:46 AM EDT, John Kirby <n3aaz_qrp_1@...> wrote:
N3AAZ
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John Kirby
Jack,
HI HI only been my XYL since 1964, me a ham since 1956 dit dit Hans BPFs (image) are a delight L4 es C30 tweeking can be fun too but, you will need three meters and, a better understanding of class E efficency than I could muster ( retired 1997) N3AAZ |
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jjpurdum
Me: ham since 1954, retired 2009, no XYL even with a "no-radio-stuff" living room. Musta made a wrong turn somewhere... :>) Jack, W8TEE
On Tuesday, April 16, 2019, 6:13:44 AM PDT, John Kirby <n3aaz_qrp_1@...> wrote:
Jack, HI HI only been my XYL since 1964, me a ham since 1956 dit dit Hans BPFs (image) are a delight L4 es C30 tweeking can be fun too but, you will need three meters and, a better understanding of class E efficency than I could muster ( retired 1997) N3AAZ |
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Nick Norman
On 16/04/2019 14:13, John Kirby wrote:
Jack,John, That dummy load - where did the design come from? I presume the leds give a rough indication of power? I'd be interested in the schematic &/or source. Regards Nick M0HGU -- 'People need vampires,' she [Granny] said. 'They helps 'em remember what stakes and garlic are for.' (Carpe Jugulum) 14:50:01 up 2:09, 9 users, load average: 0.65, 1.24, 1.44 -- 73 Nick M0HGU |
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John Kirby
Nick,
That LED dummy load is kit I built 10 or more years back and have long since lost the manual. The pcb is marked such... XTAL SET SOCIETY 10W SMART DUMMY LOAD www.midnightscience.com My web search found 'dot net' and 'dot com' and this... http://www.njqrp.club/Rainbow/rb_schem.html ... but no help with my kit. Maybe you will have more luck other than gQQgle The high Watt resistors (image) are 300 Ohm each Based on the low Watt resistors; one set of 4 (1000 Ohm) and second set of 4 ( 100 k Ohm) l >auusme< four of the diodes are zener ... and maybe all different voltage >else< how would one 'calibrate' 1W, 2W, 5W 10W with any degree of accuracy? and other 4 diodes maybe something like 1n 4148 or 914 I also >assume< LEDs are 'low' current type The rf ground plane (second image) prevents reverse engineering a schematic. 72 73 John N3ÀAZ |
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jjpurdum
I'm working on a Mini Dummy Load, which has the same OLED display as the Nov, 2018, QST dummy load (DL): but instead of the resistor network and quart can of mineral oil, which makes it less desirable for SOTA, IOTA, etc. work, we're using one of these: While this says its rated at 150W, it's about the size of the first joint of your little finger and it will NOT dissipate 150W without a lot of help. This picture shows the (4") heat sink we're adding to the back of the DL case. We tested one at 100W for about 45 seconds only to see the top half travel at the speed of light past our ears! Seriously, it literally past us before the sound got to us! We feel very safe rating it at 35W with the heat sink. It's small enough to fit in your shirt pocket, but still let you tune up politely on the air. The OLED display is driven by a Nano using essentially the same code and circuitry as the article. I have a couple of 250W units coming and will see what they can stand. Jack, W8TEE
On Wednesday, April 17, 2019, 9:08:44 AM EDT, John Kirby <n3aaz_qrp_1@...> wrote:
Nick, That LED dummy load is kit I built 10 or more years back and have long since lost the manual. The pcb is marked such... XTAL SET SOCIETY 10W SMART DUMMY LOAD www.midnightscience.com My web search found 'dot net' and 'dot com' and this... http://www.njqrp.club/Rainbow/rb_schem.html ... but no help with my kit. Maybe you will have more luck other than gQQgle The high Watt resistors (image) are 300 Ohm each Based on the low Watt resistors; one set of 4 (1000 Ohm) and second set of 4 ( 100 k Ohm) l >auusme< four of the diodes are zener ... and maybe all different voltage >else< how would one 'calibrate' 1W, 2W, 5W 10W with any degree of accuracy? and other 4 diodes maybe something like 1n 4148 or 914 I also >assume< LEDs are 'low' current type The rf ground plane (second image) prevents reverse engineering a schematic. 72 73 John N3ÀAZ |
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n4qa at_hotmail.com
Hey John,
There is always that handy multi-meter for helping with reverse engineering efforts :0) 72 / 73, Bill, N4QA |
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John Kirby
Nigel, Please l apologizes for I wander off topic 72 73 John N3AAZ |
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Roy Appleton
The only thing I found on the 10W smart dummy load. On Wed, Apr 17, 2019, 8:08 AM John Kirby <n3aaz_qrp_1@...> wrote: Nick, |
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Nigel ZS6RN
Thank you all for the feedback received (direct and via forum), after review of the schematic plus workings of a class E amplifier and applied 'thinking', the route I will follow IF proceeding to make QCX multiband, will be to construct dedicated receive, common band pass (L1, L2 and L3) and P.A. resonant circuit modules that are switched into circuit as required. Have located a suitable mechanical switch from my VERY old 'junk collection' that will be ideal for the job (miniature 8p 4w rotary from Japan).
Once project completed, be it 'standard' or 'modified', I will post a picture or two together with details. vy 73 Nigel ZS6RN ex G8DEV |
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Steve in Okinawa
I've used a few of those 150 watt terminations on various heatsinks. The power rating is no joke-- on a large fan-cooled cpu heatsink they will dissipate 149.9 watts all day long. At 150.1 they explode. Well, that's how it seemed anyway...... I've gone over to the 250 watt units for my small dummy loads now. JS6TMW
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jjpurdum
...on a large fan-cooled cpu heatsink... That's the key! Jack, W8TEE
On Wednesday, April 17, 2019, 10:24:37 AM EDT, Steve in Okinawa <sfab43@...> wrote:
I've used a few of those 150 watt terminations on various heatsinks. The power rating is no joke-- on a large fan-cooled cpu heatsink they will dissipate 149.9 watts all day long. At 150.1 they explode. Well, that's how it seemed anyway...... I've gone over to the 250 watt units for my small dummy loads now. JS6TMW
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