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How to stop worrying and love the uBitx #ubitx #ft8 #antennas #cat

masch57
 

I started putting together my uBitx (v4) months ago.  I added a better volume pot, CEC firmware, a Nextion display, and an AGC board.  I put it in one those blue metal cases from Amazon stole some knobs of an old stereo, and pretty much let it sit while I wasted too much time reading about mods, and worrying about feedlines and antennas.  But within the past week I realized that this is not my burly TS-430S, and it probably won't start an RF fire on my wall behind the tuner, so I decided to say "to heck with it" and just start flogging the uBitx.
With the exception of using an MFJ-971 antenna tuner, I went full "bull in a china shop" and did all of the following things "wrong":
 
1. Antenna is an unknown length (maybe 100ft) of 28awg enameled wire going East - West at about 7-8 feet above ground, surrounded by houses and trees. It is "counterpoised" by a 50ft (who knows how much is connected) rain gutter going North - South.  The ends of these are fed entirely without care through a wood block in the window frame into the back of the tuner.
 
2. Hooked up audio cables direct to the ins and outs on my computer with zero isolation.  Had to adapt the mic end to avoid setting off the PTT, so I stripped off an old plug, soldered a couple wires to it and hooked those with clip leads to the plug on my 1/8 patch cord.  I did have to ditch that USB extension cord I was using for CAT though, because it was noisy. Just went to the cord box and dug up a longer single cable to go from Raduino to Computer.
 
3. No ferrite beads, strapping, bonding, or other fiddly stuff was used in or out.
 
4. The Nextion is only using 2.8 of the 3.2 inches and I don't notice it.
 
5. The AGC board doesn't seem to do much and is probably wired wrong.  Don't care enough to go look for updated docs yet.  Low audio?  See #2 above -- I hooked it to the computer and listen through my headphones or speakers from there.
 
6. On some bands I can't tune much less than 3:1 and on most the tuner only says I'm putting 1/2 a watt forward.  Could be misreading (me or it), but I'm too lazy to rig up a dummy load and put the oscilloscope on it.  I leave it on "TUNE" (from WSJT-X) way too long trying to figure it out, and sometimes the back of the case gets warm.  Sometimes I've run it with the SWR meter almost pegged with the fanciful thought that it might be lying.
 
And so how did all my carelessness punish me?  With a ton of fun and true amazement at what such a shoddy, minimal setup can do, using our favorite modern mode, FT8 of course. With WSJT-X (ok, properly configured) and pskreporter.info, I have spent hours that I can't afford to waste (could be playing Fortnite!) making contacts from U.S coast to coast, and from Alaska to Mexico, and being heard from New Zealand, Japan, Europe and South America. I'm in Washington State, by the way.  And I'm operating with this fabulous antenna on 15, 17, 20, 30, 40, 60 (yes 60), and 80 meters.  Hard to tell if anything works on 10 meters these days.  But those times I mentioned when I run at an impossible SWR level, I can still get signal out (ok not always).
 
So the message is that it is quite possible, with a just stock uBitx (I didn't really need more than CEC firmware), to enjoy the absolute wonder of wafting intelligible messages across the globe on the tiniest amounts of RF.  And as for the spurs / etc., I'm sure the FCC will come for me, right after they get Billy Crowell and my neighbor's grow lights.

KE2GKB
 

masch57, If you happen to be using a Kit-Projects AGC we are working on a fix for it. Yes it has to do with the low audio but not in the fashion you would think. We are awaiting some extra tests to figure out the best fix possible for it.

To add to this, I do the same thing with my bitx, I plugged it into a switching 12vdc supply, Wired the headphone and mic into my PC no isolation, KD8CEC firmware for cat control. And a simple inverted V in a tree and ft8 has been an absolute blast! This rig has proven to be a champ even in bad swr just chugging along like it doesn't care. But that's part of the fun of QRP isn't it? Who needs Ideal conditions ;)

-- Tim Keller - KE2GKB https://shop.kit-projects.com

masch57
 

Thanks Tim, it is one of yours and I do have faith that you guys will get it figured out for the v4.  In the meantime, it's just "functionality waiting to be unlocked", and WSJT-X is quite forgiving in these matters.

KE2GKB
 

Thank you for the kind words :) !  Also actually having the AGC on is usually detrimental to to Digital mode operations. Specially where they operate well below the noise floor! it can cause some weird readings some times.

On Fri, May 10, 2019 at 9:15 PM masch57 <masch57@...> wrote:
Thanks Tim, it is one of yours and I do have faith that you guys will get it figured out for the v4.  In the meantime, it's just "functionality waiting to be unlocked", and WSJT-X is quite forgiving in these matters.


--
Tim Keller - KE2GKB
https://shop.kit-projects.com

Curt
 

Glad you are propagating and having fun. No I won't discourage you from improving your antenna, the spurs, and anything else. Nice parody!

Possibly your gutter system is the radiator and the wire is the counterpoise, it matters little.

My v4 similarly did nothing with that agc, but works fine with no agc or the vk3ye agc circuit. Many mod ideas at our club k3pzn ubitx page, your search engine likely knows the way there.

Curt

Dennis Beverage
 

Thanks masch57.  Just what I wanted to hear.  Working slowly on my V4, and right now i need to find some knobs.  Any suggestions appreciated.  Then it’s on to some sort of end fed, single wire, antenna.   Got HOA restrictions to work around.  Maybe build a Cheepo dummy load too.  Probably be back here for coaching on hookup to my Linux based computer as I’ve never played with whisper, jtx, ft8 or any of the many other digital qrp transmission systems.  Be fun to get started though.  Words for the day:  “DON’T WORRY, BE HAPPY.”

sodypop
KJ6VGB

Curt
 

Dennis

check out QRPGUYS for some antenna ideas.  they have a tuner for an end few halfwave antenna, a 3 band vertical matching unit, and other antennas there.  I imagine you can stash a good antenna there somehow.  FYI - a half wave tends to radiate from the middle of the wire (where it is cut to be a half wave) - something that may help you if you can get this portion in the clear. 

Dummy load - find some resistors - 2 watt ones - that parallel to make close to 50 ohms.  for example 220 / 4 = 55 ohms (certainly close enough).  or two 100 ohm resistors, just don't hit them as long. 

Knobs?  well is there a hamfest nearby?  W8DIZ may still have some knobs http://kitsandparts.com/store2.php  otherwise look around the web

Curt

masch57
 

Hey Dennis, glad to be of encouragement.  The ham fests usually do have useful some bits and pieces - just make a list and take it with you, because you will get distracted by all the awesome boat anchors.  Pickup a cheap manual antenna tuner if nothing else, a small one that has metering for QRP would be nice.  I got a like new one for $35.   Then you can wire up (through the tuner) to any old invisible hunk of wire and as long as its got some length you'll get something going on at least a few bands.  And don't be afraid to snake it around to get some length.  Changing bands requires re-tuning, but that knob-twiddling is what makes you feel like you're really doing some radio operating. 

Speaking of knobs, if you change out that stock volume pot for one with a 1/4 inch shaft, then it will match the encoder shaft, and lots of knobs from yard sale or thrift shop items may work.   Mine came from an old Yamaha receiver I had in my junk pile.  Just yank a knob or two off that thrift shop stereo, and if it has 1/4 inch half moon hole, give 'em a few bucks for it and you'll get a knob assortment. 

Do what Curt said for the dummy load -- find some 50 ohm non-inductive (no wire-wound resistors) something or other and quit transmitting into it when it starts smoking.  I wonder if a potato would work?  But I would caution that use of a dummy load is usually associated with measuring stuff that you could opt not to worry about.

Jack, W8TEE
 

Coming soon to a theater near you...

Inline image

Good up to 70W for 10 seconds; QRP levels 'til the cows come home. Cost: About $20.

Jack, W8TEE


On Saturday, May 11, 2019, 7:09:45 PM EDT, masch57 <masch57@...> wrote:


Hey Dennis, glad to be of encouragement.  The ham fests usually do have useful some bits and pieces - just make a list and take it with you, because you will get distracted by all the awesome boat anchors.  Pickup a cheap manual antenna tuner if nothing else, a small one that has metering for QRP would be nice.  I got a like new one for $35.   Then you can wire up (through the tuner) to any old invisible hunk of wire and as long as its got some length you'll get something going on at least a few bands.  And don't be afraid to snake it around to get some length.  Changing bands requires re-tuning, but that knob-twiddling is what makes you feel like you're really doing some radio operating. 

Speaking of knobs, if you change out that stock volume pot for one with a 1/4 inch shaft, then it will match the encoder shaft, and lots of knobs from yard sale or thrift shop items may work.   Mine came from an old Yamaha receiver I had in my junk pile.  Just yank a knob or two off that thrift shop stereo, and if it has 1/4 inch half moon hole, give 'em a few bucks for it and you'll get a knob assortment. 

Do what Curt said for the dummy load -- find some 50 ohm non-inductive (no wire-wound resistors) something or other and quit transmitting into it when it starts smoking.  I wonder if a potato would work?  But I would caution that use of a dummy load is usually associated with measuring stuff that you could opt not to worry about.

masch57
 

"I've seen pigs fly, but the day they put a microprocessor in dummy load..."
I thought it was joke picture until I saw the power display, and, um, on second thought, I'll get in line to buy that.

Jack, W8TEE
 

The major difference between the Mini DL and the one shown in the Nov. 2018 QST is the use of an RF power resistor (ebay 401311455234) and a 4" heat sink.(Amazon B07D9ZTTN2). The change makes it easier to use the DL, especially in the field, since you don't have a quart of oil to lug around. The downside is that it can't handle 150W for several minutes. This is part of a new Projects book that Al and I are working on.

Jack, W8TEE



On Saturday, May 11, 2019, 11:25:24 PM EDT, masch57 <masch57@...> wrote:


"I've seen pigs fly, but the day they put a microprocessor in dummy load..."
I thought it was joke picture until I saw the power display, and, um, on second thought, I'll get in line to buy that.

Dennis Beverage
 

Thanks for all the good info folks.  Many good suggestions.  Will be getting into those in the next couple of weeks.
sodypop

Gerry Kavanagh
 

Looks like a posh version of this:

Vince Loschiavo
 

Gerry
which kit is that in the tin??
vince

Wayne Leake
 

 Looking at two pictures, it looks to be a NANO with a TFT, maybe touch screen?
 Interesting, being as I just received two NANOs, though planned to use one to make a clone of a raduino.
 Maybe both, in the back of my mind.
 For a dummy load, I havea commercial grade 100-110 watt dummy load that I got on Ebay some years back. It uses an RF resistor mounted to a large heat sink, well worth what I paid for it.
 I do have to use a UHF to N adapter, as it has an N connector.
 Lots better than the Cantenna was. Lighter, no worry about spilled oil of whatever type.
 I used transformer oil in the one I built. MY brother may have used mineral oil in his, being as he was less likely to search for, and find a source for transformer oil. Mine did leak a teeny amount through the pressure vent, just enough to make an oil/dust mix, LOL.
 Anyway, I'd kinda like to build this mini dummy load with meter for QRP testing.


Gerry Kavanagh
 

Hi Vince, Wayne... It's based on work done by DuWayne KV4QB - http://kv4qb.blogspot.com/search?q=power+dummy
I have a few spare boards if you are interested...
/ Gerry

Tom, wb6b
 

Hi,

Good things come to procrastinators... This KV4QB site has a lot of interesting Ham related microprocessor projects. Including adding a TFT display to a uBitx. And a cool simulated analog meter using a small OLED display. 

He has a project for a 63 db step attenuator using eBay attenuator modules. I recently bought two to do the same thing. And when that day comes I have some spare time I was going to hash together some kind of Arduino code to control them. Right there on his site is code to do just that. Maybe if I stay busy with client projects, my soldering iron will build the thing for me (Maybe like Disney's Fantasia. Although I seem to remember things went terribly wrong when inanimate objects were set off to do work). Well, maybe, procrastination won't be rewarded at that level.

http://kv4qb.blogspot.com/2019/04/63-db-step-attenuator.html

Tom, wb6b