Tag: QCX

More QCX modifications (and other musings)

So as I called out in my last blog that the 30m QCX test was a success.  In 25 minutes I had 10QSO before my battery died.  You may recall me commenting that during the hike  out, I was wondering if I could somehow reduce the weight and some of the additional hardware by using just the inductor and capacitor and direct wiring into the PCB on the QCX.   QRPGuys makes a mini version of their single band half wave EHFW:  Enter the QRP Guys Mini NOTune Half wave EFHW.   Finally having a night I can work on it I set out to get as much as the matchbox part of the build done.  First up, time to remove the BNC adapter on the QCX:

img_3894For the sake of giving myself some options down the road I just snipped the leads off the BNC adapter, and then carefully worked the anchor studs out.

Next up it was time to work on the plastic enclosure for the antenna and get that prepped.  I actually like that the matchbox they supply with the kit is not pre-drilled.  This gives you some options, or more over, does not mean you have holes to plug if your intentions end up similar to mine..  I did not drill the big hole for the BNC connector obviously.

The instructions are pretty straight forward on this and I had the solder work done within an hour.   One thing I’ll call out now is that the QRPGuys mini is the same height as the QCX enclosure, so it wont look too awkward.

Midpoint check-in: img_3891

Thinking that I was not going to be using the BNC adapter hole I thought put the main antenna out one side, and the counterpoise on the other.  That later ended up being a mistake because the screw stub was now covering the 3.5mm jack for the key.  Whoops, one more hole I now have to fill. Maybe this is why I should not work late ;).

After jamming some John Denver most of the night, I got to the point that my next step was drilling into the enclosure and given it was past 11pm I opted to wait till morning, and took advantage of a mid morning break between meetings.

<The Next Day> 😀  Marked the holes on the enclosure, pre-drilled with a bit that was about the same size as the supplied self tapping screws, then hit the enclosure with a step bit to go just a touch wider.

Checking for fit
Checking for fit

Sweet, the mounting holes were lined up perfect, and the wires come thru with plenty of length.  After this I put some electricians tape around the inside of the opening to keep wire/metal from touching the enclosure.    I unfortunately did not have any clear silicon caulk, and was too lazy to head to the hardware store, so I opted to use some white latex/tile caulk that I had around.  It is just a temporary thing, but the goal was to have some sort of seal between the enclosures.  Oh and to also seal up that extra hole I put into the antenna matchbox.  It’s ugly and you will see that down below., but for now it will get the job done.

At this point I went ahead and re-added the QCX into the enclosure, secured it on two of the mounts for testing, and then soldered the new connections to my antenna nubs.   I then plugged in the battery to make sure it still powered up, and was still getting the same power out, and voltage in readings it was before.  No smoke and the numbers looked good :D.  Might as well go ahead and see if this setup actually works, so borrowing the radiator off the PCB version of this antenna I ran out to the meadow behind the house where I do my testing from.    W00T:  Success:  After a couple of run thrus of the pre-recorded test cq message I setup a while back I was picked up by VE6WZ which is about 900 miles away on the RBN.   Not bad given this QCX with its current setup/battery puts out 1.85W of power.   For those that do not know, apparently the build specs on the 30m QCX are a little off for inductors L1 and L3, most folks who have offered feedback suggest changing those inductors to 16 turns and not the 19 it calls for in the instructions.  I have not yet done L1 but I did do L3 which did boost power a little.  Inductor L1 is in a weird spot, and I am not sure I want to deal w/ the headache of re-attaching it once I get one side off.  Besides from a summit, 2W is plenty of power, and given the RBN did pick me up from the Tahoe Basin I call it a success as is.

QCX ready for testing..
When I operate tests I goto the meadow behind my house, the neighbor there has a picnic table that is perfect for staging.

Yes that white caulk is ugly, I’m thinking I’ll scrape that off and redo with a clear silicon.  I also ordered some new 22awg wire for the new radiator in a different color. The yellow one is a little bit short, but I know that radiator on the PCB version of this antenna is resonant at 10.118 and I will still use that antenna with my KX2.

So now that everything is back together, I took and weighed the entire kit as I will carry it to a summit.   It is coming in at a whopping 1lb 2.2 oz.   The kit contains: palm pico paddle, small ear buds, 1400mah battery, MSR mini-hog tent stake to secure the far end and of course that QCX.  A pretty simple rig for those days where I want to go far with minimal weight, and get there quickly.    Next modification maybe to go with a touch sensitive keyer.  Find a way to build a battery into the enclosure and the only *extra* stuff I’ll be carrying are the headphones.

 

I’ll be testing this out on a live activation this coming Saturday.  Anyone want to buy a KX2? (seems like 30m and a 2m HT will get the job done for the most part, at least in the areas I like to activate from.  Not sure I’m ready to sell the KX2 yet, just kidding, I do chase from home with the KX2.

Speaking of QSOs, I finally got around to designing and then ordering some new QSL cards.  I intend to start shipping out QSL cards as response to ones received over the past couple of years next week.  Better late then never :D.  What prompted that decision was in a matter of a couple of weeks I received ~10 QSL cards because I had been making some new contacts, including some with IOTA folks.  I like getting them, only fair I should respond in kind.    I went with qslpostcards.com because a few of the QSL cards I’d received over the years had their URL somewhere on the card.   The quality of the ones I’d received seemed pretty good, and they were a good price. (250 cards for $69.00).  I like supporting small businesses too and these guys are HAMS.   Those finally came today.

That is all for now, hope to QSO you from a summit in the future!

72 de N6JFD.

The kit gets lighter and W7N/TR-025

Here it is towards the end of April, spring is in full swing in some areas, however the Sierras are still coated with feet of snow, but the mountains in NV are calling and open with easy access.   So for the past two years I have been operating with a KX2 and that is an amazing rig, full of features, and I am sure i am only scratching that surface, and my kit weight has varied over that two years as I have added/subtracted batteries changed up antenna configurations etc, but it does come in around 5lb.

All that said last year I went thru level 1 of CWops and started doing some CW on my activations.  I immediately went from hoping to get 10 contacts, to always getting more then 10 contacts when I started doing CW as the bulk of my activation.  I’ll still hit some 40m SSB because some of my friends still are SSB.   Why I brought up old news, is that going to cw opened up 30m for me, and on those weekends when 20/40 are in use for some contest, that can make an activation a bit more challenging.  What I have found with 30m is I still get the same chasers I do on 40/20, but the signal reports are not as strong, with the exception for W5N, and W7A which are stronger.  W7O is down in the 3s and W7W is in the 4s for me and I can consistently hit W0C.   While I am not saying 30m will always get me the most number of contacts all the time, it will at least get the job done, and the regular chasers will do their best to work you, especially if they know you are mono-banding.

About this same time the NASOTA slack channel really started to grow.  A few of those fellow SOTA folks are kit builders, and love tinkering with their rigs etc.  K6ARK has added a touch sensitive keyer directly into his MTR3b as an example, since then he even built a micro-pixie with built in matching unit and direct attach end fed for a SOTA capable rig that he has used on an activation that weighs in the 3oz range.  KT5X out in NM is always looking to make a lighter kit as well, and often writes the NASOTA groups.io forum with his updates.  KE6MT has also been a fountain of information on the builder front and has helped me immensely (he better, I’m his associate association manager ;P  ).  That said, I took it upon my self to order a 30m QCX (from qrp-labs.com) with the intention of using that as a light-weight SOTA rig on those days where I want to do a lot of miles, and I may be shooting for a lighter pack to focus on miles while still carrying the 10essentials, or I am time limited.  The Black Diamond Distance 15l fills the bill well, and I used it on a recent co-activation with Rex on Waterhouse Peak.  Maybe I will be one of the first SOTA guys to do an UltraThon AND an activation on the same event.  (doubtful, but one can dream).

My current kit:

  • KX2
  • 4.5mah BioEnno battery (I get ~11 hours of operation on a single charge with the KX2 at 10w)
  • LNR Trail Friendly, or QRPGuys 20/30/40 Vertical antenna
  • 15 foot feedline (for the vertical)
  • Mic, Keyer, headphones etc..
  • Fishing pole for antenna mast.
  • fit into an REI “medium” bathroom travel bag.

That five pound mark is not too bad overall, and I know folks who carry more, and even with that list, there are some changes I could make to get it lighter yet.    End Feds are great just draping off the side of the  mountain as a “sloper” and in some cases, some peaks already have things you can use to help go inverted vee (like tree limbs or no longer used antenna towers).  So I can drop the fishing rod all together in the future.

I have set my goal to be less then 2lb overall because I have a few hikes I want to try as a “HaRunk” (ham radio trail run).   So I have set out on how to accomplish this mission, enter the QCX and a new kit

57756889132__6c08cef7-cd06-4c2b-b9ac-c72258477e8aI have chased a few folks with the QCX from the QTH, but now it was finally time to use the QCX as my activation rig.  It was on Easter Sunday and on a day that 30m propagation was not great and I was not on summit till noon.  SotaWatch showed that I was the first spot in over two hours.  I managed seven QSO over 25 minutes and then my battery decided it was time to shut off for recharge (oops..been testing a lot, forgot to check levels).  Either way it was a successful activation on a unique summit.  Full disclosure it was also the first time I have done an activation without using the decoder, and I managed to get a good copy on all those who called me whom I could hear, so I am getting better there too.  Contacts included: AG6VA, K0RS, KR7RK, W7USA, WA9STI, W7GA and K7RJ.  According to RBN I was reaching the VE6WZ beacon up in Calgary, approximately 700 miles.  Last time I checked, I was putting out 2watts of power, but that was before I really tuned my EFHW.  On the approach drive in *4×4 road* I managed to make it to within a mile of the summit, but overall this is a drive up summit.  Either way, b/c I am in run training, the 1 mile 400 foot elevation just helps with the training, and I do my best thinking when I’m walking (more on that below).     Those structures you see on the summit proper are from past deployments I think, all the radio towers, cell towers, and TV towers have been moved to other nearby peaks, overall (at least on 30m) this was an RF quiet peak.

Now on to the kit you see pictured above: (Phase one of weight reduction)

When I started tinkering with the idea of a single band antenna I went and snagged a qrpguys NoTune end fed HW antenna.    I was still lugging that big 4.5mah battery, so I am thinking next up there will be to go snag an 1800-2200mah LiFE/LiPo battery;  that should give me 3-5 hours of operation overall.  Weight difference there is almost a pound.   I love having that mono band EFHW antenna, but I was concerned that banging  the PCB around on rocks, or letting it hit snow, or snag on a limb could be detrimental.   While I was hiking out, it dawned on me, that all I really needed from that PCB is the transformer and capacitor, and some way to shove it inside the QCX enclosure or protect it another way.  I actually went back to the QRP guys page b/c I’d heard rumors they were making a self contained matchbox version of the same antenna, and sure enough they have a mini version.  Purchase complete, hopefully here by the end of the week.  That actually helps me solve a couple of issues as I can use the matchbox to cover the opening that removing the BNC from the QCX will create.  I will also be able to use that to wire the components direct to the QCX PCB.  (I am just a rookie at the tinkerer thing, so things will probably look/be clunky at first).  I will have to plug the hole on the matchbox for the BNC, so a new problem to solve, but not major.  Honestly the best outcome is to somehow figure out if I can get the full setup inside the QCX enclosure, and then tap two screws for counterpoise and antenna thru the enclosure.   I will also be able to roll the wire (42’6″) around the QCX case as a winder.  Moving to this will also eliminate the need for a feedline, or a BNC/BNC coupler and with lighter battery will help achieve that 2lb goal I am shooting for.   I am hoping to have that all setup for the Lake District SOTA weekend in the UK, as I am looking to do some mileage on my first day over in Wales to snag Snowdon and YLlwedd before heading up to Ambleside.    I may actually break it on Mt Shasta the weekend prior to heading out.

Once i get the new changes put in, I’ll start doing some power drain measurements and add those to a followup post.  This is the part of SOTA that makes Ham Radio fun, the tinkering and playing and seeing what can be accomplished with small gear.

So let me re-iterate: I do not condone leaving the 10-essentials at home, but we always have room for improvement in reducing pack weight.   Given enough time and creativity really coming up with ways to build a walkabout kit with SOTA gear that borders on featherweight on the back is in and of itself a fun exercise.

Get out there and enjoy the hills!

72  de N6JFD