Topics

SOTA CW Starter Kit


Mike Molina
 

For the past few weeks, I've been slowly putting together a SOTA CW starter kit. The design goal is simple - create a CW kit for SOTA that is cheap, lightweight, and works great.

Here are the major components:

  • 20m or 40m 5W QCX Kit ($57 w/ shipping), plus one of my 3D printed enclosures for it. The QCX requires 4-10 hours of construction time.
  • SOTABeams Antenna ($75)
  • Fiberglass mast ($15)
  • Bioenna LiFePO Battery ($65)
  • Cables, solders, etc.
This past week I used the kit to make my first CW contact, about 400 miles away. So for a little over $200 and some kit assembly you'll have a complete CW rig that you can take out on SOTA. You can also use the rig as your home CW rig, and can even get an optional 50W amp for the QCX. If you're interested in learning more, let me know. I'm also curious if anyone else has suggestions about cheap CW rigs that are worth taking out on a SOTA summit.

Remember that Technicians have pretty extensive CW privileges, so don't feel like you immediately have to upgrade to General, though I would recommend you do anyways ;)

- Mike (KN6EZE)


Jeffrey Kabel
 

What SotaBeams antenna are you using? $75 seems pretty steep for a wire antenna, especially if your goal is a cheap setup. A single band dipole is easy to make for the cost of the materials, or places like QRPGuys sell various antenna kits for cheap.
Also, have you considered getting a RC LiPo or LiFePo battery from somewhere like HobbyKing? I've got my lithium batteries from there, and they're a lot cheaper than the Bioenno ones, even including the charger you have to buy (but only once).

Jeff aa6xa


Mike Molina
 

Hi Jeff,

I'm using the Band Hopper 2 (40m/20m). It's a bit pricey, but I figured after spending all that time on the QCX 40m build, I would get myself an antenna that "just works." Thanks for the QRPGuys and HobbyKing tips, though it looks like QRPGuys is suspending orders due to COVID-19.

For you and everyone else, here are some of my immediate needs:

  • New mast - I purchased one off of eBay for $10 that extends to 5m (advertised as a 7.2m mast), but I'm looking for something 6m or higher. The Band Hopper 2 is recommended to be at 6m, so my current mast is sub-optimal. Any recommendations?
  • Good outdoor antenna - I recently picked up a NanoVNA and am ready to get building my first serious 40m antenna. Based on where I live, a dipole at 20' or so over the house, strung between two 10' chain link top rails on each side, seems like my best bet. I feel like I'm going to need a 1:1 balun (maybe) and some good antenna wire, plus some coax spanning maybe 30' at most. Been looking around but haven't decided on anything yet.

My goal is get set up here at home with the QCX (40m @ 5W) in a configuration that will help me make additional CW QSO's for much-needed practice.

I'm pretty new to all this, so open to any and all suggestions!!!


Mike Molina
 

Following up on my previous email (I posted the same thing below to online to a SOTA group on Slack):

Random question for the group. I'm relatively new to ham radio (licensed in October last year) and am working on both a home and portable setup for 40m CW. I recently build a 40m QCX that I'm using. Here's my situation:

I have room to string a dipole above the house at 20' in height, leaving about 6 feet of clearance above the house. I plan to use cheap Home Depot aluminum chain link top rail guyed down to the ground. There's also a tree in the yard that's about 20' in height as well. My goal with this antenna, and the reason I chose 40m, is to be able to make reliable NVIS / regional contacts to practice CW with. I'm also looking forward to making distance contacts, but my height limitation at home might mean primarily NVIS for now. In the field I'm using the QCX with a SOTABeams Band Hopper 2 (40m/20m) to make CW contacts. I'm planning on building an NVIS portable setup as well. So here are my questions:

  • For the home rig, does anyone have any recommendations on what wire to use? I saw SOTABeams carries some thin wire that I can use to string up between the lengths of top rail.
  • Any reason why I shouldn't go with a dipole for my first home antenna? My goal is simplicity of design and setup. I have a NanoVNA that I'll be using for tuning.
  • Should I invest in a 1:1 balun or choke balun? If so, where's a good place to get the parts for one. I'd rather 3D design and print any sort of housing rather than shelling out 10-20x the cost for something pre-built, but am willing to buy one to save the hassle.
  • Any recommendations on parts for the feed point? I was thinking about a simple banana binding post, maybe with a 3D printed enclosure, but am open to suggestions.
  • I'm planning on using RG-174 over a ~30' run... any problems with that?

Any feedback whatsoever would be much appreciated. Trying to get to the point where I can reliably practice CW at home and then take it out into the field for SOTA. Thanks in advance!


Jeffrey Kabel
 

I wouldn't worry about getting a higher pole. If you're on a summit, it's like being on a hundred (or thousand) foot tall tower. You can, and people have, just lay the wire on rocks or bushes on the summit and activate without a problem. Those $10 eBay poles are great, don't have to worry about it if you lose or destroy one. I think most activators have a small collection of them. :D

And if you like building kits, the 1watters and 5watters from Kits and Parts are fun little radios. I have a 5W40 that I've been taking on activations. K7QO made some great build videos, explaining what each section does and showing how to test it section by section. (1watter5watter, but they're basically the same)

-- Jeff aa6xa


N6JFD
 

I too concur on the height comments. You already have an advantage
being on a summit above all else. For the past year-ish I've used
EFHWs and span them with my trekking poles (see image below). Oh and
for your QCX, you can get pretty creative with modifications. I built
a 30m QCX last year with a fully integrated antenna and cw key (from
QRP guys). I used their mini notune half wave, and their CW key..
(Here is my blog write up on that)..
https://n6jfd.net/2019/05/02/more-qcx-modifications-and-other-musings/
Good luck hope to hear you OTA

On Mon, Apr 6, 2020 at 7:24 PM Jeffrey Kabel <kabelj@...> wrote:

I wouldn't worry about getting a higher pole. If you're on a summit, it's like being on a hundred (or thousand) foot tall tower. You can, and people have, just lay the wire on rocks or bushes on the summit and activate without a problem. Those $10 eBay poles are great, don't have to worry about it if you lose or destroy one. I think most activators have a small collection of them. :D

And if you like building kits, the 1watters and 5watters from Kits and Parts are fun little radios. I have a 5W40 that I've been taking on activations. K7QO made some great build videos, explaining what each section does and showing how to test it section by section. (1watter, 5watter, but they're basically the same)

-- Jeff aa6xa


Dan AI6XG
 

There are many ways to do antennas for your home station.  It depends on your priority:  get something up so you can get on the air ASAP knowing you may not have the ideal setup or put something up that you won't need to mess with later.

A balun is a good idea but not essential, there are MFJ 1:1 that are relatively cheap and provide a convenient feed point for the dipole.  Just solder the antenna legs to the balun and your coax connected to the SO239.  Wrap with some electrical tape and you are good to go.  Saying that I have put up simple dipoles with no balun.  I use a dog bone insulator at the center feed, wrap the coax over the insulator and solder the braid and center conductor to the dipole legs.  This worked for a few years until I upgraded with the balun feed.  But it gets you on the air pretty quickly.  There is stress at this feed point so the insulator used needs to be strong.  Keep this in mind when considering 3d printed parts or binding posts.  Even a short piece of 1/2" PVC pipe makes for good center and end insulators.

For wire, ideally you want to use hard drawn Cu or copper clad steel that will not stretch.  HRO, DX engineering etc. have antenna wire you can use.  Or simply use Cu wire intended for house wiring.  It is soft drawn so it will stretch but if you don't have a lot of stress on the wire it will work for quite a while.  You may have to occasionally trim the wire for better SWR.   If you are looking to hide your antenna then the poly stealth wire works well.

My preference for your feed would be RG58 instead of RG174 unless you are trying to be super stealth.  RG174 or RG316 is great for lightweight short runs for SOTA.  With a short run of 30 feet there won't be much difference in loss.  But RG58 is easier to get, should be stronger, and easier to source connectors.  

GL de AI6XG