Category Archives: HF Portable

Field Day Preps Complete!

My Field Day preps are done. Tested the EFHW and its ready to roll on 20m and 15m. There is 12Ahr of solar charged battery ready as well. I won’t be able to join the club at the NWS office as I have a commitment in the morning I have to deal with. I may start late but I am ready for operations in the backyard. Will get some water bottles and snacks for daytime ops. There is a 30% of rain tomorrow afternoon so I’ll keep an eye on that as well to see if I need to deploy the tarp tent. Rain means clouds so that may help moderate the heat. Today the NWS is advising people to stay indoors between 1pm and 5pm!

Tested the EFHW a bit and am finding Common Mode Current issues if I run higher than 90W. The SWR increases with power and foldback starts kicking in if I try and run at 100W. This should not be a problem on FD as I’ll be running at 5W where everything behaves itself. I’ll be trying computer logging this year as well. If things get real tough on Phone I plan to try PSK31 and have setup some DM78- macros for that.

Looking forward to a great Field Day in the outdoors!

Completed Linked EFHW

I completed the linked EFHW later yesterday afternoon and tuned the 15m, 17m & 20m bands. I removed about 6″ of wire to tune 15m, 2″ to tune 17m and about 3″ to tune 20m. The antenna is deployed vertically on a SOTAbeams Travel pole up 30 feet. I am using a TV mast tripod as a base. In the field I would lash the mast to a fence post or other similar support.

I tested the antenna on my base rig at 100W and made three easy SSB contacts. Two of these were EU DX contacts. I  left it tuned for 20m and ran WSPR for the last 12 hours. Here is the map:

2017-06-22_7-27-12

This works out to 112 unique heard spots with 66 unique heard by spots when running 1/2W. Looks like the antenna is a winner for Field Day! Only thing I will likely try today is adding a 1:1 choke as I am seeing the SWR swing a bit on SSB transmit.

Linked EFHW Coming Together

I purchased the following for $1 at Home Depot yesterday to form links for the EFHW I plan to use for Field Day:

Photo Jun 21, 10 47 20 AM

These are buckles to make paracord bracelets. Here is how the resulting link looks like using these, a couple of cable ties and a pair of Anderson Power Poles:

Photo Jun 21, 11 01 22 AMPhoto Jun 21, 11 01 32 AM

I have made initial wire cuts for 15m, 17m, 20m and 40m. I also cut 1/10 wavelength counterpoise wires for each band. I have also prepped the Travel Mast and the TV Tripod so I will hopefully setup later this afternoon (when it cools off a bit) and tune the wires. I’ll run 15m-20m as a vertical and 40m as an inverted V.

The only other prep I am working on today is I’ve taken the solar generator box I built last year and set it up outside with the two 15W panels to charge them up.

Update: Just did the calculations on the 40m inverted V and found that I probably don’t have enough space to lay that out in the backyard due to obstacles. Will configure the first half as a vertical and then the remaining half as a sloper which I’ll aim towards the north and terminate 4 feet off the ground. Only need a radius of about 16ft. A quick run on EZNEC show the following pattern:

2017-06-21_13-10-142017-06-21_13-10-32

Plan B for Field Day Antennas

I was pondering what I would do for a Field Day antenna after yesterday’s debacle with the Homebrew Buddipole and military mast. It just hit me a few minutes ago. I’ll run the EFHW antenna as a vertical on 20m and 15m. It is a proven performer and it is resonant thus no tuner needed. I’ll use the TV Mast tripod Cliff gave me to support it during the contest on the SOTABeams Travel mast.  What I will do this week is set that up and cut some links for 15m, 20m and possibly even 40m. Will be much more manageable as a vertical. I have 5 days to work out the details. Tomorrow morning I’ll put put the battery packs and solar panels to top off the charge. This should work!

Epic Fail! – Homebrew Buddipole on Military Mast

I took out the military poles and tripod today for the first time with the intent of getting the homebrew Buddipole up around 30 ft. The mast itself works pretty well with the tripod hub. I mounted the Buddipole on top as I have before with the painters pole except this time I replaced the thread adapter with a 3/4″ PVC pipe adapter and used a length of pipe to fit inside the mast section. I guyed it near the top. I sent it up and it promptly got swung around in the wind and tangled in a tree. After twisting and turning awhile I got it clear and up to 28 ft then tied off the guys. I left the last section off as I did not have enough coax to get it in the shack.

Started operating on SSB and made a strong 59 contact into Arizona then noticed that my SWR was swinging around. Looked outside and saw that one half of the dipole was swinging into more of a v-beam. Moments later it fell off completely. Doh!

Photo Jun 17, 1 25 23 PM

The section landed cleanly and did no damage but I had to take the whole thing down. Guy lines get tangled, the aluminum mast sections are burning hot to the touch and my temper starts flaring. Did I mention it’s 97 degrees outside with 51% humidity?

So I carefully sort out the guy lines, move the tripod a few feet away from the tree and place a wedge in to keep it from swinging as much. Sent it up again and adjusted the guy lines. Went back inside the shack and hooked up the SWR meter. It started a sweep and was looking good when I heard a SNAP and the meter SWR reading went full scale. I looked out the window and sure enough the half of the dipole fell again. On inspection I was not so lucky as I broke the whip off at the base. Doh!

So thus ends my Field Day Preps today.I am goign to use something much simpler next week. Either the Homebrew Buddistick which I have used before, an end fed vertical up about 30 feet or a 1/4 wave vertical for 20m with four ground radials. The Buddipole is going to be limited to lower heights using the painters pole. If I had more time I’d try an inverted V for 20m using the Spiderbeam mast.

 

Buddipole 1:1 Current Balun

Here is the 1:1 Current Balun for the Homebrew Buddipole antenna. I sourced the parts kit from Ebay and just had to assemble it as before. This is ready to test as soon as tomorrow. I am planning to setup the 30 ft military pole with the Buddipole for the first time tomorrow if the wind cooperates. This should work very well at 30 ft!

Photo Jun 13, 2 49 18 PM

Photo Jun 14, 5 25 02 PM

Buddipole Tweaks

I was going to try and adjust the loading coils on the homebrew Buddipole but after reviewing the SWR plots in more detail I have decided against this. The resonance point is on the high end of the band but I’ll be operating mainly voice. The SWR is below 1.6 across the band and the reactance is within ±3 Ohms of the resonance point. Better to leave it alone at this point.

I did add a couple of cable ties to the arm to allow me to better control the antenna swinging in the wind. I am working to build another 1:1 current balun which I will replace the BNC to binding post adapter I am runing now. It will be interesting to see if adding this balun will change the SWR curve. Here are the current curves:

BUDDIPOLE CustomBUDDIPOLE CustomA

Hopefully I can retest the deployment of this antenna this weekend perhaps at 20 ft and with luck maybe at 30 feet on the military mast.

Field Day Antenna Selection

Working on Field Day antenna selection this week. I am down to using the Homebrew Buddipole, Buddistick or end fed vertical antenna this year. I plan to operate as 1B battery operation so I am limited to 5W on SSB. This will be my main challenge  this year given the worsening band conditions as the solar cycle continues the drop.

A previous post showed some data on the homebrew Buddipole mounted at 16 ft with a painters pole. I am working on a few tweaks now that will bring resonance into the band and simplify the azimuth adjustments.

The Homebrew Buddistick served me well in 2015 but band conditions are shifting. Here is some modeling data comparing the Buddipole at various heights vs the Buddistick on 20m:

2017-06-12_10-39-07

The Buddipole at 16ft and 20 ft outperforms the Buddistick down to about 25 to 20 degrees. The Buddistick has more gain below these take off angles. At 30 ft the Buddipole is better or equal to the Buddistick from 60 degrees all the way way down to zero.

One thing I could do is use both antennas and switch back and forth as needed. This would not be overly complex to do. My challenge is getting the Buddipole up above 16 ft. If I can get setup using the military poles I can get the Buddipole up to 30 ft and only use the one antenna.

 

 

Camera Tripod Adapter

The Homebrew Buddistick and the Magnetic Loop antenna both require mounting on a camera tripod. Up to now I had been using a tripod without the pan head and inserting the 3/4″ PVC pipe with a pressure fit. This worked OK for awhile but eventually the tripod fitting pulled out and the tripod was ruined. I have been thinking for some time about how to make an adapter that would fit the standard tripod pan head and allow me to mount the antenna. A trip to Home Depot this afternoon yielded a solution. I built a mount with these four components:

  1. 2″ Pipe PVC cap – These have a flat cap surface
  2. 2″ to 3/4″ PVC pipe adapter
  3. 2″ PVC pipe coupling
  4. A 1/4″-20 threaded insert.

Building this was simple enough. First drill an 11/16″ hole in the middle of the pipe cap. Then using a 6mm hex key drive the 1/4-20 insert into the pipe cap until it is flush. Here is the cap mounted on the tripod:

Photo May 28, 4 35 19 PM

To complete this adapter install the coupling along with the 3/4″ adapter and it will be ready to mount the antenna. Here is the finished adapter mounted on the tripod:

Photo May 28, 4 35 37 PM

I finished this just in time as I need it to start testing the Homebrew Buddistick as I’d like to compare it’s WSPR performance to the Homebrew Buddipole.

UPDATE 6/13/2017: This turned into a fail. I tested this mount on the mag loop antenna and the weight and balance was too much for the tripod head. The clamp mechanism snapped and rendered the head useless. I removed the head and and am back to using it as before, i.e. with the pvc pipe jammed onto the tripod vertical post.

Homebrew Buddipole Shakedown Testing

Sometime ago I built a homebrew version of a Buddipole horizontal dipole antenna. I only deployed it once to test and have not really used it much since. I am considering using this antenna for Field Day this year on the 20m band and wanted to test it out. Happy I did for several reasons. Here is the antenna deployed at 16ft with a painters pole:

Photo May 27, 1 47 33 PM

The antenna is guyed at two levels. The painters pole is inserted into a speaker stand tripod. Here is the SWR plot:

BUDDIPOLE Custom

Most of SWR is below 2 however the resonance point is outside the band on the high side.  So I have to lengthen the antenna slightly. The whips are already at their max so I will have to adjust the loading coils. One more turn on each should give me room to adjust with the whip lengths if necessary.

Something else that needs to be addressed is that the antenna swings around in the wind. I need to add an attachment point for a separate line to secure it from swinging. The old “Armstrong” method of swinging the antenna around. Finally, I need to put a true 1:1 current balun at the feed-point. I have the kit to build one and will do so this week.

The antenna has performed well. I called CQ this afternoon and made 5 contacts from South Dakota to Florida and North Carolina. Band Conditions have been fairly bad with considerable QSB. Europe will open up in a couple of hours and will try it again then.