Homebrew Buddipole on WSPR

Here are about 18 hours worth of 20m WSPR data on the Homebrew Buddipole at 16 ft. So far 137 unique spots. Looks like it will provide good coverage for Field Day. I’ll be comparing this again the Homebrew Buddistick next.

buddipole wspr

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.

 

 

Reached 100 DX entities – unofficially

I made a 20m SSB contact to Guadalupe in the Caribbean yesterday which got my unofficial DX count to 100. It is unofficial because I don’t have the electronic confirmation either though QRZ or LoTW. My official tally is 85 for DXCC and 88 for QRZ DX World. It has taken awhile to get here and the new antennas I have been testing help quite a bit. Wish more folks could confirm either through QRZ or LoTW!

SWR Meter Bulb Replacement – Win!

I use an MFJ-822 SWR meter with my base rig and it has served me well. Only issue is the small incandescent 12V bulb burned out making it hard to read in a low light situation. I replaced the bulb with a white LED rated at 12V by MPJA. This did require a bit of careful surgery but was successful. One screw removed the case. The bulb is connected with a small Molex connector. The meter connections have to be un-soldered in order to get at the bulb. The meter movement is gently pried off the cover. Here it is disassembled:

Photo May 23, 3 20 57 PM

The bulb used in the MFJ meter is not field replaceable. It is glued into the meter plate. I gently popped it out and then drilled out the hole for the LED. A bit of super glue holds it in place. Reassembly was straightforward, just be careful to re-solder the meter correctly. Here is the meter with white LED goodness:

Photo May 23, 3 49 57 PM

Keep in mind that doing this retrofit likely voids any warranty you may have with MFJ so do it at your own risk and as always, Your Mileage May Vary.

Mini60 Bluetooth Retrofit – Epic Fail

I was going to make one last attempt at getting the mini60 Bluetooth module to work by removing it and redoing the baud rate programming step. Too many applications of the soldering iron affected the small solder pads and traces on both the module and the Mini60. I removed the module and put the Mini60 back together again. Everything is still working as before but no Bluetooth goodness. Better to just but the Mini60 with the Bluetooth module installed.

Mini60 Bluetooth Install – One step forward, two steps back

Per my last post, I found the jumpers needed to get signals and power to the Bluetooth module. I can now successfully pair the Mini60 with either the Amazon Fire or my PC. That’s as far as it goes though as neither application is transferring data. The USB link still works ok but nothing over the Bluetooth link. I verified continuity to the USB chip and even tried reversing the signals to no avail. Not sure what to try next. I’ll let it sit until I get a replacement power switch in. I burned up the original when I tried to solder it back on to the PCB.

Mini60 Bluetooth Progress – Nothing is Ever Easy!

I soldered the bluetooth module onto the Mini60 at the five solder pads. At this point I installed the battery and shorted across the switch terminals to test ot. The Mini60 comes up ok and I can place it into PC Link mode but the module is not powered up. Turns out there is is no 3.3V coming in at the pad I soldered it to. I have removed the module and rechecked the voltage and there is no power. Sigh…

There is not schematic or PCB layout for the Mini60 but it is very close to the SARK100. I found 3.3V coming out of the USB chip but have not found how its piped to the second PCB. So work has stalled and I’ll have to check all the required signals by tracing manually.

Update 5/16/17: Ok I think I found the problem. There are three pads that need to have jumpers installed to connect the top board to the bottom board. These three pads bring in the UART RX and TX signals and the 3.3V to the pads where the Bluetooth module is installed. Will solder the module back in place and test later today. The instructions at http://www.die-jetzis.de/bt_install.htm indicated only two pads. Looks like there are several variations of this board. I have noted that several folks have reported issues with the  Bluetooth module not responding. This is the likely cause as it is not clearly documented. Here is the board and the three pads are just left of the BT module:

Photo May 16, 9 34 26 AM

Transmit Power Using JT-65

I came a cross a very helpful web page in determining the amount of power needed for JT-65. It is called dbCalc and allows you to enter your transmit power and signal report and then calculates what your report would have been with other transmit power levels. I tried this out today on 40m JT-65, lowered my power in half and still made several DX contacts to Japan and Argentina.  You can easily measure how your signal is doing at a given power by sending a CQ and then checking the Pskreporter reports. Feed these into dbCalc and you can optimize your power settings for given band conditions. I suspect that in most cases operators are using a lot more power than necessary to make JT-65 contacts which makes it harder for weaker signals to get through.

Disassembly of the Mini60 Antenna Analyzer

Opening up the Mini60 Antenna analyzer is fairly straightforward. Fours screws on the side remove the back cover. This will expose the battery which can be removed easily by disconnecting the molex connector.

Photo May 14, 2 13 21 PM

The circuit board needs to be removed completely which requires the power switch and coax connector to be desoldered from the board. Desoldering tools and braid are highly recommended. Remove the four corner machine screws and the board should come out. Flip the board over and you will see the silk screened area where the bluetooth module is soldered.

Photo May 14, 2 41 11 PM

Surgery on the Mini60 Begins…

I started the bluetooth module retrofit of the Mini60 Antenna Analyzer today. First step is to configure the BC04-B Bluetooth module as the only baud rate supported is 57600. To do this I needed to buy a USB to TTL module from Ebay:

s-l1600

Instructions for programming the new baud rate and wiring the module can be found here: http://www.die-jetzis.de/mini60_bluetooth.htm. The painful part is making the connections to the USB to TTL converter. I had to solder four small solid wires to the necessary pads which is tricky as the pads are small and its hard to keep everything positioned. I needed a set of third hands, magnifiers and pair of tweezers but I got them on. The programming went as advertised. Once programmed I removed the wires and prepared to install on the Mini60.