WSJT-X has arrived! I purchased the Flex 6500 for exclusive use in digital modes. I have the 6500 configured to listen for SSTV (Slow Scan Television) signals and EasyPal digital transmissions on the 20 meter band. At the same time I’m running two instances of wsjt-x on other bands.
Making Contacts via FT8
After following the set up instructions, and getting the audio and RF levels correctly set, I was making contacts via FT8 ‘right out of the box’. I’m running the Flex 6500 barefoot (100 watts) into a Comet CHA-250B multiband vertical antenna on a test stand in my backyard. The results were immediate. One of the first few contacts I made via FT8 was DX with JA0IXW. Not bad!
I have been able to complete almost every contact I’ve attempted so I’m pretty confident my little digital setup is working AOK! I’m putting out a very clean 100 watt signal.
For all intents and purposes, my SO2R operation is self-contained. I use a Flex 6700 dedicated to SO2R operation. I’m operating through an SPE Expert 1K-FA amplifier. This allows using two TX antennas and a wideband RX Magnetic Loop antenna. I enjoy fully automatic operation utilizing one Flex SCU (Spectral Capture Unit) per TX antenna. Really a perfect setup! This configuration has now been thoroughly tested and fine tuned to my operating preferences. Battle tested in contest with more multi band contacts than was ever possible for me while working manually. (the M word). In comes the EA4TX AS2x2 switch to enhance station operation.
I can now freely operate on any band at any frequency, and always have the lowest SWR and the appropriate drive level set automatically. We all know nobody has time to wait around for you to tune up during a contest! You’ve got to be there or be square!
Flex 6500: Dedicated To Digital
Now that I have the SO2R contest station squared away, I’ve turned my attention to the Flex 6500. I have MMSSTV running on 14230, EasyPal on 14233, and two instances of WSJT-X running on any two of any of the other bands that may be open, 24/7. I can work digital modes back and forth between any two bands with a click of the mouse.
For that matter I can also TX from any of the running programs with a single click thanks to the Flex DAX TX feature that switches the TX slice automatically. Combine that with a multiband antenna, and the possibilities are endless!
Watch That Front End!
So now that the digital station is setup and running what’s the problem? Well it’s not a problem yet, but very well could be.
The Flex radios have some built-in protection for the front end of the radio, but it would not be wise to count solely on that feature for complete RX front end protection. In the SO2R setup I added an Array Solutions RXFEP on the RX only antenna to protect the RX when the amplifier is not in operation to switch the RX only antenna automatically. When the amp is off, I have an extra level of protection.
With the 6500 running 24/7 digital modes it would not be hard for me to imagine accidentally TX ‘ing at 1,000+ watts while forgetting the other radio is nearby in RX mode (aka an ‘Inband Radio’). It would just be a matter of time before this type of accident would take place. I could easily make this mistake, so I must add a level of protection against it. In a multi-transmitter environment this is a requirement.
EA4TX AS2X2 Antenna Switch
I researched several antenna switches for the purpose of disconnecting the Flex 6500 antenna when the SO2R contest station is transmitting. Keep in mind I need to be able to transmit 100 watts through the switch. I quickly learned that the the first two “RX Antenna Switches” were not intended for use where the second radio is also a transmitter. Instead they were designed to switch out a receiver only. You cannot transmit back through the second RX port. So the first two switches were eliminated.
I came across the EA4TX AS2X2 and found it could handle 200 watts. It is not an RX only switch, it is a two port switch designed for switching (or exchanging) two antennas (TX and/or RX) between two radios. I’ll only need one side of this switch as I only need to disconnect the Comet CHA-250B antenna, not necessarily switch it with another.
I purchased the EA4TX ARS-USB rotor controller and have been very happy with its quality and performance, so another EA4TX product is welcome. Yes, I saw the single star review. I’m not worried because I know DX Engineering stands behind what they sell, as pointed out in the review.
UPDATE: The AS2x2 arrived today and is now installed at the antenna input of the Flex 6500. Whenever the Flex 6700 is in TX, the antenna to the 6500 is disconnected. Better to be safe than sorry.
I jumped right into the FT8 fray. I setup a Flex 6500 specifically for use in the digital modes. FT8 in particular. Like everyone else, I heard a lot about the mode and decided to give it try. It wasn’t long before I realized that logging my FT8 contacts manually was not only cumbersome, it created opportunities for data entry errors. I use DXLab’s DXKeeper for logging, and a quick google search revealed that JTAlert provided connectivity with several popular logging programs, including DXKeeper. The main feature of interest to me is JTAlert’s ability to link WSJT-X to the DXLab Suite of programs. Using JTAlert as a bridge, I could connect my FT8 operations directly to the DXKeeper logbook!
Setting up the Flex to work with WSJT-X was relatively easy. I was making contacts and having a blast. The Flex 6500 is using a multiband antenna (CHA-250B vertical) so I can change bands with a click to be wherever the action is. I also have a second instance of WSJT-X running in order to monitor a second band. So the logging can get fairly complex. After the first two data entry errors, I knew I had to find a solution.
JTAlert has a lot of features that I am not currently taking full advantage of. As I get more adept at working FT8 I’m sure I’ll find a use for some of these extra features. There are filters to help you find contacts you need so that may be a useful feature down the road, as I currently need everything!
It turns out that despite all the fun as I was having, I was doing it wrong. I would soon find out that my FT8 operating skills left a lot to be desired. After reading the article Hinson’s Tips for FT8 and in particular the section that explained the “Hold TX Freq” feature, I quickly realized what I was doing wrong.
It turned out that under certain operating conditions I had been unintentionally QRMing stations that I had just made contacts with.
If “Hold TX Freq” is not selected the TX frequency changes to the calling frequency for every CQ call you reply to.. For example, let’s say I replied to a station that was calling CQ, and after the contact was complete, I changed over to calling CQ myself. I was then transmitting in the previous stations ‘slot’ and QRMing them. Bad practice! Needless to say, I’m very happy to have read Hinson’s tips! I think the “Hold TX Freq” should be the default setting!
One could say that JTAlert has claimed a legitimate place in the station automation scheme.
The Comet CHA-250BX vertical has been on the test stand long enough. It’s time to move it into a permanent location on the property.
I plan to put the CHA-250BX on the top of one of the support masts that currently hold up one end of my “Height Compromised Dipole“. It’s in the corner behind a palm. I read a few eHam reviews that mentioned good results were achieved by mounting the CHA-250BX just 10 to 15ft above the ground. The antenna height affects the take-off angle, and apparently 10-15 feet is yielding some good results. I’m already working some DX barefoot via FT8, so I know the antenna performs OK. With all the testing, I now have a baseline to compare the performance against once it’s at the new height.
New Location For The CHA-250BX
If you look closely at the image below you can see the mast in the corner of the yard. I had it strapped to a huge stake that I drove into the ground. It was held in place using hose clamps. It stood up straight for years until part of the palm died and knocked it loose. I’m going to extend the current 100ft Andrew CNT-400 with another 50ft of the same coax.
Recycle The Base Parts
The test stand is an old umbrella stand. I plan to fit the weighted base squarely into the corner against the cinder block wall, and secure it using the big stake, and the 50 lb sandbag.
This steel mast is 15ft tall, a 5 ft section on top of a 10 ft section. When I re-deploy the mast I will switch the 5 ft section to the bottom, this way, when I have the antenna ready to go I can stand on a step ladder and insert the 10 ft section much easier. If 15 feet is judged to be too tall to stabilize, I will eliminate the 5 foot section.
Square In The Corner
The umbrella stand will fit perfectly into this corner.
I have some mollies leftover from a recent flower trellis repair. I can use some of them as anchors for the steel straps if it looks like I’ll need them..
Comet CHA-250BX At Ideal Height
The 5 ft section will be reinforced using two sets of steel straps (at 1 and 5 feet above ground), and an additional guy line to reduce or eliminate any sway. I’ll add a pulley to the top for the dipole, and hang a weight from the end insulator to reduce stress on the mast when it’s windy. I’m also going to devise a wooden support beam that will go in between the mast and the 90 degree concrete corner. I’ll be able to tighten the steel straps to keep the mast firmly against the beam. I’ll square one end of the wooden beam for the corner, and make a cutout for the mast diameter on the other end. This should be a rock solid base. The antenna is 23.8 feet tall, and weighs 7 lbs. with a 67 mph wind rating.
I have a spare ground rod which I will install at the base.
Update: Sat 05/18/19
XYL: Where Did You Put That Antenna?
Tucked away nicely in the corner of the yard! Barely noticeable to the XYL.
There are several articles out there about antenna height versus take-off angle. There seemed to be some consensus that a height of 3 meters above ground offered some improvement in performance.
I decided the antenna would not be stable at the proposed height. Its proximity to neighbors property is also a factor. So instead of 15 feet, I mounted it at 10ft (3m)
OK. Let’s see what kind of results we get. The antenna had to move anyway, so hopefully we get some good results.
I leave two instances of WSJT-X FT8 running 24/7. Then, when I get home from work, I scroll back through the RX windows to see what was heard while I was away. I’ve been running it this way since I first put up the CHA-250 vertical back in March 2019.
I’d left it on 40m since yesterday afternoon (just over 24 hours) and came home today to find EU callsigns in the FT8 console for the first time. Lots of DX calls, among them Italy, Croatia, Morocco, Mauritius, Ecuador, Japan, Indonesia, Philippines, New Zealand and on and on. Keep in mind this is just the past day on 40m! I never saw anything like this when the antenna was on the test stand.
If you have your CHA-250BX mounted on the ground give it a try on a 10ft mast! Let’s see how many of these newly heard DX callsigns can be worked!
the bonus: antenna separation
An added bonus! The increased antenna separation between the vertical and the RX Loop has eliminated the de-sense I was seeing on the 6700’s HF RX. As I work FT8 I am usually listening to 80m on the 6700/W6LVP Loop. The antenna separation is now sufficient that the FT8 transmissions no longer interfere with other HF RX in the shack. Perfect world.
it Turns out to be a major upgrade!
EA3KU 05/21/2019 05:15 FT8 100w 40M Sent -11 Rcvd -20
F6AOJ 05/25/19 04:28 FT8 100w 40M Sent -17 Rcvd -22
EA8TH 05/2519 06:23 FT8 100w 40M Sent -19 Rcvd -22
WSJT-X was installed on 03/09/19 and my DX contacts up to this point included JA’s and ZL’s and VK’s, but I hadn’t copied any EU callsigns before raising the antenna. Now I’m working into EU, so I am very pleased with this upgrade.
Time spent building the digital side of the station is proving to be time and effort well spent. The dedicated digital rig is paying off big time, as DX contacts are coming in on all bands. The DX results are better than anticipated!
dedicated digital rig
Flex 6500 – Four Slice Receivers: Two running WSJT-X, one running MMSSTV, and the fourth running EasyPal. Add a Comet CHA-250BX Vertical @ 10ft and that’s it!
Barefoot Digital: 100 Watts into a Vertical
I wanted this to be a simple barefoot operation with a dedicated radio and antenna. I’m using a Dell 7050 micro PC and have the Flex displays “cranked down” in order to limit CPU usage to a range of 40-60%. Works great!
Evenings here have become a lot more interesting!
Every day this new digital mode attracts more and more people to the airwaves. It works with the briefest of openings and the software needed is free to download. It takes up about 60Hz only and works great with weak signals.