Saturday, October 29, 2022

PSK31 Fldigi Macros for Field Day

These are the PSK31 Fldigi macros I setup for Winter Field Day last year.

I came across a lot of PSK31 activity by chance (7.070, 14.070), but it took a while to figure out how to take part..

Frustratingly the information needed to simply get setup and get going is not found in one place. I like to give points to field day/contest stations but not seriously compete. Are they trying to get more people into contesting by keeping it mysterious?

Info collected from:


I set these up on an empty macro row in Fldigi:

ANS CQ (Answer CQ):

<TX>
<CALL> <CALL> de <MYCALL> <MYCALL> k
<RX>


W/FD Exch (Send exchange for your station, e.g. 1H is single home op, WWA is western WA):

<TX>
<CALL> 1H WWA 1H WWA de <MYCALL>
<RX>


73 (Send when your exchange was copied):

<TX>
73 de <MYCALL>
<RX>


QSO @>> (Start free text message):

<TX>
<CALL> de <MYCALL> <MYCALL>


RX (Go back to receive):

de <MYCALL> k
<RX>


Friday, September 9, 2022

First Year on 6 meters

Six meters has held an interest since I first got into ham radio in the 90s, however in New Zealand (like many countries) the spectrum around 50 MHz was widely used for analogue TV broadcasting which kept most away from the band. There were always stories about the weird and whacky propagation on this band, but if you wanted VHF DX life started at 2m and went up from there.

Around 2009/2010 I made a couple of brief SSB QSOs on 6m using an off center fed dipole over an 800 mile path between the upper North Island of New Zealand and the Otago region in the lower South Island with ZL4. These were on SSB and were very fleeting - enough to exchange callsigns and a signal report, then the band was gone again. This really does leave you wanting more!

Late 2021 I'm on 6m with a three element LFA Yagi at 30 ft height from Seattle (where I now live). During late fall I logged a few QSOs then the antenna on its temporary mast setup got blown down. I had the antenna fixed and back up by March 2022.

I started 2022 E season with 16 grids confirmed from the previous year, mostly up and down the west coast, with one from Florida. As of September I have just over 200 grids confirmed, 42 states including Alaska, and 10 countries including Argentina, Chile, Fiji, Japan, Norway, and a real surprise - Greenland!

I really like this band, it's a bunch of fun with multiple modes of propagation (Tropo, Es, TEP, meteor scatter, EME, and even F2 during solar max), and several digital modes available to take advantage of them (FT8, MSK144, Q65). And the fortune to live somewhere where there are reasonable levels of activity on the band certainly helps.

The Pacific North West is cursed as one of the worst places in the world for 6m Es - on PSK Reporter one can watch the band wide open over Europe, the East Coast, Southern US, South America, around the Pacific and various places in-between while in Seattle absolutely nothing happening. As frustrating as that is we did get some good results!

The last new grid for the season is (most likely) CN76 activated by Barry K7BWH early September.

6m grid squares worked/confirmed
6m US grids confirmed (green) 2022


6m FT8 QSO with LA8AJA
Norway QSO on 6m FT8 with LA8AJA

6m FT8 QSO with OX3LX
Greenland QSO on 6m FT8 with OX3LX Upernavik Island activation


VE3VN did up a nice post on their 6m E season over here.

K5ND publishes a well written eBook on 6m - Capture the Magic of Six Meters.

Thursday, June 23, 2022

HamAlert Automate Telnet Login

HamAlert is a useful tool to receive alerts for when a desired station appears.

I use this with the Club Log band slots integration to alert for new countries on bands I don't yet have confirmed.

With the Telnet option I keep a window open where the alerts scroll by quietly and I can glance at to see if there is anything new.

Typing in usernames and passwords is a chore, here is a shell script that'll auto login (replace username and password stars as required):

#!/usr/bin/expect
set timeout 30
spawn telnet hamalert.org 7300
expect "login: "
send "K1LH\r"
expect "password: "
send "*****\r"
interact

Here it is in action:

HamAlert telnet session


Friday, June 17, 2022

WSJT-X FreqCal & Waterfall Flattening

Simple method using WSJT-X to do frequency calibration of an Icom IC-7300 (or any rig with a reference adjustment), and waterfall flattening.

Frequency Calibration

I got the idea from this post https://groups.io/g/icom705/message/532

Let the radio warm up for a couple hours or so in a room at average operating temperature. Mine is on 24/7 since I leave it running overnight on 160m FT8, or 6m MSK144 to spot meteor scatter stations, so there is no warming up and cooling down :-)

WSJT-X has a FreqCal mode - the manual covers how run a calibration cycle which will work with any radio by configuring WSJT-X to do an internal adjustment compensating for the radio, or it can also be used to align the radio it self - easy if it offers a reference adjustment via a menu option.

If in range of WWV or WWVH, or another (highly) accurate time standard broadcast, edit the FreqCal frequencies (Settings > Frequencies) to use only those you can receive.

Switch to FreqCal (Mode menu) and select one of the time standard frequencies from the frequency/band drop down.

WSJT-X sets the radio to USB mode and 1500 Hz below the carrier frequency, it then measures tone or heterodyne and displays the frequency.

If your radio has a frequency reference adjustment such an the Icom IC-7300 (Menu > Set > Function > REF Adjust) adjust it until you are close as possible to 1500 Hz in fMeas column or 0.0 in DF column.

WSJT-X FreqCal

Here I was able to get very close using WWV on 10 MHz, I see about the same DF on WWV at at 5 and 15 MHz. It will drift slightly with changes in room temp which you can see by repeating the measurement.

If the radio doesn't have a user setting for frequency reference, execute a WSJT-X frequency calibration cycle per the manual with the Measure box checked (this writes the fmt.all file in logs directory). I found I had to let it run for at least two or three cycles. Edit fmt.all and remove any lines with a * at the end, then run solve for calibration.

The latter may be more accurate, WSJT-X will apply the offset needed internally, but I didn't like it showing this offset subtracted/added to the WSJT-X frequency display (blame OCD) and it only applies to WSJT-X when it is running.

More words about FreqCal by AG6EE at WSJT-X Calibration.

Waterfall Flattening

A good guide by KA1GT - https://bobatkins.com/radio/wsjtx_wide_graph.html - while orientated for EME use the steps can be followed to optimize your waterfall.

After running through all that this is what my waterfall looks like

WSJT-X waterfall Ref Spec

The one signal at 1090 Hz is -17 dB on a quiet 6m band.

Wednesday, May 11, 2022

2m 5/8 over 1/4 wave vertical ground plane

Hustler CG-144 is one example of this type of antenna, I also had one of these from a different mfgr as my first 2m base station antenna, which worked ok.

Searching for information or a description of how this antenna works, how to build one, or a model turned up nothing. The only real unknown is the phasing coil, after sleuthing around the internet for a bit I found this phasing coil from Improving the Super-J. This appears to be fairly close to the CG-144 measurements, and does the trick. There is nearly 180 degrees of phase shift from one end to the other, and with a 1/4 wave element under it, and 5/8 above it close to 50 ohm match.

EZNEC model - 2m-58ovr14-wave-GP.

Issues: Bandwidth is narrow in the model (~2 MHz < 1.5:1), maybe because of 12 AWG wire to keep it simple.



EZNEC antenna view
Antenna view

EZNEC elevation plot
Elevation plot 2 meters height above average ground

EZNEC create helix
How to create the coil with EZNEC Create Helix function


Sunday, April 10, 2022

Try Out 6m Q65-A EME or Terrestrial

With a 6m Yagi and weak signal digital mode Q65-A it's possible to receive EME (Earth Moon Earth) signals during moonrise or moonset.

Q65 can also be used for terrestrial contacts where other weak signal modes such as FT8 may not succeed.

It's also possible to do "QRP EME" on 2m and 70cm, see QRP EME - An incomplete Guide (KG5CCI).

Note: Unlike on FT8, WSJT-X wont make use of Split fake it/rig to keep the TX audio in the middle of the filters, if you get too far away from 1500 Hz power output will start to drop off.

More info


Configuring WSJT-X for Q65 and 6m terrestrial

Mode > Q65

6m > 50.275 MHz

File > Settings > Enable VHF and sub-mode features (not sure that is required)

File > Settings > Decode after EME delay - only used for EME, leave unchecked for terrestrial - though I’ve had this checked and its worked ok.

Decode > Fast for terrestrial (remember to set this back to normal or deep for FT8 and other modes). Enable averaging, and Auto clear AVG after decode on.

Terrestrial: On the main WSJT-X screen set the offset to 1500 Hz, F Tol to 100 or 200, Submode A, T/R 15 or 30 - these last two settings indicate the mode, e.g. Q65-15A, Q65-30A.

Once a QSO starts change F Tol to 100, 50, or 20.

WSJT-X Wide Graph has a Q65_Sync setting.

https://wsjtx.groups.io/g/main/topic/83263895 that post has a lot of info about terrestrial Q65. Suggests that using 15s T/R for Q65-15A is very close in performance to 30A, and twice as fast. Also covers other sub-mode combinations and QRP use.

In practice 30-A on 6m seems to be the most commonly used Q65 submode.


Here is a more recent QSO on 6m Q65-30A with W7OUU who is 500 mi / 800 km south east of me in Idaho, the band was otherwise closed with no FT8 activity.

They were running 1.1 kW with 7 elements, I was running 85 watts with 3 elements. This QSO took around 45 minutes to complete, and 15 minutes before I got the first decode (Q65 averaging at work):

WSJT-X Q65-30A QSO

I was able to reliably decode them on nearly every cycle after the first decode, with my much lower power output and lower gain antenna it took some time for them to decode my messages, but we got there in the end, and DN22 is a new grid on 6m for me too!

I've since worked W7OUU again, and WB7UNU in Spokane 200 miles east for another new grid with the band was otherwise closed.

Final thought: Since Q65 uses averaging to build confidence in subsequent decodes, and can take advantage of any propagation mode (tropo, aircraft scatter, meteor scatter, etc), this QSO may have used a combination of these to complete with enough "fragments" eventually making it though for a successful decode.


Auroral Propagation

With a recent Auroral opening (23-Mar-2023) on 6m was the first time I'd experienced this. On SSB and CW the signals were quite distorted which is normal, but they are readable.

It was then suggested to try Q65-30C. Listening to the tones with the volume up they sounded distorted, and yet it worked reliably. I was able to complete a couple of QSOs quite easily with good decodes on each sequence, and one on SSB:

Auroral 6m QSOs

This was quite a nice surprise, as the distorted FT8 signals I heard did not decode. Q65 certainly seems to be the magic mode for the magic band!


Earth Moon Earth

My interest in EME starts in the mid 90s when I was a freshly minted new ham, friend and I got invited (likely we invited our selves) to see Paul ZL1PE's 2m EME setup. Back then it was CW only (no digital modes existed then for EME, or much else).

Paul had built an H stack of four long boom 2m Yagi's with elevation and azimuth rotator, home brewed an amplifier using something along the lines of a 3CX1000 (I forget exactly), high gain masthead pre-amp and high powered coaxial relays, the feedline was hardline. Amazing stuff to see, and a lot of effort for a propagation mode where you could only use CW when the moon was up.

With the advent of digital modes and home computers faster than we could imagine 30 years ago and now take for granted, the barrier to entry for EME is much much lower.


Much thanks to Bob ZL1RS for most of the EME information.


Where is the moon?

Find when and where the moon is with something like https://www.timeanddate.com/moon/


Antennas, ground gain

With a Yagi pointed at the horizon (a regular horizontal Yagi installation) the added advantage of ground gain can be made use of during moonrise and moonset.

Antenna height, higher not always better! Consider these two 4NEC2 plots of 7 element Yagis at different heights, one at 7 meters / 23 feet vs 18 meters / 60 feet:

4NEC2 Yagi elevation plots
Plot by Bob ZL1RS


Red is the Yagi at 7 meters, it has one broad lobe that will cover between the horizon and about 15 to 20 degrees elevation. The same antenna at 18 meters, has 3 lobes, the moon will pass through each of those much quicker and be "lost" in the nulls.


Assessing the local noise floor for EME

Test 1 - Disconnect the antenna and with WSJT-X note the noise floor with the dB meter bottom left. If there is a difference of more than 10 dB when connected, the local noise floor might be too high.

Test 2 - Preamps - With antenna aimed at moonrise/set direction, turn preamp(s) on and AGC to fastest setting. If any signal level is registered on the S meter (indicating AGC action in the receiver) the local noise floor might be too high.

For me living in city my local noise floor is too high based on the second test as I get AGC action in the receiver. I'd need use to higher gain Yagi(s) with elevation rotators to get away from the noise sources when the moon is (much) higher in the sky.


Configuring WSJT-X for Q65 and 6m EME

Mode > Q65

File > Settings > Enable VHF and sub-mode features (not sure that is required)

File > Settings > Decode after EME delay (that one is important)

Decode > Deep (some say fast is more sensitive). Enable averaging, and Auto clear AVG after decode on

On the main WSJT-X screen set the offset to 1500 Hz, F Tol to 100 or 200, Submode A, T/R 60 (these last two settings indicate the mode, e.g. Q65-60A).

WSJT-X Wide Graph has a Q65_Sync setting.


Frequencies, where to find others on EME

Most EME activity is in the 50.180 to 50.210 area with 50.188 to 50.208 being most popular for sked arrangements. You wont find it tuning around.

A DT of 2.5 seconds indicates EME, DT of 0.0 or 0.1 indicates terrestrial propagation modes.

ON4KST runs an online chat service (runs in browser), goto http://www.on4kst.info/chat/start.php and choose EME all bands/mode, this is where coordination between stations happens.

HB9Q EME Logger is another.


Transmitter Power with EME

Receiving Q65 via EME is the first step, transmitting typically power levels around 1 kW are used.


Sunday, March 6, 2022

Geo whitelist, and Tor exit node blocklist (ipsets)

I wrote these two scripts to use ipsets and iptables to block Tor exit nodes, and to whitelist countries (e.g. drop all traffic from those not in the ipset).

They will load the last saved ipset file if the iptables rule is not loaded (assumes system was rebooted) which is fast. They will handle download errors and reload the last saved ipset file. Once loaded and when the scripts are run again they will update the ipsets and save the ipset files. The US has a fairly large number of netblocks, and it can take a little bit of time to create the ipset. I could not find any other examples that had this level of "self sufficiency" so I wrote my own.

https://github.com/lonney9/ipsets

Times are a changing, and I dont see the need to have my Oracle Cloud instance or IRLP node accepting connections from anyone anywhere.

Monday, January 24, 2022

Gain Master Antenna Model

A center fed 5/8 wave vertical covering 26 to 28 MHz, matched using coax for a capacitor and a stub, DC grounded, mechanically and electrically simple, no ground plane needed.

I ran across this interesting antenna design on VK5ST QRZ bio after completing a 10m FT8 contact yesterday.

Gain Master antenna diagram

Gain Master SWR plot

Ok, that got me interested, center fed verticals don't get much attention. A while ago I discovered on my own they are pretty good, much better elevation pattern stability compared to end fed over a ground plane, quieter on receive and they perform quite well in my opinion :-)

As with all antenna designs, it's always good to model them to see what we can learn, and what to expect before getting too excited..


EZNEC Gain Master elevation plot

EZNEC Gain Master SWR plot


When modeled 15ft above average ground it has a shade more gain at 2.6 dBi, maybe half a dB more quickly looking at a conventional 5/8 ground plane model I have.

The SWR response is quite broad, 2 MHz bandwidth at 1.5:1 or better. This would flatten out even more with feed line losses etc. This antenna could easily cover the New Zealand 26 MHz CB band, 27 MHz CB band, and the bottom of 10 meters!

Model: Gain-Master

I had to change the capacitor value to 14 pF which resonated the antenna at 27.3 MHz and provided a very near perfect 50 ohm match leaving the stub length and position as is.

Transmission line 1 is the length between where stub attaches and the capacitor.
Transmission line 2 is the shorted stub length.
V1 where they meet is the 50 ohm feed-point (source).

----------

How does this antenna work?

Specifically the function of the capacitor and stub to match it.

The good thing about antenna modeling, is we can take antennas apart and put them back together again to learn how they work by making a change and looking at the result.

At the center of a split 5/8 wavelength dipole in EZNEC we see 180 + J 420 ohms:
  • Top half is wire extending beyond capacitor, bottom half is the outside of the coax shield down to the choke.
  • Capacitor in series with the center conductor tunes out the inductive reactance leaving 180 ohms resistive.
  • 50 ohm point is found where the stub attaches, the coax from this point running down to the choke is matched to 50 ohms.
  • The length of coax between the end of the stub (hanging off the side) and the capacitor forms the total stub length.
  • Assuming I got my math right: The length of the stub is a 1/4 wavelength at 25 MHz when the VF of 0.66 is taken into account! Why this length I'm not sure, we can shorten the stub to be a 1/4 wave at 27.2 MHz and with some trial and error find the 50 ohm point and a cap value that gives a 50 ohm match.

From there the antenna is simply a center fed vertical dipole made out of coax. The wire beyond the capacitor is the top half, the coax shield down to the choke is the bottom half, the stub hanging off the side would appear to have little to no effect.

An example of a 1/2 wave vertical dipole made of coax and wire is K9YC's Vertical Dipole, except being a 1/2 wave it doesn't need a matching network as its resonant on its own and close enough to 50 ohms. A simple series matching section could make it perfect. It wont have the same broad bandwidth however. Uses ferrite for the choke which is a much better choice especially for high power use.

As for the choke, its size and number of turns isn't close to anything on the chart at http://www.karinya.net/g3txq/chokes/. An analysis would need to be done on the Gain Master choke to better understand it. Since it remains an unknown I would personally use a ferrite choke such as those used by K9YC's vertical dipole as an example. For more about air core chokes see Air Core Coax Chokes: Good, Bad and Ugly by VE3VN.

Getting back to the stub for a moment, using a shorted 1/4 stub I've seen used as a technique to broadband inverted L antennas on 160m - http://mobileers.com/main/wp-content/uploads/2017/01/N9LYE-22L22.pdf (web.archive.org - original is gone). Experimenting with the model as a 5/8 split dipole (source in the center) and the capacitor to get 180 ohms resistive, adding a 1/4 wave stub by it self does have a broad-banding effect, but that is likely a bonus secondary function of the matching stub in the Gain Master design.

----------

I ran the model through AutoEZ to use variables and the optimizer, it made very incremental changes to the values for the capacitor, the stub length and position - basically nothing to be gained, this design is perhaps already quite optimized!

Adding a 1 to 5 meg ohm 5W metal film resistor across the cap to bleed off static buildup also a good idea.

Sunday, January 23, 2022

Old logbooks and the power of LoTW

For ages in the back of my mind was the fact that I had old HRD log backups from 2007 - 2010 when I first became active on HF in ZL (New Zealand).

Recently the itch needed scratching, so I set about the process of getting these old logs into MacLoggerDX (my current logging application), and uploaded to LoTW.

Reading through some of the comments I made at the time was quite a trip down memory lane. Since these were all voice/SSB contacts well before FT8 ate the world (don't worry I use and enjoy it too along with PSK31 mostly), most contacts were turned into a good chat about something, sometimes I'd put a few notes about the QSO in the comments.

First problem is the current trial version of HRD would not successfully import the old backups. I was unable to find an installer for an older version anywhere..

The HRD backups are in Microsoft Access mdb format, and fortunately I have a full copy of Office 2010. I was able to export the log table as a CSV, pull that into Excel and fix up some of the info, and the HRD date/time formatting to match the ADIF format. I was then able to convert the CSV to ADIF using SM4XAS's CSV2ADIF Converter, and import that into MacLoggerDX under my ZL station callsign. From there I uploaded logs to LoTW (after setting up the cert and location, and temporarily reconfiguring MacLoggerDX operator callsign and LoTW location to match).

So that all worked, not knowing how many if any would get LoTW conformations I got a nice surprise when 16 out of 151 came back with matches:

Confirmed LoTW QSOs

The G stations I vaguely remember working, there were a couple more that didn't get conformations. First ever 50MHz/6m QSO via a very brief opening to the South Island, and the Georgia one I remember. But the "I can't believe that just happened QSO" on 80m SSB to Argentina using 100W and a low trapped dipole at the time didn't get a conformation even though it appears they are an LoTW user.

So I guess if you have some old logs laying around, clean them up and get them into LoTW, make them useful and see if there are some surprises waiting..

Sunday, January 16, 2022

10m Surprise

Two days ago a CME occurred, I happened to be on 10m FT8 as prior to this the MUF map suggested the band might open.

Ten minutes before mid-day my eyes just about fell out of my head when I saw northern EU stations calling CQ up-to 17 dB SNR! A quick look at SolarHam confirmed there had been an CME event, and that I had indeed caught the effects of it as it happened.

Over the next couple of hours logged Finland (4 stations), Norway, Denmark and Sweden. Nothing below or beyond that area showed any signals here.

The polar path was having the usual effects on signals, from "fuzzing" them on the waterfall, to one or two decodes and then nothing, quite a number of partially completed contacts in the FT8 sequence. The signals from northern Europe would come in waves, they'd be there for a couple of minutes then gone again, a few minutes later they're back for a few.

ZL even appeared for a little bit, but nothing else across the Pacific.

EU on 10m, that's a first for me.

10m PSK reporter

10m QSOs

Yesterday 10m served up another surprise, while I didn't get any openings to new DX, some very short hop propagation appeared, and I logged three WY stations consecutively, and finally got NM on 10m which completed the last two states I needed for WAS on 10m. That makes ID on 15m the last one needed to complete 5-band WAS.