Should contest rules allow and act upon 599K QRM reports?

Sunday 11 December 2022

MM3T in CQWW CW 2022

 I soooo much wanted to use the Flexradio 6500 for this contest just to justify its purchase, but in practice sessions before the contest I could not get SO2V, semi SO2R or 2BSIQ to work with N1MM+. The problem was that there are so many guides written for old versions of both SSDR and N1MM+ and the wrong version of radio (ie 6700 or 6600) that only confusion and wasted time results. I tried setting up 2 slices on the same band but annoyingly if I clicked with the mouse on the screen N1MM+ would crazily swap the audio to the wrong VFO meaning I just couldn't use it. After a week of reading every available guide I finally gave in having never been beaten by anything radio/computer related in nearly 40 years.

I packed up the 6500 and instead switched to using my trusty FTDX101D. The difference was instantaneous, I was playing radio rather than fighting interacting software with different authors. The added benefit was that now I had a hope of dealing with ridiculously poor signal quality from the likes of Todor LZ4TX.  Todor hasn't yet realised that with big antennas and big power comes the added responsibility of ensuring a CLEAN TX. On 10m Todor is around 599+30 here but the big problem is the width of his transmission which during the last YO contest reached 25KHz wide on the FTDX101D effectively wiping out 10m. A quick internet search revealed that he uses an Alpin 200 (2.5Kw) linear amplifier and a 7 element yagi on 10m. I guess he hasn't read the manual properly and doesn't know driving it full tilt will cause problems.

Anyway with the 6500 safely packed away , I finally got down to selecting my entry category. I'd have loved to do a 10m mono band entry as 10m was in great shape, but Todor could show up and with the resulting 25KHz of key clicks and QRM I would have just had to pack up. I've always dreamed about activating a rare island and experiencing handling big pile-ups and really enjoy short, snappy efficient Qs and trying to get the run rate up. I would be working right up to Christmas and was involved with trying to deliver a new product in a stressful environment so didn't want to completely knacker myself for Monday morning. The 'classic' category being only 24 hours would help and also would ensure high run rates. I wanted all bands to be able to move according to the conditions. No cluster was allowed, but I intended to RUN RUN RUN anyway to see how many Qs I could make. This doesn't make sense if I was trying to win the contest as you need to S&P to get multipliers, but this wasn't going to happen anyway as there are too many retired contesters who have invested in their properties and antenna farms and can therefore run with substantial pile ups for the full 24 hours no matter their skill level. I've listened in to some of my competition and the amount of inefficiency on show should really relegate them into obscurity, but their station always secures the result. With this is mind and my pip-squeak scaffold pole in the garden, I decided to have fun and train for pile-ups instead.

I would be using an Optibeam OB10-5w wire, 5 band yagi (2-3 element on 10m, 2 element on 15m. moxon on 20m) at 5m over the ground. I live in a residential area of a large town and have close neighbours who have been very patient with me over the years. I want a bigger station, but in reality I'd have to move to larger premises to achieve it. At 5m over the ground, if my antenna were to come down the wrong way it would still land in a neighbours garden, so I'm already pushing the envelope. My garden resembles a long strip of land with the house in the middle, so I can just about shoe horn in a straight 40m length from the back garden over the house roof to the front garden. The antenna used for this location was an 80m doublet fed with 300 ohm ribbon feeder but due to the centre proximity to the house bedrooms, I wouldn't be able to use it late at night.

The back garden support for a doublet leg is a 5m light weight aluminium pole. I decided that this could double as the initial vertical section for a centre loaded  quarter wave inverted L for 160m. I designed a coil that would give me the correct inductance that when coupled to the top of the pole and then extended with a 10m wire section would be resonant on the 160m band. The resulting antenna was a real inefficient mess, but I hoped it would allow me some contacts with some of the bigger stations.

The stage was set for an all band effort and with my category picked and strategy decided for me, I got ready for the contest.

The contest started and Todor was no where to be seen (result!), but 10m wasn't in such good shape as it had been during the week lead up to the contest. I operated for 24 or the 48 hours and made 2430 Qs (around 0.6 Qs per minute), peak rate was around 130 Qs per hour on 20m.




The dirtiest signal encountered belonged to DP9A. They moved onto 14.042 at 08:00 (1KHz above me) and instantly wiped me out. I QSY'd up and asked them to QSY (ignored) then later on I asked them to check their linear amp, but just got ignored again. With my run frequency smashed I had no alternative to give them my frequency. At 6KHz wide key clicks, my radio (FTDX101D) just couldn't do anything to allow me to continue on my frequency. A quick look up of the internet on their callsign (DP9A - Callsign Lookup by QRZ Ham Radio) revealed another superstation. Why oh why do they spend so much money on antennas and ignore their transmit IMD? I think we all know why... they are cheats, plain and simple. It is advantageous to make make your transmit signal as dirty as possible to punch a hole in the band where your receiver can survive all the other stations trying to compete. The result is a lovely clear frequency to pick up rare multipliers. It must be fantastic to operate during CQWW CW within a 6KHz window clear of QRM unheard of to most competitor actually playing by their license conditions. Maybe the Bavarian Contest Club can educate them before they do too much damage to the clubs reputation.

Sunday 28 August 2022

Cw contesting and sending /QRP at the end of your call... just don't do it!

 There is no such thing as /QRP.

In a contest its all about efficiency, why in the world would a contest operator want to know you are running QRP? In my 30+ years of contesting I have never written /QRP into my contest log. When someone sends this, I always send back the proper callsign without /QRP. You would think this would be a good clue that he is regarded as a poor operator when no one ever acknowledges the /QRP he sends.

The type of person that normally does this is always sending slow and will repeat this nonsense twice to ensure you get his pip-squeek signal. The effect is normally to slow the contest operators Q-rate and maybe lose other waiting stations due to the length of time it takes him to complete the Q.

If you want to play games during a contest like turning your power down to mW level, please try to at least be efficient with the exchange:

a) Do not sign /QRP

b) Do not repeat your callsign twice ...ever

c) Do not stick in another TU because you want the other op to know you are very grateful, they will not thank you for it.


Wednesday 3 August 2022

IOTA 2022 experience using Flexradio 6300 and v3 SSDR (multiflex)

 After previous years (since inception of IOTA) of hard effort (dxpedition to EU123) and then having the door slammed by the RSGB on any effort during COVID in 2021 (as I was on holiday in EU5 at my own holiday accommodation), I decided not to bother with the contest this year. Instead I would use it test out Flexradio SSDR multiflex capability. For the Flexradio 6300, this allows 2 ops to have apparently separate receivers (using the 2 available slices of the 6300) and also share the transmitter of the 6300.

I used a laptop running N1MM+ and connected to the 6300 using Smart CAT for frequency and mode for the log and also to emulate a winkey for CW transmission of N1MM+ macro messages. I also had a Flexradio Maestro, so I connected that to the 6300 so I didn't need to run SSDR on the laptop (to keep the load on the laptop to a minimum).

My fellow tester (MM0GBK) used a laptop running N1MM+, but this time used Smart CAT and SSDR software as his interface to the 6300.

Both stations were located in the same room and were connected to the 6300 via the same ethernet switch. I was using CW and MM0GBK/P was using SSB

Multiflex is automatically invoked by the 6300 when detecting multiple connections (6300 is capable of having 2 connections: in this case Maestro hardware and SSDR software running on a laptop). Transmission capability is allowed on a first come first served basis and the other connected user is 'locked out' whilst the transmission is in progress.

This type of operation is best suited to S&P which allows both users to search for unworked stations and then take turns at working them sharing the same transmitter. This worked perfectly during the contest and seemed to handle the occasional time we would both try to transmit at the same time (no power out indicated to the loser). Running leads to the other user having too little time between transmissions to find stations.

All in all zero lock ups were observed by both users however, cw generation via Smart CAT emulator wasn't well timed with occasional sidetone audio aberrations (not sure whether they were transmitted or not) even though an Intel i5 8 core was in charge without SSDR running (Maestro doing the heavy lifting). This led to me to think I'd be better off with a real winkey or some other keying method.

I would not recommend Flexradio, SSDR or multiflex to any serious contester due to rx latency, inaccurate cw generation, cost, hardware reliability, complexity, etc, etc, etc. However interesting the concept, it just took too long for the company to get it right and as a result has lost all momentum and user base (especially in CW contesting).

Currently the majority of Flexradio users are digital and SSB mode users. CW has never been implemented well, with the company mainly listening to the American full break-in casual ops instead of world wide serious contesters. Casual CW ops may like the Flexradio offering, but this should not be confused with serious contesting equipment.

Saturday 12 February 2022

FTDX10 headphone receive audio hiss problem and solution

 The FTDX10 is a great radio, but the audio through the front headphones socket is awful. Listening through the headphones, if you turn the volume to minimum there is an annoying hiss within my hearing range (approx 200Hz -> 12KHz). When the volume is turned up slowly you start to hear the real receiver noise come up, but you can still hear the false hiss above the real audio. If you keep turning the volume up the receiver noise then completely overcomes the false hiss, but the volume is now too loud for comfortable listening.

My problem is that I am predominantly a CW operator and am therefore only interested in sound <1KHz in frequency coming from the headphones (normal specification 20Hz to 20KHz). Non music, communication headphones (20Hz to 10KHz) help with this problem, but I couldn't find a pair of communication headphones that would get rid of the annoying false hiss from the FTDX10, suggesting that the false hiss frequency content was below 10KHz.

I thought about audio filtering solutions out there like Timewave DSP-599ZX or MFJ-751B but the last thing I wanted to do was spend more money on another box after shelling out over a grand for the radio. I also wanted to use the radio portable and wanted to keep any solution as simple as possible. I therefore opted to make one myself. I wasn't completely sure what part of the audio spectrum was causing my discomfort, but it was likely that an annoying hiss would be caused by frequencies above 1KHz and as I only needed frequencies below this for CW this seemed like a good target frequency to begin attenuation from.


Remembering that headphone audio is stereo, I would need 2 identical low pass filter circuits, one for the left and one for the right audio channel. Most headphone leads consist of 2 wires for each channel audio (L&R) each of which has an individual screen, but the screen is common from the 'S' part of a TRS (TipRingScreen) audio jack.

I wanted to be able to swap headphones but the keep the low pass filter in line, so the solution was to create a 15cm stub of audio cable terminated at one end with a male TRS audio jack (3.5mm male TRS audio jack in the case of the FTDX10) to go into the radio. The other end of the stub would be open wire for connection into the twin low pass filter circuit, the output of which would then go to a female TRS audio socket which my headphones would plug into. The picture above shows my headphones jack plug on the left hand side, the twin low pass filter circuit in the centre and the open wire end of the stub going to the radio on the right hand side.

The picture has enough detail to get the component values, but the calculation for the cut off frequency goes as follows:

f = 1/2 x pi x R x C

therefore

1/2 x 3.14 x 1500 x 0.1uF

= 1061Hz

Its only a single stage audio filter so the roll off is gentle as the audio frequency goes up, but it achieves total attenuation of the annoying audio hiss without too much wanted audio drop.

Remember, avoid directly grounding either of the audio channels to the screen. Please test with a DVM to make sure you haven't made a mistake before connecting to your expensive radio.

Try it, however you do so at your own risk. I think you will like it!