Friday, 26 June 2020
Today’s blog is directed to those that may be new to 6m or new to using FT8 on 6m. Some of the things discussed will make your experience on the magic band better for you and better for your neigbours.
Unlike using FT8 on the HF bands, 6m presents some different challenges, especially if you operate in a region where there may be a lot of other locals also using the band at the same time.
Although the weak-signal capability of FT8 has made it possible for many smaller stations or those with makeshift antennas to take advantage of the unique propagation 6m has to offer, it also can create problems for other users of the band when used inappropriately. In regions of dense population, even small stations can create very high local signal levels, often making it impossible for their neighbours to hear weak signals. This is not deliberately-caused QRM but arises when some operators operate 'against the flow’ and transmit on the opposite ‘sequence’ to everyone else in their local area.
On HF, one can transmit or listen on whatever time sequence they wish. Chosing ‘TX 1st’ or ‘TX 2nd’ is usually determined by who you hear calling CQ or who you wish to work. On 6m however, in a densely-populated region of local operators, chosing to transmit whenever you want to is a luxury that can create big problems for your neighbour who may be trying to hear that weak DX signal while you are transmitting!
These problem will not occur if everybody in the region uses and follows the same transmit-receive periods, so that everyone is listening or everyone is transmitting at the same time ... one or the other. Unfortunately, this ‘ideal’ system falls apart easily when one or more of your neighbours is not using the same sequence as everyone else.
For the past few years, a protocol that seeks to alleviate this problem has become popular and well accepted by those familiar with it. Those new to 6m may not know about it or understand the reasoning behind it.
Above all, I would urge new users of the band, or to the FT8 mode, to first listen carefully for a few minutes, before beginning operation, to determine what the majority of stations in their local region are using for sequencing. If they are using ‘TX 1st’, then your choice of ‘TX 2nd’ will likely cause hearing difficulty for many others, as well as for yourself.
Although there are no strict rules, there is a very successful and well-practiced protocol, and that is that the ‘easternmost’ station transmits on ‘1st’ while the ‘western end’ goes 2nd’. This is why you will hear most eastern stations in the morning hours transmitting ‘2nd’, as they are usually calling or looking for Europeans to their east, who are transmitting ‘1st’. By the same token, you will also hear western stations transmitting on '2nd', who are also looking for Europe to their east, transmitting on ‘1st’.
This sequencing protocol usually reverses later in the day when signals from Asia become a possibility, and all North Americans then become the ‘easternmost’ stations and will transmit on the ‘1st’ sequence ... unlike in the morning. I can easily see how newcomers to the band could become confused, when they hear both sequences being used! The best thing, once again, is to listen carefully first and then ‘go with the flow’.
You can read about the UK's Six Metre Group's initiatives regarding these protocols HERE.
OK... so you’re not interested in EU or Asia? Then it shouldn’t matter to you which sequence that you use and best operating practice would again be to ‘go with the flow’ in consideration of other users.
A few days ago I saw a prime example of exactly what not to do, in too many respects. I made a posting on the ON4KST 6m chat page that VE1SKY in NS (Nova Scotia) was being decoded here, mainly to alert others in my region that European signals might be coming next, as hearing the VE1s in BC is often an indicator that the European path is building.
In less than a minute, an S9+ local began calling ‘CQ NS’ on the exact opposite sequence of all others ... effectively blocking the waterfall and any possible hope of hearing weak EU signals. I’m sorry, but this is just terrible operating procedure, with almost zero chance of success, while showing no consideration for nearby users.
Just like working DX on CW or on phone, the best way, as it always has been, is to ‘listen, listen and then listen some more’. You will work FAR more DX by listening and calling at the right time, than you will by calling CQ.
I also see some local stations everyday, calling endless CQs, often for over 60 minutes straight and often with many replies that go unnoticed. With FT8, one can check ‘work 1st’, go away, and return later to see who they might have ‘worked’. Perhaps this is what these operators are doing, but they should understand that they are also creating non-stop QRM for other users ... those that choose to listen carefully to the band rather than to endlessly CQ. Once again, this is just poor practice.
You may argue that if nobody called CQ, then there would be no contacts made. There is nothing wrong with a few CQs but CQing for an hour? And don’t worry, there will always be other stations CQing endlessly for you to hear, even if it’s not a great way to operate.
With a little pre-planning for sequencing and consideration for your neighbours, everyone can and should be able to enjoy 6m FT8 with very few problems ... and that is my hope for all of us.
After forty-eight summers of CW and phone on 6m and two summers on FT8, these are some of my initial thoughts on how to best operate for maximum success and consideration for other band-users.
The latter is part of the basic framework upon which amateur radio was originally established, when back in 1914, the ARRL described in their 'Code of Conduct' for amateurs ... "The Amateur is Gentlemanly. He never knowingly uses the air for his own amusement in such a way as to lessen the pleasure of others."
Now, let the magic, and the pleasure, continue!
Monday, 22 June 2020
This time the hunting ground is the 50kHz slice from 190 - 239.9 kHz as well as any beacons on 'half-way' frequencies (see below for more info).
From CLE coordinator Brian Keyte (G3SIA), comes the following CLE info:
Do try not to miss our 257th co-ordinated listening event - it starts this Friday at midday. This should be an ideal CLE to try out for the first time, but everyone is welcome of course.
Days: Fri. 26th - Mon. 29th June, Midday-Midday, your local time
Frequencies: NDBs from 190 - 239.9 kHz
PLUS: Normal NDBs with carriers on 'half-way' frequencies nnn.5 kHz
from 190.5 - 999.5 kHz (some ‘gentle’ listening!)
So for all of us it is a CLE in two parts - the first part is hunting for the NDBs whose published frequencies are lower than 240 kHz.
The second part is hunting for the NDBs whose carrier frequencies are 'half-way'. E.g. 267.5 OPW, 333.5 VOG, 370.5 LB, 377.5 MO (in OCE), 381.5 SJX (in Ml), 390.5 ITR and 433.5 HEN 'Normal' NDBs - no DGPS, please.
(Most Europe listeners will hear few or none from part 1, while
listeners away from Europe will hear few or none from part 2)
The seeklists from REU/RNA/RWW will help you - you will find them from the CLE SEEKLIST link on the CLE page http://www.ndblist.info/cle.htm
Please send your final CLE log to the List, if possible as a plain text email and not in an attachment, showing 'CLE257' and 'FINAL' in its title.
(Loggings from both parts can be shown in the same list)
Please include on EVERY line of your log:
# The date (or just the day 'dd') and UTC (days change at 00:00 UTC).
# kHz - the beacon's nominal frequency.
# The Call Ident.
It is important to show those main items FIRST - any other optional details such as Location, Distance, etc. go LATER in the same line.
Don't forget to give your OWN location and details of your receiver and aerial(s), etc. Others will be interested to know, especially new members - and old ones with failing memories like mine!
Listening on the 'half-way' frequencies means we might also catch some interesting non-CLE beacons - please tell us about those too, but in a separate list. If any of them are UNIDs whose carriers seem to be on 'half-way' frequencies include them in your main list of course.
Joachim and I will be processing the incoming logs as usual - please look out for our 'Any More Logs?' email at about 19:00 UTC on Tuesday evening, with a list to let you check that your own log has been found OK.
Do make sure that your log has arrived on the NDB List at the very latest by 08:00 UTC on Wednesday 1 July.
From: Brian Keyte G3SIA ndbcle'at'gmail.com
Location: Surrey, SE England (CLE Coordinator)
(If you wish you could use any one remote receiver for your loggings,
stating the location and owner - and with their permission if required.
A remote listener may NOT also use another receiver, local or remote,
to make further loggings for the same CLE)
- determine, worldwide, which beacons are actually in service and on-the-air so the online database can be kept up-to-date
- determine, worldwide, which beacons are out-of-service or have gone silent since the last CLE covering this range
- will indicate the state of propagation conditions at the various participant locations
- will give you an indication of how well your LF/MF receiving system is working
- give participants a fun yet challenging activity to keep their listening skills honed
The NDB List Group is a great place to learn more about the 'Art of NDB DXing' or to meet other listeners in your region. There is a lot of good information available there and new members are always very welcome. As well, you can follow the results of other CLE participants from night to night as propagation is always an active topic of discussion.
You need not be an NDB List member to participate in the CLEs and all reports, no matter how small, are of much value to the organizers.
Remember - 'First-time' logs are always VERY welcome!
Reports may be sent to the NDB List Group or e-mailed to CLE co-ordinator, Brian Keyte (G3SIA), whose address appears above. If you are a member of the group, all final results will also be e-mailed and posted there.
Please ... give the CLE a try ... then let us know what NDB's can be heard from your location! Your report can then be added to the worldwide database to help keep it up-to-date.
Have fun and good hunting!
Friday, 5 June 2020
The following blog was originally published four years ago and with the ever-growing number of new 630m stations, some may find the information helpful.
Amateurs and and U.S. experimental licence holders operating on the LF and MF bands, are limited in the amount of power they are legally able to run. Unlike the HF bands, where maximum power limits are expressed in either DC power input or PEP output, LF and MF operators are required to observe ERP or EIRP limitations. Canadians operating on 2200m are limited to 1W EIRP and to 5W EIRP on 630m.
Although this doesn't sound like much, mustering this amount of effective power can be quite a task on either band, especially on 2200m. This is due to the very poor efficiencies encountered when using antennas that are so small in size compared with what would be considered 'normal'. For example, a typical 1/4 wave vertical used on 40m is about 33' high and with a good radial system can achieve efficiencies in the 80% range, while the equivalent antenna for 2200m would be 550m or about 1800' high ... a little large for most suburban backyards!
The equivalent of a normal 2m 'rubber-ducky' antenna when built for 2200m would be over 600' tall, while one designed for 630m would be around 170' high! A 2" stub used on your 2m hand-held would be the same as a 56' vertical on 630m. Consequently, most LF / MF backyard antennas will realize efficiencies of less than 1% and likely, quite a bit less.
In order to reach the maximum radiated power levels allowed usually requires several hundreds of watts, especially on 2200m, where near kilowatt levels are needed. These small radiated power levels might seem discouraging but they don't account for radio's great equalizer ... propagation. More than anything else, RF loves to radiate, and at times, what can be achieved on these bands with such low effective radiated powers is stunning
It would seem that Industry Canada did us no favors when they stipulated LF / MF power levels to be measured in EIRP and not the, much easier to calculate, DC power input level ... or perhaps they did. I think that, unlike on HF, imposing EIRP rather than DC input power limits puts everyone on an even playing field. Amateurs with lots of real estate and room for a larger, more efficient LF antenna, will be required to run much less power to reach the allowable EIRP and 'stay legal', compared to someone with a small backyard in the suburbs ... the latter can legally generate the higher level of DC input power required to reach the EIRP limits since their smaller antenna is operating at less efficiency. However, determining EIRP is not as cut and dried as measuring input power.
With some fairly sophisticated (ie. expensive) field strength measuring equipment, not typically found in amateur radio operations, ERP / EIRP can be readily determined. This means that for most amateurs, alternate methods must be used.
Neil, WØYSE in Vancouver, Washington, who runs an experimental 630m station under the call of WG2XSV, has produced an excellent treatise on calculating your station's EIRP level, providing a step-by-step procedure to follow.
In order to determine your ERP / EIRP, you must first determine your antenna's radiation resistance. Two methods of calculating the antenna's radiation resistance for both verticals and top-loaded verticals (inverted L's or T's) are demonstrated, using the physical size of the antenna in relation to the frequency of operation. Once this value is known, the antenna current is measured while transmitting. These two values allow the Total Radiated Power (TRP) to be calculated. The TRP is then multiplied by 3 to yield the EIRP or by 1.82 for ERP. Roughly speaking, 5W EIRP is the equivalent of 3W ERP. Thanks to Neil for this helpful resource.
An alternate method of roughly determining ERP / EIRP values is an interesting new online 'antenna simulator' at the 472kHz.org site. Using known physical sizes along with your ground quality description, the calculator will indicate what total power output is required to produce various levels of ERP and EIRP as well as expected antenna currents, at 472kHz. It's a good starting point if you are either planning a new antenna system or perhaps, repurposing an HF antenna such as an 80m inverted-L or an HF center-fed dipole for use on 630m.
Neil has also sent the following comments that will be of interest to those planning a sloping-wire tophat:
I'm sure there will be a lot more information and discussion about this topic once the LF and MF bands are released in the U.S.A. but in the meantime, calculating your ERP / EIRP levels is not as hard as it might initially seem ... and is likely accurate enough for most agencies overseeing amateur radio activities.