Well Jonathan GW2HFR/P is having a very successful AM activation this morning, from Foel Goch GW/NW-039 (one of my favourites).
I look forward to reading his activation report and picking up some tips on how to get the best out of AM portable before the AM Weekend.
Unfortunately, I am busy with gigs (and driving between them, and catching up with sleep after them) now on AM Weekend, but I still hope to get out and at least do 1 or 2 local activations.
Thanks Tom - that was good fun !
I am sorry to Don and others that I mentioned doing another 2âpointer. Running up NW-047 after GW4VPX/P made me rather hungry having not eaten since 5AM - went back home for some proper lunch. Its amazing how fast you can activate when you really push yourself though.
I didnât get any pictures, nothing beats climbing a mountain with the rising of the sun. Started on 17m the CME G1 event had wrecked 17m propagation although a contact with a JE1 wasnât too bad and then making a reasonable contact with VK5PAS on 20m later made it worth the early morning get up.
I was running around 20W O/P using my homebrew HF linear on AM. KX3 as per usual with reduced Mic gain to suit - its different on most rigs from its correct SSB setting.
Aiming to get the WS 19 out again for the 2nd of April, there is a âdebateâ on suitable battery technology at the moment.
Sat in the garden reading my Digital Signal Processing book and drinking a beer ! loving this weather 
Jonathan
Iâve just written a news item about the AM weekend for the weekly WIA news broadcast which is also distributed via email and as an MP3 audio file.
I received several enquiries about the AM event from AM users and members of an AM net on 7.125. Both were intrigued by hearing of the SOTA crowd proposing to use AM for a weekend and both invited me to let others know that callers on 7.125 would be welcomed. Some of the older equipment used on the net is crystal locked so if you want contacts, an occasional cq on the net frequency will provide opportunities.
Similar interest might well be found in other countries.
See you on AM, on the AM weekend 1-3 April.
73 Andrew VK1DA/VK2UH
Hi All, especially DL based amateurs.
I have just received a private email from Thomas DC1TRX where he points out that acoording to the German DARC bandplan - Bandpläne - DARC - the only HF band where modes with a bandwidth greater than 2.7KHz may be used is 10m. There is text at the end of the band plan suggesting that included in âall modesâ is AM as long as you donât interfere with anyone else in the process (or thatâs how I read " alle Betriebsarten - CW, Phonie und die Betriebsarten, die bei Aktivitätszentren genannt werden ( plus AM, bei RĂźcksichtnahme auf Nachbarstationen )").
I have checked at the Bundesnetzargentur (the government body in Germany who are responsible for Amateur Radio licensing) and I cannot find anything specific for the HF bands - here is a link to that webpage -
So I âbelieveâ the DARC bandplan is only a guideline and as such we can operate AM from Germany on 20m and 40m (for example). I believe the mode allowance for up to 6KHz wide modes on 10m is actually meant for FM and that AM is allowed in the âall modeâ sections of the HF bands.
Can a DL based member please confirm this as we donât want SOTA activators and chasers running AM where it is not allowed.
73 Ed.
P.S. Thomas tells me he thinks the DARC bandplan is based on the IARU Region 1 bandplan, so itâs now even more important to get this clarified as it could affect all region 1 countries! I canât believe that AM has been stopped in all Region 1 countries however - and as always a bandplan from a national soceity or the IARU is secondary to what the Government department defines.
IARU Region 1 bandplan specifically states AM is OK in the All Modes sections of the bandplans with the following rider:
"The use of Amplitude Modulation (AM) is acceptable in the all modes segments but users are asked to consider adjacent channel activity when selecting operating frequencies. "
Thanks Andy, thatâs the way I read it as well. The German (DARC translated from IARU Region 1) document states:
âCW, Phonie und die Betriebsarten, die bei Aktivitätszentren genannt werden( plus AM, bei RĂźcksichtnahme auf Nachbarstationen)â
Which is basically the same text as you quoted, thanks.
I would have been surprised if AM had been banned in Germany / Region 1!
I have let Thomas know as he intends taking part in the SOTA world-wide AM weekend.
I wonder how many KW+ SSB stations are going to complain about a 5 or 10w portable AM station with a dipole âsquashingâ their signal because of the width of the AM signal???
73 Ed.
Further research by Thomas has found the following decison by the Justice ministry in Germany:
http://www.gesetze-im-internet.de/afuv_2005/anlage_1.html
This decison does not include the option that the IARU does, to allow AM use on the HF bands on the basis of non-interference to others. From this judgement AMPLITUDE MODULATION CANNOT BE USED IN GERMANY except on 10 metres and above.
This means no German based stations will be able to take part in the AM activity weekend on any band lower than 10m.
Ed.
At this point the words of an Al Murray joke spring to mind.
Rules, rules, rulesâŚ
Authorities are obsessed with them and the people fear em !
Some radios appear to generate AM-compatible signals by merely injecting carrier onto an SSB signal.
would that kind of signal be permitted in Germany? Ie. single sideband with a carrier? That has essentially the same bandwidth as SSB.
Andrew VK1DA/VK2UH
It appears to be controlled just on bandwidth - a maximum of 2.7KHz. I suspect carrier and one sideband would still be more than 2.7KHz.
Itâs interesting that the DARC Bandplan (which is taken from the IARU region 1 bandplan), says AM is OK as long as no interference to others is caused (as in the English original IARU bandplan) however the legal ruling from the government department has left this point out.
I am surprised that the government department is so specific. I would have thought it would be to their advantage not to get involved in this level of detail, rather letting the Amateur community self-control as long as no interference is caused to other RF based services.
There must be some DL operators reading this thread - can you please confirm or correct my reading of the AFuV/JURIS document as if my reading of it is correct (German is NOT my mother tongue), this means a total ban of the Amplitude Modulation mode on the HF bands (apart from 10m), in Germany.
Ed.
The carrier plus one sideband should not be more than 2.7 kHz, unless the ssb transmitter has a particularly wide ssb filter in it, in which case even on ssb it would exceed 2.7khz. The width of most standard ssb filters (usually ceramic filters if at 455 kHz) is 2.4 to 2.5 kHz at the -6db point and the carrier is normally placed slightly down one edge of the response curve, producing an effective voice response of 300 to 2700 Hz or a width of 2.4 kHz. The bandwidth of the transmitted signal in AM-SSB mode, from the carrier frequency to the top end of the response curve would be approximately 2.7 to 2.9 kHz. It is a matter of definition how you measure the bandwidth of an ssb signal, at the -6db point or some other place.
I think each operator will need to make up his own mind about whether AM is permitted in the form emitted by their own radio. If you know your radio does transmit both side bands when on AM, and you donât think you should transmit that signal, donât. Itâs simple.
Thanks for drawing our attention to that problem, Ed.
73 Andrew VK1DA/VK2UH
Hmm, looking at the TS2000 and Ft817 manuals, they both say âlow levelâ modulation at an early stage in the circuit is used, but both rigs specify that they run A3E - which is carrier with double sideband. No where in any of the manuals that I can find for either of these rigs, state the actual bandwidth used when in AM mode (which the audio levels set correctly).
No wiserâŚ
Ed.
817 users (probably 857/897 too)
I would have thought that its a simple case of your minimum bandwidth occupancy being twice that of your SSB width.
e.g
If your SSB width is 2.7khz then your minimum AM width is 5.4 khz. Which sounds right, as I remember the KX3 width is about this and its nominal U/LSB SSB width is about 2.7khz by default.
Usually they bridge the sideband reject filter and de-balance the modulator effectively reinserting carrier onto the normally DSB-SC. Problem using this method is the carrier strength can be modulated as well as the audio.
See if that suits your authorities regulations.
Hi Jonathan,
Just found for the TS2000 a menu option (22) DSP TX Filter for SSB/AM - which can be set to several values from 2 - 3 KHz (deafult is 2.4). But does this mean that both sidebands on AM will be restricted to that setting or each sideband (I suspect the latter). The âmagic figureâ is 2.7KHz maximum bandwidth usage.
Andy, thank for the link, Iâll go and check it out.
73 Ed.
It depends on how the DSP code has been written. I would suspect that your TX filter is specific to SSB only.
You should be able to use your audio equalizer to good effect to narrow the audio width down Ed as essentially this has exactly the same effect as the SSB shaping filter
DSP radios are well behaved. My Collins ART-13 with its 811-A modulator stage doesnât give a hoot about BW its about 11 khz wide when its pushed 
very effective of getting rid of contesters on 80m.
Letâs run down the checklist:
Collins? Check.
Black crackle paint? Check.
2x811 high level mod? Check.
813A final? Check.
Cold shower now needed? Check
Image from Western historic radio museum website, copyright acknowledged. ( http://www.radioblvd.com )
The AFuV does not care about modes but only about occupied bandwidth. For all amateur bands between 160 m and 12 m (inclusive) it gives the following terms of use: âMaximum allowed bandwidth of transmitted signals 2.7 kHzâ - so effectively AM and ESSB are banned below 10 m.
Side note: The 30 m band is limited to 800 Hz - therefore no phone operation on 30 m in Germany.
I do not know why German legislative bothers about occupied bandwidth within the amateur radio bands.
To my mind during the celebration of the 65th anniversary of the DARC in 2015 there was an event with AM transmission on amateur bands - seems there can be exceptions. But I do not remember exactly and also cannot find evidence in the internet.
73 de Michael, DB7MM
Thanks Michael,
I had hoped someone would come back and tell me I had read the AFuV/JURIS document incorrectly - unfortuantely it appears I have got it right.
The DARC Bandplan states that AM is acceptable on all HF bands (except 30m) as long as you donât cause interference to other stations - this guideline is taken directly from the IARU Region 1 band plan. Why the AFuV document chose to drop this text is beyond me, but it basically bans AM for German stations from the HF bands other than 10m.
Start of Rant. I believe that it is wrong that a government organisation wastes tax payers money deciding what modes can exist in Amateur Bands! At least those bands where Amateur Radio is the primary user, we as a community should self regulate and the government bodies only need to take action should we interfere with other services. "End of rant"
73 Ed.
