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The 29-29.1MHz sub-band continues to be the best place to find HF AM. This is the HF band with most space, although there are AM enthusiasts on 160m and other bands. When these bands are not busy AM has its place.

When 10m goes “off the boil” 29MHz AM will be ideal for local nets with very simple gear. Ranges are fine for local nets. Also there is a ready supply of ex-CB kit around, although making a wholly homebrew QRP rig for 29MHz AM is a nice group project. There are some ideas for starters on my main website.

As an example of how effective 10m AM can be see http://www.macnaughtonart.com/10metlog-ss24.htm .

In many ways, 6m (50MHz) is an ideal band for experiments. Short RF leads are always good, but 6m is a forgiving band and you can get away with HF constructional techniques. It is 2MHz wide here in the UK and this means all speech modes can be fitted and used. The page below shows a number of links to 50MHz projects.

See http://www.pg1n.nl/articles.php?lng=en&pg=145 .

See also my Sixbox 6m AM transceiver .

This little top band AM transmitter and a companion receiver were first published in the GQRP club SPRAT magazine. This TX version was built by M0DAD. Where the noise floor allows, 160m AM is quite popular for local nets.  There is something nice about “rolling your own” builds and getting satisfying results without spending a fortune. For daytime local use 160m AM is a great mode and rigs are simple. I am still surprised that more is not made of AM on 10m at night for local nets here in the UK.

See http://www.delboyonline.co.uk/m0dad/construcion/poppet_top_band_am_transmitter.htm.

Well designed DSB transceivers are much simpler than SSB rigs as no SSB filters and mixing to final frequency is needed. They must not be over-driven to avoid a spreading signal. The PA needs to be linear too. These issues being carefully considered, you end up with a rig that has the same bandwidth as an AM rig but with a suppressed carrier. DSB transmitters are usually received as an SSB signal. The downside is that if a simple direct-conversion receiver is used then there is no rejection of stations sitting on the other sideband. So, they are best on quieter bands, rather than busy HF bands. Bands like 10m, 6m and 4m are probably good candidates.

Although not impossible, it is quite difficult to demodulate a DSB signal on a simple direct-conversion receiver. DSB rigs are ideal as simple transceivers to communicate with SSB rigs.

See http://home.alphalink.com.au/~parkerp/projects/projmicro40.htm

Also: https://aa7ee.wordpress.com/2013/10/19/the-vk3ye-micro-40-dsb-transceiver/

As you may recall, I am quite a fan of super-regen receivers. Nothing as simple is able to match their AM sensitivity, but they tend to have poor selectivity.

With the availability of very low cost 433MHz modules (TX and super-regen RX) designed for AM data, these modules could be ripe for conversion to ultra-simple 70cm AM voice transceivers. One local friend, Andrew G6ALB, is currently carrying out experiments to see if this is feasible. I hope to work him on 70cm AM using such a rig in the months ahead. Sadly, I am still too clumsy to do any building work – very frustrating.

I am wondering if anyone else has tried these modules in such a circuit? With a simple MMIC PA (50 ohms in and out) the power output could be lifted to around 25mW carrier or more. With V2000 verticals this should be good for local ranges. Even at the low milliwatt level from these QRPp modules several km range should be possible with co-linear antennas.

UPDATE 2310z:   I wonder what sort of power the TX modules typically produce with linear (speech) modulation rather than 5V square wave data modulation? Presumably much less than their rated power, so an add-on PA may be essential?

Around the world, several administrations allow some access to 5MHz for amateurs.  Mostly, these are channelised allocations, which are far from ideal. What is needed is a continuous 60m band, say 200kHz wide. There was/is some hope of this being allocated to the amateur service at WRC2015 which is due to take place late this year.

I wonder what the chances of radio amateurs getting this band are? I have rather lost touch with the news on this. Certainly it was to be an agenda item. With decreasing solar activity, this would be ideal for the amateur community. I do hope it happens. Even if allocated at WRC2015, it could be a few years before administrations can make the necessary changes. If anyone has any further news I’d appreciate being updated.

Because of my poor voice (as a result of my cerebellum brain bleed) I tend to use digital techniques, like WSPR and JT65, but I still enjoy AM.  Like many, I’ve worked transatlantic AMers on 29-29.1MHz with real QRP and simple antennas using AM. It makes a great change from SSB.

One could be forgiven for thinking AM is a dirty word at the RSGB.  In UK Band Plans published in the February 2015 edition of RadCom, AM gets no mention on 28MHz and 50MHz and gets a (begrudging) comment as a footnote only in the 144MHz Band Plan when other modes get “centres of activity” mentions. AM is alive and well in the 29-29.1MHz sub-band. AM on the 144MHz (2m) band here in the UK can be found on and around 144.550MHz. There has been AM on 29-29.1MHz for years and years and years – in fact almost as long as I’ve been active on the air. Yes, this is in the all-mode section, but why not say this is the 28MHz (10m) AM sub-band? Also, why are 144MHz AM users asked to “consider adjacent channel activity”? AM should easily fit in 6kHz!!

Yet again, AM is being treated as a dirty and outdated mode. Here in the UK, ex-PMR AM rigs ripe for use on VHF can be picked up for virtually nothing and there is certainly room for AM on all bands from 28MHz upwards. AM has its enthusiasts on other bands too, but yet again the RSGB seems keen to kill off this mode. Why I wonder?

Allegedly, a RadCom article on digital TV in the 146-147MHz band was pulled last month at the last minute because “someone at the RSGB” thought it would not fit in the new band! Sometimes one wonders. Maybe the day when I only get SPRAT is closer than I thought? Thankfully, there are many good articles in RadCom.