UK Vintage Radio Repair and Restoration Powered By Google Custom Search Vintage Radio and TV Service Data

Go Back   UK Vintage Radio Repair and Restoration Discussion Forum > Specific Vintage Equipment > Vintage Amateur and Military Radio

Notices

Vintage Amateur and Military Radio Amateur/military receivers and transmitters, morse, and any other related vintage comms equipment.

Reply
 
Thread Tools
Old 21st Aug 2021, 9:10 am   #1
Bazz4CQJ
Dekatron
 
Bazz4CQJ's Avatar
 
Join Date: Apr 2009
Location: Oxfordshire, UK.
Posts: 3,534
Default AM on 80m - Much Happening?

I just checked Google to see what I could find on this topic and there was next to nothing. Can anyone enlighten me? This is "long-range" activity planning for the... winter

Thanks
B
__________________
Data beats opinions most times... that's my opinion, though I have no data on that.
Bazz4CQJ is offline   Reply With Quote
Old 21st Aug 2021, 9:38 am   #2
Silicon
Octode
 
Join Date: Jun 2007
Location: Coulsdon, London, UK.
Posts: 1,401
Default Re: AM on 80m - Much Happening?

I expect you know about the VMARS net on 3615kHz.
Silicon is offline   Reply With Quote
Old 21st Aug 2021, 11:16 am   #3
Aub
Octode
 
Aub's Avatar
 
Join Date: Mar 2005
Location: Nuneaton, Warwickshire, UK.
Posts: 1,346
Default Re: AM on 80m - Much Happening?

There's a net every morning on 3615 using AM. It sometimes starts as early as 0630 and often goes on until 0900.

73
Aub, G4KQL
__________________
Ignorance of The Law is No Excuse - but I didnt know that!
Aub is offline   Reply With Quote
Old 21st Aug 2021, 2:08 pm   #4
G3VKM_Roger
Heptode
 
G3VKM_Roger's Avatar
 
Join Date: Jun 2012
Location: Southeast Norfolk, UK.
Posts: 699
Default Re: AM on 80m - Much Happening?

A new group called the Amplitude Modulation ARS has recently been set up and held their first AGM a couple of weeks ago. They have a forum on Groups.io and a club callsign G5AMS but their web site isn't set-up yet. Contact:- secretary@am-ars.org

The society are planning to use 3625 kHz, which was the old AM channel before 3615 became popular, but they are encouraging AM operation on other bands.

73

Roger/G3VKM
G3VKM_Roger is offline   Reply With Quote
Old 21st Aug 2021, 6:59 pm   #5
Bazz4CQJ
Dekatron
 
Bazz4CQJ's Avatar
 
Join Date: Apr 2009
Location: Oxfordshire, UK.
Posts: 3,534
Default Re: AM on 80m - Much Happening?

Thanks for the replies. I was hoping that there would be a bit more activity than weekly nets. I need to repair my inverted V and I'll listen on 3615 and 3625kHz and see what I can hear.

B
__________________
Data beats opinions most times... that's my opinion, though I have no data on that.
Bazz4CQJ is offline   Reply With Quote
Old 22nd Aug 2021, 5:28 pm   #6
G6Tanuki
Dekatron
 
G6Tanuki's Avatar
 
Join Date: Apr 2012
Location: Wiltshire, UK.
Posts: 10,578
Default Re: AM on 80m - Much Happening?

3615 is usually the best centre-of-activity: there's a Dutch/French/Belgian net that comes up around 3600/3605 on a regular basis with many of the stations using military or 'fish-fone' radios too; they're friendly and don't seem upset by my attempts at schoolboy-French, though the Belgian/Walloon dialect drops down the deep cavern between my French and German linguistic skills.
G6Tanuki is offline   Reply With Quote
Old 23rd Aug 2021, 8:00 am   #7
G3VKM_Roger
Heptode
 
G3VKM_Roger's Avatar
 
Join Date: Jun 2012
Location: Southeast Norfolk, UK.
Posts: 699
Default Re: AM on 80m - Much Happening?

Quite a bit of operation on 3705kHz AM by Dutch stations, usually ex-mil gear like BC-610s.

73

Roger
G3VKM_Roger is offline   Reply With Quote
Old 27th Aug 2021, 1:33 pm   #8
Sinewave
Octode
 
Sinewave's Avatar
 
Join Date: May 2016
Location: Oxfordshire/Bucks borders, UK.
Posts: 1,373
Default Re: AM on 80m - Much Happening?

I had a listen this morning, was just a bit before 6.30 when 3615 became active with a few people, tried to bring the stations in a little but they were at the back of the noise.
__________________
Avometer, vintage Fluke and Marconi collector.

At 144-146.00Mhz, keeping one wavelength apart.
Sinewave is offline   Reply With Quote
Old 27th Aug 2021, 1:54 pm   #9
Aub
Octode
 
Aub's Avatar
 
Join Date: Mar 2005
Location: Nuneaton, Warwickshire, UK.
Posts: 1,346
Default Re: AM on 80m - Much Happening?

If you suffer with high local noise, it may be better to listen on one of the websdr sites. I use the Weston super mare one.

Cheers

Aub
__________________
Ignorance of The Law is No Excuse - but I didnt know that!
Aub is offline   Reply With Quote
Old 27th Aug 2021, 2:43 pm   #10
Bazz4CQJ
Dekatron
 
Bazz4CQJ's Avatar
 
Join Date: Apr 2009
Location: Oxfordshire, UK.
Posts: 3,534
Default Re: AM on 80m - Much Happening?

On 80m, my magloop works well in terms of avoiding noise; it's a Wellbrook clone. The inverted dipole I have is less noisy that some earlier horizontal antennas.

B
__________________
Data beats opinions most times... that's my opinion, though I have no data on that.
Bazz4CQJ is offline   Reply With Quote
Old 27th Aug 2021, 3:13 pm   #11
Restoration73
Nonode
 
Restoration73's Avatar
 
Join Date: Jun 2013
Location: Surbiton, SW London, UK.
Posts: 2,446
Default Re: AM on 80m - Much Happening?

Many of the luxury 1960's radios have the 2-5MHz frequency range, I have two
Panasonic (R-100 and T-100Y) and these use a ferrite rod on this range.
I can normally hear the VMARS guys, of course the radio can be rotated for best
reception. It is also easy to make a 1 transistor bfo for ssb if needed.
Restoration73 is offline   Reply With Quote
Old 27th Aug 2021, 3:55 pm   #12
Sinewave
Octode
 
Sinewave's Avatar
 
Join Date: May 2016
Location: Oxfordshire/Bucks borders, UK.
Posts: 1,373
Default Re: AM on 80m - Much Happening?

I'm using a DX Commander which gets 80m as an inverted L. Usually strong stations rise above it. At times noise can be as low as S3 and on some bands not register at all, but what I were listening to this morning just wasn't coming in very strong. I could well do with raising the end of the L higher on another pole.
__________________
Avometer, vintage Fluke and Marconi collector.

At 144-146.00Mhz, keeping one wavelength apart.
Sinewave is offline   Reply With Quote
Old 27th Aug 2021, 7:27 pm   #13
Bazz4CQJ
Dekatron
 
Bazz4CQJ's Avatar
 
Join Date: Apr 2009
Location: Oxfordshire, UK.
Posts: 3,534
Default Re: AM on 80m - Much Happening?

The only rig I've got currently which could do "AM" on 80m would be my Icom IC 718, which I've not previously used on AM. I find there are some comments on Google that earlier Icom rigs did a fair job of putting out an AM signal, but some say the 718 (for reasons not specified) is not as good for AM.

Anyone have any experience of 718's running AM?

B
__________________
Data beats opinions most times... that's my opinion, though I have no data on that.
Bazz4CQJ is offline   Reply With Quote
Old 27th Aug 2021, 9:25 pm   #14
Jon_G4MDC
Octode
 
Jon_G4MDC's Avatar
 
Join Date: Nov 2015
Location: Welwyn Garden City, Hertfordshire, UK.
Posts: 1,317
Default Re: AM on 80m - Much Happening?

Japanese rigs achieved "AM" in various ways - I will say almost.
Is it one sideband with a bit of carrier leaked in?

Is it a carrier, AM modulated in an early stage, and then linearly amplified-ish?
FT221 Style? They tried all these.

Even the very modern DSP rigs supporting AM leave you to set up carrier and mod depth for yourself - at least - AFIK.
They could be very good once sorted out but I wouldn't be sure about the off the shelf settings.
Jon_G4MDC is offline   Reply With Quote
Old 27th Aug 2021, 9:57 pm   #15
Bazz4CQJ
Dekatron
 
Bazz4CQJ's Avatar
 
Join Date: Apr 2009
Location: Oxfordshire, UK.
Posts: 3,534
Default Re: AM on 80m - Much Happening?

Reading more about this on Google, it seems that this is really a problem simply solved by strictly limiting the carrier power to 1/4th the normal peak SSB level and backing off the mike compared to the SSB setting.

Probably does not compare well with real AM, but adequate for purpose.
B
__________________
Data beats opinions most times... that's my opinion, though I have no data on that.
Bazz4CQJ is offline   Reply With Quote
Old 28th Aug 2021, 5:36 am   #16
Radio Wrangler
Moderator
 
Radio Wrangler's Avatar
 
Join Date: Mar 2012
Location: Fife, Scotland, UK.
Posts: 18,544
Default Re: AM on 80m - Much Happening?

Reinserted AM carrier in transmitters has to balance the phase of the carrier with the phases of the sideband components. Sometimes this is impossible because the sideband components have gone through a very tight filter. The sideband-carrier phasing has to be right at the receiver's AM detector because the carrier acts as the control for what amounts to synchronous detection. If the carrier is at 90 degrees to where it should be, your AM detector becomes more of an FM detector.

David
__________________
Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done
Radio Wrangler is online now   Reply With Quote
Old 28th Aug 2021, 7:34 am   #17
Andrew2
Octode
 
Join Date: Mar 2010
Location: Dukinfield, Cheshire, UK.
Posts: 1,868
Default Re: AM on 80m - Much Happening?

We have our little AM net on 1963 kHz every Fri and Sun evenings at 20:30 hrs local time. We have dwindled from about half-a-dozen regulars to 3 these days, but still we stagger on. Noise is a big problem for some, and we have got around it by using loop antennas such as the Wellbrook or homebrew clones. My rig is homebrew and generates its AM by unbalancing the balanced modulator (normally this generates the DSBSC for SSB use) and switching in a wider filter. The carrier osc is also shifted 1.5 kHz to centralise it . All this goes on at the IF, which is finally heterodyned up to the required frequency and amplified linearly up to around 35 watts PEP. So all this is preset within the rig and there are no level pots to tweak on the front panel. The only user control is power level which acts in the final driver stage.
I've never understood why the black box rigs used such a strange method of generating AM (all that carrier insertion and level pot business) when it's so simple to do it properly.
__________________
Andy G1HBE.

Last edited by Andrew2; 28th Aug 2021 at 7:47 am.
Andrew2 is online now   Reply With Quote
Old 28th Aug 2021, 8:20 am   #18
Radio Wrangler
Moderator
 
Radio Wrangler's Avatar
 
Join Date: Mar 2012
Location: Fife, Scotland, UK.
Posts: 18,544
Default Re: AM on 80m - Much Happening?

Those with SDR modulation are probably a better bet.

David
__________________
Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done
Radio Wrangler is online now   Reply With Quote
Old 28th Aug 2021, 9:51 am   #19
Andrew2
Octode
 
Join Date: Mar 2010
Location: Dukinfield, Cheshire, UK.
Posts: 1,868
Default Re: AM on 80m - Much Happening?

Quote:
Originally Posted by Radio Wrangler View Post
Those with SDR modulation are probably a better bet.

David
Yes indeed. One of our occasional net members changed to an SDR rig a few months ago and his AM is immaculate.
__________________
Andy G1HBE.
Andrew2 is online now   Reply With Quote
Old 1st Oct 2021, 6:49 am   #20
Sinewave
Octode
 
Sinewave's Avatar
 
Join Date: May 2016
Location: Oxfordshire/Bucks borders, UK.
Posts: 1,373
Default Re: AM on 80m - Much Happening?

Listening to 3615am now. Seems very active. I made some improvements to my inverted L for 80 so thought I'd have another go. plenty of people on this morning's net.
__________________
Avometer, vintage Fluke and Marconi collector.

At 144-146.00Mhz, keeping one wavelength apart.
Sinewave is offline   Reply With Quote
Reply

Thread Tools



All times are GMT. The time now is 9:16 am.


All information and advice on this forum is subject to the WARNING AND DISCLAIMER located at https://www.vintage-radio.net/rules.html.
Failure to heed this warning may result in death or serious injury to yourself and/or others.


Powered by vBulletin®
Copyright ©2000 - 2021, vBulletin Solutions, Inc.
Copyright ©2002 - 2021, Paul Stenning.