Re: LF: AW: 503.7 Multi-function beacon ... Its working !

[Andy Talbot <andy.g4jnt@googlemail.com>]

Its exactly the same RF hardware as the WSPR beacon was - the only difference is in the PIC code. 

 

Details are :

  100W RF Out (peak / carrier)

  7m high Tee antenna with 14m top span.

  Gain estimate -27dB - based on Rrad / Rload measurements

  ERP 23dBm.

 

There may be some small /low-res photos of the antenna in the 73kHz archives somewhere - but I don't have good quality electronic copies.  They were taken on film a few years before before digital photography became all-pervasive.

 

For info, the controller consists of an AD9852 DDS clocked from a 13MHz TCXO (*4 internally for a 52MHz DDS clock) controlled from a 16F628 PIC.  A Motorola Oncore GPS receiver supplies timing information as serial data and a 1PPS UTC reference pulse.

 

An early version of the PIC driver code can be found at http://www.g4jnt.com/NEWHFBCN.ASM  The latest version has a few improvements, such as raised cosine shaping on the CW pulse rather than the linear ramp in the code shown

 

Power Amp. is a Kalmus broadband module,  flat over  0.5 to 40MHz, rated at 200W max - so at 100W is substantially backed-off for good linearity.

Andy  G4JNT
www.g4jnt.com

2009/3/8 Graham <g8fzk@g8fzk.fsnet.co.uk>

Andy,

 

Looks like I have a signal 6/10 db over the  noise during the  day from 1200  slow rise from 1500  peak at 1800 , dip at 1700  and  + 23 dB at 2015 .. seems to  be a 1 hour qsb cycle as well

 

I think Gary is set up  also for  24 monitor period ... Im seeing signal levels recorded that are not  showing on spec lab ..

 

Q, do you  have some details of the  beacon,  power , erp, or  web links I can add to  the info page ?

 

Tnx- G ..  

 

From: Andy Talbot

Sent: Sunday, March 08, 2009 6:26 PM

To: rsgb_lf_group@blacksheep.org

Subject: Re: LF: AW: 503.7 Multi-function beacon ... Its working !

It is no trouble to continue the transmission.  I have set up the equipment in the garage where it does not get in the way of other shack activites, and won't do too much damage if the euipment blows up!  So I can leave it running for a few weeks unless the antenna is needed for other purposes..

Andy  G4JNT
www.g4jnt.com

2009/3/8 Beckmann, Gerhard <beckmann.erlangen@freenet.de>

Hi Graham,

 

Thank you for your statement!

Well actually, especially Scattergram or equal measurement methods would be of interest regarding the aspect of signal path monitoring. (direct wave / sky wave via cross correlation of pulse delay values).

However, the aspect of interferences by using 500us pulses has to be taken into consideration but may be there are coming up suitable solution by the LF-group.

Another method of monitoring the signal path on 500 kHz could possibly performed by using the “PSK Sounder” software from ZL2AFP. And what I saw on a first glance it should be usable for transmission and reception in order to monitor the signal path situation.

 

By the way:

Do you know if Andy is continuing the Multi-function beaconing on 503.7 kHz?

In this case I would try long term signal monitoring by GB3RAL..exe and PSK message decoding within the next evening sessions.

 

vy 73 de Gerhard / DK6NI

 

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Von: owner-rsgb_lf_group@blacksheep.org [mailto:owner-rsgb_lf_group@blacksheep.org] Im Auftrag von Graham
Gesendet: Sonntag, 8. März 2009 15:36

An: rsgb_lf_group@blacksheep.org

Betreff: Re: LF: AW: 503.7 Multi-function beacon ... Its working !

 

Hi, Grerhard,

 

Andy's post about the  new beacon came out of the  blue, (as is the signal hihi), Working on this,  I've simply added a page to the  uk500khz news group and posted links about to  generate some interest and make sure the beacon details are known to hams and swl's out side this reflector ..

 

The only thing that occurs to  me is that there is a possibility for reception reports to be  directed to the 5 meg group , I note that the  graph generator by G4IRX  requests your call and locator  before processing the file and presenting you with a plot. so I will see if anything can be done to  prevent this , the data format is of course distorted by having only one active beacon.. so it will show up .. but may as yet be unexpected ...!

 

I note from previous email that the pulse aspect of the  beacon is required for precise measurements, I think that may be possible to set up a 'experiment'  but the aspect of interference to  other users may be significant, Andy has referred to the concept of 'phase reversal' in a continues carrier system (or medium pulse ?) that would perhaps be a acceptable mode of modulation, weather it could be transmitted by a 'normal' transmitter im note sure , but its worth noting that activities on 500, to date  are not 'funded' as such and time and capital out lay are part of the 'hobby' and such hardware requirements  and software re-writes are beyond many of the active stations. but perhaps as interest spreads .. things may change ..?

 

Tnx-

 

Graham

 

G0NBD

IO83LK

 

 

 

 

 

 

 

 

From: Beckmann, Gerhard

Sent: Sunday, March 08, 2009 11:06 AM

To: rsgb_lf_group@blacksheep.org

Cc: 'Robert Hemesley'

Subject: LF: AW: 503.7 Multi-function beacon ... Its working !

 

Hello Graham, Hello Andy,

 

reading about your activities concerning Multi-function beacon I tried yesterday evening to catch your signals, but unfortunately with no results copying your sig. May be condx were not good enough.  Moreover I had some bad manmade QRM from TV and PC.

 

      As Rob Hemesley told you I am active in 5-MHz-beaco- monitoring specially concerning  scattergram monitoring in order to analyse signal path situation (direct wave / sky wave behaviour).

      But I am running both analysis software, GB3RAL.exe and Scattergram.exe and it would not be any problem to modify the internal PC-clock specially regarding GB3RAL.exe in order to analyse the long term signal level of your Multi-function beacon. So I will try to continue monitoring your Multi-function beacon hopefully that condx will be better in the next evening sessions (hi).

      If there will be Scattergram acties in future I certainly need some more dB signal level, but it would be very interesting to investigate the signal path situation.

      Of course, this is more interesting for those participants who are located in a distance range between 150 and 300 km in order to monitor the slide crossover from direct wave to sky wave signal path.

       However, thank you very much for implementation of your very interesting Multi-function beacon project and I will keep on running my monitoring activities and will inform you in any case about further results.

 

vy 73 and a lot of success by running Multi-function beacons, I will be “on the qui vive” !!!

 

de Gerhard  /  DK6NI  (JN59LN)

 

By the way:

Dial frequency 505.2 kHz, is that o.k.? (because GB3RAL.exe is decoding with 1500 Hz too).

For BPSK31-decoding I am using DigiPan Vers.2.0

 

================================

 

 

 

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Von: owner-rsgb_lf_group@blacksheep.org [mailto:owner-rsgb_lf_group@blacksheep.org] Im Auftrag von Graham
Gesendet: Samstag, 7. März 2009 23:46
An: rsgb_lf_group@blacksheep.org
Betreff: LF: 503.7 Multi-function beacon ... Its working !

 

So far so good .. quite a step up in signal round 2100 hrs 

no frequency decode before then , 15 db over noise at 2130

 

but a trend showing

about  1 hour slow qsb

 

any other reports ?

 

G ..

 

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