[OZAPRS] HF APRS Antennas?

Sun Nov 30 12:43:23 EST 2003

Hi APRSers,
I've been listening on about 10.149.2lsb for a week or so and haven't 
heard a single packet. I'm on a 1/4 wave vertical on the roof of my house.

I'm just wondering what type of antenna is being used by the APRS HF 
gateways..and do they have any directivity?

Regards,
Ron
vk3ecv

Brian Beamish wrote:
> Hi
>  
> Before I start I am not a new on the block "Whiz Kid" with all the 
> technical know how and jargon I came up the hard way starting with 
> absolutely no electronic knowledge having to study and sit for essay 
> type exams and 10wpm CW.
>  
> I must add here that I am also 100% for the dropping of CW and other 
> licence changes anything that encourages and brings new blood into our 
> hobby I am 100% for it.
>  
> I got into the "Digital Modes" way back in the 70s starting 
> by rebroadcasting the WIA and VK4 News on RTTY firstly typing in on to 
> paper tape and transmitting on HF with the use of a Model 15 
> teleprinter, I progressed from there still on RTTY to a Commodore 16k 
> Pet I actually used to connect to the ARRL in USA with the Commodore 
> Pet with the grand speed of a 300 baud  via a acoustic coupled modem 
> over the phone to get snippets of news not available here.
>  
> Satellites and Packet for me came along about the same time and I 
> grabbed them with open arms ending up running the VK4BBS Packet BBS 
> station for some 13 years, this station still runs under the VK4WIE 
> callsign looked after now by the City of Brisbane Radio Society SysOp 
> Ari VK4PKT, to this I added the first HF Packet gateway out of VK to USA

> and also into Asia (AsiaNet) along came the digital satellites and I 
> added the first VK Satellite gateway HF packet went to PSK but slowly 
> disappeared and about the time that I passed the BBS over to the CBRS 
> satellite gateways were on the way out and Wormholes were on the way in.
>  
> Why tell you all this really only to let you know that whilst not so 
> much on the technical side I have had considerable experience on the 
> operational side of RF digital communications during this time I have 
> made many errors in fact it all has been " flying from the seat of my 
> pants" all trial and error but what an exciting and fun time have I had 
> doing just that and what a thrill it was when things all panned out and 
> worked correctly but is sure was not without a lot of trial and error, 
> APRS has been the same.
>  
> HF Packet is different, Really different to VHF APRS.
>  
> With the changes in licensing about to take place and reading the grape 
> vine I imagine that there are those, hope they do, currently on VHF APRS

> who will hopefully want to give HF APRS a go. Whilst I personally look 
> forward to seeing you there in the near future I should make you aware 
> the HF APRS is vastly different to VHF.
>  
> Looking at your map and seeing stations move about I doubt if you will 
> really recognise these differences for after all for a station 
> Monitoring on HF, VHF or via an Internet Gateway the results are 
> virtually the same but actually operating is vastly different.
>  
> 1. On HF a beacon at either 15 or 30 minute intervals is all your will 
> hear of a HF APRS Gateway.
> 2. The HF Gateway does NOT digipeat on HF it may though do so on either 
> or both VHF or an Internet Gateway.
> 3. HF gateways gate traffic to VHF and internet but there should NOT be 
> traffic the other way round, ie VHF and internet to HF.
> 4. You can NOT connect to a HF Gateway whilst some VHF gateways allow
this.
> 5. Your beacon should NOT contain Speed and Height etc just the very 
> basic location no more.
> 6. You do NOT use 1200 baud on HF your use the slower 300 baud.
> 7. Your beacon should NOT be long, mine at 21 character takes almost 4 
> seconds to transmit when more stations get on I will reduce this even 
> further but it still will be around 3 seconds, bonuses of having a 
> shorter beacons on HF include having a far better chance of being heard 
> error free, it is only the error free beacons heard and passed on by the

> HF gateway, and allows more stations to operate on HF at a similar time.
> 8. You can NOT ping, query, send messages or chat etc on HF you must go 
> to VHF or Internet to do this.
> 9. You generally can NOT track other stations, unless heard direct by 
> you, on HF again you should  go to VHF etc to do so.
> 10. Try to NOT interfere other HF APRS stations with your beacons which 
> is hard due to HF Skip as you may not hear them..
> 11. You should NOT send Objects or the like on HF go to VHF or the net 
> if you must send objects NOT HF.
> 12. You MUST Net with a HF Gateway like VK3SB or VK4DMI if you don't you

> will just NOT get heard.
> 13. Please use the recommend path of only GATE,WIDE when on HF 
> especially if you want to remain friends with the HF SysOps.
> 14. Above all you should think of others particularly on HF for if you 
> thought VHF a challenge you have NOT tried HF yet.
> 15. You do NOT really need a TNC for HF APRS just a tracking module like

> a TigerTrak is all that is required.
>  
> Give HF APRS a try really needs a few more there 
> and certainly another two or three suitably place HF Gateways around 
> VK/ZL would be most welcome, look forward to hearing your beacons there.
>  
> Hope that the above gives some food for thought to those contemplating 
> operating on HF APRS.
>  
> B C N U
> Brian VK4BBS
> Brisbane.
>  
> Yes this is an plug for I like VK4DMI are very happy with our APRS, SSTV

> and GPS product and service of Tigertronics it is worth having a look 
> there http://www.tigertronics.com/ especially whilst the Aussie Dollar 
> is so good.
>  
> 
> 
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