[OZAPRS] HF to VHF Confused

[Ray Wells]

I would seem that our various experiences over the years are quite 
different and variable.

Having travelled through the region David intends visiting I can only 
recommend 20m to get signals to populated areas. From experience 
gathered over a 10 year period on HF with the BBS, there is no question 
that 30m wins hands down for signal quality and reliability, with 20m a 
not so close second on some routes. I've been using 40m for the BBS for 
maybe 8 years now and anything over about 400km is generally unreliable. 
Those findings are, of course, somewhat variable, except for 30m which, 
on some routes provided 22 hour per day forwarding. There is also a big 
difference between a short position frame and multiple (short - paclen 
64) frames required for bbs traffic.

Give that Mother Nature can sometimes be unkind (we recently experienced 
many weeks where 40m was totally useless - the O.W.F. was about 3.5Mhz), 
the more options that are available, the better.

The amateur service does, at least, have the option of alternative bands 
and that enhances the possibility of establishing contact.

The IPS online prediction service, Grafix, is brilliant for predicting 
HF paths and optimum working frequency (OWF).

Cheers ... Ray vk2tv


David and Justine Olsen wrote:
> Andrew
>
> Thanks for clarifying that.
>
> I wonder what range you did your testing over? I travel regularly in 
> Central Australia SA Deserts and the Kimberley and can talk to home 
> (Townsville) most days on 40m and 8MHz VKS.
> For me personally the ability to report my position at beginning and 
> end of day is more important than during midday, and I think that 
> would be the case for most people traveling away from VHF regions. 
> Just how many of us are standard calls I have no idea. I am doing my 
> advanced call study now, but 5 months of travel will put a halt to 
> that :-)
>
> Anyway it will be fun to see what happens if I run the iGate 24/7 
> while I am away, and have my vehicle reporting position for 5 months. 
> I think not too many people would have the opportunity to run a test 
> like that one.
>
> I will be in Simpson Desert from May to mid June then Cape York (20m 
> will be useless Cape York to Townsville except from the very tip) Then 
> in the Gulf and Kimberley Regions until end Sept
>
>
> David
> VK4MDX
>
>
> On 27 Mar 2009, at 17:17, vk5ex.andrew at gmail wrote:
>
>> Hi David and all,
>>
>> In the past there were a few HF gateway stations about that were'nt 
>> directly connected to the internet. I have in the past been in this 
>> category myself however It would be nice to know, who / if there are 
>> any HF gates still running that dont have a direct connect to the 
>> aprs-is ?    Hence the recommended use of GATE,WIDE2-1 for HF mobiles.
>>
>> And .. we ( VK5 ) have also done a resaonable amount of testing on 
>> 40m for possible HF APRS use back a few years ago. Similar time frame 
>> to what Brian was alluding to in his email. At that time we didnt 
>> have much success either on 40m, alaways going back to 30m, with 
>> perhaps 20m as the second choice. I reckon the main problems were 
>> daytime noise levels at the HF gates, along with some funny multipath 
>> stuff. Anyway It'll be interesting to see how 40m performs for you 
>> this time around. Like you say it would probably be a good option in 
>> the long run.
>>
>> Regards .. Andrew .. VK5EX
>>
>>
>> ----- Original Message ----- From: "David and Justine Olsen" 
>> <davejust at bigpond.net.au>
>> To: "Australian APRS Users" <ozaprs at aprs.net.au>
>> Sent: Friday, March 27, 2009 13:45
>> Subject: [OZAPRS] HF to VHF Confused
>>
>>
>>> I note reference on the Australian aprs site to HF iGates 
>>> digipeating  to VHF. Not sure why?
>>>
>>> My plan for HF at least initially, was to simply receive on 7036 
>>> MHz  and upload the data to an APRS server, so that HF stations can 
>>> be  tracked. This will be easy to do as it doesn't require anything 
>>> other  than my radio, antenna and computer equipped with soundcard 
>>> and  internet connection. Am I missing something?
>>>
>>> David VK4MDX
>>> _______________________________________________
>>> Ozaprs mailing list
>>> Ozaprs at aprs.net.au
>>> http://aprs.net.au/mailman/listinfo/ozaprs
>>
>> _______________________________________________
>> Ozaprs mailing list
>> Ozaprs at aprs.net.au
>> http://aprs.net.au/mailman/listinfo/ozaprs
>
> _______________________________________________
> Ozaprs mailing list
> Ozaprs at aprs.net.au
> http://aprs.net.au/mailman/listinfo/ozaprs
>

_______________________________________________
Ozaprs mailing list
Ozaprs at aprs.net.au
http://aprs.net.au/mailman/listinfo/ozaprs