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I have today made some changes to the way that APRS2SOTA attempts to ensure that a spotted callsign matches the format that users might expect to see for a spotted summit. That is it will add a regional prefix when it thinks one is required.

The original method of doing this was quite a complex set of individual checks in the code based on the assocation and required code changes each time something was noticed that was not as expected. The new method is effectively a lookup table (although that is still complex) and can be changed without changing the code itself and should make it more flexible and easier to update.

If you see any spots from APRS2SOTA that appear to have the wrong (or no callsign prefix when one might be expected) then please let me know the details of the spot (Date, Time, Summit and Callsign) and and what you think is wrong and I will try to correct this for future spots.

Stewart G0LGS


Hello Stewart,

I understood this features is adding CEPT prefixes automatic based on the summit reference (dxcc ref)? This is great because on my FT1 editing a messages is cumbersome anyhow. This will save time and make editing a previous spot message a lot more usefull.
I guess the lookup table will only convert for CEPT countries activated by someone from a CEPT country?
Thanks for clarifing,

73 Joe


The code does NOT know anything about CEPT.

It checks if the activating callsign matches callsigns known to be from the DXCC of the Association (i.e an activator with an ON-OT prefix on ON summit, or a K/N/W or AA - AL prefix on a know USA Summit etc).

When the spotter’s callsign does not match the Association it inserts a prefix - the prefix will either be the same as the Association prefix (i.e S5/G0LGS for an S5 summit) or one from another lookup table (i.e PY/G0LGS on a PP2 Summit or W0/G0LGS on a W0C - W0M Summit etc).

As my lookup tables do NOT (yet) cover all possible Associations they may need some tweaking.

Note: The code should use any prefix that the APRS2SOTA user includes in the information they send via APRS (so you can be DL/call on a SP summit).

Stewart G0LGS

Thanks for the details. Now it’s clear.

73 Joe

Hi Stewart.

What happens when somebody activates from a part of the AZ of a border summit, such that their correct prefix does not correspond with that of the SOTA ref?

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As it says above if the APRS2SOTA user sends a callsign with a prefix as part of the APRS data the code will use what is received from the user - only when NO callsign is given in the APRS data or when the callsign in the APRS data does not specify a country prefix will the code add one based on the summit location.

This is the way the program has worked for a long time - the changes made yesterday should just make it much easier for me to fix any issues as they arise without having to change the code (I need to change the file containing the lookup tables).

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…as mentioned in DM/BW-461 - sorry for sudden QRT today. (Not that APRS2SOTA was being used then…)

Understood now. Sounds good. Thanks.

But still what if no prefix is supposed to be added? This past summer I activated W1/AM-061, but I activated from the Canadian side of the border, so my callsign remained VE2DDZ not VE2DDZ/W1 and certainly not W1/VE2DDZ, is there a work around?



Sorry I have not responded sooner - I just had not seen this message.

The system uses a lookup table from which it tries to determine if a country Prefix is required - because my understanding of CEPT is that you use a country prefix.

It does not know anything about border summits so it can only make assumptions from the information it has available.

The system does not deal with Suffixes - if you want one then it should do that if you send it with the callsign you want in the APRS data like:

ve2ddz/w1 w1/am-061 1.81 ssb test only

The lookup table is based on my own understanding and assumptions (as I have nothing else to go on) as to what callsigns are valid in each Summit region without any prefix.

If it is posting spots with prefixes that are wrong or not required then I may need to update the table it uses and for that I need a clear explanation as to what it should be doing (bearing in mind it does not do Suffixes and making it pick between using Prefixes or Suffixes just seems too difficult).

It is better to pass this information as a private message on this reflector or direct by email.

Anyone working a spotted station on-air should be listening to what is being sent and NOT relying on what is posted on SotaWatch.

So my understanding is that when I work a W1 summit, if I use APRS2SOTA then I will be spotted with an incorrect callign.

If I operate on the Canadian side of the border where my callsign is VE2DDZ, I will be spotted with the incorrect callign W1/VE2DDZ.

If I operate from the American side of the border where my callsign is VE2DDZ/W1, I will be spotted with the incorrect callsign W1/VE2DDZ. If I use the correct callsign VE2DDZ/W1 in the message sent to APRS2SOTA, I will be spotted with the incorrect callsign W1/VE2DDZ/W1 (I tried this in a test as well).

If the APRS2SOTA is set up to post spots with incorrect callsigns, I think it is better to discuss it in the forum so other users are aware of the problem.

As I already said:

APRS2SOTA is configured to post a spot based on the what I believe is normal CEPT method of using the Country prefix and NOT a suffix.

Anyone working a spotted station on-air should be listening to what is being sent and NOT relying on what is posted on SotaWatch .

When I have some time I may look again at the code to see if I can fathom out a way of not adding a prefix when the APRS user sends a callsign, but for now it does what it does.

“APRS2SOTA is configured to post a spot based on the what I believe is normal CEPT method of using the Country prefix and NOT a suffix.”

There is an exception to that ‘rule’. Form ARRL: "Canada is the exception to the above. The US and Canada share an automatic reciprocal operating agreement. US amateurs must carry proof of their US citizenship and their valid US license. Identification for US amateurs is the US call separated by a stroke and the appropriate Canadian prefix identifier (e.g. N1KB/VE3). In all other instances, or as specified by the national licensing body, the prefix goes before the call sign.’’

(Ref: http://www.arrl.org/international-operating )

Since it is reciprocal, we canadians operating in US must identify ourselves with a suffix (e.g. VE2PID/W1).

‘’ …the prefix is appended to the issued call sign. Examples: a Canadian Amateur would use VA3RAC/W4 in the US 4th call area. A US Amateur would sign as K8HI/VE3 in Ontario.’’

(Ref: https://www.rac.ca/operating/operation-in-foreign-countries/ )

I have manged to implement a quick change that should spot whatever callsign with or without any Suffix or Prefix is sent along with the other APRS data (it assumes the sender knows what they are doing).



Thanks for doing what you do - APRS2SOTA is so very handy.

Happy Holidays!