[Dxspider-support] Thought from the wife!

[Dirk Koopman]

On 22-Feb-2000 Neil Smith wrote:
> Shooting from the hip here as usual, I bet at least fourpence that Dirk has
> already thought of this and it's implemented in some dark corner I'm as yet
> unaware of.

I'm not certain that I am aware of it either. But there are certainly several
dark areas of the code which I am currently exploring together with rations
for several days, a strong light and stout hiking boots...

On a more serious note though, user filters are difficult subject for me, not
because a filter is intrinsically difficult to implement, but more because it
is difficult for people to specify what they want at all, never mind
efficiently.

There is the added problem of sometimes you want them and sometimes you
don't.

I am grateful for any suggestions here (code, of course, is even more
gratefully received [and no Steve, I havn't forgotten the satellite stuff]).

One seemingly nice solution to the user specifying problem is the one used by
AR-Cluster:-

"Filtering algorythms were added to allow the user to filter spots based on
both the country and state of the spotter.   Little pistols can narrow their
received spots to those in their general srounding areas.  Big guns can
extend their spot range by opening up their spot filters.  A new implemented
protocol AR17/AR18 allows for a more effeicient distribution of spots
through the cluster network.    New commands for spot filters are:

    SET/FILTER CTY/PASS K,VE      ' Spot country filter
    SET/FILTER CTY/REJECT JA
    SET/FILTER CTY/OFF
    SET/FILTER STATE/PASS TX,AR,OK
    SET/FILTER STATE/PASS K1,K2,K3          ' Pass East Coast spots
    SET/FILTER STATE/REJECT K6,K7           ' Reject West Coast spots
    SET/FILTER DX/REJECT K
    SET/FILTER DX/OFF
    SET/FILTER BANDMODE/PASS 20-CW,20-RTTY,20-SSB
    SET/FILTER BANDMODE/REJECT 6-CW,6-RTTY,6-SSB,6-FM
    SET/FILTER BANDMODE/REJECT UHF,VHF,MW
    SHOW/FILTER CTY
    SHOW/FILTER STATE
    SHOW/FILTER DX
    SHOW/FILTER BANDMODE

Additional filters were added so a user can also filter spots by his country
needs:
     SET/FILTER NEEDS/CW +R1FJ,VP8/h,JY,ZS8,VU4,VU7
     SET/FILTER NEEDS/SSB 3D2/r,3Y/b,BV9P,JD/o,JD/m
     SET/FILTER NEEDS/RTTY R1MV,SV5,T33,ZK1/n
     SET/FILTER NEEDS/ON
     SET/FILTER NEEDS/OFF
Also added filtering for VHF, UHF and MW (microwave)"

If you like this sort of thing then I could do something along these lines
relatively easily. I have the "power of perl" regexes so it seems a shame
just to limit what can be done to simple things like that shown above, but
maybe it will get SOMETHING out there.

Another issue that isn't addressed here is ordering and either implicit or
explicit compounding. 

Does the example above allow a VP8/h spot on 20m from K1 or not? Either answer
could be wrong for someone.

Do we need a filter test routine? What is the best syntax for that?

Discuss.

Dirk G1TLH
-- 
Dirk-Jan Koopman, Tobit Computer Co Ltd 
At the source of every error which is blamed on the computer you will find
at least two human errors, including the error of blaming it on the computer.