[SkyKing]

Hi Bob.. and anyone else with/or contemplating an Argus display:

Don't have a KLN90B GPS unit just yet - still shopping price and serial #, but in the meantime I'm going to drive the Argus 5000 with the Apollo 618 Loran. BTW, funding for Loran systems was recently extended well beyong the year 2010, and it is a VERY viable alternative - money wise - to a panel installed GPS system.

Since the Argus gets all of its position information from the NAV system (whether it be Loran, GPS, etc.), there is a time delay in the successive position fixes of the ground track due to the fixes being filtered, so the aircraft's heading information isn't going to be instantaneous as far as the moving map is concerned... there's a delay and this is especially true with the Loran versus GPS.

Another thing to consider... the Apollo 612 Loran units are "VFR" only, and the Apollo 618 and the King KLN88 can approved for either VFR or IFR.

Also, I've now discovered that the II Morrow Apollo 612 and 618 Loran receivers only "talk" or process information in their outputs to the Argus at a 1200 baud rate, as compared to a 9600 baud rate with the KLN-88 Loran, so the King unit will process heading changes faster, but still not instantaneously. So, you still need to get heading info from the KI-525A to the Argus. I believe they call it "ARINC 407 output".

King manufactured the KI-525A "standard" HSI unit without the bootstrap and is P/N 068-3048-00 (the important part to note are those last two zeros, i.e. the dash- "00". Luckily, as it turns out, the KI-525A which I have installed is P/N 068-3048-01, the dash "01" indicating that it DOES have the bootstrap pickoff. So far so good.

An interesting 'factoid" I've discovered in thinking through the installation and making all this stuff work together, is that the Argus 5000 or 7000 is approved for use with an IFR approved LORAN C, GPS, NMS or other long-range nav system, BUT if the database has expired, the minimum range in all modes is limited to 2 nautical miles. Maybe they do this so there is incentive to keep up with purchasing the 56-day database updates! This is sort of like Xerox copiers... when the copy cartridge rolls up on 20,000 copies, a counter halts the process... although you're still good for another 40,000 copies from it if you know the 'game' plan. That's how 'they' keep you coming back to the trough!

Also, for those that weren't aware, none of the S-TEC autopilots require an A/P interface or 'coupler' in order to communicate with the King KCS55A system.

Right now it looks like hooking up the Argus with the Loran and the ADF will be fairly simple... but when I get ready to add the KLN90B, then, as you say Bob, the switcher has to be added and for "IFR" certified through the avionics shop... and this is where it starts getting expensive.... @ $70 an hour!

SkyKing