VORTAC issue
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Hi community
I was doing some IFR training flight and had bumped into some issue.
I had my eHSI mode set to TCN with frequency set to T/R SEL102X which is a VORTAC type Enroute having a range of 100nm. My position is about 60nm from SEL which should not be a problem. However, once i tuned in to SEL 102X, my HSI worked okay only for approx. 10 sec and then i lost its signal. I checked by switching to a nearby TACAN OSN 094X about 60nm away from my position too, working perfectly well. I then switched back to 102X, same situation happened that it only lasted about 10sec then signal lost again. Signal with SEL 102X seemed to only starting to become stable within 20-30nm but it is a Enroute type which should cover more distance, shouldn’t it?Does F-16 in BMS capable of receiving VORTACs signal? Is the way of setting it same as setting T/R TACANs with HSI mode set to TCN or did i do anything wrong here?
Just confused why a VORTAC coverage distance is so short & signal seems very unstable.
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Does BMS 4.xx model ‘line of sight’ reception for electromagnetic signals? If so, was there terrain at the time this anomaly was happening? Has hysteresis been modeled in the TACAN system?
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@tgw Yes LINE OF SIGHT is modelled. Terrain is definitely a factor. In my case I’ve already climbed to FL150-FL200 so terrain should not be the factor anymore in theory.
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@philip40912 I wanted to check but where about is SEL located ? I looked over the KTOnav map but could not find it. Too bad with the interactive maps gone, they had a search function
Edit: Found it, just west of Seoul airport.
Now, I haven’t tried your flight but just from the chart it seems like it could be “forgotten”, compared to INCHEON and YAUNGJU that are clearly marked on the nav map:
I will try and see if I get the same issue you describe
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Have you tried tracking outbound on the 278 radial of SEL to get the clearest line of sight as you go feet wet and to see how far you can pick it up (IRL there is an airway there)? Yes, you are at an altitude that should give you maximum service volume, but maybe it is a line of sight issue with terrain (or a bug). In RL, there are just some radials between two VORTACs that aren’t usable because even if you try to get a navaid on flat or higher ground, there can still be issues.
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@jayb
SEL is the one on the bottom that you circle in Red.
In the KTO AIP file the name of this station is called Anyang although on this map it is shown as Wonko. -
@philip40912 Probably is a line of sight situation. The signal is masked by some ground