For 100mW I’m quite blown away by the range of these things…
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I plugged in an external GPS antenna on my Heltec tracker and it definitely got GPS lock a lot faster and with better accuracy.
The fitted GPS antenna is functional though and does OK when out and about.
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30km
I think that only passes positions and objects but not messages. Is this the setting you had when you got messaging to work?
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I have just found an old rubber duck hand held antenna - these can’t be that bad, they must be better than the stub supplied??
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As long as they cover 70cm, then yes.
I’ve just tested my new antenna on the nanoVNA and at 439MHz SWR is around 1.5, much better than the 5 with the supplied stub.
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Yes, obviously it’s from a 2/70 hand held.
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Better than the stock stubby - yes. But not necessarily particularly good. Dave JKS and I have both tested quite a lot of these on network analysers and, in general, the dual band ones are optimised for 2m and they are poor at 440 MHz.
The antenna that I have recommended is a single band antenna that has a good VSWR at 440 MHz. It not a miracle antenna but gives solid performance at 440 MHz.
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I must of missed your link @G3CWI Richard, could you please send again? I’d be interested in getting a couple. Many thanks
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I don’t think that’s the case. My home igate was operating with the default m/10 filter but passes positions far further away than 10km. It’s using an m/30 filter at the moment. I find the information online a bit confusing and sometimes contradictory. I’m also not sure how the messaging works in situations where the user is in range of some igates that support messaging and others that don’t. Some experiments needed I think.
And I have no idea how message packets relayed by digipeaters are dealt with. They could easily come from well over 100km away.
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Two antennas ordered 
let’s see how they perform. I’m off to do Cadair Idris on Tuesday evening, so it’ll have its first outing.
@G4TGJ thanks for the links
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You may be right, but this is my reading of the spec.
The filter only applies to packets received from the internet. So if your iGate receives a packet over RF from 1000km away it will still be sent to the internet.
Your iGate sends the filter to the APRS server and so this will only send your iGate packets from stations within the distance set in the filter.
So your iGate will receive and gate packets from RF over any distance. It will only transmit on RF packets received from the internet that refer to stations within the filtered distance.
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That makes sense. But for things like self spotting, we would need to be able to pass the “ack” data back over distances that could exceed 150km so we need to set the filter to something like m/200 perhaps. What do you think?
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Is the ACK needed? Or will the tracker keep retrying if it doesn’t get it? Most iGates are RX only so will never send the ACK.
Is the ACK between tracker and iGate, or between tracker and APRS server?
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The ack is pretty useful if you don’t have cellphone coverage - where APRS messaging might be most useful. Also some other interactions are two way (weather forecasts for example). No doubt we will find out as we experiment.
The relaxed license conditions mean that igates can be 2 way without an nov so hopefully all will be set up that way. Maybe we need to write a guide for igate configuration for SOTA/messaging use?
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That is an excellent idea.
Might be worth gleaning some of the snippets of information about getting the things to upload the firmware (e.g. necessity of setting the Heltec Tracker into boot mode, and how etc.)
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Maybe we need a SOTA LoRa APRS Wiki? I’m not sure to set one up but it can’t be too hard.
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If your IGate re-transmits all the APRS-IS traffic within an area of 125000 square km, the channel will get very busy?
Perhaps you could limit it to Message packets only - have a look at the “t/m” filter: Server-side Filter Commands
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The Nagoya N771 type antenna is pretty poor at 439.9125MHz; really optimised to for 144MHz.
The antenna that comes with most LoRA boards also doesn’t appear that good up at 440MHz.
The best antenna I’ve come across for use with LoRA at the UK allocated frequency of 439.912MHz is the TX433-BLG-40
Which now seems to be available from Amazon:
Although there is some variability (1.7 to 1.2) at 440MHz so I tend to buy 5 at a time, test them and send back any that are wildly out. They’re generally excellent (VSWR) at the EU LoRA frequency 433.775MHz. Admittedly, they a tad unwieldy to attach to a tracker, so I’ve also ordered a couple RF Solutions FLEXI-SMA-433 on Richard’s recommendation - to give them a test. I ordered four from CPC (as delivery is free over £20) so I can compare.
Dave
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Im not sure how much traffic there actually is but your general point is valid of course. I think this is where a Wiki would come in handy. Some such as yourself, who understands the filters, could suggest a suitable filter string. Do you have messaging enabled at your station? It would be nice to do some tests.
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