Hi All,
I love APRS.
In the North Okanagan we have a great APRS digipeater atop Silverstar mountain, but historically there have been no local IGates. For our local APRS traffic to get to/from the internet, it had to go though Kelowna, Kamloops or iGates well north of us, usually going through another digipeater, using up valuable hops.
A little background: IGates gate RF APRS traffic into and out of the APRS-IS network (via the internet). This facility not only enables sites like aprs.fi and aprsdirect.com to show positional and telemetry data, but also facilitates features like SMS gating and email gating.
After waiting a little bit too long one day when doing some APRS message testing, I decided to setup a IGate for Vernon. I chose a Microsat WX3in1 Plus 2.0 device for the brains of the system. Some might say that software modems like Direwolf on a Raspberry Pi are where it's at today, however, these Microsat "solutions" are very well reviewed, are quite reliable as they are optimized exclusively for APRS, and show packet decoding results among the best for hardware and software TNCs.
I hooked the Microsat up to an Icom IC-2300H radio. This radio is quite robust with mil spec ratings and a TCXO. It can easily run 65 watts TX for the APRS iGate all day long without a fan.
I hooked the radio up to a Sinclair FP20107-3 high-Q bandpass cavity filter tuned for 144.390 MHz. While this adds around 1 dB of insertion loss in the RF chain, this pre-filter helps the radio's receiver do a better job.
I hooked the filter up to a PCTEL MHB5800 5/8 wave VHF antenna tuned for highest resonance/lowest VSWR at 144.390 MHz. This is a simple, robust, low visibility antenna which offers a bit of gain.
In total, approximately 6 feet of RG-142 coax links the RF components.
Lastly, I bought a little insurance policy for the system by adding an Alpha Delta ATT3G50 arrestor inline between the filter and the antenna. The arrestor is grounded via an 8' electric fence post ground stake.
The setup is located in one of my sheds, far from the LED lightbulbs and other household noise makers. This has allowed me to turn the radio's squelch down quite low.
Please go ahead and try sending some APRS messages, SMS messages or emails via your APRS-equipped radio. If your traffic needs an IGate to get to it's destination, you'll likely see the traffic use VE7KPZ-10. Let me know your results.
FYI and 73,
Mike VE7KPZ
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Status as of May 5:
Not a lot of traffic gated back to RF (although more than just my 10 test packets)... but then everyone is stuck at home due to the whole COVID-19 scenario right now. Decent RF decoding efficiency considering the antenna is still in my basement at this status update time, however, I have a feeling some of the packets are simply malformed and their transmitters/setups may need adjustment. We do not have a lot of APRS RF congestion here in Vernon so I very much doubt the bad packets are due to doubles.