9 March 2018  |   

Being in a very restricted situation in term of antennas in Paris downtown where I live and after having spent many years testing various magnetic loops and other shortened antennas, I decided to give a try to a remote station following examples of remarkably efficient “remote” stations good friends of mine were able to implement (in particular F6FVY and F1RAF).

The purpose of this short article is not to go into all the details of the configuration of each component of the installation  but rather to share the current overal design (knowing that it is constantly evolving …) and some points that have occasionally been a source of problems in order to give other OM wishes to embark on this adventure that is quite within the reach of an average OM, the proof is that I got there 😉

First of all, for the clarity of the article, I’m providing some definitions: the side “control station” or “site of control” = the place where the OM is, the side “radio station” or “radio site” = the physical location of the transmitter and the antennas.

The first question is to know what we want to do in terms of remote traffic: phone, CW, HF, VHF/UHF, power, antennas, portability of the control part, budget, etc. Obviously, everyone has to establish their specifications as best as possible, and considering the desired future modifications, in order to make the right choice from the beginning. The technical choices to set up remote control are quite numerous and the internet is already full of descriptions that I will not list here but rather describe the elements that led me to the solution that I selected for my station. My personal specifications were:

  • Possibility of making CW with a local “Iambic” key at the control site
  • Have the front part transceiver at the control site rather than a computer screen and a keyboard (OK, that’s my side “I like buttons” !!!)
  • Handle several HF antennas including a Yagi (rotation)
  • 100 watts at the beginning with possibility to upgrade to a higher power latter on
  • Possibility to have a simple control station light to carry to be able to do remote operation everywhere and not only from my home QTH in Paris
  • The desire not to leave a PC running on the radio site all the time. However, no problem to leave a Raspberry Pi up and running 24 / 24h, 7 / 7days.
  • Implement a simple solution due to my relatively limited time to devote to this project

With this specifications, I headed for the easy solution that the RemoteRig RRC-1258 represents.

Rather than a long description, the following diagram helps to understand the general organization of the station in its current configuration (see future developments).
Click on the link below for the file in pdf format:
F5RDS_Remote_design2

The main features are:

  • TS480SAT: good receiver, equiped with its 500 Hz filter for CW. The internal ATU is welcome to cover all bands. The front part is of course on the control station side.
  • The Raspberry PI 2 supports the “RemoteQTH server” which is remarkable of conviviality for my taste: access to the web interface either via a PC or on a Smartphone to manage the following functionalities: selection of the antennas, control of the rotor of the Yagi, monitoring of the temperatures. Great job of the team that makes this free application available to OMs. see https://remoteqth.com/remoteqth-server.php
  • RemoteQTH interface to control the Yaesu G450C rotor. it is developed on the basis of a nano Arduino that runs with the K3NG code. The rotor module in RemoteQTH server is very nice with an azimuthal map that integrates in real time the gray line and the position of the sun. A little DIY with an operational amplifier to connect this interface to the control panel of the G450C, especially to adapt the position readout …
  • The antenna selector: on the basis of a kit of RemoteQTH: when it is not powered, all the central lead of the coaxial cables are grounded and the central lead of the plug that goes to the TS480 is also grounded of the aluminium box which is of course connected to the ground of the station. When powered, only the selected antenna is online and all others still have their central leads to ground
  • The TS480SAT’s “CAT control” works perfectly via a USB connection between the PC and the RRC1258 control and between the RRC1258 radio COM2 and the TS480SAT via its DB-9 serial port.
  • The current antennas: Double G5RV 2x31m at 13 meters high for 160/80/40/30m, TA33JR Mosley for 20/15/10m, homemade WARC trapped dipole with 17 and 12m and a simple rotary dipole for the 6m. Other antennas are in preparation, see the “developments” section
  • Main startup by the GSM Switch that also allows the capacity to reboot the Internet router and the Raspberry
  • Main temperature monitoring planned via the Raspberry (for the moment, only the internal temperature sensor of the radio room is wired) and visual surveillance of the inside of the station via the IP camera (not essential but it can sometimes help to understand what is happening !)
Here is the TS480SAT and the RRC-1258 MkII radio station side
The remote antenna switch (kit RemoteQTH 6×1 mounted in an homemade case)

Raspberry Pi 2, relay board driving the antenna selector and 5 volt power supply for the relay card

Missing on this photo above is the I2C bus for temperature sensors, added since – warning : pay attention to the limited length of the I2C bus and add bus extenders if necessary and protect with ferrite beads, see later in the post.

Remote performance

The internet connection rate is usually not a limiting factor, this is the latency that is more critical. The average “ping time” is around 25 to 30 ms between the my Paris control station (Fiber “Free” Internet Service Provider, just to let you know, “Free” is not a free ISP !) and the radio station located 300 km away in the Allier (“Orange” Internet Service Provider with DSL). Around 20h, it can increase to around 50 ms but never more. In CW, I configured a latency of 50ms and everything goes smoothly. Obviously, no problem for the voice with such a latency.
Note from Laurent, F6FVY: beyond 200 ms, it is no longer possible to use the remote. So before investing in hardware, make your Ping measurements between your two sites to be certain to have latency that meets this criterion. According to my personal tests, I think that beyond 100 ms (but below 200 ms), the Remoterig still works with voice but it is already very tough to use CW with the keyer on the control site (it might still be possible to do CW with a keybord and appropriate buffering but I have not tested this personally). I have latencies of this order when using 3G or 4G with my Smartphone sharing wifi connection for testing from the control station.

Free dynamic DNS

Having no fixed IP address to the radio site, I use No IP which has the merit 1) to be free (at least for now, but subjected to account reactivation every month), 2) to have a client embedded in my internet routers from my two current ISP “Orange” and “Free”. Of course, there are other providers of DDNS, for you to test and choose according to your DSL routers.
Very practical, the DDNS allows to have a domain name on the radio site and to no longer worry about IP addresses management. You need to enter your domain name in the configuration of the Remoterig and to connect to your Raspberry server but also to take remote control of the internet router if need occurs to reconfigure something (provided you have previously configured the router so that this remote access becomes possible with an administrator password).

HF interference issues

A classic story, mixing between HF and DSL. At home, it is often your wife or children who do not fail to let you kindly (!!!) know that, curriously, the flow of the internet connection drops. In remote, it hurts you directly, either by small disrruption in the audio feedback and/or cuts in the transmission, or, when it is more serious, by a desynchronization of DSL at the radio side or a complete crash of the DSL router. At first, I did not realized  what was happening but I quickly made the link between the transmission power and problems. This is where we greatly appreciate the GSM Switch when everything is crashed: an text message to shut down the station and DSL router then a second one a minute later to restart everything; significantly faster than 700 km of car back and forth in my case to troubleshoot ! Usually, RFI problems are common especially on low bands like 160m (closer to the DSL frequencies). For me, the problems were noticed especially on the 40m band (loss of DSL starting from 25 w and more but no problem between 5 and 20w) and on the 10m band (HF feedback into the Raspberry and crazy shaking of the relays of antenna switch – not nice for the PA when happening during transmission).
On the advice of Laurent, F6FVY, 4 kg of ferrite later everything was back in order! Ferrite material 43 on coaxial cables flush with the antennas and at the entry point in the station. Same on control wires of the rotor of the beam. 3 ferrites on the RJ45 line between RRC and router, toroid+ filter + toroid on phone line wire before entering the router (see picture below). Ferrites on power supplies (220v, 12V and 5V side), relay control wires, USB lines … In fact, wherever there are wires. And of course, the shields of all coaxial cables are all connected to the station ground.

Future developments

  • Wifi connection for the RRC of the radio station (to limit the breakage only to the DSL box in case of lightning strike on the phone line)
  • Antennas in preparation:
    • 4 square for the 40m band with a K3NG controller
    • Verticals for 80m and 160m on 18m Spiderbeam pole
    • “Beverage” antennas of 120m length (oriented SE / NW) and 140m length (oriented N / S) – that is more complicated than it seems in a remote setup to ensure a safe switching sequence. I must admit I have not yet clearly defined how I’m going to do that with the Remoterig. To be continued …
  • Solid-state RF amplifier: choice of amp “remotable” not yet done. The models from SPE seem to me good candidates for remote use due to their integrated ATU but there are many other possible choices.
  • Remote weather station and external webcam, etc

And probably more ideas to come…
A big thank you to Laurent, F6FVY, and Nicolas, F1RAF, for their valuable advice that inspired me strongly in the realization of this – still in progress – project!
Olivier, F5RDS