radios:dr-m06th
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| radios:dr-m06th [2026/01/08 17:38] – [Modifying an Alinco DR-M06TH 6m transciever for packet usage] g5rkt | radios:dr-m06th [2026/02/13 23:17] (current) – [Modifying an Alinco DR-M06TH 6m transciever for packet usage] g5rkt | ||
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| After tapping the discriminator & modulator the radio was bench tested using an 857D and a pair of NinoTNCs; it works on 4k8 IL2Pc beautifully. The main issue with testing was those Aerial Facilities dummy loads are **superb** at 50MHz! | After tapping the discriminator & modulator the radio was bench tested using an 857D and a pair of NinoTNCs; it works on 4k8 IL2Pc beautifully. The main issue with testing was those Aerial Facilities dummy loads are **superb** at 50MHz! | ||
| - | Ticking away happily as GB7WIN' | + | Ticking away happily as GB7WIN' |
| + | |||
| + | Mods: | ||
| + | - Inputs for TX audio, pre/ | ||
| + | - Ouptuts for RX audio, pre and post filter\\ | ||
| + | - 6 pin mini-DIN connector on the rear\\ | ||
| + | - Selectable " | ||
| + | - 2nd IF filter replacement | ||
| + | - Second receiver SDR tap\\ | ||
| - | (Jan '26 update - the radio has gone rather deaf, perhaps the front end LNA has been taken out by lightning or something... not sure. We have a proper surge arrestor on our feeder but who knows. Investigations commenced!) | ||
| =====Schematic detail===== | =====Schematic detail===== | ||
| Line 61: | Line 68: | ||
| The tap wires were routed around the front central case mounting post before soldering to reduce the chances of pulling a trace off the board. The eagle-eyed viewer will notice an extra wire in the area of the "flat audio in" wire - yes, I pulled off the orange wire's pad when adding the green wire. Silly billy. Nonetheless it was an easy fix :) | The tap wires were routed around the front central case mounting post before soldering to reduce the chances of pulling a trace off the board. The eagle-eyed viewer will notice an extra wire in the area of the "flat audio in" wire - yes, I pulled off the orange wire's pad when adding the green wire. Silly billy. Nonetheless it was an easy fix :) | ||
| + | =====Filter replacement===== | ||
| + | The radio is set up to receive +-5KHz FM voice, but on packet we're using +-2.5KHz deviation. I replaced the second IF filter (CFW455F, -6dB BW +-6KHz, -40dB BW +-12.5KHz) with a tighter filter (CFW455H, -6dB BW +-3KHz, -40dB BW +-9KHz). | ||
| + | |||
| + | =====SDR Tap===== | ||
| + | To give us a bit more information about what is happening on site I opted to fit an SDR tap to the radio and feed it into an RTL-SDR Blog v4. Initial experiments show that with an S9 signal into the receiver and 45dB gain set on the RTL a -30dBm signal is reported by the SDR, and in full power transmit a -10dBm signal is reported; well within the maximum input power of the RTL dongle. | ||
| + | |||
| + | The SDR tap board employed was the PATV type with no LPF as this board is being fed directly from the input LPF in the radio. | ||
| + | |||
| + | {{: | ||
| + | **Receiver front-end** | ||
| + | |||
| + | Q1 is the input LNA and feeds a low-pass filter consisting of L4, L5 and L6. The hupRF board was tapped into the pole of L6 to provide a second receiver. | ||
| + | |||
| + | {{: | ||
| + | **SDR Tap board installed** | ||
| + | |||
| + | The whole thing just fits into the radio underneath the main PCB; liberal application of Kapton tape and some sticky foam on the underside of the case holds it in nicely. I opted to drill yet more holes in the casting to fit a rear SMA connector to prevent mechanical accidents :) | ||
| ---- | ---- | ||
| - | de G5RKT, | + | de G5RKT, |
radios/dr-m06th.1767893914.txt.gz · Last modified: by g5rkt