Retevis RT3 Charger modification

I recently bought a Retevis RT3 radio and assembled a DVMega hotspot to dabble in DMR radio.  While the RT3 seems to be a decent handset for the money the charger leaves a lot to be desired.  Unmodified the charger will not cut out until the battery reaches 8.6 volts which is well above the 8.4 volts of a full battery.  This must be a hazard or at best will ruin the battery quickly.  However it is easily rectified as described here RT3 Charger Mod.  I didn’t have suitable smd resistors but I still used regular wire resistors to make up 390 ohms.  However even after the mod another shortcoming was evident – the charge rate is around 150ma so takes overnight to charge.  I purchased an 8.4v charger from the orient for less than 5 euros including delivery: 8.4v Intelligent Charger

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The “intelligent” 8.4v charger.

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Before modification (the 2 wires on the left were the result of the previous modification to reduce the charger voltage).

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After modification

The modification is very simple – the charging circuit in the dock needs to be bypassed by cutting the positive track near the dc jack.  Then connect the dc directly to the charging terminals.  The red wire on the right of the picture (negative –  just needs to be relocated to the dc jack (note the track cut just to the right of this).  The yellow wire is the positive.  The positive terminal was hard wired to the underside of the circuit board – this needs to be cut.  Now reassemble.  Note that the charging led no longer functions but the new charger has a status led on it so that’s not a problem.  A full charge (to 8.4v) now takes just 2 hours and 40 mins – respectable.  That’s two birds with one stone hi.

My first contest win!

On Easter Monday I took part in the 70 cms Counties Contest.  I entered the low power (10w) SSB/FM section and set up on the top of Tountinna (about 450m ASL).  It is a great location with the added bonus of being able to drive to the top.  I used a Yaesu FT-897 for SSB and an Icom IC-207h for FM.  The FM antenna was a Diamond X300 and I just used the mobile antenna on the car for SSB – yes it seems everyone uses vertical polarization on SSB during contests!  I did bring a 7 element beam but didn’t use it.  I managed 29 contacts in 14 counties and received the top score overall.

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Finally the WAW Award

In theory it should have been easy to work nine Irish special callsigns but the reality was different as inter-EI propagation is virtually nil on bands above 80m at the moment.  But I managed to get them all in the log mixed between SSB & CW.  I didn’t manage any digital contacts yet.  Bands varied from top band to 15m.

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Awol again

Yes I know I should be writing a bit more here but I’ve been busy.  I’ve been to rallies in Coolmine and Limerick and got a few bargains too.  I picked up a Kent twin paddle/straight key combo (unusual) at Coolmine.  In Limerick I picked up a nice little Yaesu FT-50R for 10 euros!  I did need to fix the power button and buy a battery but a rugged little handheld for 30 euros overall is not bad.  I also picked up an antenna analyser at a good price too.

I also managed to get my main HF antenna (an end fed half wave) up a bit higher in the air and also in a fairly straight line.  Its now working without a tuner on most of 80, all of 40, 20 and 12.  It does need a small bit of help from the tuner on other bands although the swr is not bad.  When I get time I will try to get it tuned better but in any case it is working quite well for me.

Recent DX worked includes  C5YK (15m RTTY, 12m SSB), 6W2SC (20m CW, 17m SSB, 17m CW, 17m RTTY), 9Q6BB (15m CW), A45XR (40m CW), VP2V/K6TOP (20m CW), 9X2AW (15m CW), TI2CC (17m SSB), ZP6ARO (15m RTTY), 3B9FR (20m CW), HR5/F2JD (17m RTTY), XT2SE (15m SSB, 17m RTTY), LU5CQC (10m JT65), 5U5R (17m SSB, 17m CW, 17m RTTY,  20m RTTY, 15m SSB) – ATNO, 9N7EI (17m SSB, 30m CW), TU7C (17m SSB, 17m CW, 17m RTTY), YD3PIT (15m JT65), 9G5X (17m SSB, 17m CW, 17m RTTY, 15m CW), JW6VDA (40m SSB), S21ZED (40m CW) – ATNO, 5A1AL (17m RTTY), ZF2CJ (17m RTTY), EK/R2DY (30m RTTY), D4Z (20m SSB), S21ZEE (30m CW, 17m CW), OX3XR (30m CW), HC2AO (40m CW), 3B8MM (17m RTTY, 15m RTTY), 4S7VBG (30m CW, 20m CW), YI3WHR (20m SSB) – ATNO, 5H3MB (20m RTTY) and plenty from Stateside.  Band conditions were not particularly good but as you can see there was plenty to work including our own lads in 9N.

The bands are hopping again

Even though propagation is still poor there is quite a bit of activity on the bands at the moment with a lot of dxpeditions active.  Recent DX include TL8TT (17m CW, 17m SSB, 15m SSB, 20m RTTY), 4S7VG (15m CW) – ATNO, C6AUM (17m CW), P49X (17m RTTY), PZ5RA (20m RTTY), V31VP (15m RTTY) – ATNO, 3XY3D (17m CW), JY9FC (15m CW, 17m CW), V31AT (15m CW), 5J0NA (15m CW), C5YK (15m SSB, 15m RTTY), UK7AZ (15m RTTY), 7P8EUDXF (15m CW), VP6EU (15m RTTY) – ATNO, 3DA0TM (20m SSB) – ATNO, 9M2TO (15m CW), VU2ABS (12m JT65), P29LL (15m CW) – ATNO.  Worth noting is that the past few mornings 12m has been open to Asia/VK  although its mostly JT65.

Its a funny old game – radio

Despite the poor HF conditions I still managed to get 2 new entities today – Pakistan on 15m JT65 and Hawaii on 40m CW.  And I got the KH6 on the first call which was sweet.  It pays to keep ones ears open!  And I got RI1AND on 20m JT65 yesterday for a new band so I’m quite pleased with myself.