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New QRP SDR transceiver!
SDR/DSP - Tuesday 27 June 2017 23:29
 
A few weeks ago I ordered a new transceiver. The mcHF. It's a SDR QRP HF transceiver. It's a kit. There are two kinds of kits. One with all pcb's and components and one with the SMD components already placed on the pcb.

I ordered the kit with all SMD components already placed on the PCB. After a few hours of building the transceiver was ready for the smoke test! It worked. No smoke. There was only one push button that caused the transceiver to power off. After some searching I found a short between two pins of the mpu.

The mcHF worked perfectly after fixing the short. There was just one thing that concerns me. In receive mode the current was 410 mA at 13.8V. The linear regulators where getting very hot. I mounted them on a heatsink but they where still getting very hot. Most of the current is draw at the 5V regulator that is in serie with the 8V regulator. The current at the 8V line was only about 16mA. So if you multiply 0,410 x (13.8-5) is about 3,6 Watt of heat disipation. The transceiver itself uses only about 2 Watt (0,410 x 5 V) .

So why not replace the 5V linear regulator with a switched regulator? Noise?!? I bought a drop-in switched regulator (Wurth 5V/1A Farnell: 173010578) and connected it with a few wires to the mcHF board. It worked. The current dropped to 163 mA. (That is less then a KX3!) After connecting a dummy load there was no increase in noise. So that looks good. I still have to build it in the mcHF enclosure and find out if there is still no increase in noise. But so far so good. The mcHF is now a really cool transceiver!

Note:
It is not a simple modification as a simple drop-in replacement. The thing is you want the input of the switched regulator connect to the DC power input (12-13.8V) of the mcHF not to the 8V regulator. If you do that the 8V regulator still heats up and the improvement is minimal. But if you connect to the DC input there is no way to turn the mcHF off. I think I need something with a pnp transistor to switch the 5V rail off when the 8V rail is off.

Update 28-06-2017:
Today I put the switching regulator inside the mcHF and the noise level increased to about S1. But worse I found some spurious here and there. With stronger ones every 300kHz (the switching frequency). So I think I have to say: Nice try but it didn't work! :-(
So back to the linear regulators. At least I have something to warm my hands on a cold SOTA summit.

More info about this great open source project:
http://www.m0nka.co.uk/

By: Erwin | Permalink | 2 comments
 
 
Activation summit PA/PA-005 and PA/PA-006
Summits On The Air - Sunday 11 June 2017 21:59
 
Today I activated two summits in PA. PA/PA-006 Signaal Imbosch 110m and PA/PA-005 Galgenberg (Terlet) 102m.

Both in SSB with a new home brew 50 Watt amplifier. On PA-006 it output was 15 Watt and on PA-005 30 Watt. Reports on PA-005 where indeed a bit better. I used the Yaesu FT-817nd on a 3 cell lithium 3100 mAh battery. The amplifier had its own 3 cell lithium 5200 mAh battery. As with most of my activations I used a End Feed Half Wave antenna on a 10m pole with a home brew tuner.

We walked from a parking place to the two summits and back. Total of 20 km. Nice wetter and beautiful nature.







QSO's logged
Date: 11-06-2017
Summit: PA/PA-006
UTCCallBandModeRST sentRST recv
11:11DL1DXL40mSSB-55
11:12EA2CKX40mSSB-52
11:12DK2RMP40mSSB-55
11:13HB9AGH40mSSB-55
11:142E0KVJ40mSSB-55
11:14OM1AX40mSSB-55
11:15G0RQL40mSSB-55
11:16G3RDQ40mSSB-55
11:16OK1SDE40mSSB-57
11:17G4WSB40mSSB-55
11:17GI0AZA40mSSB-55


QSO's logged
Date: 11-06-2017
Summit: PA/PA-005
UTCCallBandModeRST sentRST recv
13:24G4WSB40mSSB-57
13:25OK2BDT40mSSB-55
13:25G0RQL40mSSB-58
13:26GW0PLP40mSSB-54
13:26DK2RMP40mSSB-57
13:27DL1DXL40mSSB-55
13:28GI0AZA40mSSB-57
13:28HB9CEX40mSSB-59
13:29M0MDA40mSSB-57
13:30EA2CKX40mSSB-52
13:30F6FTB40mSSB-55
13:31GM4WHA40mSSB-45

By: Erwin | Permalink | Write a comment
 
 
Antarctica 13778 km !
Digital modes - Wednesday 9 November 2016 22:57
 
I just made a contact with RI1AND in Antarctica! On the 30m band in JT65 mode. That is a distance of 13778 km!

I used 25 Watt and a 2 x 7 m dipole at 6m above ground. The band seems dead but with JT65, signals can be seen in the waterfall screen and can be decoded. This is so amazing! :-)








By: Erwin | Permalink | Write a comment
 
 
Activation summit F/VO-073 Le Haut Koenisbourg 733m
Summits On The Air - Monday 15 August 2016 15:20
 
The first summit in France this year. I went here by bicycle. 16km from the camp site. Climbing the last 8km to the top. Climbing about 500m in altitude.

Because of the terrorist threat and the chatteau attracts a lot of tourists, there were some military police with heavy automatic guns checking everyone's bags. I didn't come for the Chatteau on the summit so they didn't check my backpack with all the wires, batteries and electronic stuff what just might be A home brew explosive. (with some imagination). The 10m fibre mast looks like A riffle! But all went well.

Not many QSO's because after 15 minutes it started to rain. Also my internet connection didn't work so I could not spot my self on sotawatch. But after this activation I figured out how to spot via SMS.





QSO's logged
Date: 04-08-2016
Summit: F/VO-073
UTCCallBandModeRST sentRST recv
13:01IK3DRO40mSSB5957
13:02OE7PHI40mSSB5957
13:06PA5KK40mSSB5957
13:08S57ILF40mSSB5955
13:14S57T40mSSB5959

By: Erwin | Permalink | Write a comment
 
 
Comming SOTA activations
Summits On The Air - Friday 5 August 2016 00:15
 
From 4 august till 14 august 2016 I try to do some SOTA activations. I'm in France in the Alsace/Vosges.

I will be QRV in CW on 40m around 7.032 MHz. As I am still a beginner CW OP please be gentle with me. 12-15 wpm with a little more space between the characters will do :-) Please no pile-ups hi!

My equipment:
- Yaesu FT-817ND 1 - 5 Watt output
- 10 meter fibreglass pole
- End feed half wave sloping antenna for 20-30-40m
- QRP Long wire tuner for EFHW antennas
- Internal FT817 battery
- 1900 mAh 10 x AA NiMH battery
- Inline microphone compressor

If 40m doesn't work I will try 30m CW on 10.118 MHz +/- QRM.

Hope to work you!

SOTA sites:
www.sota.org.uk
www.sotawatch.org
www.sotamaps.org

By: Erwin | Permalink | Write a comment