Sunday, 21 June 2015

G11 SDR - Multiband filter board

The multiband filter board for my G11 SDR has been sitting on the shelf for a few months. Last Saturday I decided it was time to get it assembled. The additional board provides Wideband receiver and TX on all HF bands + 6m.

 The first job was to modify the G11 SDR, by removing a couple of relays, doing a small mod around the micro and fitting the jumper cables for the Low Passs & Band Pass filters.
Removing the relays it is a bit tricky, I used the a desoldering pump to remove the solder and help with pliers. The other tricky bit is to solder one of the BPF coax shield to the board on a very densely populated part of board.

Multiband LP & BP filter board
The filter board built is very straight forward, once all the capacitors were accounted for and sorted by value, the only time consuming job is to build the toroids,..lots of them & lots of loops... patience required here. I used the technique with the vice + a chinesse stick ... which saves a lot of time.

Filter board installed in G11 SDR
Once installed, the manual gives you some clues on how to check the band pass filters & low pass filters.

 G8FEK  BBGen - broadband noise generator
I used the G8FEK BBGen broadband noise generator as a noise source to check all the filter operation. In the first instance, I just looked at the S-meter for the 3 conditions explained in the manual - RX1 antena, RX2 antena & Board control cable off.

For fine tuning / minimising insertion loss through the filter board, I am planing to use Noise Figure Measurement software by VK1OD to measure noise power of the audio output - but I need first to investigate how the inductance of the various toroids impacs the pole, zeros & gain at various frequencies of the LP & BP filters.

Calibrating the G11 SDR multiband board

Finally, I checked the sensitivy of the receiver on 10m vs. my Yaesu FT-817 ND using the BBGen and NFM software by VK1OD with an additional laptop as the audio measurement device as per the application notes on G8FEK.

The G11 SDR has better sensitivity than my FT-817 by a few dBs on 10m (both pre-amp on). I need to check some of the other bands. I found this tool useful to look at the sensitivy specs/values

The final step was to calibrate the G11 PA to 10W output power on all the bands.

On the Air:
I got the upgraded G11 on the air on Saturday, as I went into 17m, I heard and logged K8CW on 17m cw. On Sun morning, 10m Es conditions were good and logged on SSB my SOTA friends EA2BD & EC2AG on SOTA summits.

73 Angel

Tuesday, 16 June 2015

First time on 6m

First time ever on 6m. Good conditions across EU on ES 6m this evening. Some stations coming at S9+
 I put up a vertical dipole on a 7m pole. 1.43m per leg + better qrp balun.
FT-817 5W

6m homebrew - vertical dipole

S59A cw
HA5JI cw
S52NR ssb
HA3LI cw
F4VPX cw
EA3AR cw

Monday, 1 June 2015

CQ WPX CW Contest - more new DXCCs added to the log

I dipped into the contest as an when I had time this weekend...(12hrs) with a few minor improvements on the antennas vs. last Nov CQ WW.

G7FEK aerial @ 8m with remote LDG RT-100 tuner
Two dipoles for 15 &10m on the ceiling (indoor) of the top floor looking E-W

All time new DXCCs:
D44AC     40m    21.23z
ZF1A        15m    13.29z  (indoor dipole)
MD4K      40m     21.34z
5H3EE      20m     19.06z
5K4R        20m     21.37z

This pushes my QRP DXCC worked count to 107.

Other long haul DX:
FY5FY      20m     20.37z
JH3AIU     15m     17.17z
B7P           15m     17.30z
KP2M       20m      09.50z
UP2L        40m       20.30z
A65BP      20m       19.37z

South Korea, Thailand, KL7, KH6 & a few others escaped my grip.

Worked all continents except OC.

QSO map
Submitted log score

- 10m was pretty much dead
- 15m was variable
- 20m very very quiet during the mornings...and open almost all night
- I was surprised to work D4 on 40m, a bit unexpected. (30wpm)
- Not much hear from OC (VK, ZL,..) 
- The additional 2.5m additonal I elevated the G7FEK was well worth it, my RX seemed better.
- The optimised audio settings for the G11 (following a note from Tasa, the designer) worked pretty well.

Mikel EA2CW - SOTA colleague, also participated in the contest with 100W & a G5RV on a 6th floor of an apartment block in Bilbao. He gave me a call on Monda evening to discuss the highlights of the contest and had a good chat about antennas. He did about 1258QSOs & 1.8m points over 36hrs.
I aslo exchanged some emails with Tasa YU1LM - who achieved 858 & 818k points over 36hrs - QRP category with 84m loop antenna at 8-12m.Great effort...

I wonder how other QRPers did....?