I’m Randy, a 39-year old ham living in Amersfoort, which is located about 25 miles east from Amsterdam. Licensed since aged 17 (1997) and active on all bands from 160 meters up till 3cm tough VHF, UHF and SHF are prefered in (SSB) voice, ATV, CW and weak-signal/DIGI modes.

On the day to day job I work as Independent technical consultant specified in Linux Infrastructure  solutions. Also doing some hands-on support stuff for repeater group Hobbyscoop, the annual Ballon Fox Hunt and trying to promote HAMNET-activities with a group of ham’s throughout the country.

The 1th station from the Netherlands on 144, 432 and 1296 MHz in the QRP section and the 2nd station on 144 and 432 MHz in de low-power section based on DAC and NAC results during 2018.

IC-9700 mod: enable AF out on mic

To enable the AF output on Pin 8 of the MIC socket (AFO line), solder a bridge across test point CP421 on the DISPLAY board.

Schematic: Service manual, p. 10-17.
Board layout: Service manual, p. 7-10, to left of R421

May 2019 NAC contest on 144 MHz

Only worked 3 hours. 37 QSO’s in 20 grids. ODX: SK7CY (639km). My result: 3th place in the Netherlands

May 2019 VHF/UHF contest

Spend some hours in the shack. The (temporarily) results (I wasn’t active on 1296 MHz this weekend):

1st place in the Netherlands (C-SO-LP) on 144 MHz
2nd place in the Netherlands (C-SO-LP) on 432 MHz

Icom IC-9700 Service Manual

The IC-9700 Service Manual is available. Download it here. The document is in English, dated March 2019 and contains specifications, inside views, interface information, the adjustment procedure, the part list, mechanical parts, board layouts, the wiring diagram, the block diagram and a schematic diagram. In total the document is 93 pages and about 10 Mbyte in size.

IC-9700 Fan mod stabilizes TCXO

Another interesting post appeared today on the IC-9700 reflector. It describes how to improve frequency stability.

I have modified my IC-9700 to keep the fan continuously running at a reduced speed by fitting a 6.8V Zener diode across the appropriate switching transistor. (N.B. I have documented the process with pictures of where I installed the diode, and I am trying to get the file uploaded to the files section of this site.)
The fan now runs continuously. I can’t hear it in my shack because I have a number of other pieces of equipment which much noisier fans!
I have done some brief frequency stability tests on CW transmissions using a 1 minute on – 1 minute off cycle. Using an HP 53131A with GPS Disciplined external reference, observing the frequency to approx 0.1Hz resolution (N.B. This frequency counter uses reciprocal measurements so the gate sample time is approx 0.5Hz for this level of precision allowing rapid frequency fluctuations to be observed.)

Continue reading

Spring in the shack

Easter. It means a long weekend off. Time for me to be busy in the shack. I started with a ride to SM/Ikea to buy some cupboards. One to the left of the desk to house the VHF and UHF amplifiers and rotators, the other one on the desk to make more room for radio’s. It looks really clean right now. I only have to find a way to lower the monitor about 15 centimeters, since it’s somewhat too high right now to be comfortable.

I also mounted the CG-3000 tuner with about 11,5 meters or wire on a pole. The end of the wire is aggravated with some nuts and thrown into a tree at the back of the house. It’s tunable from 160 meters till 10 meters with about 11,5 meters of wire. I dont have the ambition to be very active on HF, but missing the 30-meters and 17-meters band to keep my CW-skills up2date since there is almost no activity on 2-meters besides the yearly Marconi contest.

The FT8 farmer

Did I already mention rule 1 till 3 if you transmit in digimodes?

  • 1. Check your ALC
  • 2. Check your ALC
  • 3. Check your ALC

Don’t be a farmer spreading out harmics on the complete spectrum like the guy below. Your ALC shout *not* come in red. Or even better: not giving a bar at all. The example below is the audio level from PC to TRX is set way too loud.

The guy is calling CQ for over half an hour and nobody is answering because nobody is able to make any successful decodes.

Icom IC-9700 Firmware v1.06

Icom just posted a new firmware version for the IC-9700. The version is v1.06 and has these improvements:

  • Improved accuracy of the automatic reference frequency calibration.
  • Fixed unintended indication on the DR screen.
  • Eliminated RX audio gap when changing the IF filter in the DV mode.

Icom IC-9700 Inside Pictures

Today, Robin (G1MHU) posted some pictures on Facebook. Embedding the pictures doesn’t work but follow this link to see them. Looks like Icom already added a foam block on the TCXO for stability. But. There is enough room to add a heater, cooler, whatever inside the box.

Pluto SDR hack: Add a 2nd CPU core

The Pluto SDR is easily ‘hacked’ to extend the frequency range from 325-4000 MHz to 70-6000 MHz as described earlier. Another hack is to enable the 2nd CPU core on the ADALM Pluto. After logging in to the unit, ‘cat /proc/cpuinfo’ shows only one core. Now enter ‘fw_setenv maxcpus’ in the console and reboot the Pluto with the command ‘pluto_reboot reset’. Now the 2nd CPU core is enabled.

Icom IC-9700 and 10 MHz GPSDO lock

Many people are confused about the 10 MHz reference lock input on the IC-9700. And so was I. While all of us expected the VCXO was locked to the 10 MHz input (which in most cases will be locked to a GPSDO) it isn’t. Unlike the new IC-7610, which is locked, the 10 MHz input on the IC-9700 can only be used to calibrate the transceivers’ VCXO. And even this doesn’t seem to be most accurate.

According Rex (VK7MO) tests, he had a 4 Hz error on 144 MHz, a 40 Hz error on 1296 MHz. Icom has work to do to fix this (and the ALC / Power Overshoot) error. A fix could be a (more) permanent lock/sync, but a fix could also be made in the fan controller, since the temperature is directly involved with the IC-9700’s drift.

People using the IC-9700 for FM (repeaters), satellite, FT8, etc. should not worry. People using the IC-9700 for weak-signal modes and EME should, and not putting the old locked IC-910(0) or TS-2000 on sale, yet.

IC-9700 receiving from a GPSDO signal source. RX only but with case temperature above 30 degrees so the fan turns on and off.

April 2019 NAC contest on 1296 MHz

Only worked for 1,5 hours. 8 QSO’s in 7 grids. ODX: SK7MW (617km). I had to run low power due to the IC-9700 Power Overshoot. 🙁

Icom IC-9700 Power overshoot

Damn you Icom. Again, and again, and again. Yes. Alse the IC-9700 is equipped with the famous ‘power overshoot’ or ‘ALC overshoot’ issue most modern Icom transceivers have. Apparently Icom can’t get a grip on this issue. Bad news for people using transistor based amplifiers (SSPA) in SSB mode.

Since the IC-9700 had a ‘TX PWR LIMIT’ function, setting this to 7%* will prevent the amp from going in protection mode. The bad side is that the amp only running about 50% of the effective power.

* In my case I’m using a Gemini 2-500 amp with 4W drive level requirement. If your amp needs 10W input, raising the 7% to [try something like 13%] the value you need. And no. 7% does not mean 7 Watts, thus overloading. The value (percentage) isn’t linear. Measuring the (avg) output will tell you.

Update: Setting the tx-delay to 20 ms solved the issue tripping the SSPA.

Icom IC-9700 frequency modification

The first IC-9700 frequency modification appeared online. Marcus (PA2DB) from HamShop.nl posted this. The modification only works on European models and by removing 2 diodes the frequency can be expanded by a few MHz to the USA market. That means 2 MHz extra from 146-148 MHz (which is a welcome modification for UK users since they have temporarily access to 146-147 MHz) and extension from 440-450 MHz. No wideband or MARS/CAP modification available yet. I guess the diodes can be found in the front.

April 2019 NAC contest on 432 MHz

The most remarkable tonight were the very poor conditions. I was able to work Dan (OZ1BEF) as usual, but with 55 signals maximum, with the help of airplane scatter. Normaly his signal is always 59+.
Another stations further away that should always be workable is SK7MW but tonight I didn’t hear the Swedish club station, tough they were spotted on the cluster.
Later on in the evening the openings towards the UK were a bit better but still very moderate.
Totals: 16 QSO’s in 7 grid locators. ODX: OZ1BEF with 510km. I could work more but did not gave CQ myself. Just busy with the new IC-9700, pre-amp settings, compressor settings, etc.