So, your expensive piece of technology had a bath?

Picture by Patrick Hoesly.

It happens. Sometimes technology packed expensive electronic equipment (decide to) get in touch with liquid substances. As many online sources will tell, hope is not lost the very moment the two incompatible objects get in touch. I will not reveal any new method, just what I have done.

Let us consider the case of a smartphone (Galaxy S) being dipped in clean drinkable water.

First of all: read the picture on the right.

As soon as the bath is over take the device apart (battery, main body, back cover, memory card, SIM card) and dry it wth towel/napkin. Don't shake it, but turn it around to get the water out of holes such as the earphone and USB sockets. Then let it dry for at least 48 hours. Be patient: you aim to recover your data from the device, don't you? This should be your first target. If your device works afterwards then it is luck or well designed technology. Or a combination of both.
I dried mine in a bowl filled with (uncooked!) rice close to a heat radiator. Temperature should have peaked to more than 40°C, but heat is not a must: leave it longer.

When you are ready plug the battery and keep your fingers crossed. If the device powers up be prepared to extract your data using the standard method.


Additional notes.
Some online resources mention water-sensitive labels all around these expensive mobile devices. I haven't been able to spot them on the external body of the i9000. Anyway do not lie to the customer service if you are going to return it.
If your device allows to use an external memory card, it is probably wise to save your mobile-authored data on it, or take periodic backups. It is more unlikely that a self-contained hole-less memory card becomes damaged with water (anyway let it equally dry).

UV-3R data cable (homemade)

I had ordered an USB-to-UART TTL adapter to debug the rotary encoder on the Frequency Reader. While it was on the way to my lab, I solved the encoder problem, so the adapter had to be tested somehow.

Around the shack I had found a cable terminated in a 4-way 3.5mm jack, probably from an old digital camera. That is the connector of UV-3R data cable (and external ear/microphone too), so I gave it a chance. Steps were:

• identify which cable goes to which connector ring
• draw a map of pin matches between the cable and the adapter
• test the whole thing (as shown in the picture)

My ugly UV-3R data cable (not for permanent use)

At first there was no communication with the radio. Then I swapped RXD and TXD connections: UV-3R software downloaded radio parameters. Cool. Note that the UV-3R says nothing on the display about the data cable being inserted or ongoing computer communication. If data is uploaded to the radio it will automatically power cycle.

The adapter is based on the CP2102 chip and costs 3 USD (2.3 EUR) shipped from Hong Kong. Both WinXP and Vista 64bit recognized the device (XP grabbed the driver from an online source).

The same adapter can be used to build a data cable for the FT817, or other transceivers that expose a serial port with TTL logic levels instead of RS-232 voltages (ICOMs, ...).

New frequency formatting for I.F.R.

My development board with the new display

... and new display too.

On the I.F.R. firmware I have modified the way the frequency is displayed when there is no transverter connected or configured. Information on the first line is right aligned, "Hz" symbol expanded and decimal separator dot added to make the frequency value look nicer.

On the picture you can also see a new display I received: orange on black. For operations in a dark environment it is less bright than the white on blue LCD. Last but not least it matches 817's amber display color (not too closely, I know).

TX-only transverter for 4m - with mixer

The picture shows my TX-only transverter with the diode ring mixer (SBL-1 or ADE-1) component added. The circuit has not grown a lot, but it does indeed work.

The canned oscillator is now terminated in a 1kohm trimmer and feeds the IF port of the mixer. RF from the HF transmitter goes to the LO port. Trimmers will most probably be replaced with fixed resistors.

As a signal generator I used the FT-817 at 24.9 MHz. Listening on a panoramic receiver I could clearly hear LO-HF (20 MHz) and LO+HF (69.8 MHz). The frequency counter on the mixer output picked up the LO-HF difference, which was expected since there is no bandpass filtering afterwards.

I tried swapping HF and LO signals but the result was the same. Signal output decreases if the HF trimmer reduces the mixer drive.

Next step is to build a resonating termination followed by an amplifying buffer. G3XBM circuit calls for a BF199, which is already sitting on the workbench, committed to take part into this project.

TX-only transverter for 4m

While I have no news about a possible 4m allocation for Italy in the next months, I have started working on my TX-only transverter - a "txverter"? - for HF-to-70 MHz.

The idea behind this project is that the IC706MKiiG receives on 4m, so there is no need for a full transverter, provided the operator accepts to operate split. It is a KISSAL principle: Keep It Short Simple And Lazy :-)

I decided to replicate G3XBM's simple transverter, TX chain only. I will build it manhattan/dead-bug style using an ADE-1 passive DBM mixer.

The picture shows first components placed on the copper clad board:

• 5V voltage regulator
• canned oscillator @44.900 MHz
• HF input attenuator of about 30dB (50, 680, 100 ohms)

Current drain at 12V is about 18mA, all for the voltage regulator and the canned oscillator.

The output of the latter is not a sine wave on a 100 MHz scope&probe, but it swings 0-5V if left floating.

I plan to blog how the circuit grows and how it performs.

UV-3R VHF second harmonic

Definition: a second harmonic is a spurious emission of a transmitter located at twice the fundamental frequency (or first harmonic or "dial"). In most cases the second harmonic is not produced on purpose.

UV-3R, especially the single-line display, exhibits too little suppression of the second harmonic of the VHF transmitter. This occurs when the RTX is used on the VHF HAM band (144-146/148 MHz). Suppression gets better and within required limits when the VHF transmitter is used above 150 MHz.

This means un-modified UV-3R is not certified for VHF amateur radio operations. Transmitting, say, at 145.500 MHz, will result in a parallel transmission on 291.000 MHz, which is probably allocated to a Defence Ministry. In the Files area of the Yahoo! group some LPF modifications have been measured and described in detail. Unfortunately they are not for everyone.

So, what options do I have?

• use unmodified UV-3R on VHF only if strictly needed, being aware you might be disturbing communications around 290 MHz. On UHF the little "R" is spurious emissions compliant.
• insert a VHF band/low-pass filter between UV-3R and the antenna
• have someone apply the LPF modification

Why is it so? No one has figured out why the VHF signal is so dirty. It might be a driver/final wrong bias current. UV-3R Mark II is apparently performing better, but still above the required suppression level.

Back up pictures during long trips

I have had an interesting chat about methods for preserving your digital pictures (movies) while being out on an important and long trip. In other words, how to make sure you precious shots come back home with you.

Assumption: you have a way to read memory cards through a computer (not necessarily yours) or use a stand-alone card copier.


Memory cards are pretty cheap. So, why not bringing along an additional extra set, making a copy of a full card and sending it to your home address? You may even prepare addressed envelopes with a thin cardboard reinforce inside. Stamp can be bought as if you were shopping for postcards and you don’t even need a trip to a post office unless you want a Registered letter. Better to send one card per envelope. Once you have safely backed up your picutres (at home), extra cards can be reused for the following adventure.

If you know a trustworthy local, leave her/him your backup copies, either an external HDD or extra memory cards. This will minimize the risk of loss/damage on the journey back home too. If nothing bad happens to your "originals", she/he will keep the hardware afterwards as a reward for the service offered.

Online storage populated overnight is another option, if your hotel has a fast and cheap Internet connection. (If you carry your own laptop consider using Dropbox through my referral link.) But if you shoot a lot (and in RAW ), it might not be practical.


Worried about someone stealing your shots? Either the postman or your local contact person? Encrypt the backup card content with a tool like TrueCrypt. Format the card/disk to resume full, unencrypted, functionality.

Fast knob rotation solved

Good news: I have solved the puzzle of missing steps with fast rotary encoder rotations. It was a piece of inefficient code, which has now been rearranged using AVR's Pin Change INTerrupts ("PCINT").

The 96 states / 24 cycles per rotation encoder is now read properly: it doesn't miss a step.

Now the FR/IFR firmware has to be adapted to a new form of interaction...