I’m a keen user of ALE on the HF bands and recently purchased an Icom IC-7200 to use as a dedicated ALE station. I picked the IC-7200 as I liked the form factor, the fact that is is a dedicated HF radio and that it has a built in USB interface. The only problem with using the IC-7200 for ALE use is that the TX bandpass filters are switched in and out using relays as the radio scans through the bands. This causes an annoying “click, click, click” sound when the radio is changing bands and, when scanning at 5 frequencies per second, can put considerable wear on the relays. Luckily, there is a fix for this problem…
The Quiet Relay Scan (or QRS) mod is a tricky procedure that involves removing a small SMT component and adding a small SPDT relay. It is not for the faint hearted. You need a very steady hand and plenty of experience soldering small SMT parts. The full details can be found over on the HFLink website at http://hflink.com/icom/ic7200/.
I used a small relay from the local Maplin store, part no: N15AW. You will also need a small piece of double sided foam tape and some thin hook up wire. A good tip is to use the most flexible wire that you can find. Using stiff wire or wire with any amount of “spring” will ensure that the tracks of the PCB will lift and then you will be in the market for a new main board!
The first step is to wire the relay as shown in the instructions.
Next, remove both the top and bottom casing of the IC-7200. Using the instructions, find the points where the relay will attach and the component that needs to be removed. 3 of the relay connections are made to the main board. The other connection is made to the filter board by passing the relay wire through the chassis of the radio.
I found a suitable place for the relay and used the double sided foam tape to stick it into position.
Route the relay wires and solder into position. I used a small 12W soldering iron. The most tricky connections are made once EP2972 has been removed. It is very important that no stress or strain is placed on the relay wires once they have been soldered to the board in this location. Even a tiny amount of force will cause the thin PCB tracks to lift. I personally applied a small drop of hot glue to the joints to prevent any movement. Never use superglue on a PCB.
The final step is to check that the mod is working and reassemble the radio. To test, turn the radio on, set to “fast tuning” mode and spin the dial. You should hear no clicking as the radio goes up and down through the bands.
I can confirm the the mod works very well and has absolutely no impact on the received signal. It also does not affect TX as the TX filters are switched in when the PTT is pressed. I have had many good reports since the mod was completed.