One of the complaints I had about the IC 705 was the capacity of the battery . It's only 1800 mah. After doing some research, I found out that Batteries America offers a much higher capacity battery. Their battery is rated at 3350 mah. That's almost double the capacity of the stock Icom battery. Batteries America part number is: BP-307Li I also ordered the quick charger to go along with the above battery. Batteries America has a package deal for both the battery and charger that will save you a few dollars.

Icom's published current drain on receive is between 500 and 800 ma. I used a Fluke VOM to check the current drain and found the current drain to be a lot less. I removed the Icom clip on battery and supplied 8.4 volts from an adjustable power supply. There must be a boost circuit built into the radio, that is in line with the clip on battery, because the radio would not put any power out with only 8.4 volts from the external power supply. The current drain for receive with the display on is only 335 ma with 8.4 power supply voltage. To get 5 watts out, I had to increase the external voltage to above 10 volts. At 5 watts out the current drain was 1.6 amps into a 50 ohm dummy load. At 12 volts, the radio can put the full 10 watts out. With 12 volts supplied to the radio, at 10 watts out the current drain is 2 amps and receive current drain is only 225 ma. At 13.8 volts of supply voltage the receive current drain is now only 200 ma. Using the BP-307 Li battery should offer you a reasonable amount of time to operate portable in the park. You can not get 10 watts out using either of the two batteries. By using a 3 cell LiPo battery, fully changed, you will get about 7 watts out.

So why does Icom say the current drain is between 500 and 800 ma? For the clip on battery to supply 10 volts or more, you have to use a boost circuit. By doing so, you increase the current drain on the battery.

There are numerous battery charging options for the 705. One option is charging via the USB cable. When the radio is connected to a computer and the computer is on, the battery is being charged. This can be an advantage or a disadvantage? For me, I turned that feature off. When operating portable, powering the radio with the radio's battery and hooked to the computer via USB cable, leaving the USB charging on, the radio will add to the computer's battery power drain. The battery can also be charged via the DC power cable. Whether the radio is on of off, with power applied to the radio, the battery will charge. You can change this so the battery is charging only when the radio is turned off.

Setting up the transmit audio and band width is most important. There is so much bad audio on the bands from hams that just do not have a clue as to what they are doing. Here are the settings I use and I have gotten all good audio reports.

Set the Mic Gain to 50%. Turn on the RF speech processor and set it to 5. The next item to address is the transmit band width. Tap the, "Function" button and go to screen #1. "TBW" stands for transmit band width. If you like broad band audio like most rag chewers prefer, set this to, "Wide" (100 hz to 2900 hz) If you like working DX and breaking pileups, you would want to set this to, "Mid" 300 hz to 2700 hz. The Mid setting cuts off some of the base in you audio. You want to cut off some of the bass for working DX or breaking pileups.

The stock microphone that comes with the radio does a nice job. The speaker in the microphone does not sound as good as the speaker in the radio. By only plugging in the smaller plug on the microphone cord, the speaker in the radio will stay active. All of the microphone functions will still work by not plugging in the larger plug on the microphone cord. The larger plug is strictly for the speaker in the microphone.

A word on an antenna tuner: I've read the Icom manual numerous times and there is not one reference as to how high of an SWR it is acceptable to use with this radio without an external ATU. The only reference I saw was where they mention that the Icom's external ATU should be able to lower the SWR to a value of 2 to 1 or less. I ran a few tests checking when the radio goes into SWR protection. At 10 watts out with an SWR of 2 to 1, the radio still puts out its rated power. The reflected power is 1.2 watts. Since the radio uses reflected power and not SWR as a reference for protecting the finals, with lower power out you can run into a higher SWR. So at 5 watts out and an SWR of 2 to 1, you only get .6 watts reflected. With less reflected watts the radio can handle a little bit higher SWR. I found that the radio still puts out the full 5 watts into an SWR of 2.5 to 1. I set my SWR limit at 2.5 to 1 when running 5 watts out. I set my 705 for a maximum power out of 5 watts. For portable operating I either run 5 watts QRP or 40 watts from another radio.

Since I only use matched resonant antennas and I don't operate into an antenna with an SWR higher than 2.5 to 1, I don't need an external ATU. That's not to say that I won't take an ATU with me when I operate portable. I do plan on purchasing the Elecraft T1 low power ATU.

Hardware: There are five threaded holes in the bottom of the radio. One hole is 1/4" - 20 UNC threads and mostly used for a camera tripod or the above Neewer Z flex camera bracket. The other 4 threaded holes accept the follow metric screw size: M4- .07 x 10. These can be purchased at most box stores or hard ware stores.

Pros:

1. Filtering….Between the twin pass band tuning, being able to narrow the CW bandwidth down to 50 cycles, noise reduction, auto notch and noise blanker you can get rid of a lot of interference and bring out the weak signals.

2. Display…. With so much information on the display, you would think it is too busy and you could easily loose your way. Not so. There may be a lot of information on the screen but it is very informative and very well laid out.

3. Function layout….The medium power HF radio I use from time to time is laid out terribly when it comes to functions that are used on a daily basis. You may have to go through up to 10 screens of information just to turn on the noise blanker. Not so on the 705. This radio is so well laid out. Push one button and the display gives you access to numerous function. Just tap the icon for what you want to either toggle on and off or tap the icon for 1 second to turn on and adjust the value. Almost every function you would normally change can be accessed by a push of a button or push of a knob. Somebody at Icom really did their homework.

4. Backing up the configuration….Once you set the radio up to exactly how you like it, this includes the CW memory keyer and digital voice recordings in the 8 memory slots and the memory channels, it can all be backup to a micro SD card that’s plugged into the radio. Go portable and make some mistake that really screws up the operation of the radio. No problem. Turn the radio on, access the SD card and do a quick restore. In less than 30 seconds you up and running.

5. Frequency tuning rates…..You can choose between up to four tuning rates from super slow to super fast. Just touch the frequency range, on the screen, that you want to change. Even the multi function knob on the radio steps you quickly through the band. Even the stepping range the knob uses has numerous values to choose from. My choice is 5 khz tuning steps.

6. Do all radio….. For those that like a, “One Radio Do Everything”, this radio has it. To be able to cover 1.8 mhz up to and including the 440 mhz band in all modes including D Star is simply amazing.

7. D Star….If you like operating D Star, this surely is the radio for you. It can be used in three different ways. First like an HT. You use to the radio to bring up a local repeater to access a reflector. Second, the radio can access a reflector via its built in WiFi. Third, the radio can be programmed to be a stand alone hot spot so you can use an HT to access the IC705 used as a hot spot.

8. CW auto tune….The button that starts the external ATU to work can be reprogrammed to auto tune on a CW signal. If you are not sure if you are on the exact same frequency as the CW signal you are listening to, just tap the tuner button on the radio and the radio will auto tune and put you on the exact same frequency.

9. Digital Voice Recorder…..The 705 has eight DVR memory slots. Each slot can record a message up to 1-1/2 minutes long. That’s a total of 12 minutes of record time. The CW memory keyer also has 8 memory slots. Each of the 8 memory icons can be labeled so you know what they are, not just 1 to 8.

As a general coverage receiver, again this radio shines. I don’t want to bore you with everything this radio can receive. What I can say is an SWL'r would be in heaven with this radio.

Cons:

1. No ATU…..I find this as a major flaw. My KX2 is super small and it has a built in ATU.

2. Too small of a battery….Since Icom already makes a 3050 mha battery that can replace the 1800 mah battery that comes with the radio, that is the battery that should have been supplied with the radio at time of purchase.

3. Transmit audio equalizer….The 705 allows three choices to taylor your transmit audio. Being a software defined radio, it should not have been all that hard to incorporate a 7 or 9 band audio equalizer.

4. Power plug….Almost all manufactures use a 5.5 by 2.1mm DC power plug, I see no reason why the 705 could not have used the same connector instead of using the 5.5 by 2.5 mm DC plug. Consistency would mean that you don't have to carry around all different types of power cables when setting up portable.

5. Angle of the radio….Icom should have attach retractable feet on the bottom of the radio that can be extended to tilt the radio at an angle for better viewing of the display and easier operation of the radio.

6. The operating manual.....It goes without saying that more work needs to be done in this area.

7. RTTY decoding…..The 705 can decode RTTY and this is a nice feature. But, you can only respond by using only canned messages that you can program in the 8 memory slots. You should be able to send RTTY via the CW paddles.

As far as my cons go, they are not really deal breakers. I do think an onboard broad band ATU should have been incorporated, but when using low power one should really use a matched resonant antenna to maximize one's signal. Plus the 705 can easily handle up to a 2 to 1 SWR and still supply full power out. By limiting your power level to only 5 watts out as I do, you can transmit into a load of up to 2.5 to 1 SWR and still get 5 watts out without any issues. The ATU's in most radios today are programmed to handle SWR values of up to 3 to 1. So this radio being able to handle up to a 2.5 to 1 SWR is not to far from operating on radios that have an ATU that can only handle up to a 3 to 1 SWR with the use of their ATU.. So would an onboard ATU really make that much of a difference? I guess that really depends on how bad your antenna match is.

ATU-10 from Banggood.com

There are times I find myself in need of an ATU. One example is when I use my half wave end fed 40. I can not always erect this antenna in the clear. I did purchase the LDG Z100 Plus 705 with the interfacing cable. The unit does as advertised but I am not impressed with its performance. My biggest complaint is, when interfaced and the radio tells the LDG to tune and it does not know the antenna is matched and resonant, the LDG adds capacitance and inductance which actually raises the SWR. It's too dumb to go into bypass. I resolved this by not using the interface cable. Now I only tell the LDG to tune where needed. Most of the time I turn the LDG off by toggling between bypass and tune using the button of the front of the unit.

Size matters to me and the LDG ATU is too big. Another downside is it uses SO-239 connectors instead of BNC connectors. Everything I have relating to QRP operating uses all BNC connectors, including my home brew two position antenna switch. I do want to get my hands on an Elecraft T1 ATU but Elecraft can't get the parts from the manufactures to make them. So the hunt was on for a small ATU with internal batteries and BNC's instead of the dreaded SO-239 connectors. Here is what I came up with.

I ordered the above pictured ATU-10 from Banggood.com. They can be found on Ebay as well. I did not provide a link for ebay because some ebay adds are dated. There is a very good demo posted on YouTube.

Here is an overview of the ATU-10.

My ATU-10 arrived yesterday ( 11 June 2022 ). Here are my findings:

The package contained an allen wrench and a USB cable for charging the battery as well as for updating the firmware. The package DID NOT include the interface cable for the Icom 705 nor did it included any paperwork.......no manual! My battery showed about half charged and firmware version 1.4 was installed.

The needed interface cable is nothing more than a stereo audio cable with 1/8" male plugs on both ends. But, the ATU works without the interface cable, it's just not controllable from the radio. As for the matching, I can say it works as good as or as bad as my LDG Z-100 Plus. Where ever the LDG provided a match, so did the ATU-10. On 80 meters where the LDG did not do so well, neither did the ATU-10.

I first tried the ATU-10 without the interface cable. I just sent a carrier from the radio and the tuner went into the tune mode. It's that simple. It takes anywhere from 2 to 5 seconds to find a reasonable match.

To use the ATU-10 with the interface cable, there is the setup procedure. Hook up all of the cables, including the interface cable to the IC705. Now turn the ATU-10 on. Once booted, turn on the IC705. Go into the, "Function" screen and tap the, "tuner" icon. You are ready to go. You do not have to change modes to have the ATU-10 go into the tune mode. In any mode on the radio, like SSB, just key the mic and the tuner will tune. Give it a second or two and you are ready to go. Change bands and key the mic, same results. I lost communication between the radio and the ATU-10 when I went to 80 meters. I have no idea why? I just turned the radio off, then back on and everything was reset...ready to go.

In order to put the ATU-10 into bypass, tap and hold the button on the front of the ATU-10 two seconds. This will reset the relays to default. Next turn the unit off, the ATU-10 is now in bypass. Since I only need the ATU-10 on the top of the 40 meter band, I let the unit off until needed.

When I received my ATU-10, in noticed all of the hardware was not that tight. I retightened each nut and allen screw.

User group for the ATU-10 and the ATU-100.

Pros:

Size...the ATU-10 is small enough to carry in your shirt pocket ( 5" x 2-3/4" x 1" )

Antenna connections… BNC. All of my cables used when I set up portable use BNC connectors.

Power source ….the ATU-10 has two internal rechargeable batteries so no external power source is needed. Since the ATU-10 uses latching relays, the only power that is needed is for the display. The display has a time out timer and the ATU will turn off after 30 minutes on non use. The ATU will last you for months on end before needing to be recharged.

Display… the display shows SWR, power out and the state of charge for the internal batteries. It also shows what firmware is installed. The display will fall asleep after 5 minutes of non use. If power is applied, the display will wake up. The entire ATU will turn off after 30 minutes of non use.

Construction…..the ATU-10 is built inside of a solid metal enclosure.

Cons:

Loss of communication….more than once communication was lost between the radio and the tuner. Easy fix by turning the radio off and then back on but this is very inconvenient.

No manual.....not even a little sheet of paper showing the specs. Whatever you need to know can be found on this site. ATU-10 info.

Final notes:

For the price, it think this is a great buy. It does exactly what I want it to do, provide a reasonable match to make the radio happy. You can use the ATU-10 with any radio at a power level of 10 watts or less. It’s a perfect size for backpackers. I don’t think the interfacing between the radio and the ATU-10 is all that importable. I myself choose not to use the interface cable. Since the tuner will go into a tune mode if the SWR is too high, that’s all that is really needed.