HR500 & IC705 tuning power output issue

[N1IG - Anthony]

Has anyone else noticed that their IC705 tunes at 10w full power when connected to 12v at the side connector? Even if you've adjusted max TX power on the IC705 to 2.5w?

Pretty sure that the max the HR500 can take is <5w, and it might get damaged over time if running your IC705 on external power.

[jcve...@gmail.com]

Hi Anthony,

If you are using the HobbyPCB IC705 interface, it takes care of that issue. You are correct 10W is too much power for the amp. When the Icom requests a tune, either due to a band change or initiated by the user, the interface unit reads the current operating mode and power settings, sets the mode to FM, sets the power to 2 watts, keys the TX, tells the ATU to tune, waits for a response, unkeys the TX then restores the original mode and power settings. The interface unit will never request the 10W tuning signal from the Icom.

If you are using some other method of activating the ATU you could be seeing the 10W tuning signal.

73,

Jim WA2EUJ

[N1IG - Anthony]

Hi Jim,

I am using the hobbypcb interface.  But the mode doesn’t change to FM, and the DRV meter on the HR500 shows 10w or a bit more.  

And I still have the issue where HR500 isn’t telling the IC705 to stop TX, even though it’s found a tuning solution.  

Anthony - N1IG

[AC1I]

Actually, according to Jim, the HR-500 can handle the 10W tuning signal with no problem.

Patrick AC1I

On Monday, January 20, 2025 at 2:36:10 PM UTC-5 N1IG - Anthony wrote:

[N1IG - Anthony]

Gert said that using over 10w fried his HR500.  

https://groups.google.com/g/hardrock-500-technical-forum/c/sk_iZa_diB8/m/jRNl4OGBCgAJ

[jcve...@gmail.com]

If you tune with the amp in bypass mode 10W isn't an issue. But if the amp is on-line and you hit the input with 10W you can definitely do some damage. Make sure that you have the latest Arduino Sketch in the IC705 Interface. I seem to recall that the 10W issue has been addressed.

Jim,

[AC1I]

This is what I was told:

" The ATU can handle even more power bypassed because it has 16A relays. It's coax in and out so it should have low SWR as well. You can use the ATU even if you aren't using the amp. Just leave the amp off and you can still tune and it will recall solutions when you change bands or antennas. the Max power for tuning is 10-15W but it's protected and will drop-off line if you try to tune with too much power. I think it'll tell you 'Too Much Power'", 

I suppose it is a question of how much over 10 watts he tuned with. In my tuning interface I used to tune my HR-500 at 2.5W with the false tune methodology, but after receiving this info I switched to a stand ICOM tuning procedure and just tune during the normal ICOM tuning cycle at 10W with no ill effects. I still tune the HR-50/50+ at 2.5W using the false tune methodology.
,

[N1IG - Anthony]

I just downloaded the HR50-IC705 2024 sketch from https://drive.google.com/file/d/1RS2upaWNaT1UsGGdKW5YYAioT6E2uxM4/view?usp=drive_web,

and uploaded it to the interface.  It still does not drop the power during tuning or change the TX mode when the IC705 initiates a tuning cycle.  

On Monday, January 20, 2025 at 2:45:42 PM UTC-5 jcve...@gmail.com wrote:

[jcve...@gmail.com]

I may be confusing the IC705 with the Hardplace Branch. I found some release notes for the 4.2A release:

HR50 Firmware Version 4.2a       10-May-2022

This version of HR-50 firmware has been tested on a HR-50 Rev G, with an ATU with firmware v1.5.

1. Added support for IC-705 auto-tuner interface, where after completing the tuner function (ICOM transceiver mode only), the amp is not re-engaged until the external PTT or internal COR lines are released. This indicates that the radio (IC-705) is no longer activating PTT and no longer requesting the tune function. This is done to ensure that the IC-705's auto-tune RF power (10 watts) is never applied to the RF amp input. NOTE: This is only done when the HR-50 transceiver selection is set to ICOM.

 

HR50 IC-705 Interface Arduino Board Firmware Version ???        10-May-2022

2. Removed previous code that was placing the HR-50 into QRP mode during an auto-tune function. This firmware should only be used with HR-50 firmware v4.2a or newer.

Please test this out and let me know if you see any problems

If changes are needed, can make a v4.2b … etc. release

All of this code was developed by users, not HobbyPCB.

73,

Jim WA2EUJ