ICOM IC-A24 Picks up noise - JHP-520 doesn't?

[daluds]

Hello,

I recently was given a new ICOM IC-A24, and I wanted to upgrade from my JHP-520 since I was having some trouble with the tower responding to my transmissions. The A24 is also bit easier to read with the larger display and buttons, and it has a 12v battery option to connect to a SLA battery that I use to power my GPS.

I tried the IC-A24 today, and it works great with the engine off. However, once I get the C-85 running the radio picks up noise that interferes with the reception. I put the JHP-520 back in and its fine. I do not have shielded spark plugs in the C-85. The IC-A24 cuts out every 10 seconds too so maybe its a bad unit? Ah - I just pressed Function WX-Alert, and it stopped cutting out every 10 seconds.

The antenna is just a 50ohm coax cable routed under the back seat, and an BNC adapter M/M adapter sticks out through the fabric under the belly. The antenna from the radio is then connected outside to the adapter.

Any ideas why the ICOM IC-A24 picks up so much noise and the JHP-520 doesn't? Maybe the ICOM is a bad unit?

Thanks!

Icom A5 with shielded wires and resistor plugs, no noise. I also have a couple of capacitors on the mags.

[JoeS]

Some receivers have circuitry that "clips" the peaks off of noise impulses. In other words the receiver is shut down for the short duration of the pulse. The Icon, if it does indeed have this feature may have an inferior design or a defective circuit.
Joe

[newcub]

Some receivers have circuitry that "clips" the peaks off of noise impulses. In other words the receiver is shut down for the short duration of the pulse. The Icon, if it does indeed have this feature may have an inferior design or a defective circuit.
Joe

It could be that the receiver has ANL(Automatiac Noise Limiting) but it is not turned on. The manual gives this method to turn on "ANL"

"Push [ANL•SCAN] to turn the ANL function ON/OFF.
“ANL ” appears on the display while the ANL function is ON."

[daluds]

I believe ANL was turned on when I tested the radio. I'll try it again with it off.

[140pilot]

I use the A 24 with my A 65 non shielded and just strap it to my leg with the whip antenna. It is very noisy but I can read aircraft near the field and they seem to be able to hear me. Once out of the pattern I have to turn it off though. I dont go near towers so cant say how that would work.

Same radio in my Cessna 140 with shielded system has no issues at all.

[WWhunter]

I have one of the ICOM handhelds and even with the ANL button "on" it is terrible at picking up engine noise. I have shielded wires so I wouldn't think it would be a problem. If I remember correctly it is coming from the left Mag.
The thing drives me nuts if I fly with buddies and try to stay on a frequncy we can talk on. The constant popping/whirling makes it very useless and I normally have to just shut it of. My King KX99 does not have the same issue.
Never have been happy with that ICOM.
WW

[daluds]

If I can't get it working then I'll have to sell it, and keep the JHP-520 for the Cub. If I didn't send in the rebate information I could have returned it to Spruce Aviation... Anyone want to buy a brand new IC-A24 with battery power adapter?

[cubdriver2]

I have one of the ICOM handhelds and even with the ANL button "on" it is terrible at picking up engine noise. I have shielded wires so I wouldn't think it would be a problem. If I remember correctly it is coming from the left Mag.
The thing drives me nuts if I fly with buddies and try to stay on a frequncy we can talk on. The constant popping/whirling makes it very useless and I normally have to just shut it of. My King KX99 does not have the same issue.
Never have been happy with that ICOM.
WW

I have 2 Icoms, A21 and A5 and both work great with shielded wires, the only time I get a popping/whirling sound is when using my gps with the radio on but it only happens once in a while.

Glenn

[LearJet]

I tried to use an Icom handheld to ferry our cub home from NY to Daytona Beach. Nothing I tried would get rid of the interference. Even after I got her home and rebuilt both mags, brand new sheilded harness, new plugs, a new noise filter cap on each mag, still unusable. However, when I ran the proper shielded P-lead wire from the mag switch to the mags with proper grounding on the shielding it is crystal clear. Now I have a Flightline FL-760 mounted in a box I made with mike jacks and a battery in it using an Advanced Aircraftg Electronics VHF-5T antenna mounted on a 45 degree angle in the empennage. Awsome setup. The FL760 has a built in 2 place intercom and I can talk to anyone no problems. Will run all day off the battery, probably more than that but it gets plugged in at night.