Ham radio RFI controlling my HR24s

We recently moved to a new home and Directv was kind enough to replace my trusty old HR20-700 dvrs with two HR24 units.

I'm an amateur radio operator, N6LY. I transmit 100w on 10,15,20,40,80m through an Alpha Delta DX-CC fan dipole. It's on a 33ft mast, partially over one corner of the house (2 story). Everything is grounded and tied to the main ground. I have two current baluns on the feedline.

I recently got back on the air. Yesterday, during about 7 hours of California QSO Party operation, I noticed the hr24 upstairs was recording random programs. Upon further inspection, I see that each box turns itself on/off when I key on 80/15m.

I unplugged all cabling into the HR24s except for the power. They still turn on/off (just like pressing the capacitive touch button) on the front panel.

There is no indication of any sat signal interference during operation. Only this odd controlling behavior.

I'm going to make a trip to radio shack today for a bag of snap on ferrite chokes on the power cord. If that doesn't help I don't know what else to do other than wrap the darn things in tin foil or something.

If it was the sat cabling I'd be a little relieved as I could work on the grounding system. The fact that its either getting in via the power cabling or directly into the units themselves is troubling.

Any other ideas?

 

No, they're not set to use RF remotes. I have Harmony ONE controllers that only run IR, so I have them set for IR.

I haven't had any other RF issues except for a set of computer speakers. Ferrite beads took care of that minor noise easily.

Here's the funny thing.

The HR24 downstairs, furthest from the antenna: I placed one sheet of foil on top, not the sides, of the HR24, crumpled to touch metal on the back of the chassis. No more turning off on any of my serviceable bands!

The HR24 upstairs, closest to the antenna: I placed the same foil and it didn't work. It turned on less often, but still turned on/off. I placed TWO sheets of foil around it with a 4 inch hole in the front for the IR sensor. Now I haven't been able to get to cycle when on the air.

I'm going to do a final run in the CA QSO party today, we'll see what happens.

I'm going to pick up some ferrite beads anyways, just because I was out. I guess I could make something up with black cardboard or construction paper that I could place/stick onto the HR24 boxes that wouldn't look totally ghetto. Also I'd need to cut out ventilation slits to match the side of the chassis.

I'm guessing based on evidence that it's probably getting into the RF receiver built in to the HR24s?

Could it be this simple? Totally weird right?

-Bryan, N6LY

 

I'll draw a map of the orientation of my antenna and IRDs in a few minutes.

The Sat wiring and feed line do not come near each other at all except for maybe 8ft in the attic. The sat coax is in a shielded bundle with other pre-wired house wiring. I have a 1:1 current balun at the feed point and a coil choke balun before it gets to my shack.

The problem is that on BOTH IRDs with all cabling disconnected except for power, this unwanted control happens. I'm not sure adding chokes to sat transmission line, phone, cat6 lines would do any good.

I just did a final run at the California QSO party for 5 hours straight with the tin-foil wrap and there was no unwanted behavior from the IRDs. I'll prob just go pick up some snap on beads from Radio Shack for the hell of it, but I think I'm going to have to construct some sort of foil-lined shield for the IRDs here pretty soon.

I'm not sure about adding RF chokes to any other equipment except the power cabling, which I'm still not convinced of. My gut tells me it's getting into the radio receiver. Thus no RX issues, only things happening that could be done with a remote control.

 

Doesn't seem likely to me either, but I can't discount what I see.

1. Turn off IRD (either one, doesn't matter)
2. Disconnect all cabling from IRD, except power.
3. Key down on mostly 80m/15m SSB. Other bands work sometimes, but not reliably)
4. IRD Turns on/off randomly
5. Turn off IRD
6. Wrap IRD in aluminum foil, touching metal on rear of IRD
7. Key down on 80/15m again.
8. Nothing happens on IRDs

I also run VHF/UHF, but that's been running for months with no issue. This only started with the addition of a new HF antenna at my new QTH.

 

I'm going to go buy a bag of large ferrite cores from Ham Radio Outlet tomorrow. Hopefully I'll have some luck stacking them up.

The power cords are removable. I don't see a problem in buying an extra and splicing a line rfi filter in.

If the foil works and I can back a few layers on black construction paper, that might not be bad either.

I love a good adventure mystery

 

With the antenna disconnected, 50ohm dummy load attached, it sweeps fine on an antenna analyzer. 1:1 across any frequency. I also have a Narda rf field strength safety meter that registers zero when actually sitting on top of my transmitter during key down. Nothing. I'm fairly confident that anything coming out is coming directly from the radiating elements.

 

I can do that. I'll give it a shot today.

 

I'm only running 100w - prob 1.5dbm of cable loss...so less than 100w radiated.

There are no vent holes on the top of my HR24s, only the sides and back. Shouldn't be hard making something nice that matches the vent hole cutouts. To be clear, I haven't wrapped the entire IRD in foil, just a piece on top, wrapped to barely touch metal chassis on the back, barely hanging over the left side of the chassis.

So far, foil has completely solved the issue it seems. Did a 6 hour final run on the CA QSO Party yesterday, not one problem with either IRD.

 

Thanks, ill look into it.