1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Ham radio RFI controlling my HR24s

Discussion in 'DIRECTV HD DVR/Receiver Discussion' started by AirShark, Oct 7, 2012.

  1. AirShark

    AirShark Legend

    127
    3
    Oct 28, 2006
    I wish it were possible, but it is not.

    This is a new rental house we've moved into on a small suburban lot. Like many hams, we don't always have ideal installation areas available. My old QTH had a Hustler 6BTV vertical in the corner of the yard. The only RFI problem I saw with that was a stubborn touch lamp that would move one touch graduation on some freqs. Also a set of computer speakers would growl on a separate antenna system during UHF/VHF xmit.

    I use quality cable, all Times LMR400, RG213. All cable gets swept with the analyzer and dummy load before use. I crimp on and then solder my PL259 connectors. Have been doing so for years.

    The spot I have the antenna in is literally the only place it will fit since the landlord doesn't want anything mounted to the roof. The Alpha Delta DX-CC is 41ft per leg, one leg actually doesn't even fit, I have to take it four feet over the front fence to tie down. Space limited.

    It's a 35ft mast, sunk 2ft into the ground in clay and concrete, braced at 11ft, again at slanted roofline 20.5ft. Leaving 12.5ft above roofline to the feed point.

    There's a 1:1 current balun 2ft below the feed point, another 6-inch 8-turn choke at the ground along with the lightning arrestor and ground rod (tied to main house ground),before it climbs the wall into the attic to enter the house. From the attic, it drops down inside of a wall and terminates to a nice wall plate bulkhead in the loft. 6ft of RG213 cables provide equipment jumpers at this point.

    I believe you when you say you have no problem operating with your HR24s. I also see that several people have reported RFI issues with their IRDs. You sound like you have a little more room to operate than I do. The DX-CC runs over the top of one corner of house...it also work REALLY well for me.

    I had 311 QSOs on it in two short shifts of the CA QSO party this weekend. I'm happy with it, except for this little RFI demon which I feel can be solved.


    Here's another guy with a similar problem: http://forums.directv.com/pe/action/forums/displaypost?postID=11128173#e11128173
     
  2. xmguy

    xmguy Active Member

    2,069
    18
    Mar 26, 2008
    Middle, TN
    I'm a CB radio user not Ham (sadly). I have a 50w CB radio Galaxy very near my HR24. I too use IR. I run my signal to a 25Ft Solar Con Di-Pole antenna. Never has my receivers been random ally controlled. Of course I'm only TXing on 26-27Mhz. But you are probably (as others have said) getting RFI via power. The receivers shielding between the power supply and IR/RF decoder isn't shielded for such extreme signals. A Faraday cage would be a good idea. As well as the ferrite clips on the power line into the HR24. See what helps.
     
  3. AirShark

    AirShark Legend

    127
    3
    Oct 28, 2006
    Still troubleshooting.

    I discovered that if I transmit via my HT (walkie-talkie), on 440@5watts within a few feet of my IRDs, they will turn on and off. After a few on off cycles the touch buttons on the front panel become unresponsive.

    After reboot, they're working fine again.
     
  4. AirShark

    AirShark Legend

    127
    3
    Oct 28, 2006
    Update:

    Test conditions are: IRD on UPS, disconnected from house main power. All cables except for power removed. No foil shielding.

    If I transmit on 80m SSB, the IRD turns on and off when peak power registers 100w on my Kenwood TS2000. If I transmit on UHF from my HT within about two feet, the IRD turns on and off. After several cycles, the touch sensitive buttons no longer respond. The IRD also no longer responds to radio interference. It still responds to remote commands via IR.

    All function is restored after a RBR.

    It sounds like the internal rf receiver is getting overloaded and eventually locks some component into a non responsive state..

    I suppose the rf could be getting in via the power cord. I'll be placing a few good ferrite cores later today to test. If that doesn't work, it looks like ill be building some sort of faraday cage or shielding.

    There's no way I have the energy to call DTV and request different boxes. I can't even imagine how that conversation could possibly go without me beating my head into the wall lol.

    I'll keep you posted.

    P.S.- the units are HR-24/200
     
  5. Diana C

    Diana C Hall Of Fame DBSTalk Club

    2,117
    293
    Mar 30, 2007
    New Jersey
    I think the weak link here is the touch panel. I'll bet the RF is inducing a small current in the panel wiring and causing the capacitive discharge buttons to fire. After a bit of this, the random firings lock up the logic circuit and the panel goes unresponsive.

    Not that this helps solve your problem, but it also leads one to think that adding chokes on the power cord may not be a solution. Shielding the case may be the best option.

    FWIW, I have a 2.4/5MHz hybrid wireless router sitting on the same shelf as one of my HR24s, and if I put it closer than 8 or 10 inches to the HR24 IR remote control functionality gets flakey.
     
  6. AirShark

    AirShark Legend

    127
    3
    Oct 28, 2006
    I think you're on the right track with this. Makes sense. Especially since all of the weird behavior are commands that could be issued using those capacitive touch buttons. No signal issues, just random commands entered with button instruction available on the front panel.
     
  7. AirShark

    AirShark Legend

    127
    3
    Oct 28, 2006
    Great advice.

    I'm a VE with our local group. It's seriously just a multiple choice test that where the q/a bank of questions is publicly published. You should give it a shot.

    N6LY
     
  8. NR4P

    NR4P Dad

    6,386
    280
    Jan 15, 2007
    Sunny Florida
    You just reminded me I had that problem with an HR20-700 some years back. If I used my handheld radio, 4w at 440Mhz within 20 feet of the HR20, it powered on or off with each transmission.

    My solution was getting rid of the HR20 and both the HR24 and later the HR34 that replaced it doesn't exhibit the problem. Go figure.
     
  9. ke3ju

    ke3ju Legend

    147
    1
    Aug 18, 2006
    Stroudsburg,...
    Isn't this how every ham gets their start?

    I used to run 2kw on 11 before I was licensed, now I run QRP...Ironic?
     
  10. ke3ju

    ke3ju Legend

    147
    1
    Aug 18, 2006
    Stroudsburg,...
    I don't realize 70cm was shared with devices...weird...maybe I need look at a current band plan...

    Ed KE3JU
     
  11. texasbrit

    texasbrit Well-Known Member

    5,231
    109
    Aug 9, 2006
    I don't have a radio transmitter, but I have had a similar problem with my HR24 two separate times (each one lasted about three or four days). The HR24 would change channels and skip through the guide without my touching the remote (I am using IR, by the way). On each occasion, I rerouted cables and moved some of the other equipment slightly, and the problem eventually went away, not sure exactly why. On the DirecTV technical forum, a couple of people have reported similar behavior. It's only with the H24/HR24, and I was convinced it was some sort of interference affecting the touch panel.
    Titan25's comment about his router is interesting, my hybrid wireless router is actually sitting above the HR24. Next time (if) I have a problem, I will try just moving that and see if it has any effect.
     
  12. hasan

    hasan Well-Known Member

    5,957
    54
    Sep 22, 2006
    Ogden, IA
    Lots of stuff on 70cm, including wireless weather station sensors (rain gauge, temp, etc).

    I run 700 w out on 80 - 10 m. My 80m antenna's base is only 30' from the HR20-700, HR21-100 and H20-200. All set to RF remote. No unusual behavior at all The 40m antenna is another 15' away, and then there is the beam on top of the 50' tower. No problems. Lower az/el antennas for 70cm and 2m show no issues with D* gear either.

    I do get some OTA desense from my 2 meter (144.390) aprs signal. I can observe better than 30 dB of desense without my 1/4 wave stub. With the stub, it cures everything but OTA channel 13 (around 210 Mhz), which still dies. The front end of the HR20-700 is not all that great on OTA. The same antenna connected to my Sammy TV shows no desense at all.

    The problem you are describing looks like overload, caused by very poor RF shielding in the sat box. Since you can cure it with a tin-foil electrostatic shield, I think you will need to stick with that type of cure. The sat box is permitting HF signals to penetrate the chassis and then there isn't enough rf bypassing/choking inside the box to deal with it.

    You'll have to kill it before it gets to the inside of the box, and the fact that the tin foil works, shows you how to proceed with the cure. I doubt the power line common mode choke approach will work.

    Good luck, keep us posted.

    (73)
     
  13. xmguy

    xmguy Active Member

    2,069
    18
    Mar 26, 2008
    Middle, TN
    I bought the ARRL amateur radio Technicians hand book. It not taking the test that is a concern for me. Im very versed in RF and electronics. But the ham radio equipment isnt cheap. Thats what holding me back mostly. Hey using 50w may not be legal. But i live so far in the boonies that even that isnt powerful enough to go far.
     
  14. xmguy

    xmguy Active Member

    2,069
    18
    Mar 26, 2008
    Middle, TN
    The radio I have can go ABOVE the CB band. But I dont broadcast. It has SSB too. I listen to that. Plus use my Grundig G3 with SW and SSB. Much better on 3Mhz SSB here anyway. I have considered using the 10 meter "CB" radio for Ham if I can get licenced. If I could find a ARRL center near me. Closest one is over 1 hour away.
     
  15. carl6

    carl6 Moderator Staff Member DBSTalk Club

    12,525
    958
    Nov 15, 2005
    Seattle, WA
    Yeah, it's the old "they can't cause interference, and have to accept interference" game, that nobody tests for or enforces. As hasan pointed out, there is a bunch of stuff on 430, but it is all very low power and generally won't cause interference to licensed stations.
     
  16. AirShark

    AirShark Legend

    127
    3
    Oct 28, 2006
    Well, I'm done for the night.

    First attempt at a permanent non-ghetto looking solution has failed.

    I bought some 1/4 aluminum wire mesh from a hobby store. I also bought a big bag of ferrite chokes.

    1. Place EVERY ferrite choke I bought on power cable. Same RFI happens....although now I can only get it to respond on 10m/100w. This new band is the same for every party the test. For some reason 80m isn't bothering it now.
    2. Remove chokes and ground chassis to nearby cold water pipe. No luck. Remove new wire.
    3. Spray painted on one side of the wire mesh (black). I was very proud of myself as I wrapped the HR24 like a Christmas present. I grounded it to the rear metal chassis. I wrapped the top and sides only, leaving the front panel free. I even took pictures because I was so proud. 10m/100w still causes RFI.
    4. I break out the foil again. I wrap it front to back, leaving the sides exposed and torn in front to allow for IR control. Problem solved.....again.


    I need to either get some superfine copper/wire mesh, or back some regular aluminum foil on black construction paper. Then proceed to wrap the IRD in black paper, leaving the sides open to vent. Hopefully that will work.

    Even though I failed tonight, I still learned what I need to do. I even made up a neat connector for grounding the shield. I took an rg6 connector and made it up without a center pin. On the other end of the three inch cable, I stripped away all but the outer shielding, twisted the braid together. I poked that through the screen mesh and soldered it on. This way, I can just screw the rg6 connector onto my unused coax port on the back to use as a chassis ground point.

    On a side note, does anyone wonder why there isn't a three prong cord used on this unit? I guess they get grounding through the coax shield? I double checked, my coax run is grounded at the dish.

    The fight shall continue tomorrow.
     
  17. bobnielsen

    bobnielsen Éminence grise

    8,473
    92
    Jun 29, 2006
    Bainbridge...
    Back in the mid-1950s, 11 meters was an amateur band. I made a few contacts there when I was first licensed.

    --n7xy
     
  18. AirShark

    AirShark Legend

    127
    3
    Oct 28, 2006
    Come on guys, I posted this thread to discuss RFI into the HR24.

    Let's not all get to arguing about HAM and CB pretty please.:D
     
  19. hasan

    hasan Well-Known Member

    5,957
    54
    Sep 22, 2006
    Ogden, IA
    You have confirmed the difference between an electrostatic shield and a grounded shield. An electrostatic shield is only effective if not connected to the proximate ground system (like power line ground). Once you connect the shield to ground, you get coupling from the existing poor rf ground and lose the "electrostatic isolation".

    This is why the aluminum foil works by itself, but the grid of wires connected to a ground don't.

    The problem may be two fold:

    Direct radiation, which the aluminum foil kills.

    Common mode coupling which the grounded shield wired actually make worse, not better.

    Stick with the electrostatic shield.

    Possible elegant solution:

    There a some companies that make a spray on copper ....Form up something that can go around the receiver (maybe card board?), spray it with the copper paint...it should work like the tin foil, but be more aesthetically pleasing.

    Good luck.

    73
     
  20. gribe003

    gribe003 New Member

    1
    0
    Oct 9, 2013
    Huntsville,...
    Exact same thing happens to my Direct TV control box...when I tune up, it turns the control box turns off. I think my problem is my radio is in the same room as the router and the SWM box that connects my TVs together via the cable internet. From what I gather here, it looks like good old fashioned foil wrap...I will let you guys know. Thanks!
    KG4EYG
     

Share This Page