Dish 500 dual twin LNB generating noise on 14 MHz

[RocketNJ]

Anyone have any experience with the legacy Dish 500 LNB generating noise on 14 MHz? I have a ham receiver and am receiving noise on the 20 meter band (14 MHz). I traced it down to when either sat receiver is powered up (power to LNB).

Any idea if a Dish Pro solution might work better?

[BobaBird]

I don't know if this has any bearing on the answer to your question, but it's unclear whether your Dish 500 has 2 duals or 1 Twin (see pictures (http://ekb.dbstalk.com/82) and explanation (http://ekb.dbstalk.com/35#dual)).

Does it make a difference what channel the receiver is on? For legacy LNBs, the receivers send 13v for odd transponders and 18v for evens.

[harsh]

I traced it down to when either sat receiver is powered up (power to LNB).As the receivers and the LNBs are hot all the time, it is odd that you would be getting different results between standby mode and "on" mode.

[Neil Derryberry]

Anyone have any experience with the legacy Dish 500 LNB generating noise on 14 MHz? I have a ham receiver and am receiving noise on the 20 meter band (14 MHz). I traced it down to when either sat receiver is powered up (power to LNB).

Any idea if a Dish Pro solution might work better?

How long have you had your dish/cabling up there? Could be a degradation of the feedline to the lnb or even the lnb itself leaking voltage ..it is powered all the time as another user said earlier. Your solution might just be a new lnb/feedline or at least temporarily a choke for the radio antenna.

Ham to ham.. what kind of antenna are you using?

[harsh]

Ham to ham.. what kind of antenna are you using?Is this one of those "if you show me yours, I show you mine" things?

[rcdallas]

How long have you had your dish/cabling up there? Could be a degradation of the feedline to the lnb or even the lnb itself leaking voltage ..it is powered all the time as another user said earlier. Your solution might just be a new lnb/feedline or at least temporarily a choke for the radio antenna.

Ham to ham.. what kind of antenna are you using?


Sure seems to be alot of hams on this forum.... de kd5zqn :)

Since your in Atlanta, ever talk to Max on 52?

Anyhow I'd suggest quad shield RG6.

[Neil Derryberry]

Not that I recall.. I haven't had a home rig for the better part of a year now, just mobile on 2m/440. Hopefully bonus time this year will change that.

[RocketNJ]

The ham antenna is a Spi-Ro D-52 trap dipole. the center inslator is about 3 feet from the Dish 500. One solution is to relocate the dipole farther from the Dish, but it was convenient to mount it close due to trees on the property.

The Dish500 does have a single twin LNB fed with quad shielded RG-6. It feeds into a SW-64 mounted right below the chimney.

To test I unplugged the power inserter and both satellite receivers (721 & 921) and verified noise floor on 20 meters was acceptable. Next I powered up the SW-64 (applied power to the inserter with both sat receivers off). Again noise floor was acceptable. I then powered up the 721 (which feeds ports 1 & 2 on the SW-64 and the noise floor was 6 S units higher. same thing with the 721 unplugged and 921 powered up. The moise is only present when either or both satellite receivers are powered up.

Guess I'll relocate the ham antenna this weekend (if it ever cools off!).

[robert koerner]

Next test, disconnect the feed lines from the receiver, and then plug in your sat receivers.

Disconnect the LNAs, feed line going to the receivers, plug in your receivers(S).

My guess would be crap from switching power supplies in your receivers.

Are your sat receivers and ham rig on the same circuit breaker?

[RocketNJ]

They are not on the same breakers and also they are seperated physically in the house (closest receiver to the ham radio is about 35 ft away).

I'll try to narrow down the problem but I am pretty sure it is noise being radiated from the LNB. I'm going to work on getting the dipole away from the LNB to see if the noise is reduced. Just have to figure out how to mount a 104' dipole with the trees in the way

[robert koerner]

I can understand having sat problems if you xmit.

Try posting your problem on eHam.

LNB noise blocking 20 meters does not make much sense.

73

[Neil Derryberry]

They are not on the same breakers and also they are seperated physically in the house (closest receiver to the ham radio is about 35 ft away).

I'll try to narrow down the problem but I am pretty sure it is noise being radiated from the LNB. I'm going to work on getting the dipole away from the LNB to see if the noise is reduced. Just have to figure out how to mount a 104' dipole with the trees in the way

Not familiar with that specific dipole but the length makes it sound like a G5RV clone of some sort. That said, maybe a folded arrangement might help out on the space requirement.

The sw64 is an older model switch.. is it grounded? An outside installation while acceptabe would subject it to faster wear than an inside installation - maybe relocating it inside might be of some help.

[srickard]

I am also a ham. I am unable to detect any noise related to my 942. I have a G5RV laying on the roof (restricted community). My switches are SW21s so are not powered. Good luck on your investigation.

Steve - W7JOD