No, you can't switch these without Dish Network knowing about it (I tried once).
You can, however, turn off your SD box and add the HD box to your system, but you have to do this with Dish Network's cooperation. Once your friend canceled Dish Network, his receiver's authorization was removed. The smartcard in your existing receiver is keyed to that receiver's internal ID code, and won't be accepted by the HD receiver.
They'll do the swap for free, assuming your friend actually owns the HD box. Thing is, most of the HD on Dish is only available via subscription, so even if you swap your old receiver to the new one, you may not see much HD. But that IS a first step.. try that (it is free, after all), then see what you can see.
And it may be even worse, depending on where you live and what gear you have. I have a Dish500 and a regular Dish300. The Dish300 is pointed at the 61.5 satellite, and that's apparently where most of the HD content is. If you have a Dish1000 you won't need upgraded dishes, but otherwise, you may not even be geared up to receive any HD content.
Also, make sure you're getting a modern HD receiver. The original was the model 6000… I used to have one of those. But that model only supports MPEG-2 video. Most of the HD channels are MPEG-4/AVC now, so you need a recent receiver to get that content.
No, you can't switch these without Dish Network knowing about it (I tried once).
You can, however, turn off your SD box and add the HD box to your system, but you have to do this with Dish Network's cooperation. Once your friend canceled Dish Network, his receiver's authorization was removed. The smartcard in your existing receiver is keyed to that receiver's internal ID code, and won't be accepted by the HD receiver.
They'll do the swap for free, assuming your friend actually owns the HD box. Thing is, most of the HD on Dish is only available via subscription, so even if you swap your old receiver to the new one, you may not see much HD. But that IS a first step.. try that (it is free, after all), then see what you can see.
And it may be even worse, depending on where you live and what gear you have. I have a Dish500 and a regular Dish300. The Dish300 is pointed at the 61.5 satellite, and that's apparently where most of the HD content is. If you have a Dish1000 you won't need upgraded dishes, but otherwise, you may not even be geared up to receive any HD content.
Also, make sure you're getting a modern HD receiver. The original was the model 6000… I used to have one of those. But that model only supports MPEG-2 video. Most of the HD channels are MPEG-4/AVC now, so you need a recent receiver to get that content.