scanner feed with diplexer on satellite feed-line

[RetroBandit]

I've look though a few other post that sort of cover this idea, but not exactly, so I though I'd make my first post and see what happens.

Because of some changes I want to try using satellite diplexers to share it's feed line with my Uniden scanner. Have one diplexer out side to merge the dish and the scanner antenna together then at the inside end the other diplexer to split it between the satellite box and the scanner. They advertise these to work with broadcast TV signals, so I figure it should work for a scanner also..

I understand there's some impedance mismatch, but I figure it's a way to save cable and worse drilling more holes..So just wonder if anybody else is doing it and if it works ok??

thanks

 

[prcguy]

It will work depending on what frequencies you want to get on your scanner and what satellite service you have. The satellite diplexers should pass around 50 to 800MHz with minimal loss for your scanner antenna and you need two of them, one on the roof to combine the sat and scanner antennas and one in the house to separate the signals.

Last I checked the diplexers should work with Dish Network and FTA systems but not with the current DirecTV equipment.

One type of DirecTV system uses several bands of frequencies, the traditional 950 to 1450Mhz and 1650 to 2150MHz, both no problem, but also 250 to 750MHz which will not work with a diplexer. You would get massive interference on your scanner from the DirecTV signals and your DirecTV system would be missing any channels that use the 250 to 750MHz range on the coax.

Another DirecTV system, the single wire multiswitch, or SWIM confines the TV signals in a range above 950MHz but can have other information flowing in the coax at lower frequencies like data between the dish and all receivers and video between the main server and clients. Put a diplexer in that system and you can kill all the communications between receivers and dish plus get interference in your scanner.
prcguy

I've look though a few other post that sort of cover this idea, but not exactly, so I though I'd make my first post and see what happens.

Because of some changes I want to try using satellite diplexers to share it's feed line with my Uniden scanner. Have one diplexer out side to merge the dish and the scanner antenna together then at the inside end the other diplexer to split it between the satellite box and the scanner. They advertise these to work with broadcast TV signals, so I figure it should work for a scanner also..

I understand there's some impedance mismatch, but I figure it's a way to save cable and worse drilling more holes..So just wonder if anybody else is doing it and if it works ok??

thanks

 

[RetroBandit]

It will work depending on what frequencies you want to get on your scanner and what satellite service you have. The satellite diplexers should pass around 50 to 800MHz with minimal loss for your scanner antenna and you need two of them, one on the roof to combine the sat and scanner antennas and one in the house to separate the signals.

Last I checked the diplexers should work with Dish Network and FTA systems but not with the current DirecTV equipment.

I'm not on directtv, so the frequencies should be ok, my main concern was signal loss and if it's cause interference with the scan.

thanks

 

[prcguy]

I've used many diplexers in satellite systems to get off air TV down the same coax and they work ok for that but I've not tried it for scanner use yet. There will be a little loss going through two diplexers and probably under 2dB.

Most satellite diplexers are rated to 806MHz for the TV antenna side and 800MHz public service stuff goes above that, so you may not get the whole 800 band on your scanner. There could also be some weak interfering junk from the satellite LNB that may land within the public service bands that you can hear on your scanner but that would be random and impossible to predict.

Overall its worth a try and should work fine for many people.
prcguy

I'm not on directtv, so the frequencies should be ok, my main concern was signal loss and if it's cause interference with the scan.

thanks

 

[RetroBandit]

I've used many diplexers in satellite systems to get off air TV down the same coax and they work ok for that but I've not tried it for scanner use yet. There will be a little loss going through two diplexers and probably under 2dB.

Most satellite diplexers are rated to 806MHz for the TV antenna side and 800MHz public service stuff goes above that, so you may not get the whole 800 band on your scanner. There could also be some weak interfering junk from the satellite LNB that may land within the public service bands that you can hear on your scanner but that would be random and impossible to predict.

Overall its worth a try and should work fine for many people.
prcguy

ok, thanks for bring that up.. I just looked at the database on here (Middlesex County, Ontario (ON) Scanner Frequencies and Radio Frequency Reference) and see there is stuff around 860MHz So the diplex plan mite not be for me after all unless I can find something the changes say at 900MHz..I haven't used this site in ages, long forgot my old account, so I have to find my way around it again..

thanks

 

[prcguy]

I've swept some satellite diplexers in the past and remember they cut into the upper 800 range for the TV antenna side and would cause a problem. Most satellite diplexers are very cheap and they need some space between 806MHz and 950Mhz because of the mediocre roll off on their hi pass and lo pass sections, plus the hi pass must also pass DC to power the dish LNB.

Its very possible that you could open up a satellite diplexer and custom tweak the coils and improve the 800 reception but that would take some expensive test equipment to pull off.
prcguy

ok, thanks for bring that up.. I just looked at the database on here (Middlesex County, Ontario (ON) Scanner Frequencies and Radio Frequency Reference) and see there is stuff around 860MHz So the diplex plan mite not be for me after all unless I can find something the changes say at 900MHz..I haven't used this site in ages, long forgot my old account, so I have to find my way around it again..

thanks

 

[RetroBandit]

I've swept some satellite diplexers in the past and remember they cut into the upper 800 range for the TV antenna side and would cause a problem. Most satellite diplexers are very cheap and they need some space between 806MHz and 950Mhz because of the mediocre roll off on their hi pass and lo pass sections, plus the hi pass must also pass DC to power the dish LNB.

Its very possible that you could open up a satellite diplexer and custom tweak the coils and improve the 800 reception but that would take some expensive test equipment to pull off.
prcguy

That sounds a bit out of my personal skill set, guess I'll just have to buy more coax and get out the 13" drill bit again..

 

[AK9R]

I believe that DirecTV LNBs are dependent on a DC voltage coming from the receiver. That DC voltage is also switched between 13 and 17 volts, as I recall, to switch the polarity of the LNB. Whatever diplexer you use will have to pass the DC voltage.

 

[madjoe43]

Hi all I know this is a older posting from 12-2015 but just incase I can say it will work if you use the Holland Diplexers they have a freg range from 5-2150mhz can only be done with Dish in my system I go from the dish to a DDP 44 switch that feeds 4 receivers on each output port I use a Holland Diplexer on the sat side I use a small jumper from the output of the DPP44 and my off air antenna goes to the VHF/UHF port the output of each Diplexer feeds each receiver the in my case at each receiver end there is either a 2 port separator or a triplexer then I use a 2 or 3 way splitter to feed the TV and my FM receiver. Now I have both a GRE-800 and a BCD966p2 of one of the splitter ports and I can say without a doubt it works great monitoring all systems in both UHF and 800mhz now in my case I do have a drop amp in the off air line feeding a 4 port splitter that feeds the 4 Diplexers but that's only because my lines are over 100' to each tv so the amp makes up for any loss on the long antenna runs.

The Diplexers I use on the outside coming off the DPP44 are Holland DPD2 blue label and inside at the receiver you can use Holland SYVC red label they are cheap on ebay.