Adding UHF Remote Antenna

[DoyleS]

I am having trouble getting my 508 remote to work throughout the house. I saw some threads indicating people had added an amplified antenna or possibly an amplifier with the existing antenna to their receivers to boost remote reception. Could any of you that have done this post the antennas/amplifiers that you are using and their effectiveness? I would rather do it once and do it right instead of a lot of trial and error.

Thanks,
..Doyle

[scooper]

The thing that helped my 4700 the most was simply using 5 feet of RG59 and a barrel connector, then putting the antenna on the end and up at 5 feet off the floor.

Based on other threads, if you need to use an amp, get one that does cable frequencies (I think the UHF is at 330 MHz or so), as well as raise the antenna off the unit

[Mark Lamutt]

I agree with everything that scooper said. I can personally vouch for the 5'-6' length of coax cable and barrel connector approach - it's what I have used in the past.

[DoyleS]

I can definitely give that a try. I can run a piece of coax to the top of the equipment rack and mount the antenna on the top of the rack. The rack is in a closet so we'll see how that works. Anyone know for sure the frequency of the remote? I have had inputs of 300 MHz and 900 Mhz.

[Steve Mehs]

I'm using a $40 pair of amplified Philips rabbit ears as my remote antenna, Works great! :D

[Bob Haller]

I use the VHF, UHF, FM amp. Cable I believe is the wrong frequency. Get a amp thats high gain and adjustable so you can tweak it to minimize interference.

[drjake]

I use a 35db amplified UHF/VHF antenna with thirty feet of a coax.

[Jacob S]

How long can you get the coax to go before it does no good with an amplifier? What is the best amplifier in this case?

[Bob Haller]

Put the amp at the antenna end. My cable run is 20 physical feet away but threading it thru the house it might be 50 feet of cable. When doing this short can be a LOT harder, cable is heap.

[Bob Haller]

The more the adjustable gain the better.

[AllieVi]

I installed a TV in a separate building about 120 cable feet away from the receiver. My UHF remote wouldn't control the receiver from this distance, so I extended the UHF antenna with a separate cable run that goes there ( the "antenna" there is simply the cable with about 6" or so of shielding removed). At the receiver, I combined that antenna with the existing one using a simple splitter/combiner. The remote works just fine from both places without an amplifier.

It would be possible to expland on this approach and place antennas in several strategic places around the house if it's possible to do the wiring.

[Bob Haller]

Theres a matter of antenna matching. Its hard to explain but antenna length is dependent on frequency. The UHF antennas are the length they are or good reason. Just splitting and adding antennas could easily result in it not working at all.

[DoyleS]

Bob is right, antennas receiving the same frequency need to be phased or the signals can cancel each other. If it is working for you that is fine but as a general approach multiple antennas is probably not a good idea. Again, one would need to know the frequency of operation for the UHF remote. So far that doesn't seem to be an item anyone is sure of.

..Doyle

[pbrown]

Does the direction of the Antenna matter? If I have it pointed in the direction of the area I want to use my remote, will it work any better/worse then if I point it straight up?

[DoyleS]

A vertical whip antenna typically has a radiation pattern that is doughnut shaped. Propagation or reception off of the end of the antenna is poor. The antenna is intercepting waves from the air and they will be coming from your remote. If the receiver antenna is "pointed" at the remote, you have very little area to intercept the radio waves. Vertical whips are typically pointed up. If we knew the frequency of operation of the UHF antenna, then we could determine by its length whether it was a 1/4 wave or 5/8 wave antenna and could understand its characteristics a little better. For example, a 1/4 wave antenna really needs a ground plane under it for optimum performance. A 5/8 wave antenna does not. Rabbit ears are a balanced antenna and there is a transformer or Balun that is used to convert the balanced signal to an unbalanced signal that comes from an unbalanced Coax.

(I may sound like I am answering my own questions, but I started the thread to find out what people were using as opposed to doing a lot of experimenting on my own)

..Doyle

[Jacob S]

Is it possible to convert the UHF or IR to a different type of signal that will go further or that one knows the wavelength of to get it to go further?

[Bob Haller]

As soon as I get a chance I will take a remote to a good buddy of mine with a frequency counter, and we will know exactly the frequency.

Its also possible to use the length of the whip to calculate the frequency.

Many many years ago knowledgable fellow measured the length of the whip antenna on my car, then found and monitored a 2 way radio channel I was using with some friends. This was before cell phones and lets just say we didnt belong on the channel we were using:( This acquaintance freaked me out. Then he invited me to HIS house and showed me his bootie rig setup. Needless to say neither of us blabbed about it. At the time it was very useful. before cell phones and such. I once helped a lady who broke down in a terrible neighborhood at night. I liked it since I had some health problems that were dangerous, and figued I could call for help in a emergency. Honestly we were on a not locally used business band channel. Nearest user was central ohio.

I bumoped into the guy that figuered out what channel we were on a few months ago. I asked him if he still did this. He lost interst too when cell phones became affordable. I really should of got a ham license but failed learning the code. Oddy enugh that rule has been mostly dropped today.

[DoyleS]

Basically 300 divided by the frequency in MHz gives the wavelength in meters. I am assuming that the antenna is a 1/4 wavelength antenna as that is the most common and easiest to match. I don't remember the length of the antenna but if it is 4 inches that translates to around 740 MHz and if it is 5 inches long it translates to about 590 MHz. Both are clearly in the standard UHF band which is a bit surprising that they would be there. 590 MHz is around UHF channel 50 and 740 MHz is around UHF channel 39. Now I have to go home and see if I can use the TV set as a pseudo frequency counter and see if I can see some interference when I press the remote button while on those some of those channels. This is starting to get complicated but interesting.

..Doyle

[Bob Haller]

well I tried a frequency counter. It didnt work. He didnt think it would, since its so low power and FM. Frequency varies constanty. Whiip lengtrh might not work, since we dont know if theres a loading coil in the receiver.

I looked at my amp that works. ITS MARKED VHF, UHF, FM. get the highest gain adjustable one you can by it at radio shack, so its returnable.

[Jacob S]

I have heard of someone using UHF to reach a long distance with a wireless video sender made in the 80's that is illegal to use now. Is there a way to add power inside of the receiver to get a better gain to turn channels further away or can it be done outside of the receiver in which is preferable?

Is there a way of making a remote control wired instead to make it turn channels a long ways from the receiver?

[DoyleS]

If you are comtemplating using wired then one could use IR with a remote IR receiver wired to an IR repeater. The whole goal of the RF remotes is to eliminate that need. The use of a better antenna, or better positioned antenna are items that are relatively easy to do. Using an amplifer is also an option although it would sure help to know what frequency the remote is on. The Kerk RF remote operates on 418 MHz which is below the UHF TV frequenciess but above the VHF frequencies. Whether the Dish RF remote operates in that same band is uncertain. A 418 MHz quarter wave antenna would be around 7 inches long. If one does extend the antenna by adding coax, it should be noted that this antenna is a 50 ohm antenna and should be connected with 50 ohm coax not 75 ohm like is used for Video or TV Cable.

..Doyle

[Bob Haller]

Trust me the easiest best way is to put a remote antenna where it works with a amp and run a cable to the receiver.

Or use remote transmitters that send the IR signal back on the coax to the remote TV location

Modifying a remote for more power will be a major job and likely interfere with others.

I have thought about doing that:) Put a 200 watt amp on a dish remote and buy porn PPVs. Imagine if everyne in pittsburgh got a bill for porn. What a mess it would create. I keep all my receivers locked for this reason.. I am NOT suggesting anyone do this.

[Jacob S]

Scott, maybe that explains why you got those porn PPV's on your receiver, lol.

The best solution seems to be an IR transmitter that sends IR signals back through coax. Where can I get this type of setup at?

[scooper]

www.smarthome.com carries them, among other items...

[DoyleS]

This thread took a new life of its own. When I took the antenna ( which is almost 7 inches long) off of the back of my 508 I was surprised to see a 75 ohm F connector instead of a 50 ohm BNC. Most of us have 75 ohm cable with F connectors on it so I guess we will live with the mismatch. I decided I better take the antenna into work and look at it on a Network Analyzer. Without a Ground plane, the antenna resonated at 267 MHz and measures 50 ohms impedance. With a ground plane it resonates at about 390 MHz with a much sharper resonance and measures around 60 ohms. Both of these frequencies are between VHF and UHF TV frequencies. As long as the amplifier does not roll off the gain at the bottom of the UHF band or the top of the VHF band, it should give the needed gain increase. Raising the antenna up to a better location will be my first attempt.

Thanks for all the inputs.

..Doyle

[Ericha]

The carrier frequency of my black remote is 384.2 MHz. The modulation is definitely some form of FM, probably FSK. The deviation looks to be about 1 MHz or so. When I have some more time, I'll look more closely at the Modulation

[Bob Haller]

How did you measure that. A friends frequency counter didnt work. It may ave not had enough sensitivity...

[ericha]

I made the measurement using a synthesized spectrum analyzer, with a whip antenna on the front. I didn't look at the amplitude, but it wasn't very large--probably around -50 dBm or so. If that's right, a counter wouldn't have enough sensitivity to measure it.

[DoyleS]

That frequency pretty much agrees with the resonant frequency measurements I did with the Network analyzer. Unfortunately we do not have a spectrum analyzer at work which I assume is what Ericha used. It was interesting to note the resonant frequency shift with the addition of the ground plane. Now that I can make up a small 1/4 wave antenna with Radials to mount in the closet above my equipment rack.

..Doyle

[Bob Haller]

Yeah he suggested I buy hoim a nice spectrum analyzer. :) Then he ould make my quick check for me and add it to his equiptement rack.

Thought it would be a nice christmas present:)

[firephoto]

FCC ID search page for the remotes ID code comes up with 384 MHz.

http://www.fcc.gov/oet/fccid/

search for DKN

here's the specific page
https://gullfoss2.fcc.gov/cgi-bin/ws.exe/prod/oet/forms/misc/Grant_Form.hts?application_id=45524&mode=COPY&fcc_id=DKNAMTX

[DoyleS]

I looked at that ID and thought about doing a search. That is a handy piece of information for future searching. I have bookmarked the FCC search page.

Thanks,

Doyle

[Jacob S]

That 384 MHZ finding matches what Ericha had found with the spectrum analyzer which was 384.2 MHZ. Since we now know the frequency at which the remote works at, what can we do to increase the length of the remote? Would this now allow us to know what type of antenna we should use to have the best gain? The amplifier we can use? Is there a limit to how far you can get it to work with this information that we have?

[DoyleS]

Here are my thoughts. I plan to try a 1/4 wave antenna with 4 radials sloped down at 45 degrees. That should give a 50 ohm antenna. If the radials are left flat, the impedance will drop to around 30 ohms which is not a real good match. I happen to have RG58 coax so I will likely feed it with RG58 which is 50 ohm coax. I am not going to worry about the 75 ohm F connector since RG 58 is basically the same diameter as RG59 the F connector will easily mount on the one end and at the other end I will use a PL259 Coax connector since I can easily mount the four radials to it. Once I get it done, I'll try to post a picture. Not sure with the holidays and travel how quickly I will get to it. The vertical element and radials should be 7.7 inches long. Height it important and separation from other metal objects so I plan to mount it above the equipment rack. I will try to get this to work without an amplifier. If I have to go the amplifier route then I might decide to use the amplified rabbit ears and keep the length of the rabbit ears around 7.7 inches.

..Doyle

[ericha]

Well, the modulation isn't FM, it's pulse-position-modulated AM (or really ASK--amplitude shift keying). It looks like there is a 6 ms sync, and there are a total of 18 pulses in a group that's about 50 ms long.
I suppose there may be some FM as well, but this is unlikely given the PPM/ASK

[Bob Haller]

I have to say this has really gotten high tech. I use the standard whip antenna, with a standard VHF UHF and FM radio shack amp. It works great and just for the heck of it I tried it while walking up the street today, so range is fine, about 2 houses away. My only concern is picking up others remotes. I encourage everyone to lock your PPV and porn channels just in case.

[Jacob S]

What was the distance of those two houses away from yours?

[DoyleS]

A good point on the PPV channels Bob. I am a relatively new user with no phone line attached. Can PPV still be ordered without a phone line or a direct call to Dish?

..Doyle

[Jacob S]

Yes, they can be ordered with a direct call from dish using a phone line if you are calling from the same number ($1 charge) or calling from a different number ($5 charge).