Weird question. I'm new on this.

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by RTECOLT, Jun 15, 2020.

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  1. RTECOLT

    RTECOLT QRZ Member

    Can I use a Dish (TV) antenna (without any modification) on a portable (VHF/UHF) radio? Will I have better reception? Will I listen to more frequencies?
     
  2. W7UUU

    W7UUU Principal Moderator Lifetime Member 133 Administrator Volunteer Moderator Platinum Subscriber Life Member QRZ Page

    Likely won't do much of anything. Dish TV services run up around 11 to 13 GHz - WAY above typical ham frequencies. Dish TV systems are space-based and very high in frequency. (There are ham bands way up there in frequency but not in common use like 2-meters or 440)

    What you could try if you're just wanting to listen only would be what's called a "Discone" antenna - they are typically very broad-banded and cover from around 50 MHz up to 1.5 GHz or so. There are very affordable Discone's advertised on Amazon and eBay

    But if you're wanting transmit as well, there's really no alternative than a resonant antenna for ham VHF and UHF frequencies. A discone will allow for transmit "somewhat" but likely very poor results in most cases.

    Dave
    W7UUU
     
  3. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    Simple answer: No.

    Sometimes you could use the "support" (the mounting tube that supports the TV dish) to install another, different antenna such as a VHF-UHF dual band vertical or something. They're usually strong enough to do that.
     
  4. AK5B

    AK5B Ham Member QRZ Page

    Not without modification.

    A simple horizontal slit 39" long cut as a stretched-out inverted U would turn the dish into a slot antenna for 2m vertical polarization (or about a 13" straight horizontal slot for 70cm instead). After cutting the slot with a Dremel or angle grinder, install a couple of terminals on either side to serve as a 52~ohm feedpoint and attachment point for your coax. Voila! A simple 2 meter antenna that no one else will recognize as a ham antenna!

    I picked up a big Hughs.net complete dish assembly from a nearby dumpster for just such a rainy-day project; if you should wish to do the same check out this article for all the details:

    http://www.w6nbc.com/articles/2016-03QSTdishslot.pdf

    73,

    Jeff
     
  5. KD0CAC

    KD0CAC Ham Member QRZ Page


    Sometimes it just takes getting out the tape-measure to get a feel for it ;)

    Now if you had one of the old satellite dishes around 14' across .
    But they are harder to put on a tower ;)
     
  6. KC8QVO

    KC8QVO Ham Member QRZ Page

    I would be curious what the application is. Seeing as your username is not a call sign I am assuming you aren't a ham just yet. Thats OK - keep hanging around here and work towards getting your license. There can be some riff-raff here from time to time, but all in all it's a great place for info. Thanks for chiming in.

    If your application is scanner listening (VHF+ commercial services, marine, railroad, public service, etc) there is a forum called Radio Reference that is great for that realm.

    As was already mentioned, the dish you propose is going to be a poor choice for receiving VHF+ frequencies. Another point to mention about dishes (of any type) is, properly proportioned/sized they are extremely narrow-beam width antennas = extremely directional. You likely want an omni-directional antenna - one that can receive from all directions. There are some cases where you want a directional antenna - such as living out away from any sizable population density and trying to improve reception of signals originating from the population density (generally in one direction from your location). However, that isn't the usual scenario and certainly isn't the place to start with radio reception.

    When you get in to scanner listening on public service systems you can run in to issues with "too much antenna". This comes in to play very heavily when you get in to simulcast networks in cities. Around here in central Ohio the simulcast systems have been so dense that you actually want a very weak antenna to receive them. This is because the close transmitters (sort of like a cellular grid) can confuse a scanner. If you are picking up a signal from one transmitter on one talk group, but there are 3 other close transmitters spewing the same signal, the scanner looses the handshake between the one signal and starts hopping around to the other 3. It is a real PITA as you can't follow anything with the scanner never settling.

    Generally speaking, though - the better quality the antenna the better your results are going to be.

    You can make a perfectly suitable scanner antenna out of some spare romex house wiring. I have 2x 1/4 wave length 2m ground planes in my attic. They get swapped around between a few radios and one of them is always connected to my scanner. It works great. The two antennas work for transmitting well enough for me on both 2m and 70cm also. I am not sure what the pattern looks like on 70cm, but for how I use the band here - a couple local repeaters - they work just fine for me there. Romex is cheap.
     

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