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Thread: Satellite frequency changeover relay

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    Default Satellite frequency changeover relay

    Anyone have any idea where I might look for the following......can't find anything with Google....lots of 50 ohm RF stuff, but nothing for Sat freqs and impedance.

    Looking for a SPDT 75 ohm impedance changeover relay that can handle Sat IF range......'F' connector in and out......and preferably with a low voltage DC coil.

    I want to remotely switch the output from a single-output LNB to different inputs on a multiswitch.

    I have some sealed 12V conventional relays, and a number of reed switch relays which, at a pinch, I can make up into the switching unit that I need, but it would be a lot more convenient if such a device was available off the shelf. Also, a home-brew rig will most likely present SWR, and hence insertion loss, issues (although possibly not earth-shattering).

    Will be mounted inside, so doesn't need to be weatherproof.

    Any ideas?
    Last edited by Thala Dan; 02-01-17 at 01:13 PM.



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    What about using a 22kHz switch with a 22kHz tone generator?

    (specifically designed with 75 ohm F type connections and sat frequencies)

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    Is this roughly what you are trying to use?




    Doing this (if I am right) mean you want to have a number of STB's all running on the SAME polarity at the same time and by activating the switch, you go to another group using the other polarity because with a single out put LNB, you cant have the 2 polarities running at the same time.
    Last edited by gordon_s1942; 02-01-17 at 02:13 PM.
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    Here's what I want to do:



    (Apologies for the amateurish image - graphics is not my strong suit).

    This relates back to an earlier query I posted about the availability of a dual-output, prime focus, 10700 LNB.

    I want to experiment using a single output PF 10700 LNB that I have....the schematic above is intended to enable that LNB to be used, via the multiswitch, to receive both H & V signals.

    Unfortunately, MTV, a 22khz switch won't cut it.

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    Quote Originally Posted by Thala Dan View Post
    Unfortunately, MTV, a 22khz switch won't cut it.

    Why not?

    Used in reverse, it's effectively just a relay switching one input to two devices.

    It passes power so one multiswitch connection (V) will connect 13VDC to the LNB and the other multiswitch connection (H) will pass 18VDC to the LNB, effectively changing the LNB polarity.

    A tone generator would be inserted between the switch and the LNB.

    I haven't tried this myself, but theoretically should work, as it's literally a relay switched by tone.

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    I have a 0/12 volt lnb switch somewhere Ill see if I can find it (was used back in the analog days ) but i kept it . If I find it you can have it Ill have a look when its cooler (sheds like a oven)
    same as this one .


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    Not a bad guess for a Dodo was it but I have to ask why not just replace the LNB with a dual out ?

    You do realise that whatever is connected to the Multiswitch NOT connected to the LNB will have NO Signal to any STB's connected to it?
    I stand unequivicably behind everything I say , I just dont ever remember saying it !!

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    Quote Originally Posted by gordon_s1942 View Post
    Not a bad guess for a Dodo was it but I have to ask why not just replace the LNB with a dual out ?

    You do realise that whatever is connected to the Multiswitch NOT connected to the LNB will have NO Signal to any STB's connected to it?
    The OP was previously trying to get a dual polarity, dual output 'prime focus' LNB/F.

    As per his post, he's now experimenting with his single output, dual-polarity LNB/F.

    My understanding is he's using a single multiswitch, but wants to be able to switch the polarity of the single LNB connected to it.

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    Quote Originally Posted by mtv View Post
    Why not?

    Used in reverse, it's effectively just a relay switching one input to two devices.

    It passes power so one multiswitch connection (V) will connect 13VDC to the LNB and the other multiswitch connection (H) will pass 18VDC to the LNB, effectively changing the LNB polarity.

    A tone generator would be inserted between the switch and the LNB.

    I haven't tried this myself, but theoretically should work, as it's literally a relay switched by tone.
    Thanks, mtv......sounds good in theory, and quite possibly would work in practice.

    I have a few concerns about it though:

    1. Generating the 22 khz is a bit more of an effort than generating 12V from one of the multiple little supplies I have lying around.

    2. Injecting the 22 khz into the LNB -to- Multiswitch circuit without causing signal degradation would require a level of design that I think is above my pay scale, and

    3. Although 22 khz switches pass 13/18V LNB switching voltage from receiver connection to LNB connection, I'm not sure if the reverse applies.

    Think I'll stick with the steam radio solution...........in keeping with the KISS principle

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    Quote Originally Posted by carjackma View Post
    I have a 0/12 volt lnb switch somewhere Ill see if I can find it (was used back in the analog days ) but i kept it . If I find it you can have it Ill have a look when its cooler (sheds like a oven)
    same as this one .

    i know what you mean about the shed......been thinking of installing a rotisserie in mine

    From what I've seen of the Perth weather today, I'm guessing a shed would be a good place not to be.

    That Sadoun relay is the bees knees.......it's so damn frustrating when you see all these handy little goodies available like breakfast cereal overseas (particularly at $5), that suddenly become one of life's great luxuries when freight down-under is factored in.

    If you do find one, be more than pleased to purchase and cover postage.......drop me a PM when the shed becomes fit for human habitation again

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    The switch carjackma mentioned should also work on the same principle as the 22kHz switch in reverse.... only requires 12VDC to changeover.

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    Quote Originally Posted by gordon_s1942 View Post
    Not a bad guess for a Dodo was it but I have to ask why not just replace the LNB with a dual out ?

    You do realise that whatever is connected to the Multiswitch NOT connected to the LNB will have NO Signal to any STB's connected to it?
    Gordon,

    Mtv’s explanation sums it up.

    I want to bring a prime focus dish, on Ku band, back to my 20/12 multiswitch.

    The only way I could do that, given that dual-output Ku PF 10700 LNB’s are in the same category as rocking horse droppings, was with, at least, a dual-output PF C120-mount Universal.

    This was shaping up to be a relatively expensive option, although the kind offer of an unused C120 feed-horn from a fellow Austecher stood to ease the pain a bit.

    I’ve had to put that option on ice for a while, so I thought I’d play with the single output Satking PF I have sitting in my “rainy day” box.

    The purpose of the relay is to allow the single-output LNB to be switched between H and V inputs on the Multiswitch.

    A bit clunky, but will fill the purpose for the time being.

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    Quote Originally Posted by Thala Dan View Post
    i know what you mean about the shed......been thinking of installing a rotisserie in mine

    From what I've seen of the Perth weather today, I'm guessing a shed would be a good place not to be.

    That Sadoun relay is the bees knees.......it's so damn frustrating when you see all these handy little goodies available like breakfast cereal overseas (particularly at $5), that suddenly become one of life's great luxuries when freight down-under is factored in.

    If you do find one, be more than pleased to purchase and cover postage.......drop me a PM when the shed becomes fit for human habitation again
    I found it its yours just PM me a address. I took a photo but it didn't come out to good but its the same as the one in the link I posted before .



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    Many thanks, carjackma.........I greatly appreciate the offer.

    Hope you didn't lose too much weight fossicking around in the sauna....er,shed

    Will PM details.

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    Glad I did it last night was hotter today and even worse tomorrow . Nah didn't lose any weight

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    Quote Originally Posted by Thala Dan View Post
    Many thanks, carjackma.........I greatly appreciate the offer.

    Hope you didn't lose too much weight fossicking around in the sauna....er,shed

    Will PM details.
    Sent Via Aussie post today

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