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I like to setup TV Transmitter within 40km range.. Pls Help

 
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I like to setup TV Transmitter within 40km range.. Pls Help
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JammerOne
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Post I like to setup TV Transmitter within 40km range.. Pls Help Reply with quote
Anyone can help me about this hobby ...

I would like to setup TV Transmitter ranges within 40km...

Please tell me where and what to buy to start this project ?

I appreciate your help mate ...

Thanks a lot

Rey Tan,
Philippines
Sat Dec 22, 2007 3:33 pm View user's profile Send private message
pcs
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Post Reply with quote
Hardly a hobby only, you need some serious power, we are talking killowats.

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Sat Dec 22, 2007 3:52 pm View user's profile Send private message Visit poster's website
JammerOne
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Post whats about we use power 350w .... Reply with quote
cause I like to broadcast small city I think 15km radius ...

I say 40km for the allowance fo the distance ....

let say I use 300w to 350w mate .. this will serve ...?

mate ... please tell me where I start... we should say low watt and on coming days we extend the power slowly to higher watts..

Thanks a lot mate in advance ..

Thanks

Rey Tan
Philippines
Sat Dec 22, 2007 9:06 pm View user's profile Send private message
JammerOne
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Post What about ..??? Reply with quote
Hello mate(s) ...

what about if I buy this one?

PCIMAX TV+ tv transmitter card ..... can be found here :
http://www.pcs-electronics.com/pcimax-transmitter-card-p-1202.html





or


Prefer to buy this ??
TVMAX 2000+ 3W TV TRANSMITTER ..... can be found here :
http://www.pcs-electronics.com/tvmax-2000-transmitter-p-1224.html





which one is best mates? can you share opinion ?

Thanks in advance

Rey Tan
Philippines
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Last edited by JammerOne on Sat Dec 22, 2007 10:11 pm; edited 1 time in total
Sat Dec 22, 2007 9:50 pm View user's profile Send private message
pcs
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Post Reply with quote
Yes, they work, but not 40Km range.

Otherwise, 3W TV MAX board has more range.

_________________
Best regards,
Marko - PCS Electronics
--------------------------------------------------------
Turn your PC into a FM radio station!
http://www.pcs-electronics.com
fax +386 4 2316 128
Sat Dec 22, 2007 10:05 pm View user's profile Send private message Visit poster's website
JammerOne
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Post Reply with quote
by the way mates whats is ths price per meter?



this is also the cable I want to buy for the project ...

Thanks

Rey Tan
Philippines
Sat Dec 22, 2007 10:05 pm View user's profile Send private message
JammerOne
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Post Reply with quote
pcs wrote:
Yes, they work, but not 40Km range.

Otherwise, 3W TV MAX board has more range.


Thanks mate ...

what you suggest to fit my need mate?

this one you recommend?

but I know after I buy this ... you can support me how can I extend my range the signal ...
like recommending a new amplifier ... lol ...

yes this is good mate ... we do step by step ...

after that I will buy this one



GOO GOOD thats what i mean ...

please assist me mate ...

thanks

Rey Tan
Philippines
Sat Dec 22, 2007 10:17 pm View user's profile Send private message
pcs
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Post Reply with quote
JammerOne wrote:
by the way mates whats is ths price per meter?



this is also the cable I want to buy for the project ...

Thanks

Rey Tan
Philippines


Teflon cable is usually used for internal wiring, combiners, short jumper cables etc.
Usually a meter or two completely fills your needs. This is not the cable used for long
installations, say 20 meters from transmitter to antenna. The main advantage is
teflon insulation meaning it handles high temperature very well. For this reason
you can solder it to power modules easily without insulation melting (or melting
during operation).

_________________
Best regards,
Marko - PCS Electronics
--------------------------------------------------------
Turn your PC into a FM radio station!
http://www.pcs-electronics.com
fax +386 4 2316 128
Sun Dec 23, 2007 12:39 am View user's profile Send private message Visit poster's website
electronicsseller
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Post Reply with quote
3W TV MAX board has more range and try it
Thu Apr 10, 2008 10:40 pm
klaas kramer
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Joined: 31 Aug 2004
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Post Reply with quote
you have to be carefully with what you wanne transmit. like movies. Its better to have a short range when you use it for that.

they bust you for copyrhight violation.
Fri Apr 11, 2008 8:20 pm View user's profile Send private message Visit poster's website MSN Messenger
pcs
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Post 3W VHF tv transmitter Reply with quote
Well, I just had a chance to chat with one of the users of TV MAX 2000+.

I was surprised to find he is getting 6km of range (with still good signal) with
his portable ICOM receiver. I thought it would be less for 3W of power.

_________________
Best regards,
Marko - PCS Electronics
--------------------------------------------------------
Turn your PC into a FM radio station!
http://www.pcs-electronics.com
fax +386 4 2316 128
Sun Apr 13, 2008 11:12 am View user's profile Send private message Visit poster's website
gfg
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Post Reply with quote
You need to remember, your range much above 30 Mhz is more a factor of your Hight Over Average Terrain than TX power, this is known as the radio horizon.

To get 40 Km at VHF/UHF, your formula is 1.451 x ( SQR (mast in meters / 0.3048) ) * 1.60943 = range in Km ... In Excel it looks like this: =(1.451*(SQRT(89.43/0.3048)))*1.60943

So you're going to require a 90m mast / building / hill etc.

OK, now we have taken care of that part, lets turn to the TX ... The factor you have to consider most is your fade margin, this means when its raining, foggy etc, your signal will be
attenuated. Commercial & Government broadcasters also factor in loft antennas, poor rusty antennas that date back to the 70's etc. Typically a 20 dB safety margin is used.

If you consider an average TV to have a minimal signal requirement of 60 dBuV + our 20 dB safety margin as above, your looking to achieve 80 dBuV at 40Km range.

Getting back to the formulas again, a good rule of thumb for path loss is 96.6 + (20xlog frequency in Mhz) + (20xlog distance in miles),
in excel is looks like this: =96.6+(20*LOG(500/1000))+(20*LOG(24.85351957/1.6))

working this backwards at say 500 Mhz (around channel 25 in most system) you have a path loss of say 120 dB.

Now we can calculate TX power ... Lets start with our RX signal of 80 dBuV - 107 to give us -27 dBm, add our path loss back and lets add 3dbi gain for your RX & TX antennas (-27 + 120 - 3 - 3)
This gives a rough TX power requirement of 87 dBm ... which is close enough to 90 dBm which is 1 MILLION WATTS.

This would be in line with some commercial TV towers I just looked up.

If you wanted bare bones coverage, say 50 dBuV @ 40 Km and were willing to accept signal dropouts during rain etc, you could probably lower the power 30 dB (60 dBm) to around 1,000 Watts.
You have to remember RF is logarithmic meaning anything under a 4x isn't really noticed (I.E. power doesn't go 100w, 200w, 300w, it goes 500w, 2Kw, 8kw etc).

Play around with the formulas, I typed this in quickly so double check the formulas before doing extensive research.

I've heard of a group in Italy getting ~ 2.5 Km radius using 20W UHF, perhaps start small and work your way up


GFG
Sun Oct 05, 2008 10:39 am View user's profile Send private message
gfg
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Post Re: 3W VHF tv transmitter Reply with quote
pcs wrote:
Well, I just had a chance to chat with one of the users of TV MAX 2000+.

I was surprised to find he is getting 6km of range (with still good signal) with
his portable ICOM receiver. I thought it would be less for 3W of power.


I tried to get some hard specs on the IC-R3 (I assume that's the Icom in question?), I'm assuming 50 dBuV

The maths do check out:

1) A 3W TX is 35 dBm, lets assume a net 3dB TX system gain (antenna gain subtract cable runs etc), so total output is 38 dBm;
2) Assuming a frequency of 310 Mhz and a path of 6Km, that's a 98 dB path loss;
3) Assuming a net 3dB RX system gain (antenna gain subtract cable runs etc), total received signal is -57 dBm or 50 dBuV.

At apx. 40 dB S/N, that's just enough for bare bones coverage (no rain/fog margin, no old RX antenna setups etc).


GFG
Sun Oct 05, 2008 10:18 pm View user's profile Send private message
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