Base antenna for PMR446, high gain
- Bigdave
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Re: Base antenna for PMR446, high gain
Only if you get caught,coz you have been grassed on...............
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WINNER of INB4TL, the big battle edition 16/07/23
OFTEN IMITATED,BUT NEVER INTIMIDATED.
WINNER of INB4TL,the no interest edition 18/03/24
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Re: Base antenna for PMR446, high gain
They look close enough to tv antennas to me,so probably no one will give them a second look once theyre up.Stupidly thick rg213 might give the game away though.
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- Mikel
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Re: Base antenna for PMR446, high gain
No it is not illegal to make antennasphillmobile wrote:isn't this illegal ?
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- Excalibur
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Re: Base antenna for PMR446, high gain
Someone ALWAYS has to to ruin a thread...phillmobile wrote:isn't this illegal ?
- RadioPixie
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Re: Base antenna for PMR446, high gain
Illegal where? 446 MHz beam is legal in the USA on 70cmphillmobile wrote:isn't this illegal ?
Surprised you haven't criticised it for not having a folded dipole as a driven element
73 from Dave the Pixie - 26CT052 - 26TM552 - CB Radioaficionado
- RadioPixie
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Re: Base antenna for PMR446, high gain
There's always Aircell 7mm coaxbuzz500 wrote:They look close enough to tv antennas to me,so probably no one will give them a second look once theyre up.Stupidly thick rg213 might give the game away though.
Buzz
73 from Dave the Pixie - 26CT052 - 26TM552 - CB Radioaficionado
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Re: Base antenna for PMR446, high gain
Isn't illegal either to discuss ideasMikel wrote:No it is not illegal to make antennasphillmobile wrote:isn't this illegal ?
73 from Dave the Pixie - 26CT052 - 26TM552 - CB Radioaficionado
- Adriano9966
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Re: Base antenna for PMR446, high gain
not illegal if you reduce the rf power so that the erp is equal to 500mw ...with a effective gain of 10db this is possible by simply inserting a 10db attenuator into the transmission line reducing the imput power to 50mw..remember ofcom will allow external aerials so long as the erp does not exceed 500mw .
That said so just what is the advantage I hear you cry ?? .... The advantages are twofold one is higher reception gain and the other is lower noise due to the directive nature of the antenna this translates as an increased range without increasing the erp which on pmr 446 is 0.49VM at a ten metre distance ...... even if the erp remains 500mw the gain on reception will be unchanged
I seem to remember participating in similar experiments on 934mhz CB back in the day
That said so just what is the advantage I hear you cry ?? .... The advantages are twofold one is higher reception gain and the other is lower noise due to the directive nature of the antenna this translates as an increased range without increasing the erp which on pmr 446 is 0.49VM at a ten metre distance ...... even if the erp remains 500mw the gain on reception will be unchanged
I seem to remember participating in similar experiments on 934mhz CB back in the day
- RadioPixie
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Re: Base antenna for PMR446, high gain
If 446 hobbyists wish to use a 10dB yagi, why not have them horizontal as this will drop the signal down 20dB, and reduce causing interference to other users with their vertically polarised handies.
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Re: Base antenna for PMR446, high gain
The problem with putting a 10db attenuator into the transmission line is it makes the beam useless on receive as it attenuates the received signal by 10dB, you will lose the reception gained by the beam, unless you can get inside the radio and only attenuate the Transmit side?Adriano9966 wrote: not illegal if you reduce the rf power so that the erp is equal to 500mw ...with a effective gain of 10db this is possible by simply inserting a 10db attenuator into the transmission line reducing the imput power to 50mw..remember ofcom will allow external aerials so long as the erp does not exceed 500mw .
That said so just what is the advantage I hear you cry ?? .... The advantages are twofold one is higher reception gain and the other is lower noise due to the directive nature of the antenna this translates as an increased range without increasing the erp which on pmr 446 is 0.49VM at a ten metre distance ...... even if the erp remains 500mw the gain on reception will be unchanged
I seem to remember participating in similar experiments on 934mhz CB back in the day
ʎɐqǝ uo pɹɐoqʎǝʞ ɐ ʎnq ı ǝɯıʇ ʇsɐן ǝɥʇ sı sıɥʇ
- lz1mak
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Re: Base antenna for PMR446, high gain
RadioPixie wrote:If 446 hobbyists wish to use a 10dB yagi, why not have them horizontal as this will drop the signal down 20dB, and reduce causing interference to other users with their vertically polarised handies.
Yes, you are right! We did it at contests, with two 10dBd antennas phased and with good altitude, sometimes we got 400+ miles at UHF. Horizontal, to reduse unwanted signals.
73 de lz1mak
- Adriano9966
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Re: Base antenna for PMR446, high gain
DX-Digger wrote:The problem with putting a 10db attenuator into the transmission line is it makes the beam useless on receive as it attenuates the received signal by 10dB, you will lose the reception gained by the beam, unless you can get inside the radio and only attenuate the Transmit side?Adriano9966 wrote: not illegal if you reduce the rf power so that the erp is equal to 500mw ...with a effective gain of 10db this is possible by simply inserting a 10db attenuator into the transmission line reducing the imput power to 50mw..remember ofcom will allow external aerials so long as the erp does not exceed 500mw .
That said so just what is the advantage I hear you cry ?? .... The advantages are twofold one is higher reception gain and the other is lower noise due to the directive nature of the antenna this translates as an increased range without increasing the erp which on pmr 446 is 0.49VM at a ten metre distance ...... even if the erp remains 500mw the gain on reception will be unchanged
I seem to remember participating in similar experiments on 934mhz CB back in the day
er yes good point .......but surely that is why some inline attenuators rather than being fixed would include a switch in order to switch in and out of line..... I should have mentioned that too
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Re: Base antenna for PMR446, high gain
Bloody `ell!!! This place has become a haven for the Fun Police all of a sudden stop worrying about what others are doing and chill out!!
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Re: Base antenna for PMR446, high gain
Google it.phillmobile wrote:isn't this illegal ?
pmr446 king.
- lz1mak
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Re: Base antenna for PMR446, high gain
Hello to all,
I have question. Do you have in UK day/days in the summer with higher outside activity? I mean there is better chance to try to catch more PMR446s. I am looking to get job and to take computer course there, so I will bring one or two antennas to give a try.
Marin
I have question. Do you have in UK day/days in the summer with higher outside activity? I mean there is better chance to try to catch more PMR446s. I am looking to get job and to take computer course there, so I will bring one or two antennas to give a try.
Marin