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12.12.2018
90
Clansman PRC 351. Philips RT 4600/VRC. History: Before World War II, British radio amateurs had been allocated a band at 56 Mhz. After the war ended, they were allocated the 5-meter band (58.5 MHz to 60 MHz) instead.
This only lasted until 1949, as by then the 5-meter band had been earmarked for BBC Television broadcasts. In 1956, after several years of intense lobbying by the Radio Society of Great Britain (RSGB), the 4-meter band was allocated to British radio amateurs as a replacement for the old 5-meter band allocation. For several years the 4-meter band allocation was only 200 kHz wide--from 70.2 MHz to 70.4 MHz). It was later extended to today's allocation of 70.0 MHz to 70.5 Mhz.
'Anytone AT-D868UV dual band VHF UHF DMR portable radio AT-D868S mobile radio' Ham Radio License, Satellite Phone, Hifi Audio, Boombox, Arduino, Audiophile, Survival, Gadgets Santos Rodriguez. 1) The antenna supplied is specifically tuned for VHF/UHF frequencies. To take full advantage of this receive option, an antenna consisting of at least 10' to 20' of wire is recommended.
Allocations: A chart showing how Television channel frequencies in various countries relate to the 4 meter amateur band. In addition to the traditional users (United Kingdom, Gibraltar and the British Military Bases in Cyprus), an increasing number of countries in Europe and Africa have also allocated the 4-meter band to radio amateurs as a result of the decline in VHF television broadcasts on the 4-meter band. Movement away from the old Eastern European VHF FM broadcast band and migration of commercial stations to higher frequencies have led to slow but steady growth in the number of countries where 4-meter operation is permitted. Prior to the release of 70 MHz by the Ministry of Communication for the experimental campaign I had already committed myself to this band. After having completed a Yaesu FT 847 modification as extensively covered on the 4 m website for a friend of mine, I started building a 70 MHz to 28 MHz converter so that I could be on the band.
As a subsequent project and with the help of some friends I began to build a prototype transverter based upon the DJ8S project as described in THE R.S.G.B RADIO COMMUNICATION HANDBOOK. The prototype gave good results (pictures of modules) and after a long wait we were finally given access to the band last July! In the beginning, in order to get going properly, I tried to modify an IC-706Mk2G.
Without altering other functions, things looked a bit difficult, the receiver was very deaf at 70 MHz but now works quite well, receive sensitivity is higher now having modified filters which before had a cut off frequency just above 50 MHz. To achieve this, a microelectronic tool set is needed, mainly a magnifier or microscope. Needless to say, this modification for the ICOM is not for beginners but only for experienced and well equipped technicians.
Regarding the transmitter, I am still working on it, taking into consideration that above 60 MHz the transceiver switches digitally to V-UHF bands. A possible solution could be to use the HF-50 MHz PA to generate adequate RF power output. To be operational on 4 m in good time, I decided to look for a modification of a simpler non digital transceiver. I considered many old 50 MHz rigs and I chose first an IC-201 for 2 m but I subsequently settled on the simpler IC-502A, brother of the well-known IC-202S.
U okviru legla, nikada ne treba izabrati stene koje izgleda super aktivno ili uplaseno, jer, pre ili kasnije, ono moze da postane agresivno. 
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- Category: Category
Clansman PRC 351. Philips RT 4600/VRC. History: Before World War II, British radio amateurs had been allocated a band at 56 Mhz. After the war ended, they were allocated the 5-meter band (58.5 MHz to 60 MHz) instead.
This only lasted until 1949, as by then the 5-meter band had been earmarked for BBC Television broadcasts. In 1956, after several years of intense lobbying by the Radio Society of Great Britain (RSGB), the 4-meter band was allocated to British radio amateurs as a replacement for the old 5-meter band allocation. For several years the 4-meter band allocation was only 200 kHz wide--from 70.2 MHz to 70.4 MHz). It was later extended to today's allocation of 70.0 MHz to 70.5 Mhz.
'Anytone AT-D868UV dual band VHF UHF DMR portable radio AT-D868S mobile radio' Ham Radio License, Satellite Phone, Hifi Audio, Boombox, Arduino, Audiophile, Survival, Gadgets Santos Rodriguez. 1) The antenna supplied is specifically tuned for VHF/UHF frequencies. To take full advantage of this receive option, an antenna consisting of at least 10' to 20' of wire is recommended.
Allocations: A chart showing how Television channel frequencies in various countries relate to the 4 meter amateur band. In addition to the traditional users (United Kingdom, Gibraltar and the British Military Bases in Cyprus), an increasing number of countries in Europe and Africa have also allocated the 4-meter band to radio amateurs as a result of the decline in VHF television broadcasts on the 4-meter band. Movement away from the old Eastern European VHF FM broadcast band and migration of commercial stations to higher frequencies have led to slow but steady growth in the number of countries where 4-meter operation is permitted. Prior to the release of 70 MHz by the Ministry of Communication for the experimental campaign I had already committed myself to this band. After having completed a Yaesu FT 847 modification as extensively covered on the 4 m website for a friend of mine, I started building a 70 MHz to 28 MHz converter so that I could be on the band.
As a subsequent project and with the help of some friends I began to build a prototype transverter based upon the DJ8S project as described in THE R.S.G.B RADIO COMMUNICATION HANDBOOK. The prototype gave good results (pictures of modules) and after a long wait we were finally given access to the band last July! In the beginning, in order to get going properly, I tried to modify an IC-706Mk2G.
Without altering other functions, things looked a bit difficult, the receiver was very deaf at 70 MHz but now works quite well, receive sensitivity is higher now having modified filters which before had a cut off frequency just above 50 MHz. To achieve this, a microelectronic tool set is needed, mainly a magnifier or microscope. Needless to say, this modification for the ICOM is not for beginners but only for experienced and well equipped technicians.
Regarding the transmitter, I am still working on it, taking into consideration that above 60 MHz the transceiver switches digitally to V-UHF bands. A possible solution could be to use the HF-50 MHz PA to generate adequate RF power output. To be operational on 4 m in good time, I decided to look for a modification of a simpler non digital transceiver. I considered many old 50 MHz rigs and I chose first an IC-201 for 2 m but I subsequently settled on the simpler IC-502A, brother of the well-known IC-202S.
U okviru legla, nikada ne treba izabrati stene koje izgleda super aktivno ili uplaseno, jer, pre ili kasnije, ono moze da postane agresivno.