ZETAGI is a brand usually associated with CB radio products for 27 MHz although it seems that they also make RF power amplifiers for Italian CB band at 43 MHz.
The B149 and B129 models are shown below. Note that the Irish regulations for 30 to 49 MHz stipulate a maximum power output of 50 watts PEP.
ZETAGI B149
This is designed for 42-44 MHz and runs off 12v DC. It's likely that it will work down to 40 MHz as well although the power may be slightly reduced.
Note the AM / SSB switch on the right is missing and is just a blank plate. It would seem as if this unit is very similar to the B150 27 MHz model and uses pretty much the same hardware for the B149 43 MHz model.
The B149 amplifier is intended for increasing the output power of 43 MHz FM transceivers so there is no need for a TX/RX delay to stop the relay clattering on SSB. As such, it is not suitable for SSB and is more suited for just FM and CW.
The video clip above shows an example of a signal heard on the south-east coast of England of a 43.3 MHz signal from Italy.
The CB band at 43 MHz in Italy is more of a 'working band' as opposed to the hobbyist nature of the band at say 27 MHz.
There is a short discussion about Italian 43 MHz radio on this forum.
It would also seem that the band is used is used to relay church services in Italy to elderly members of the public at home. Video of 43.575 MHz signal below. In Ireland, this is usually done on the 27 MHz CB band although some churches have been known to use 88-108 MHz!
1) INTEK - SY-5430M - MOBILE 43 MHz
...a) The Italian version has 24 channels with a 4 watt output. It covers 43.3 MHz to 43.5875 MHz. The cost is €185.
...b) The Export version has 224 channels with a 20 watt output. It covers 42.3 MHz to 45.0875 MHz. The cost is €210.
2) LAFAYETTE - MOBILE UTILITY 43 MHz 24 CHANNELS
This has 24 channels with a 4 watt output. It covers 43.3 MHz to 43.5875 MHz. The cost is €145.
Please note that these were the prices and models as of mid-March 2019. I don't know anything about the website so I can't say if it's ok or not.
I came across a piece on the web today about an Italian CB allocation at 43 MHz. This is especially relevant considering that the proposed 8 metre radio amateur band in Ireland will go from 40.0 to 44.0 MHz.
The graphic above is from a 2012 brochure from Intek. A close up of the mobile is shown below...
International Versions... Note there seems to be an 'International Version' with 224 channels! With 12.5 kHz spacing, that's about 2.8 MHz of spectrum and it seems to cover 42.300-45.0875 MHz. The power o/p has been increased from 4w to 20w.
List of 43 MHz CB radios... Alan HM-43 4 W, Dragon MX-430 4 W, Intek K-43 4 W, Intek SY-343 4 W, Intek SY-5430M 4 W, Layayette ULTILITY
Wikipedia... Here is some info from Wikipedia...
Italy has a "VHF CB" allocation at 43 MHz, usually called "Apparati a 43 MHz" or "CB 43 MHz". Italy, like many other countries, suffers from extremely lax enforcement of radio communications laws, and "freeband" modified equipment covering wider frequency ranges as well as amplifiers are widely available and openly advertised by communications equipment vendors. "Freebanding" occurs with both the 27 MHz area (often as low as 25 MHz and as high as 30 MHz) and the 43 MHz area (as 43 MHz CB equipment is often modified to cover down to 34 MHz and up to 47 MHz, using 12.5 kHz steps). There is evidence of these frequencies being used outside of Italy for illegal "CB-like" operations. Italian 43 MHz "VHF CB" or "43 MHz CB" allocation. 24 channels, FM mode, 12.5 kHz channel spacing. Each channel has a "recommended use" associated with it. Portable handheld (walkie-talkie), in-vehicle mobile and base station transceivers are available for this band. Channels are numbered in straight sequence, however many transceivers marketed for this band also include a frequency display. Due to the low-VHF band frequency characteristics of this band, it is often used as an adjunct to, or replacement for, the traditional 26–27 MHz CB allocations. CH - FREQ - USE 1 - 43.3000 MHz – Rescue, Road/Traffic Control, Forestry, Hunting, Fishing, Security 2 - 43.3125 MHz – Rescue, Road/Traffic Control, Forestry, Hunting, Fishing, Security 3 - 43.3250 MHz – Rescue, Road/Traffic Control, Forestry, Hunting, Fishing, Security 4 - 43.3375 MHz – Rescue, Road/Traffic Control, Forestry, Hunting, Fishing, Security 5 - 43.3500 MHz – Rescue, Road/Traffic Control, Forestry, Hunting, Fishing, Security 6 - 43.3625 MHz – Rescue, Road/Traffic Control, Forestry, Hunting, Fishing, Security 7 - 43.3750 MHz – Industrial, Commercial, Agricultural, Crafts 8 - 43.3875 MHz – Industrial, Commercial, Agricultural, Crafts 9 - 43.4000 MHz – Industrial, Commercial, Agricultural, Crafts 10 - 43.4125 MHz – Industrial, Commercial, Agricultural, Crafts 11 - 43.4250 MHz – Industrial, Commercial, Agricultural, Crafts 12 - 43.4375 MHz – Industrial, Commercial, Agricultural, Crafts 13 - 43.4500 MHz – For safety of life at sea, Marine Use (Ship-to-Ship/Ship-to-Shore), Marinas and Harbors 14 - 43.4625 MHz – For safety of life at sea, Marine Use (Ship-to-Ship/Ship-to-Shore), Marinas and Harbors 15 - 43.4750 MHz – For safety of life at sea, Marine Use (Ship-to-Ship/Ship-to-Shore), Marinas and Harbors 16 - 43.4875 MHz – For safety of life at sea, Marine Use (Ship-to-Ship/Ship-to-Shore), Marinas and Harbors 17 - 43.5000 MHz – To aid in the administration of sports and other competitive activities 18 - 43.5125 MHz – To aid in the administration of sports and other competitive activities 19 - 43.5250 MHz – To aid in the administration of sports and other competitive activities 20 - 43.5375 MHz – to aid in the administration of sports and other competitive activities 21 - 43.5500 MHz – For use by health professionals, doctors, hospitals, and activities related to them. 22 - 43.5625 MHz – For use by health professionals, doctors, hospitals, and activities related to them. 23 - 43.5750 MHz – For use by health professionals, doctors, hospitals, and activities related to them. 24 - 43.5875 MHz – For use by health professionals, doctors, hospitals, and activities related to them.
The long process of getting back on the air continues. I've put up antennas for 2m and 70cms in the attic of the house so at least now I have something that might be considered semi-permanent. If I go off the radio again, it's not such a big deal to get going again and the aerials won't get destroyed by the weather.
In the last week, I checked the Westflex 103 coax cable going to where the old CB vertical used to be. Using my old home brew power meter and my old Yaesu FT-290R, I established that the loss for the 20 metres or so of Westlex 103 was about 2dB at 145 MHz. This means that it should be well under 1dB at 28 MHz and that includes having a back to back SO239 connector in line. So the coaxial cable is working fine and shows no sign of water ingress.
About a fortnight ago, I purchased a CB half-wave vertical from Long Communications in Donegal. The model was a Venom which I believe may be from a company called Sigma.
Considering it was only €35 with an additional €12 for delivery, it's hard to say it is in any way expensive. In contrast to some of the verticals for the HF bands, it's incredibly cheap.
Some of the specs should be taken with a pinch of salt.
Power Handling...1000 watts.....I doubt it. 100 watts is fine but I'd have my doubts about anything close to 1000.
Gain...4.1dB.....Sounds great but it's a half-wave! 0dBd or 2.15 dBi at the most and that's if you ignore matching losses.
Frequency....26 to 28 MHz.... My tests shown below suggest that it won't be resonant anywhere near 26 MHz. Without an antenna tuner, I think 27.0 to 29.7 MHz would be part of the spectrum that the antenna could be adjusted to.
Construction and Assembly.......All the parts come in a small plastic bag which includes two U-Bolts, three screws, three washers, 3 nuts, 4 jubilee clips and a small plastic seal for the top of the antenna. All pretty obvious and the antenna can be assembled in about 10 minutes.
There are Blue marks on the aluminium sections to show how far each section should be inserted into each other.
This YouTube below from someone in the UK shows what it looks like out of the box including the Blue marks for adjustments.
One of my biggest fears was that the antenna would be really flimsy once it was constructed. To be honest, it looks fine. I can't really say the construction matches the cheap price, it seems fine.
Tuning...I mounted the antenna on a 4 metre pole and checked the VSWR with the internal meter on the Kenwood TS690. When I had the lengths adjusted to the Blue marks, the centre point seemed to be around 28.0 MHz. I then shortened the antenna so that the VSWR plot now looks like this.
Some observations and notes....
1) As I shortened the antenna the VSWR curve below the centre frequency seemed to match that above. As a result, I have inferred the plot below 28.0 MHz as I cannot transmit there.
2) The 1:1.5 VSWR bandwidth is 1.3 MHz which seems pretty good.
3) The top section of the antenna must be adjusted by 4 cms to move the centre frequency by 100 KHz. So in other words, if you wanted to move the centre frequency up by 300 KHz then you would make the antenna 12cms shorter.
4) If the length of the antenna was assembled to the Blue marks then the centre frequency was 28.0 MHz. This means the VSWR was at or below 1:1.5 from about 27.35 to 28.65 Mhz. This might be an issue for someone who wants to use the bottom end of 27 MHz as there wasn't much scope for making the antenna much longer. It should tune up fine with an antenna tuner but I'd guess most CB stations would be unlikely to have one.
5) My antenna was mounted at 4 metres above ground level. The VSWR and centre frequency may well change if the antenna was at different heights.
Performance.....Too early to say but I am hearing local Churches broadcasting at the top half of 27 MHz from about 50-60 kms away so it seems reasonable. It is certainly no worse than the old CB half wave I used to have.
Overall.......Time will tell if it survives the Winter gales but the mechanical construction seems reasonable. If I had it way above the house then I suspect it wouldn't last long. But at 4m, I would expect it to last the first winter anyway. Other than that, the performance seems as expected.
It can often be useful to listen on the 27 MHz CB band to see if propagation is likely on 28 MHz, especially when the 10 metre band seems dead. The fact that it is slightly lower in frequency can mean that the CB band will open before 10 metres for F2 and Sp-E propagation.
Many of those CB operators who are into DX-ing use 'Division' numbers. For example, if you heard '26 AB 123' then that person would be from England.
