23cm whilst often refered to as being 'microwave' 1296Mhz actually behaves much like VHF/UHF and similar technique's are generally used with regards to antennas and coax but everything just becomes a bit more critical in order to reduce RF losses.
23cm can be a very interesting band with openings on SSB being similar in nature to that of 2M and more so 70cm. Best ODX from West Yorkshire is OK (Czech Republic). Antennas are easy to erect and offer very high gain for a very small size when compared to 2M/70cm. Below is the spec for the Tonna 23 element 23cm Yagi.. I am now running ICOM's flagship VHF-SHF basestation on 23cm but previously used a Yaesu FT736R and Kenwood TS790E.
Frequency 1290 - 1302MHz (23cm) * Impedance match bandwidth @ SWR <1.2/1 * Elements 23 * Power 300W * Forward gain 17.9dBi * Boom length 1.75m * Wind area 0.06m2 H, 0.05m2 V * Weight 1.4kg
A typical 23cm setup at my QTH would works out as follows: -
Antenna Gain
17.9dBi
H100 Coax/connector losses 3db
The above calculate to give you an effective radiated power (ERP) of 22dBw or 188 watts.
I have found that stacking and baying 23 element yagis or using the 55 element version of this antenna whilst offering an increase in gain and therefore ERP brings the polar radiation pattern down and makes the beamwidth extremely narrow making accurate rotator beam headings a must.
The use of a good low noise GasFET MHA (Mast head amplifier or pre-amp) improves results no end ICOM's AG-1200 is a very good example , SSB Electronics also make high quality low noise amp but with quality comes a price expect to pay in excess of £250.00 for a top end MHA.
I am currently using Pope H100 semi hardline coax but am seriously considering ecoflex15 as a replacement as it offers comparable RF performance to Andrew LDF-450 without all the problems of running hardline in a residential enviroment.
There is very little 23cm FM activity and with the exception of the odd mobile, my experience is that most FM operation is carried out by people chatting accross town horizontally polarised simply taking advantage of the better quality and clarity of speech offered by FM modulation over SSB.
