for 902 MHz (33cm) and 1296 MHz (23cm)
The microwave bands go well past 23cm, but 33cm and 23cm are the easiest to work with and have plenty of equipment options. Additionally, antennas are easy to build for these bands. These tips focus on inexpensive ways of getting on these bands, with emphasis on equipment suitable for SOTA activations.
In the Pacific Northwest, there are three simplex "hang-outs" on 23cm:
- The usual 23cm weak signal (SSB, CW) frequency is 1296.1 MHz, with horizontal antenna polarization.
- Additionally, we use 1296.2 MHz as an FM simplex frequency (horizontal polarization preferred) to allow people with transverters to work people with FM-only radios.
- Finally, the national FM simplex frequency is 1294.5 MHz with vertical polarization preferred. There does not seem to be much regional activity on this frequency.
The usual 33cm frequencies are:
- The 33cm weak signal frequency is 903.1 MHz.
- We use 903.2 MHz for FM simplex (horizontal polarization preferred), again, to allow people with weak signal equipment and antennas to work people with HTs.
- Finally, 927.5 MHz (vertical polarization preferred) is the national calling frequency. Most radios on 927.5 MHz are converted commercial radios that use narrow band FM (nbFM). There is a modest amount of activity on 927.5 MHz FM in the Pacific Northwest.
The Alinco DJ G7T 2m/70cm/23cm Tri Band HT is about $280 from several retailers — and is a top-notch radio for all those bands. For anyone that doesn’t yet have a quality 2m HT, this might be an incremental investment. This radio is FM only, of course. Other 23cm FM handheld radios (e.g. Icom IC-T81a) occasionally show up at swap meets, QRZ and Ebay.
The Alinco DJ-G29T is a nice FM (and nbFM) radio for the 222 and 902 MHz bands. These are no longer in production and not many were made, but they occasionally show up on the second-hand market. A nice feature of the DJ-G29T is that it covers the entire 33cm band. Thus, the radio works on 903.2 MHz FM to work people with transverters, and it works on 927.5 MHz nbFM to work people with converted commercial gear.
There are a number of commercial hand-held radios made by Kenwood (TK-431 & TK-481), Motorola, and GE that can be put to service on 33cm. Typically, the radios can only do simplex in the upper part of the band (usually 927.5 MHz) and do nbFM only. Commercial conversions require programming cables and software and sometimes minor modifications like filter replacement. Do the research before you buy a commercial radio, unless the seller has already converted and programmed the radio for your needs.
Microwave Mobile Radios
Mobile FM radios are also available for 23cm and 33cm, and are an option for fixed or portable operations. A number of 23cm ham rigs have been produced over the years (e.g. Kenwood TM531, Icom IC-1201) that occasionally show up on the second hand market. These radios are heavier than an HT, but typically offer 10W instead of the 1W available from most HTs.
Finally, there are numerous 33cm nbFM mobile commercial rigs (Kenwood, GE, Motorola) available from second-hand markets. Some of this equipment is light enough for SOTA work. For example, the Kenwood TK-981 weighs 2.25 lbs and puts out 15W. The disadvantage is that these radios don't work in the weak signal end of the band.
Ideally, SOTA activations on 23cm and 33cm could be done using CW or SSB. Lightweight and compact all-mode transceivers for these bands are not readily available. Home stations must use a transverter for 33cm and either a transverter or a commercial rig (e.g. Yaesu FT-736, Kenwood TS-2000x or ICOM IC-9100) for 23cm. These rigs are not well suited for hauling up a mountain in a backpack.
Small transverters can be used with a small IF rig to get on 33cm or 23cm in a lightweight package. SG Lab (www.sg-lab.com ) makes amazingly good, lightweight transverters for these bands at about $215. You’ll need a 2m radio as the IF rig for these transverters — the FT-817 is a great choice that gives you SSB, CW, and FM capability. The SG-Lab 33cm unit is not yet in regular production but may be available by request.
For any of this equipment you’ll need an antenna. The WA5VJB cheap yagis are easy to build and have decent performance. WA5VJB also makes small PCB yagis for very reasonable prices that will make a big difference over factory whips and that you can deploy horizontally polarized.
You can also find small yagi antennas for these bands on Ebay. Pay attention to the connector and pigtail length as there are some different choices.
At these frequencies, feedline losses really come into play. You’ll want short lengths of low loss coax like LMR240 or RG-8x. Transmitted and received signals diminish considerably with RG-58 or RG-174.