A proposal for revitalizing the 1.25m band

Discussion in 'VHF/UHF - 50Mhz and Beyond' started by N0AQX, May 4, 2015.

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  1. K9STH

    K9STH Platinum Subscriber Volunteer Moderator Platinum Subscriber QRZ Page

    KKP:

    UPS abandoned their 220 MHz usage when the FCC refused to modify their licenses to use "normal" +/- 5 kHz deviation FM instead of "narrow-band" technology which, at that time, was ACSB. Using ACSB made the equipment considerably more expensive than FM and, frankly, UPS didn't want to have to spend the additional money.

    The thing that UPS used to get the spectrum was to propose only "narrow-band" technology to be used. When the spectrum was reassigned, they tried to get the "narrow-band" technology restriction removed. Fortunately, the FCC did not relent and UPS went another direction for their system-wide radio system.

    Glen, K9STH
     
  2. KW4EK

    KW4EK Ham Member QRZ Page

    And the Yaesu VX-6R does 1.5W as well on 1.25m (which is only 3dB down from their 5W output on 2m and 70cm bands). So clearly there are other brands presently on the market with 1.25m support.

    Both of which are current model Yaesu HTs which include support for 1.25m, but apparently only Kenwood, Alinco, and Baofeng/Pofung make current model 1.25m HTs? Just a reminder that one must always be careful when making absolute claims (as has been established otherwise). :)

    In fairness, there seems to be more widespread support for 1.25m among HTs than among the modern mobile and base station offerings (there are some, but they are very limited), which may also help to account for its lower utilization since HT to HT coverage distances are very short relative to a fixed elevated antenna, as is common for higher powered fixed stations. Getting more fixed base mobile and base station transceivers on 1.25m would seem to go a long ways to facilitating wider adoption. The same goes for 33cm and 23cm allocations, it would be nice if there were more offerings on the market, though most allocations above that become increasingly short range without tall high gain antennas, making them increasingly specialized.
     
  3. KC9UDX

    KC9UDX Platinum Subscriber Platinum Subscriber Life Member QRZ Page

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  4. WB2VVV

    WB2VVV Ham Member QRZ Page

    It was a bad blow to the band's weak signal (SSB/CW) community when the FCC reallocated 220-222 MHz to UPS, leaving US hams with only the remaining 222-225 MHz. It's not even a ham band outside of the US, so there was never much gear offered for the band in the first place, but hams still built transverters to get on the band with HF rigs and learned it's a great band! The weak signal part of the band was previously centered at 220.1 MHz. After the reallocation ham transverters needed to be re-crystalled for a new local oscillator frequency to move them above 222 MHz. The current weak signal part of the band is centered at 222.1 MHz. It's a great band with healthy activity and it turns out the reallocation was a huge blunder as that part of the band was never utilized as envisioned by the FCC. I would think the FCC were probably a bit embarrassed by this blunder, and would be unlikely to cause turmoil on this band again - and as mentioned the need for additional Smartphone spectrum is up higher in frequency and not down this low due to the propagation being too good and inter-cell interference being too high. In the end, an unfortunate mistake occurred yet hams adapted and recovered, so let's leave it be. BTW, I wrote an article that appeared a couple of decades ago in a 1995 QST about modifying a Uniden HR-2510 10 meter rig (an inexpensive 10 meter only rig that had briefly become popular during the previous 1989 sunspot peak) for use with transverters after marrying mine up to a 222.1 MHz transverter.
     
  5. KM3F

    KM3F Ham Member QRZ Page

    Here in the northeast, the band does get some use during the vhf/uhf contest and sprint times.
    I just recently acquired a Transverter and one beam antenna for that band and did have a few contacts on SSB.
    As of now, I have acquired a SS amplifier from the ACSB days of the mid 90s and fitted it for 222-225 band with T/R relays and PTT control board..
    It came up running 170 watts saturation so built an Attenuator to drop the drive back into the 125 watt range for SSB and to use low distortion speech compression in contesting .
    .
    Waiting for a second beam so the stacking harness can be tested out and trimmed for match.
    The amplifier is dirt cheap because no one has a use for these unless they can and do what I'm doing..
    The control circuitry is a no brainer and all hardware is mounted on the outside airflow cover so no changes inside except retuning the input stage transformers upward with an antenna analyzer for match to be sure where it is.
    Changing amplifiers is only a matter of changing the cover over and reconnecting.
    The equipment is by Linear Modulation of the UK. Very nicely build with it's own separate power supply.
    The amplifier has all FETs except the first input stage and powered by a dual voltage supply of 13 and 26 vdc.
    I obtained enough documentation and schematic to make this a nice project build and will be getting a few amplifiers and one more power supply as spares just in case there is a failure..
    The amplifier is actually a straight forward design but set up for the original application and already runs class ab1. according to the documentation and has separate bias pots for each stage.
    .
    The amplifier is built like the proverbial tank and way above amateur grade.
    This equipment was also built in that time frame by EF Johnson but have not saw an actual amplifier although I have a report that another ham does have EFJ equipment.
    As a side note, I to have a KW THF6 Ht and there is a local repeater close by and expect my presents with this equipment might spark some interest after awhile if any hams will get enough interest to work up equipment.
    I also use the THF6 to test the 222 station for distortion and function because it has all mode receive capability.
    Also don't forget to check your system out with a frequency counter so you know where your at.
    To many stations have no idea where they are at and when it comes time to fined each other during a contest, they miss the contact and move on to quickly.
    Frequency stability of contest stations is another big issue from what I've seen here.
    Well it's just ham radio and the challenge of accomplishment that otherwise would not be..
    Good luck.
     
  6. K9STH

    K9STH Platinum Subscriber Volunteer Moderator Platinum Subscriber QRZ Page

    VVV:

    Under ITU regulations, the 1.25 cm band is available to all of Region II (North America and South America) and not just to United States amateur radio operators.

    Glen, K9STH
     
  7. WB2VVV

    WB2VVV Ham Member QRZ Page

    Thanks for the clarification! Unfortunately, the band is not available in Europe and Asia which represent a very large opportunity cost to potential equipment manufacturers, the largest of whom are of course based in Asia. This is why there were only but a few off-the-shelf SSB/CW capable rigs available over the years, and those that were available are all now pretty old at this point as far as the used market goes. We're still doing pretty well though, by just building our own weak signal gear to get on the band and enjoy the excellent propagation! There are currently some very inexpensive transverters (built and kits) available on ebay for little more than $100, that can easily be married up to an older low value HF rig to get on 222 MHz SSB/CW. So the situation today is even more optimistic than it was back in the mid-90's, with such extremely low cost transverters being widely available.
     
  8. K9STH

    K9STH Platinum Subscriber Volunteer Moderator Platinum Subscriber QRZ Page

    For 222 MHz operation, I acquired a 2nd Hallicrafters HA-2 transverter and modified it to use on 222 MHz. I did add a transistor preamplifier to the Nuvistor "front end" although the Nuvistor worked fairly well without the preamplifier. Not "pushing" the 5894 final amplifier, I get between 40-watts and 50-watts out of the transmitter.

    Most of the 222 MHz operation, around here, is during VHF contests. Using a single 11-element yagi, about 35-feet above ground (but 1/2-block from the highest point in the city), I get out reasonably well.

    I also have one of those 220 MHz FM units that the Japanese flooded the market when the IEEE Class "E" Citizens' Radio Service was denied by the FCC. It puts out about 25-watts.

    Glen, K9STH
     
  9. WB2VVV

    WB2VVV Ham Member QRZ Page

    I currently have 2 SSB/CW rigs for 222 MHz. The portable one uses a more traditional NE602 mixer based transverter married up to a Uniden HR2510 10 meter mobile rig - per my QST article. My higher performance main station setup uses a Mini-Circuits double balanced mixer based transverter with a much more powerful local oscillator, married up to a very high performance HF rig. I have a few different finals, including two based on ceramic tetrodes, and one store-bought solid state brick amp.

    Here in the northeast there is activity beyond the contests whenever there is decent tropo. Of course 6 and 2 meters are still the lead bands for most openings, but when the conditions are good there is activity on the higher bands too. I have even made a CW aurora QSO on 222 MHz!
     
  10. KM3F

    KM3F Ham Member QRZ Page

    John , wee should try a contact some time after I get fully implemented here..
    Good luck.
     

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