Category Archives: Uncategorized

Ed White Hospital is closing

From the Tampa Bay Times:

Nearly 40 years after opening its doors, Edward White Hospital will close in November amid another year of empty beds and a multimillion-dollar shortfall.

It remains to be see how this will affect our prime site, but lets hope everything can remain on the building.

 

220 Base antenna

With a generous donation from our Founders Committee members we’ve purchased a Telewave 6/9 dBd gain folded dipole antenna.

Big thanks to our supplier Sandy’s Communications who was able to get the antenna below the Telewave amateur discount price for us.

This will be the main antenna on the 224.280 repeater once we get it online at our prime site.

224.280 repeater progress

Much progress has been made on building the main 224.280 MHz repeater.

The rack mount case has been constructed and fixed to the Hamtronics modules, and the GPSDO master 10mhz clock source has been integrated with the units.  This consists of a PIC 16f88 micro-controller running code that will spit out the appropriate bits to the CPU as it goes into transmit.

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The first revision of this code simply would power up, program the PLL IC and then shut down (no CPU noise).  This worked but it had the effect of running the PLL VCO at 224.280 all the time transmitting a low level (-24dBm) signal at all times.  This is enough to open the squelch of a radio about 2 blocks away.

We solved this by making the PLL move off frequency when not keyed.  When the repeater keys up, it now moves onto frequency in about 10ms and works flawlessly.

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The other major issue was microphonics due to the cheap chip caps used in the VCO circuit of the hamtronics exciter.  Cheap ceramic capacitors can be piezoelectric, and vibrations will cause them to vary (very slightly) in capacitance.   A simple taping on the box will cause the frequency to swing 10-20 khz, which is unacceptable.  The suspect capacitors were changed to mica insulated units which do not have such a problem.

Between this and the potting of the VCO coil, almost all microphonics have been eliminated from the hamtronics exciter.  A stiff rapping on the enclosure now only varies the frequency a few Hz.

Hamtronics chip caps

 

 

 

 

Florida Simulcast Group is online!

We’ve registered this domain for our use.

Expect further updates about FSG and our Amateur Radio repeaters in the coming months.

Incorporation!

Florida Simulcast Group is incorporated as a charitable non-profit corporation under the laws of Florida.  This is a big step in moving our group forward, as we can now legally function as a single entity.

Our incorporation documents can be found on our disclosures page, or sunbiz.org.

We’ll be applying for 501(c)3 Tax-exempt status shortly.  In the time being we are under provisional status, meaning all donations are treated as tax deductible under IRS code.