[Lowfer] [Hifer] Oh, COOL!

[Jay KB6WCT]

I was looking for a hifer email list, but couldn't find one.  Please 
give me a pointer if you have one.

Any one have plans for a radio at this frequency?  My RF 'chops' aren't 
quite good enough to replace the final of a QRP 20M rig.

One nice thing about this part 15 band is that low efficiency antennas 
are not a problem, you can just crank up the final to compensate.  So a 
low efficiency small loop antenna can act as another final end filter 
for the radio without impacting the performance on transmit.

Another nice thing is that the higher power section of this band 
includes frequencies that are 1/2 the frequency of CB channels 12, 13, 
and 14.  Channel 13/2 is 13.5575 MHz -- almost the center of the band.

One not so nice thing that I found in my research is that this band is 
used by electronic key-fob and id/entry cards.   It would be A Bad Thing 
to activate car alarms or open garage doors in your neighborhood.  The 
key-fobs I have found all seem to be (close to) 13.56 MHz.   I haven't 
found the modulation methods of the key-fobs or ed/entry cards.

Jay KB6WCT



John Andrews wrote:
> Zack,
>
> Yes, it can. Legit U.S. signals in that "Hifer" band (2.3 mw with a 
> ground plane, 4.6 mw with a dipole)have been copied in Australia and 
> certainly Europe. That would be a bit tough right now, but give it a 
> few years.
>
> John A.
>
> Zack Widup wrote:
>> At the last sunspot peak I was working Asia and Europe with 5 watts 
>> on 20 meters. That signal could go a long ways!
>>
>> 73, Zack W9SZ
>>
>> On Sun, 31 Aug 2008, John Andrews wrote:
>>
>>>> Ok now see?  I got the stuff to backwards engineer the input power to
>>> the antenna based upon the above 15,848 uV/30 m.  But I would have to
>>> do a PC search here to locate my notes and equations.  Field strength
>>> equations.<
>>>
>>> Backwards engineering about describes it. My guess is that his 
>>> answer will be a lot closer to 4 watts than 4 milliwatts...
>>>
>>> John A.
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