[Lowfer] New idea for Lowfer transmitting

Thu, 8 May 2003 18:57:25 -0700

Bill

there is a good near field device that can be calibrated to determine
ERP in the RSGB's LF handbook. Consists of a direct conversion rcvr
that is calibrated to a DMM with a Helmholtz coil. The article is a good
read

Bob  K3DJC

actually what will be fun to recreate would be a transcontinental Msg.
relay
done by the ARRL in the teens / 20s,, another good read is" 200 meters
and down "
by Clinton B Desoto ( SP ) Wonder if there will be enough 136 operators
to be able to do this. I think the time then was under a half hour but
not sure

lets get the band first though

B

On Thu, 08 May 2003 12:55:21 -0400 "Bill Ashlock" <[email protected]>
writes:
> I'd like to get some opinions on the following:
> 
> Background: I just sent a QRSS30 signal that was adjusted to the 
> Part 15 max 
> level of 2400uv/m measured at 300m to John Andrew's base 40 miles 
> from here. 
> At 185.3k the signal is limited to 13uv/m at 300m, and at my 
> location here 
> at work it amounts to 1.4uv/m, approx 6db above the noise level this 
> 
> morning. John's last screen copy can be seen at: 
> http://webpages.charter.net/w1tag/WA-1.jpg
> 
> The implications of this type of broadcasting are as follows:
> 
> 1. Far field antenna testing is possible for the upcoming 136k band 
> using a 
> portable SVM.
> 
> 2. Local communications, up to, and possibly exceeding 40 miles, is 
> possible 
> at any frequency from DC to 490k using digital modes. Sky wave 
> reception is 
> possible but should be rare.
> 
> 3. As the frequency is lowered the antenna efficiency goes down. 
> However, 
> like HiFer, the power to the antenna can be increased to meet the 
> 2400/F 
> value. The signal falloff with distance will follow the 1/d 
> relationship out 
> to greater distances than the present lowfer band, which in this 
> area, could 
> be an additional 6db at 40 miles, thus increasing the range much 
> further.
> 
> 4. Antenna configurations can be much simpler than at present since 
> the 
> power can be increased to meet the 2400/F value. (For example: My 
> tree 
> antenna can be used as a TX antenna)
> 
> Thanks in advance for any comments.
> 
> Bill A
> 
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