[Amps] Power metering in linears

[craxd]

Rob,

You are correct on this. Most use a 1N270 or so, but I'm not sure what 
would be needed for that wide of a range.

Will Matney


robrk at echomatrix.net wrote:

>Don't think any diodes in the circuit are linear from 160 to 10.
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>>Tom,
>>
>>Stripline type RF sensors are narrow-banded and generally won't work
>>with that type of band spread. The toroidal transformer should work if
>>the core is rated for the complete frequency range like 3-30 MHz. If
>>not, you may have to add a switch to kick in another potentiometer just
>>for 80 meters and maybe 160 meters. To get the meter to null is another
>>thing and has to be done to read forward and reflected power. You may
>>just try different toroids first before doing any modifications.
>>
>>Will Matney
>>
>>
>>Hello technicians,
>>
>>I was adding a power meter to a new homemade linear. I used the
>>directional coupler of the "Digital PEP Wattmeter and SWR calculator" from
>>an old ARRL handbook (1987). I did not get a too deep null on calibrating,
>>so the directivity was only 20 dB. As I only wanted to monitor the output
>>of a linear with that coupler, the directivity was sufficient.
>>
>>The problem: The output voltage for a given power is the same from 40-10m,
>>but nearly null on 80m and different on 160m.
>>
>>Then I tried the design from the linears in the W6SAI handbook. They use
>>Amidon 50-6 toroids. The output voltage ón 160 is about 1/2 of the voltage
>>on 10m.
>>
>>Has anyone successfully built a directional coupler with constant
>>frequency behaviour from 160-10m?
>>
>>I would like to have proven designs.
>>
>>Thanks!
>>
>>Tom, DJ5RE
>>
>>
>>_______________________________________________
>>Amps mailing list
>>Amps at contesting.com
>>http://lists.contesting.com/mailman/listinfo/amps
>>
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>>
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