[Yaesu] FT-ONE - low output.

[steve stutman]

One way to get accurate measurements at HF is to use a Telepost LP-100A.

It does make spec and performs as advertised.

It costs less than comparable Bird equipment.

73





Dr. David Kirkby wrote:
> On 05/29/11 12:49 PM, Rob Atkinson wrote:
>   
>> I don't argue about the Bird accuracy but if you don't like a 43, how will
>> you be content with any hammy hambone watt meter out there marketed to hams?
>>     
>
> I think my point is that hams don't really require great accuracy in power 
> measurement.
>
> Unfortunately I've never tested any ham meters in a lab, so I don't know how 
> good/bad they are.
>
>   
>> If you want to achieve accuracy on a budget, consider getting a thermocouple
>> RF amp meter (they show up at hamfests for a few dollars/pounds/euros but
>> are often hidden under junk because most hams don't give them much value
>> which is good for you) that measures 6 A and a good 50 ohm non-reactive
>> dummy load.   Mount the meter in an aluminum box in series with UHF jacks
>> mounted on the sides.  Measure your current into 50 ohms and calculate the
>> power.   Actually with your legal limit a 2 or 3 A meter is fine.
>>     
>
> I don't have much clue about how accurate that would be. I'm not an expert in RF 
> power measurement, but when it comes to Bird meters, I probably know more than 
> 99.99 % of hams.  At least one review on eHam describes the meter as "lab 
> grade". The reviewer is seriously mistaken.
>
> I think my main issue with Bird is the claimed accuracy and the cost. If the 
> accuracy was as good as Bird state, then I'd have no problem with the cost.
>
> But when Bird claim +/- 5% of FSD, and I know some don't even meet 10% of FSD, 
> then I do have a problem with the meter.
>
> I've often wondered how difficult it would be for hams to make a water 
> calorimeter. For high power, that's how its measured in a standards lab. Of 
> course, this would require that you transmit for a time sufficient to reach 
> thermal equilibrium, which would exceed the duty cycle of most ham rigs. Making 
> one would be a major project, but an interesting one and within the capabilities 
> of a dedicated constructor.
>
> I think for me a spectrum analyser is the easiest solution. It may not be the 
> best, but is good enough. I could calibrate a ham meter against that.
>
>
>