[Amps] Bird 'H' series inserts: Performance on 160

[Gary Schafer]

Very good comparison! At least you have an independent reference that 
does not accomplish power measurement in the same manor as the bird.

It would be interesting to see what those elements read at higher 
frequencies.

The Diawa that Mark used for comparison probably samples power similar 
to what the bird does. So it may very well drop off similar to the bird.
But then again the collins is in the same boat. But those are not that 
great for accuracy anyway.

73
Gary  K4FMX

Karl-Arne Markström wrote:
> Made a similar test with the following Bird elements
> and a test setup consisting of:
> 
> RF source adjustable to 50 and 100W output monitored on a freshly calibrated HP410C RF voltmeter with
> the T- junction and also connected via a Collins 302C-3 wattmeter to a Bird 250W dummy load.
> 
> Test frequency: 1600 kHz
> 
> 
> Power level    50 W        Reading on 50H            45W
> 
> Power level    100 W        Reading on 100H        90W
> Power level    100 W        Reading on 250H        85W
> Power level    100 W        Reading on 500H #1    80W
> Power level    100 W        Reading on 500H #2    80W
> 
> additionally a check of a 1000P (450 kHz to 2500 kHz) element was made
> 
> Power level    100 W        Reading on 1000P       85W
> 
> Comparison test:
> 
> Test frequency: 2000 kHz
> 
> 
> Power level    50 W        Reading on 50H            47W
> 
> Power level    100 W        Reading on 100H        95W
> Power level    100 W        Reading on 250H        85W
> Power level    100 W        Reading on 500H #1    85W
> Power level    100 W        Reading on 500H #2    80W
> 
> additionally a check of a 1000P (450 kHz to 2500 kHz) element was made
> 
> Power level    100 W        Reading on 1000P       80W  (!)
> 
> The readings are within the +/- 5% of full scale promised except on the 50H and 100H elements, where
> they are about 10% low.
> 
> It appears that the lower frequency limit, as expected,  is less sharply defined on the higher power elements.
> 
> 
> The Collins wattmeter, incidentally, read 70 and 130 W respectively...
> 
> 73/
> 
> Karl-Arne
> SM0AOM
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> ----- Original Message ----- 
> From: "Mark Hill" <g4fph at mjha.co.uk>
> To: "Amps Reflector" <amps at contesting.com>
> Sent: Tuesday, March 29, 2005 7:51 PM
> Subject: Re: [Amps] Bird 'H' series inserts: Performance on 160
> 
> 
> 
>>Gary,
>>
>>Aah!  That's where the 'rough science' part comes in.  I used my Jap. Daiwa 
>>(that is at least spec'd down to 1.8 MHz) as reference!  Actually the Daiwa 
>>correlates quite well against the Bird on HF.  Perhaps Bird use these to do 
>>their production cal. against ;-)
>>
>>I was expecting the 250H to exhibit a bit more (some) droop than the 2500H, 
>>but couldn't really discern any.  Perhaps a 50H would show some?
>>
>>Regards.
>>
>>Mark.
>>
>>-------------------------------------------
>>At 17:38 29/03/2005, you wrote:
>>
>>
>>
>>>Mark Hill wrote:
>>>
>>>>Anyway, to get back to somewhere near where this thread started.  I did 
>>>>some rough science checks on a 250H Bird 43 insert.  I did not find that 
>>>>using it resulted in readings that were dramatically low just below 2 
>>>>MHz.  I checked down as far as 1.6 MHz and would say that any additional 
>>>>error from using it at frequencies down to this far below its lower limit 
>>>>was negligible.
>>>>My personal conclusion therefore is that both 250 Watt and 2500 Watt 'H' 
>>>>series elements are good to go on topband.  If anyone has other 'H' 
>>>>series ones, I would be interested in any results they collect.
>>>
>>>What method did you use to measure power to compare the bird to?
>>>
>>>Note that the higher power the element the broader band it is. Don't 
>>>expect the 250H to be the same as the 2500H.
>>>
>>>73
>>>Gary  K4FMX
>>>
>>>
>>
>>*******************************************
>>Mark Hill - G4FPH
>>E-mail: g4fph at mjha.co.uk
>>Current web pages at: www.qsl.net/g4fph
>>Old web pages at: www.g4fph.freeserve.co.uk
>>-------------------------------------------
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>>2 ele delta loop beam resonant on 14180 kHz
>>-------------------------------------------
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>>
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> 
> 
>