Make sure the coupleing loops are rotated correclty.
On 3/10/06, Eric Lemmon <[EMAIL PROTECTED]> wrote:
> Jamey,
>
> If your measurement is accurate, 3.2 dB insertion loss is excessive. A
> single bandpass cavity performs best when its insertion loss is between 0.5
> and 1.0 dB. How are you measuring this? If you are using a spectrum
> analyzer with an accurate frequency reference, the preferred method is to
> put a "barrel" (double female) adapter between the two test cables and set
> the reference cursor to zero dB. Then remove the barrel and connect the
> test cables to the cavity. You can then read the insertion loss directly.
>
> If you're using the bandpass filter on the receive side, no more than 1.0 dB
> IL should be used. If you're using the filter on the transmit side to
> eliminate spurs or harmonics, 0.5 dB IL will usually be fine.
>
> 73, Eric Lemmon WB6FLY
>
>
> -----Original Message-----
> From: [email protected]
> [mailto:[EMAIL PROTECTED] On Behalf Of Jamey Wright
> Sent: Friday, March 10, 2006 8:12 PM
> To: [email protected]
> Subject: [Repeater-Builder] Bandpass Cavity Insertion Loss
>
>
> I just got through tuning up a Phelps Dodge VHF bandpass cavity. The
> measured loss through this thing is 3.2 dB. I am generating at -10 dBm.
> The level measured on the output is -13.2 dBm. It is a Phelps Dodge VHF
> bandpass cavity but I can't find a model number on it. Is this amount of
> loss normal?
>
> Thanks in advance.
>
> Jamey Wright
> KD4SIY
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