I'm using either the KD6OZH circuit built dead-bug style or the VE1ALQ
circuit along with the KD6OZH PLL circuitry for my phase-locked LO's.
Both LO's work great with that PLL circuit.
But yes, at 903 MHz the accuracy is going to be pretty good and the
stability will also be good without the PLL. I don't use a PLL on my 1296
LO either. If you have a known beacon in your area you can use that to
calibrate the LO. I have the K3SIW beacon to listen to here.
I may take a different approach on 47 and 78 GHz. K3SIW has a design for a
direct frequency synthesis LO he's using on 47 GHz. It's similar to the
circuit WA1ZMS uses in his world-record millimiter-wave equipment but
Garry has made a few improvements.
73, Zack W9SZ
On Fri, 8 Aug 2008, Steve Tripp \(K1IIG\) wrote:
> Demi now makes a "drop-in" synthesized LO for their transverters which can
> be (must be) locked to an external 10mhz oscillator. I believe they cost
> around $60. I have one ordered with my 10ghz transverter. VE1ALQ makes a PLL
> outboard LO that can be used on most LO frequencies and must also be locked
> to 10mhz. I have ordered 2 of these for various tranverters but have not
> idea how difficult they are to incorporate into the transverters. I do not
> think you need to go this route to stay within the band with any of the oven
> xtal oscillators.
>
> Steve
> K1IIG
>
>>
>> Sure. Depends on how much you want to put into frequency accuracy.
>>
>> My 902/902 transverter uses a crystal oscillator that doesn't drift at all
>> after about a minute of warm-up and then only drifts a kHz at most. The
>> IF rigs I use don't drift at all. I use an FT290RII and an HTX-100 with a
>> built-in 144 MHz transverter.
>>
>> I have seen no need to phase-lock the 903 LO to a 10 MHz reference as it
>> is stable and accurate enough without. I have no cencern that I am
>> anywhere near the band edge when transmitting on 902.100.
>>
>> My transverters for 2304 and up all have phase-locked LO's and the 10 GHz
>> LO is accurate to within about 200 Hz at worst and very stable. They only
>> get better for the lower bands.
>>
>> 73, Zack W9SZ
>>
>>
>> On Thu, 7 Aug 2008, James French wrote:
>>
>>> Since I have opened this can of worms... :) I should ask this then.
>>>
>>> Do we want to be this close to the band edge with the use of trans-
>>> verters?
>>>
>>> What about drift and other things? Some that I know use the MFJ 2m
>>> SSB/CW transceiver as the IF for their transverters and they do drift
>>> a LOT even after being warmed up.
>>>
>>> I am VERY leary of operating that close to the band edge since I am
>>> still a greenhorn to my HF frequencies and don't have the equipment to
>>> test things out all the time unless you count my rat shack frequency
>>> counter.
>>>
>>> James W8ISS
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