When I operate on 902 or 1296 with my DEMI transverters, I have
generally tune between 1296.07 to 1296.18 to find a station. They are
all over the place. I never realized how significant the differences
were until I realized that was why I was hearing no one. Same thing on
902/903. Once you figure it out, no big deal. One station or the other
just sends a string of dashes for about a minute and that solves the
problem.
Steve, N4JQQ, EM55
BTW, anyone using a MM preamp on 900?????? I have been concerned about
picking up a bunch of trash but tuning around the band here reveals no
other signals, no phones, no baby monitors or anything. I am guessing
most of this stuff has moved up???????
Zack Widup wrote:
> 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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>>
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