[NLRS] 10 GHz contest spreadsheet

[Dr. Gerald N. Johnson]

A 6 cell lead acid battery drawn down to 11 volts has very little energy 
left so the voltage tumbles rapidly under load at that point. The LM2940 
family is what I plan to install in place of the 78S09 in the DEMI 
transverter. I also plan to work at minimizing DC voltage drop with 
fatter DC wires, like 10 gauge instead of 14 gauge, maybe even 8 gauge 
mains and then short wires to the transverter, PA, and IF. I was 
figuring low voltage was pulling the oscillator frequencies, but tests 
this week have shown that not to be the case.

So next I'll have to see about loss of LO power to the mixer. Most 
mixers are hypersensitive to LO drive on the low side and the conversion 
loss rises rapidly with low LO drive. Indeed a diode mixer without 
enough LO to overcome the forward conduction barrier voltage doesn't mix 
at all unless by the slightly varying reverse biased capacitance 
variation which isn't much.

My vintage DEMI transverter seems to have a 5 volt regulator for the 
oscillator that is fed by the 78S09 but frequency changes slowly with 
low voltage as if its the heating from the PTC thermistor that is 
changing with supply voltage.

73, Jerry, K0CQ

On 10/27/2015 7:30 AM, Zack Widup wrote:
>
>
> I've been using the LM2940T-X.0 voltage regulators wherever I need a
> lower voltage. Usually the 9.0 volt ones but occasionally the 8.0 volt
> ones. For circuits where I have determined that a low supply voltage
> will pull the LO frequency, I use a boost switching supply to generate
> about 18 volts or so and then use the LM2940T-12.0 to maintain 12
> volts and the others for lower voltages. This has made the LO stay
> rock-solid down to 7 volts from the supply at the expense of drawing a
> little more current. The LO's are also phase-locked to a 10 MHz OCXO.
>
> Activity along the Lake Michigan lakefront was nowhere near what you
> folks experienced in your area. I ended up with about 11,000 points.
> But it was a blast and well worth it to make 18 QSO's on 24 GHz in
> addition to the 10 GHz ones.
>
> 73, Zack W9SZ
>
>
> On 10/26/15, Dr. Gerald N. Johnson<geraldj at netins.net>  wrote:
>>
>>
>> I sent in a paper log, and I used N0UK's web page for computing
>> distances. Final score about 60,140 points, not enough to beat Gary but
>> a pretty good showing. I'm working on the rig trying to find out why it
>> seemed to quit working at Storm Lake on Saturday in September. Battery
>> voltage was a bit low and I need to make sure the charging circuit
>> charges. For that I have mounted a Radio City miniature digital meter in
>> a box with long leads so I can hand that box at the front glass of the
>> pickup topper and see it from the cab to see if the voltage rises while
>> driving. I'm also testing the transverter, PA, and FT-857 at low
>> voltage. While the 857 spec is 13.8 +/- 15% which puts a lower limit at
>> 11.7 volts it doesn't lose sensitivity or frequency control down to 9
>> volts supply. And listening at 1136 MHz the transverter crystal still
>> controls the frequency, moving about 1.4 kHz from the frequency with 12
>> volts. That doesn't match my counter display a few years ago of moving
>> 100 kHz per 1 second counter gate. I suspect now that low supply is
>> dropping the 9 volts to the multiplier MMICs and killing the transmit
>> and receiver mixer LO drive and so its "gain" with a great deal more
>> loss. Will have to do more sophisticated testing to see that. The 1136
>> signal radiated to an external receiver stay up until the supply voltage
>> got down under 7 volts. The multipliers all depend on a 78S09 that needs
>> a couple volts of headroom. I think a low dropout regulator in its place
>> could solve my problem, or a small battery booster if it doesn't create
>> too much RF noise. I found some boost regulator boards rated at a couple
>> amps from Marlin P Jones a few months ago. I bought AC line filters to
>> clean up the input and output once I put one or two in a shielded box,
>> if I go that way.
>>
>> I did make a little test run of John's software that I downloaded and it
>> seemed to work.
>>
>> 73, Jerry, K0CQ
>>
>> On 10/26/2015 10:28 PM, John Toscano wrote:
>>>
>>>
>>> Folks, I sincerely apologize for not keeping up with my email, in
>>> particular, the requests for a current copy of my contest logging
>>> spreadsheet. My thanks go out to K0MHC and W9FZ for their efforts in
>>> getting copies out to people.
>>>
>>> Thank you also, Jerry, for trying your best to help, but the versions of
>>> the logging spreadsheet on my qsl.net web page are no longer the current
>>> one. Jim and Bruce connected people with a newer, improved version. I
>>> need
>>> to replace the obsolete versions of the file, and Jerry's posting will
>>> serve as a reminder to me that I need to clean up after myself.
>>>
>>> Since the submission deadline has already passed, I guess it's too late
>>> for
>>> me to be of any help for this year. Again, my apologies. I hope everyone
>>> who played in the 10 GHz and Up Cumulative Contest this year had a good
>>> time and did well. I'd cross my fingers hoping to re-join you folks next
>>> year, but unfortunately, I haven't recovered enough strength and
>>> coordination in my hands to do that simple thing. So I'll hope for it
>>> anyway, without relying on crossed fingers to increase the chance that
>>> the
>>> wish will come true.
>>>
>>> 73 de W0JT/5
>>> EL09vu (New Braunfels, TX) and EL09ro (San Antonio, TX)
>>>