To bring all my tvtrs up to date I ordered replacement PLL LOs from DB6NT and retro fitted them vs the lovely OCXOs from ID Eletronik.
Nothing wrong with the OCXOs but they need to be heated all the time to maintain good LO stability over long term and so Ive gone GPS locked for all my kit
The DB6NT LOs are very small and neat and hardly fit the space where the oven LO went.
They have two options ... they will run on their own without 10 MHz in and still are very good heater stabilised LOs at 2ppm but when 10 MHz from a GPSDO or Rub. std is applied to the reference port they lock up against it.
My G3RUH GPSDO stability is :
Warm-up Accuracy
After 30 minutes < 10-10 typical
After 60 minutes < 10-11
Stability (Allan deviation) typical
1s < 1x10-12 1000s < 2x10-12
10s < 3x10-12 10000s < 3x10-13
100s < 5x10-12 1 day < 5x10-14
so even at 10-11 thats pretty accurate at 10 GHz!
Hmm if I did my maths right thats about 10 Hz at 10 GHz!
The DB6NT has one distinct advantage over anything currently on the market ..... phase noise!
The DEMI board is only about -70 dBc/Hz at 1000 Hz where are the DB6NT boards are in the range of -152 dBc/Hz
what does that mean to the average user......
well poor phase noise is going to destroy any strong signal capabilities ... get on high ground in a contest or near a beacon and your in trouble. See Pauls article
http://www.w1ghz.org/new/Phase_Noise_and_MDS.pdf
he sums it up nice!
"definite phase noise, especially for each other, making spotting difficult. At times, AF1T, 80 km away, caused spurs near our frequency (we try to stay ~30 KHz apart). Enough birdies to make tuning for stations an adventure."
It also destroys your MDS capability too .... Nick GM4OGI and myself calculated poor phase noise at this level would reduce MDS capability by about 3 dB.
Paul W1GHZ measured around 2 dB MDS reduction. Don't sound much but when your hunting for signals in the noise then 2 - 3 dB is going to kill things pretty quick.
I am not employed by DB6NT BTW .... but I know he will only sell stuff that he knows stands up to scrutiny.
anyway ....
my tvtr for 6cm is a 432 MHz IF DB6NT unit, with a 0.7db NF preamp. TX side is about 20 watts with a DB6NT SSPA.
the box is a fiberglass resin IP67 rated - quite light and easy to drill!
relay is a small 18 GHz teledyne 28V driven from a small DC-DC converter.
You can see the DB6NT sequencer in the corner too.
10 GHz is not much different .... in fact almost identical
same DB6NT tvtr / preamp combo
this time SSPA is 12 watts.
and a 4 port transfer from 28 V.
both tvtrs work extremely well ...... both have worked well over 900km in Europe on Rainscatter
Ill post some more pics of the 9cms kit .... same style but 2 x toshiba PAs combined ... about 100w out.
Ill have finished the new 23cms tvtr soon (DB6NT G3 GPS locked with a 60w PA) and will post something about that soon
73 Simon ZL4PLM
All the DEMI MicroLOs need something in the 180 to 190 MHz range. You could use one in the VK5EME 23cm transverter and possible in the 2.4 GHz transverter if you wanted an IF of 146 MHz. But you would still be pushing it thru the VK5EME LO kit.
At least world wide people are moving to 3400 for 9 cm. The DEMI kit I have for 9cm came with a crystal for 3456 and I had to use some "smoke and mirrors" to be on 3400.