I registered and ordered a sample with 1 MHz in and 10 MHz out (CLK0) and OE (other options disabled)
Posts by PA3FYM
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Could be ... but it only removes the jitter. When you've a good 25 MHz source it's not necessary.
Perhaps the 10 MHz version is good enough to remove the jitter from a Ublox when the Ublox is generating 10 MHz ? If that is the case then a GPSDO is not necessary and a simple Ublox NEO-7 (or similar) may be used (?) . Experiments have to proof this
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I see ! OK, then I was to quick with ordering. I only downloaded the PL902xxx datasheet.
OK, did you already order, and is there a part with 1 MHz ref in and e.g. 5 MHz or 10 MHz out?
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With some efforts (because it's very small!) I managed to decode the description, which is indeed K167 (also what I ordered). In the specific datasheet (Mouser) it appears to me this is the max frequency it can handle/produce with 2.5 V power supply?
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No , no ... it's not your fault ; -)
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Ok ... my frustration, I was not able to find essential information in the datasheet, is solved. It seems that the PL902 has to be programmed (by MicroChip?) for every design. It is e.g. possible to insert 1 MHz (jittery) refclock and get 10 MHz out.
I still have one halve of a HC390 unused, so that can be divided by 10 to insert it in my 'original' circuit. -
Fully agree and true. Btw I was not opposing the phenomenon of talking back, but the fact it has to be in FM.
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Founding father of this feed is G0MJW and I assisted with finding the right feed point to let it produce CP. It is modelled in CST Studio and a MP4 movie of the simulations canbe seen here . Will try to find the picture of the dimensions.
In the meanwhile you can look at these ones here or here or here or here or here : -)
Edit: below the dimensions of the feed. Spacing between patch and reflector is 3mm. I have the feed point at X,Y = 8,28 and a cropped square reflector.
2300 - 2500 MHz simulation done by G0MJW is below. It confirms the right position of the feed point is critical for CP, i.e. balloon perfectly circling around Z = 50 + j0 Ω ! :
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GM3SBC Lot's of photo's ... here is my equivalent (one (dual band ) feed ... one dish and one (1) photo), in other words ... 'plus simple' (!) :
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DL4SAC I know the talkback for ATV (here on 144.750) ... but ... 'not all have the power for DATV-signal' <-- bad luck !!
So, it's simple (in my opinion... which is just an opinion ...) when you don't have the power ... don't (want to) talk back (!) -
OK, I think I jubilated too early. I just placed the PL902 in between the Ublox and PLL and started listening to the CW beacon. a few moments ago I tried to build the reference into a housing and saw that the PLL did not lock. I measured the output of the PL902 and found a fuzzy signal.
So, I fooled myself yesterday and listened to my TCXO ('free running'), so no surprise I had no jitter (TCXO is already vy stable and accurate).
It seems that you've to 'program' the PL902.
When I go to the clockwork.micrel.com site, it shows that minimal output frequency (CLK0) is 5 MHz (!) with 1 MHz ref in. Now I have to figure out how to do this ...
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My comment? "Build a transmitter for 2400 MHz" (and join the party)
After all .. the rationale of the legal radio amateur service is that one is allowed to transmit (inside the HAM bands of course)
Free translation from a Dutch saying: "Don't whistle with bisquit in your mouth to the football referee in the field, while you are outside the playing field"
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Personally (which is just an opinion) I don't think it's a good idea to produce FM on the NB linear transponder. If people want to talk back use the WB transponder, or better... two persons uplink .. and they can see AND hear each other or .. leave your picture black (or whatever produces the least band width) and uplink (digital) audio ?
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DD0KP I already did in this thread, scroll back, there is a screenshot and the sketch .. below the screenshot.
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From what I 'roughly' read is that the people sreaming for a jammer are not active themselves.
So, first become a 'user' (i.e. transmit yourself') then complain.
If you're not able to transmit, refrain from comments . <- period -
I use a ATTiny13 to program the Ublox with a string of bytes which puts it in 1 MHz REF-out mode
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Just added a PL902 between the Ublox and phase comparator.
Well .... it's a MASSIVE improvement! I'm astonished!
Still have some phase noise left compared to my normal reference, but I think this might be the loop filter. However the jitter is not audible anymore!
Claudio thank you for the hint!
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Jan PA0SSB made a hardware version of this method. He uses an old DRO LNB for reception. In his shack he generates a reference signal (12.8 MHz TCXO) which is multiplied (with varactors etc) to somewhere around 10.x GHz. This indoor signal is pointed to his dish outside (into the LNB). On the IF side you've two (instable!) signals but stable relative to each other. He amplifies the reference signal, mixes this with the wanted signal (the RX signal) ... and there you go!
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Yes, then it may be the lack of dynamic range of the receivers. Listening to the websdr I also saw degradation, but when I looked at my own setup the spectrum / noise floor remained stable.
I saw the noise floor degrade once, but then somebody uplinked a VERY strong carrier.
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How do you receive the beacons ?