[Hackrf-dev] advice on a txco to buy?

[Orrin Winton]

Hello folks, have had my HackRF for about a week and am going thru
Michael's tutorials & other tutorials. Love this device.

Are the eBay items described as "New External TCXO clock PPM 0.1 for HackRF
One GPS Applications GSM/WCDMA/LTE" for $10-12 the appropriate part to buy?
(noob here)

Or can some similar item be bought that has SMA jacks on it and can be
connected via cable to the jack on the rear of the HackRF?

The $10 clock looks like it'll require leaving the top half of the case
off, is why i ask.

At 434 MHz doing hackrf_transfer i'm getting 700 to 1000 hz drift
(downwards in freq) on a replayed CW signal, in ten minutes, which (if i'm
calculating this correctly) is 1.6 to 2.3 ppm.

I'm being careful to use the correct antenna on the HackRF, keep gains low,
and use low xmit power (2W) on my amateur transceiver across the room (to
record an rf_transfer). Possibly i should put an attenuator on the 2W radio.

Thanks for comments.

Orrin in NE Calif.

[Chuck McManis]

Orrin,

I expect that if you continue in your journey in software radio you will
find that a solid 10Mhz reference to be a good thing to have in general.
(which you can use to drive the HackRF). I ended up getting an RF signal
generator from Crowd Supply (
https://www.crowdsupply.com/era-instruments/erasynth) which works really
well for this and I can use it with all of my SDRs in addtiion to the
HackRF. A friend of mine recommended this one (
https://www.tindie.com/products/AnalysIR/10mhz-ocxo-frequency-standard-module-or-kit/)
which is basically $77 when you get all the parts and it is assembled) so
lower cost but equally movable from SDR to SDR.

Cheers,
--Chuck

Post by Orrin Winton
Hello folks, have had my HackRF for about a week and am going thru
Michael's tutorials & other tutorials. Love this device.
Are the eBay items described as "New External TCXO clock PPM 0.1 for
HackRF One GPS Applications GSM/WCDMA/LTE" for $10-12 the appropriate part
to buy? (noob here)
Or can some similar item be bought that has SMA jacks on it and can be
connected via cable to the jack on the rear of the HackRF?
The $10 clock looks like it'll require leaving the top half of the case
off, is why i ask.
At 434 MHz doing hackrf_transfer i'm getting 700 to 1000 hz drift
(downwards in freq) on a replayed CW signal, in ten minutes, which (if i'm
calculating this correctly) is 1.6 to 2.3 ppm.
I'm being careful to use the correct antenna on the HackRF, keep gains
low, and use low xmit power (2W) on my amateur transceiver across the room
(to record an rf_transfer). Possibly i should put an attenuator on the 2W
radio.
Thanks for comments.
Orrin in NE Calif.
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HackRF-dev mailing list
https://pairlist9.pair.net/mailman/listinfo/hackrf-dev

[Giuseppe Marullo]

I was needing (and still searching) for a txco for the HackRf but I
would like something internal to the box, not sure about what is sold on
Ebay. Anyone could recommend something that surely would fit inside the
Standard enclosure?

Anyway if you really want to address the problem, spend a little more
and use something like this one:

https://www.ebay.it/itm/Trimble-GPS-Receiver-GPSDO-10MHz-1PPS-GPS-Disciplined-Clock-sine-and-square-wave/252162780444?hash=item3ab612ad1c:g:PqcAAOSww-Baabwy

It is a second hand trimble gpsdo module, enclosed with a aluminum box,
add this antenna:

https://www.ebay.it/itm/Maxrad-GPS-TMG-26N-26db-gps-timing-antenna-antenne-N-female/232793495105?hash=item363392d641:g:XOgAAOSw5VFWMReh

and you could have like 10ppt (parts per trillion) accuracy if you keep
it powered on for several days.

Most important part is that it self checks accuracy, and depending on
the module inside (at the moment trimble not Symmetricom beware) you
should be able to use Lady Heater (http://www.ke5fx.com/heather/readme.htm).

Another alternative is QRPLabs:
https://qrp-labs.com/progrock.html plus
https://qrp-labs.com/qlg1.html

cheaper but in kit and without enclosures.
I have both, and generally they are very good for the price. QRPLabs is
off by like ***@10MHz, didn't have the time to investigate why.



Subscribe to time nuts mailing list if you want to know more (*much*
more, possibly even too much) about timing:

www.leapsecond.com

Cheers!

Giuseppe Marullo
IW2JWW - JN45RQ

Post by Chuck McManis
Orrin,
I expect that if you continue in your journey in software radio you
will find that a solid 10Mhz reference to be a good thing to have in
general. (which you can use to drive the HackRF). I ended up getting
an RF signal generator from Crowd Supply
(https://www.crowdsupply.com/era-instruments/erasynth) which works
really well for this and I can use it with all of my SDRs in addtiion
to the HackRF.  A friend of mine recommended this one
(https://www.tindie.com/products/AnalysIR/10mhz-ocxo-frequency-standard-module-or-kit/)
which is basically $77 when you get all the parts and it is assembled)
so lower cost but equally movable from SDR to SDR.
Cheers,
--Chuck
Hello folks, have had my HackRF for about a week and am going thru
Michael's tutorials & other tutorials. Love this device.
Are the eBay items described as "New External TCXO clock PPM 0.1
for HackRF One GPS Applications GSM/WCDMA/LTE" for $10-12 the
appropriate part to buy? (noob here)
Or can some similar item be bought that has SMA jacks on it and
can be connected via cable to the jack on the rear of the HackRF?
The $10 clock looks like it'll require leaving the top half of the
case off, is why i ask.
At 434 MHz doing hackrf_transfer i'm getting 700 to 1000 hz drift
(downwards in freq) on a replayed CW signal, in ten minutes, which
(if i'm calculating this correctly) is 1.6 to 2.3 ppm.
I'm being careful to use the correct antenna on the HackRF, keep
gains low, and use low xmit power (2W) on my amateur transceiver
across the room (to record an rf_transfer). Possibly i should put
an attenuator on the 2W radio.
Thanks for comments.
Orrin in NE Calif.
_______________________________________________
HackRF-dev mailing list
https://pairlist9.pair.net/mailman/listinfo/hackrf-dev
<https://pairlist9.pair.net/mailman/listinfo/hackrf-dev>
_______________________________________________
HackRF-dev mailing list
https://pairlist9.pair.net/mailman/listinfo/hackrf-dev

[Phil Karn]

Post by Giuseppe Marullo
I was needing (and still searching) for a txco for the HackRf but I
would like something internal to the box, not sure about what is sold on
Ebay. Anyone could recommend something that surely would fit inside the
Standard enclosure?

I got this GPSDO. Works very well so far. It's not inside the box, but
the stability and near foolproof nature of GPS make it worthwhile.

https://www.ebay.com/itm/NEW-10MHz-Sinwave-PLL-GPSDO-GPS-DISCIPLINED-OSCILLATOR-adapter-GPS-ANT/262038924752

Perhaps some Nth generation HackRF should have one built in. It just
takes another antenna connector.

Phil

[Giuseppe Marullo]

Post by Phil Karn
I got this GPSDO. Works very well so far. It's not inside the box, but
the stability and near foolproof nature of GPS make it worthwhile.

Hello Phil,I just need something that would fit inside the box, I
already own two GPSDOs.
I would like something when I am portable, self contained.

That unit is nice, but I would stick to something that is supported by
LadyHeater, that one seems not.

I have another GPSDO from QRPLabs that is nice and cheaper but
apparently you have to trust it about being "in spec" no way to self
check accuracy.

Trimble instead does provide it through LadyHeater, and it is nice to
know how accurate it is after you power it up.

Should I upgrade, this time I would head for a Cesium clock!

[Giuseppe Marullo]

Ok, found:

http://www.nooelec.com/store/tiny-tcxo.html

20USD and will fit inside the enclosure.

Now I need to fix the broken PA. Component is obsolete and I ordered 3
from a  UK seller. The switches are only available in China for low qty
, any recommendation for a trusted source?


Giuseppe Marullo

IW2JWW - JN45RQ

[Phil Karn]

Post by Giuseppe Marullo
http://www.nooelec.com/store/tiny-tcxo.html
20USD and will fit inside the enclosure.

Here in San Diego the local microwave ham gang gets a supply of surplus
10 MHz TCXOs from old Qualcomm Omnitracs mobile units. It helps that
most of us are retired Qualcommers...

Phil