VK Logger Ham Radio Forum Archive

Hi all

Has anyone played with these, available on eBay?



Just wondering how they might go as a 10MHz reference for a transverter LO.

Phase noise - excellent
Stability - seems ok
Price - good!

USD$52 delivered ex China

One quarter of the price of a rubidium standard.

Comments?

gday adam this is the one I used on my 10 ghz trvtr and also will use on 5.7 ghz, they work well after 10 min warm up to stabilize. cheers . mark VK2AMS http://cgi.ebay.com.au/ws/eBayISAPI.dll ... K:MEWNX:IT

Also, you won't go far wrong with an Isotemp 134-10 - they are a highly regarded OCXO. Plenty on eBay normally for good prices.

73 - Rob VK2GOM / G0MOH

Hi

I second Rob's comment re the Isotemp 134-10. Very stable. I use it for my 1.2GHz, 2.4GHz, 3.4GHz and 5.7GHz transverters. However, they are stable enough for 10GHz and probably 24GHz (not tried). They get pretty close to the final frequency after 10 minutes from switch on. After about 40 minutes there is no noticeable drift when listening to SSB on 5.7GHz. All my microwave contacts are done from portable locations so I have a 12v SLA battery in my transverter which powers the 10Mhz oscillator. This is turned on when I leave home so the transverter is ready to go when I arrive on site.

73
Iain

I've picked up a few OCXO's that all perform admirably after half an hour warm-up. When compared to the output of a trimble thunderbolt GPS reference it's quite stable and well good enough for field day use. On a Lissajous display the two signals create a perfect circle that closes then opens again over a 120 second period. Not sure how to explain that in technical terms but I think that quite a good indication.

Thanks guys, have checked them all out, and most of these OCXO seem to have similar specs.

I can see why Rob likes the Isotemp... James Miller G3RUH has produced a GPSDO using the Isotemp 134-10 as the VCO.
http://www.jrmiller.demon.co.uk/project ... manual.pdf
That offers a good upgrade path. Start with the OCXO and add the GPS lock later, if required.

Looking at this Isotemp 134-10 listing, the seller has marked +volts, GND, and O/P.
http://cgi.ebay.com.au/10MHZ-ISOTEMP-Re ... 0489162873
Is he suggesting the Reference pin 2 is not normally used?

Adam
The Isotemp 131-100 that I have does not use the reference pin. There is a 3mm hole in the case which is covered by the label. Inside this hole. mounted on the PCB inside the case is a very small trimpot for putting the osc. on frequency. The hole is underneath the date.

73 Bruce VK2EM

Hi

The other pins on the 134-10 are a reference voltage output which you can connect to one side of a pot, a frequency adjust input which you connect to the wiper of the pot. The other side of the pot goes to ground. Use a 10k ten-turn pot. The last pin is an output which indicates when the oven reaches it's correct temperature (> 3.5v).

Pins are (from left to right):
+12v
10MHz Out
Ground
Freq. Adj. In
Ref. Voltage Out
Oven Monitor Out

73
Iain