[App_rpt-users] Hamtronics receiver issue with AllStar RTCM
Joe Leikhim
rhyolite at leikhim.com
Wed Mar 30 23:42:35 UTC 2016
Skyler;
Here is a wideband VHF 136-156 MHz radio that will solve your ham club
problems for $35 each. If these were UHF I would be buying a bushel
full. You will need to get the programming software from Ritron. I think
it is free.
There are similar models with an enclosure, but for much more $$.
See the auction below on E-Bay:
Seller dale575
Ritron VHF Transceiver PCA, 136-156MHZ, 5 Watt, Model DTX-142-GCWD-I
http://www.ebay.com/itm/Ritron-VHF-Transceiver-PCA-136-156MHZ-5-Watt-Model-DTX-142-GCWD-I/191557457767?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D35389%26meid%3D4bbbffc700cc4aefba654c3ce0d394f8%26pid%3D100005%26rk%3D2%26rkt%3D6%26sd%3D401085025343
On 3/30/2016 12:11 PM, Skyler F wrote:
> Factory tuned from the factory. And I don't even have a signal
> generator / counter good for RF. We got one hamtronics board, and
> won't buy another until we get this one working.
>
> On Wed, Mar 30, 2016 at 10:08 AM, Joe Leikhim <rhyolite at leikhim.com
> <mailto:rhyolite at leikhim.com>> wrote:
>
> Were these receivers factory built and tuned or did individual
> club members build them? Either way, you might try others from the
> lot. If you have only a rudimentary signal generator and / or
> frequency counter, perhaps I can walk you through some "field
> expedient" steps over the phone.
>
>
> On 3/30/2016 12:01 PM, Skyler F wrote:
>> I don't have the test equipment to go through all of the dirty
>> Local Oscilator, SINAD, etc., so I will have to wait on that a
>> few weeks before the president of the club gets back in town.
>>
>> WHEN I bypassed the capacitor and resistor ( 1k and .03µ) , the
>> RTCM was able to calibrate squelch. The LED flashed several times
>> and then was steady. Maybe the capacitor is the wrong value.
>> There was no code on it, but based on the resistor code, the
>> value was correct.
>>
>> 73
>> Skyler
>>
>> On Mon, Mar 28, 2016 at 4:08 PM, Joe Leikhim
>> <rhyolite at leikhim.com <mailto:rhyolite at leikhim.com>> wrote:
>>
>> If you are using an external reference, you cannot make up
>> for the 2nd LO error if it is wildly off. There is an easy
>> SINAD related test in EIA-603 that is called Offset
>> Acceptance Bandwidth that would indicate if the IF were off
>> center. Things that could go wrong apart from simple
>> misalignment of the Quad Detector coil could include the LO
>> crystal being way off frequency, the IF filters being wrong
>> BW or off spec pass frequency.
>>
>> Given the symptoms, I am putting my money on a misadjusted
>> quad coil.
>>
>> Joe
>>
>> On 3/28/2016 5:06 PM, Bryan Fields wrote:
>>
>> On 3/28/16 2:51 PM, Joe Leikhim wrote:
>>
>> 1) Make sure the receiver First Local Oscillator is
>> adjusted correctly
>> on frequency. (Fo -10.700 MHz) Likewise the second LO
>> should be at
>> around 10.2450 MHz. The second LO is not adjustable,
>> so any minor error
>> would have to be made up with the TCXO U3. After this
>> second step:
>>
>> Then :
>>
>> 2) Make sure the general alignment is set properly,
>> especially the
>> discriminator coil T2 which responds to 10.7000 MHz
>> from a signal
>> generator, has an S curve response. In my experience
>> with these sort of
>> Quadrature Detector chips, you can get a false sense
>> of IF centering
>> where the noise component is suppressed. You might
>> try adjusting for
>> maximum noise first without the 10.7000 MHz signal.
>> Be careful you don't
>> jam the coil slug.
>>
>> These are both very good points i didn't consider. I
>> normally don't check my
>> reference oscillators in the hamtronics as they are using
>> an external 10MHz
>> source.
>>
>> You will want to check SINAD on it as well, if it's not
>> making spec (and those
>> hamtronics are very sensitive), something else is wrong
>> with it.
>>
>>
>> --
>> Joe Leikhim
>>
>>
>> Leikhim and Associates
>>
>> Communications Consultants
>>
>> Oviedo, Florida
>>
>> JLeikhim at Leikhim.com <mailto:JLeikhim at Leikhim.com>
>>
>> 407-982-0446 <tel:407-982-0446>
>>
>> WWW.LEIKHIM.COM <http://WWW.LEIKHIM.COM>
>>
>> _______________________________________________
>> App_rpt-users mailing list
>> App_rpt-users at ohnosec.org <mailto:App_rpt-users at ohnosec.org>
>> http://ohnosec.org/cgi-bin/mailman/listinfo/app_rpt-users
>>
>> To unsubscribe from this list please visit
>> http://ohnosec.org/cgi-bin/mailman/listinfo/app_rpt-users and
>> scroll down to the bottom of the page. Enter your email
>> address and press the "Unsubscribe or edit options button"
>> You do not need a password to unsubscribe, you can do it via
>> email confirmation. If you have trouble unsubscribing, please
>> send a message to the list detailing the problem.
>>
>>
>>
>>
>> --
>> Skyler Fennell
>> amsatnet.info <http://amsatnet.info>
>> KDØWHB
>> electricity440 at gmail.com <mailto:electricity440 at gmail.com>
>
> --
> Joe Leikhim
>
>
> Leikhim and Associates
>
> Communications Consultants
>
> Oviedo, Florida
>
> JLeikhim at Leikhim.com <mailto:JLeikhim at Leikhim.com>
>
> 407-982-0446 <tel:407-982-0446>
>
> WWW.LEIKHIM.COM <http://WWW.LEIKHIM.COM>
>
>
>
>
> --
> Skyler Fennell
> amsatnet.info <http://amsatnet.info>
> KDØWHB
> electricity440 at gmail.com <mailto:electricity440 at gmail.com>
--
Joe Leikhim
Leikhim and Associates
Communications Consultants
Oviedo, Florida
JLeikhim at Leikhim.com
407-982-0446
WWW.LEIKHIM.COM
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.keekles.org/pipermail/app_rpt-users/attachments/20160330/008b3569/attachment.html>
More information about the App_rpt-users
mailing list