RST 542 comm "help please"

Our club just purchased an ASK13 with a RST 542 installed. Unit is working great and we just need to add appropriate TX and RX crystals for 122.9 and 122.975. Jim at RST Engineering has been zero help. When I call him he just rants that "Jan Crystals" has the specs and wants me to only correspond via email with him. Of course he does nothing via email except denegrade me for not asking the right quesions of "Jans Crystals". "Jans" is more than willing to fabricate the proper crystals but they need to know 1) Pf Load 2) Ohms 3) Tolerance. Can anyone on this forum supply me with the above info? I would greatly appreciate it as I have reached a complete dead end with Mr. Jim of RST.

Thanks,
Lane

In your shoes, I'd look at the ones already installed and just buy ones of the appropriate frequency like them .

I do not have access to the radio this week as we had it delivered to Chilhowee for Octoberfest. I don't think the required info is on the crystal can.. I suppose I can have it bench tested to determine the specs. I am hoping some hacker might know the specs offhand.

Lane

On 10/3/2012 1:42 PM, wrote:
Our club just purchased an ASK13 with a RST 542 installed. Unit is
working great and we just need to add appropriate TX and RX crystals
for 122.9 and 122.975. Jim at RST Engineering has been zero help.
When I call him he just rants that "Jan Crystals" has the specs and
wants me to only correspond via email with him. Of course he does
nothing via email except denegrade me for not asking the right
quesions of "Jans Crystals". "Jans" is more than willing to
fabricate the proper crystals but they need to know 1) Pf Load 2)
Ohms 3) Tolerance. Can anyone on this forum supply me with the
above info? I would greatly appreciate it as I have reached a
complete dead end with Mr. Jim of RST.

Is this radio still legal?

Crystals weren't cheap when I had a radio that needed them. I suggest
buying a much newer used radio, with all the frequencies, that has support.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)

On Wednesday, October 3, 2012 6:28:06 PM UTC-4, wrote:
I do not have access to the radio this week as we had it delivered to Chilhowee for Octoberfest. I don't think the required info is on the crystal can. I suppose I can have it bench tested to determine the specs. I am hoping some hacker might know the specs offhand.



Lane

My goodness - why bother with a kit radio when a hand-held stay-strapped to the panel and connected to an external antenna would most likely be cheaper AND better? Just my $0.02 as a long-time electrical engineer ;-).

TA

Well, four crystals will cost $140. A handheld will cost $215 then $60 for microphone and it quits working two thirds through the day when the battery goes dead. This particular radio is working great, mounted in the panel so it is not a potential missile, has the microphone/speaker already set up and uses the same 12 volt battery we are already set up with in our other gliders.

I agree we would never install a six channel radio from scratch but this is a little different in that it is working beautifully but on the wrong frequency. I suppose we could just move the club to a field that uses 122.8!

I find it hard to defend this radio except for the fact that we have it and it is working. As I originally asked, we would like to know if anyone may have the specs on the crystals used in this radio.

Lane

"Eric Greenwell" wrote in message ...
On 10/3/2012 1:42 PM, wrote:
Our club just purchased an ASK13 with a RST 542 installed. Unit is
working great and we just need to add appropriate TX and RX crystals
for 122.9 and 122.975. Jim at RST Engineering has been zero help.
When I call him he just rants that "Jan Crystals" has the specs and
wants me to only correspond via email with him. Of course he does
nothing via email except denegrade me for not asking the right
quesions of "Jans Crystals". "Jans" is more than willing to
fabricate the proper crystals but they need to know 1) Pf Load 2)
Ohms 3) Tolerance. Can anyone on this forum supply me with the
above info? I would greatly appreciate it as I have reached a
complete dead end with Mr. Jim of RST.

Is this radio still legal?

Lane,

Typically this type of a units have a frequency tripler circuit. If that is
the case the crystal is cut at 1/3 the output frequency. To find out check
frequency of the 122.8 crystal to see is 40.933. If it is, the tolerance is
only 0.001%. (10 parts per million.) If it is a 122.8 crystal the tolerance
is 0.003%

It has been too long since my electronics classes (50+ years) for me to be
able to derive the Pf Load and Ohms from the schematic diagram.
http://www.rst-engr.com/rst/support/RST-542.pdf

I'm sorry that I can't be more helpful.

Eric,

The simple answer to your question is "No". As of Jan 1, 1997 aircraft
radios must be type certified. The frequency accuracy to meet the 25 Khz
channel spacing is 0.003%. Commercially built radios such as the Genave
Alpha series are no longer legal. The RST-542 and Genave are similar in
design. Radios built today have a sticker indicating that they are FCC
certified.

Wayne

you are right about the genave 10, but not the 100 or certain models
of the betea. There is a website easily googled that you can check if
the radio is legal. If not, I would buy an older Icom A21 and use the
akaline battery pack which will run 40 hrs on 10 AA's

The FCC currently requires that an aircraft radio has either 720 or 760
channels with 25 KHz spacing. As a result such radios as the 10 channel
Genave Alpha 10 are not on the obsolete radio list, nor are any other radio
with less than 720 channels. They are obsolete by definition. There is a
link that identifies obsolete 720 & 760 radios on the following web page:
http://wireless.fcc.gov/services/ind...craft_stations

Wayne




"aerodyne" wrote in message
...

you are right about the genave 10, but not the 100 or certain models
of the betea. There is a website easily googled that you can check if
the radio is legal. If not, I would buy an older Icom A21 and use the
akaline battery pack which will run 40 hrs on 10 AA's

On Thursday, October 4, 2012 11:51:25 AM UTC-5, Wayne wrote:

The FCC currently requires that an aircraft radio has either 720 or 760 channels with 25 KHz spacing. As a result such radios as the 10 channel Genave Alpha 10 are not on the obsolete radio list, nor are any other radio with less than 720 channels. They are obsolete by definition. There is a link that identifies obsolete 720 & 760 radios on the following web page:
http://wireless.fcc.gov/services/ind...craft_stations

Wayne

Drifted a bit from the OPs question. But since it is going this way...

The link that Wayne provided states that the requirement is 30 ppm, and that THE MAJORITY of radios that meet this have either 720 or 760 channels. It does not say that "If you don't have 720 channels or more, it is not to be used for transmiting." It does say that if you have an older radio, it can be updated, but must be done with an FCC Type accepted upgrade kit. You cannot do it by putting in a better crystal, etc. Unless that is the FCC Type Accpeted method for that radio.

At the bottom is a list of Unacceptable Radios. There are many less than 720 channel radios on this list, so I am not willing to accept the "by definition, if it has less than 720 channels, it is obsolete" interpretation. RST radios are not on the list. If it was designed to meet the 30 ppm, why would it not be a legal for use now radio?

Lane, there is at least one RST 6 channel radio here locally. I will check with the owner and see what info is in the manual and maybe have him take a look inside the radio.

Steve Leonard