Topics

Frequency calibration

Frank
 

I just finished a Hilltopper 40. It works well, but I'm a little fuzzy on the  frequency calibration.
I'm using a receiver to monitor  and am having trouble matching with the sidetone freq.
I noticed that when the correction is applied and the Cal jumper is removed the actual transmit
frequency is not the same as the annunciated frequency. T his does not sound right to me.
Also when using the alternate method with a freq counter, I assume that I'm monitoring the 
output at the BNC connector. What am I tuning to?
I've been inactive for many years and don't have any equipment anymore, so I'm enjoying
listening with the Hilltopper and brushing up on CW before I start having QSO's again.

Any information will be greatly appreciated
Thanks and 73"s    Frank  KB4VU
    

Charles W. Powell
 

Frank,

You may have to repeat the calibration several times to get the transmit frequency to match the specified frequency..  At least one of the units I built required a considerable amount of fiddling to get it right.  If you have a frequency counter you should be able to get it spot on.  If your counter doesn’t have a 50 ohm dummy load, I’d connect to a dummy load and then connect the counter to that either with clips or a “T” connection at the dummy load.  The finals will withstand a little no-load abuse but I don’t recommend it.

If you do any programming, I’d also change the timeout from 5 seconds to 10 seconds.  I did this on all the Hilltoppers I have built and it works fine, but I wouldn’t go more than 10 seconds.  I changed mine because the Elecraft T1 wasn’t fast enough to tune in 5 seconds.  The tuning timeout is set in the same part of the firmware.

Anyway, once you have the radio calibrated to the correct frequency (boot-up should be at 14060, I think) then set the receive offset using the fine trimmer cap.  Default offset frequency is 800 Hz, which is the default pitch of the sidetone.  This can be modified in firmware if you prefer something different, like 700 Hz or 600 Hz.  Supposedly the bandpass is at 800 Hz but I have no trouble with any of my Hilltoppers at 600 Hz.  If you modify the firmware, then it becomes necessary to recalibrate the receive offset, but it’s not necessary if you are happy at 800 Hz.

Does that all make sense to you? 

72,

Chas - NK8O


On Apr 7, 2019, at 7:41 PM, Frank <prpntfmr@...> wrote:

I just finished a Hilltopper 40. It works well, but I'm a little fuzzy on the  frequency calibration.
I'm using a receiver to monitor  and am having trouble matching with the sidetone freq.
I noticed that when the correction is applied and the Cal jumper is removed the actual transmit
frequency is not the same as the annunciated frequency. T his does not sound right to me.
Also when using the alternate method with a freq counter, I assume that I'm monitoring the 
output at the BNC connector. What am I tuning to?
I've been inactive for many years and don't have any equipment anymore, so I'm enjoying
listening with the Hilltopper and brushing up on CW before I start having QSO's again.

Any information will be greatly appreciated
Thanks and 73"s    Frank  KB4VU
    


Frank
 

Hi Charles,
  Thanks for the reply.
I was trying to use a communications receiver with an up converter that covers the hf bands, but it just is not 
working like I hoped it would.
I am using a dummy load and a freq counter clipped to the load and am getting good stable readings.
Whenever I adjust the offset in the cal mode and then go back to the normal mode, the actual transmit freq
does not match the annunciated freq. Is this right? When powered up it announces 7.030 but the actual
transmit freq is what was set in the cal mode.
Maybe I just don't understand what the cal process is doing. I just like to know what freq I am transmitting on.
Well it's late and I'm going to bed, tomorrow is another day.
Thanks again Charles
73's  Frank  Kb4VU

Charles W. Powell
 

Alright Frank.  Sorry - you did say HT-40.

72,

Chas - NK8O

On Apr 7, 2019, at 10:10 PM, Frank <prpntfmr@...> wrote:

Hi Charles,
  Thanks for the reply.
I was trying to use a communications receiver with an up converter that covers the hf bands, but it just is not 
working like I hoped it would.
I am using a dummy load and a freq counter clipped to the load and am getting good stable readings.
Whenever I adjust the offset in the cal mode and then go back to the normal mode, the actual transmit freq
does not match the annunciated freq. Is this right? When powered up it announces 7.030 but the actual
transmit freq is what was set in the cal mode.
Maybe I just don't understand what the cal process is doing. I just like to know what freq I am transmitting on.
Well it's late and I'm going to bed, tomorrow is another day.
Thanks again Charles
73's  Frank  Kb4VU

Dave Benson
 

Frank-

You want to be sure that the CAL jumper is already in place when you apply power.

After 5 seconds of RF output, the RF output will disappear and you restart that process.  As you do, the frequency will start up ever closer to your target frequency of 7030.00

When you're at the target, remove the CAL jumper and cycle power once more for normal operation.  Any mismatch in sidetone pitch between the Hilltopper and a second rig means the trimmer cap needs adjusting.

Hope this helps -   73, Dave- K1SWL


On Sun, Apr 7, 2019 at 10:10 PM Frank <prpntfmr@...> wrote:
I just finished a Hilltopper 40. It works well, but I'm a little fuzzy on the  frequency calibration.
I'm using a receiver to monitor  and am having trouble matching with the sidetone freq.
I noticed that when the correction is applied and the Cal jumper is removed the actual transmit
frequency is not the same as the annunciated frequency. T his does not sound right to me.
Also when using the alternate method with a freq counter, I assume that I'm monitoring the 
output at the BNC connector. What am I tuning to?
I've been inactive for many years and don't have any equipment anymore, so I'm enjoying
listening with the Hilltopper and brushing up on CW before I start having QSO's again.

Any information will be greatly appreciated
Thanks and 73"s    Frank  KB4VU
    

Dave Benson
 

Chas-

Thanks for your explanation- much more thorough than mine!

- Dave, K1SWL


On Sun, Apr 7, 2019 at 11:10 PM Frank <prpntfmr@...> wrote:
Hi Charles,
  Thanks for the reply.
I was trying to use a communications receiver with an up converter that covers the hf bands, but it just is not 
working like I hoped it would.
I am using a dummy load and a freq counter clipped to the load and am getting good stable readings.
Whenever I adjust the offset in the cal mode and then go back to the normal mode, the actual transmit freq
does not match the annunciated freq. Is this right? When powered up it announces 7.030 but the actual
transmit freq is what was set in the cal mode.
Maybe I just don't understand what the cal process is doing. I just like to know what freq I am transmitting on.
Well it's late and I'm going to bed, tomorrow is another day.
Thanks again Charles
73's  Frank  Kb4VU

Frank
 

Hi Dave and Charles,
   Thanks for the replies.
I got up this morning and calibrated the Hilltopper. I don't know what I was thinking yesterday, sometimes I
tend to over complicate things.
I just used the freq counter and it is within 2Hz on transmit. I used a little 300 mw transmitter I built to set
the rx offset. I will check that tonight when I can receive a good strong signal from W1AW.
I put in the sidetone volume and rx gain mods when I built it and it seems fine.
I really enjoyed building it and am going to order the 20 meter version and look forward to using them.

  Thanks again & 73's  Frank  KB4VU

Dave Benson
 

Frank-

Thanks for the feedback- glad it's squared away!

73- Dave, K1SWL


On Mon, Apr 8, 2019 at 6:57 AM Frank <prpntfmr@...> wrote:
Hi Dave and Charles,
   Thanks for the replies.
I got up this morning and calibrated the Hilltopper. I don't know what I was thinking yesterday, sometimes I
tend to over complicate things.
I just used the freq counter and it is within 2Hz on transmit. I used a little 300 mw transmitter I built to set
the rx offset. I will check that tonight when I can receive a good strong signal from W1AW.
I put in the sidetone volume and rx gain mods when I built it and it seems fine.
I really enjoyed building it and am going to order the 20 meter version and look forward to using them.

  Thanks again & 73's  Frank  KB4VU