Topics

My Hilltopper 40 is alive (sort of)

Gary Kohtala
 


I finished my Hilltopper 40 last night. It really looks good. When I put power to it I got a blast of CW as expected. Hitting the paddles brought forth some 
beautiful code.  Power output seems to be more than adequate. I was spotted several times on RBN, even as far west as Utah. I was running my 135' OCFD.
Unfortunately, as others have reported, the CW sidetone and freq readout are excessively loud, so loud as to cause my tinnitus to ramp up. I will most certainly
be changing that resistor in order to put the side tone at a more pleasant level.   Tuning the band brought some CW signals. My first impression of the receiver
was that the sensitivity was way low. Also the receiver audio is unacceptably low. Having the gain wide open brings very low audio to the headphones. I tried
several pairs and settled on the best one I had.  I actually get more audio out of my Cricket 80a.  One thing I did notice is that strong signals jumped up
noticeably loud in the headphones and are quite copiable, however weak signals were very difficult to copy much of the time. I wish there were a few more decibels of AF
to spare. Then I could back off on the receiver gain for a comfortable experience.    Now there is the distinct possibility that I have a problem. I am going to
go back through and reheat all of the solder joints in hopes of uncovering a cold one.  I'd like to get a first impression of the Hilltoppers from others that have
built and use them. I must say that I absolutely love the built in keyer. It works exceptionally well with my single paddle. And I really appreciate the CW frequency
readout. That's very innovative. If anyone has any suggestions as to what to look at and where, I'd appreciate hearing from you.  I expected to end up with adequate
receiver audio but alas, have not. More than likely it is my problem. Thanks for any suggestions.

Best regards,

Gary, K7EK

Radcliff, KY (EM77at)

Charles W. Powell
 

Gary, I don't know how to quantify this exactly.  I found my Hilltopper radios have all had minimal background noise.  If you want to increase the audio output of the rig, you can DECREASE the value of R9.  I actually increased it because the rig to me is so boisterous, for the most part, that I wanted it a little quieter and to make the audio chip less prone to overload. I hear a fairly comfortable signal at -107 dBm, which is generally about where the noise floor sits on any given band on any given fairly quiet day.  R9 is 22K - try a 10K or what-have-you, or if you don't want to remove it, put another resistor in parallel on the bottom of the board.  Another 22K on the bottom will give you about 11K all together.  (I went up to 100K on mine, but I might end up modifying that after I use it in the field with that configuration.

I also use earbuds with this radio because they are more efficient than most headphones.

72,

Chas

Gary Kohtala
 

Hmmm.. Thanks Chas. What I would really like to do is increase receiver audio amplitude and decrease sidetone amplitude.
It sounds like both are tied to R9. The sidetone is so loud that it hurts my ears and makes my tinnitus kick up.
I did some reheating of solder joints but no noticeable change.  I did notice on some louder signals like the RTTY that's
all over 40m causes the receiver to go into a screeching mode that blows my ears out. I am not sure what that is but 
powering off and back on makes it go away. Guess the RTTY is often so loud that it overloads the receiver. Anyway, 
thanks for your suggestions.  I still have to build my Hilltopper 20. Will be interesting to compare the receiver 
performance in both. Have a great weekend.

Best regards,

Gary, K7EK

--



On Friday, February 8, 2019, 08:55:55 PM EST, Charles W. Powell via Groups.Io <doctorcwp@...> wrote:


Gary, I don't know how to quantify this exactly.  I found my Hilltopper radios have all had minimal background noise.  If you want to increase the audio output of the rig, you can DECREASE the value of R9.  I actually increased it because the rig to me is so boisterous, for the most part, that I wanted it a little quieter and to make the audio chip less prone to overload. I hear a fairly comfortable signal at -107 dBm, which is generally about where the noise floor sits on any given band on any given fairly quiet day.  R9 is 22K - try a 10K or what-have-you, or if you don't want to remove it, put another resistor in parallel on the bottom of the board.  Another 22K on the bottom will give you about 11K all together.  (I went up to 100K on mine, but I might end up modifying that after I use it in the field with that configuration.

I also use earbuds with this radio because they are more efficient than most headphones.

72,

Chas

Charles W. Powell
 

R8 is sidetone, R9 is receiver audio.  Believe me, I have dissected that part of the radio trying too get my HT-30 to work!  Fortunately R8 is easiest one to get to.  Try a 100K resistor there.  If you successfully remove R8, move it to the bottom of the board and tack it in parallel with R9.  See what you think.

Yes, the screech mode happens when the frontend is overloaded.  It sets the radio into self-oscillation.  Tonight wasn’t a good night to be listening.  I have a neighbor 1 mile away who runs QROO and loves low band CW and RTTY contests.

73,

Chas - NK8O

On Feb 8, 2019, at 11:35 PM, Gary Kohtala via Groups.Io <gary.k7ek@...> wrote:

Hmmm.. Thanks Chas. What I would really like to do is increase receiver audio amplitude and decrease sidetone amplitude.
It sounds like both are tied to R9. The sidetone is so loud that it hurts my ears and makes my tinnitus kick up.
I did some reheating of solder joints but no noticeable change.  I did notice on some louder signals like the RTTY that's
all over 40m causes the receiver to go into a screeching mode that blows my ears out. I am not sure what that is but 
powering off and back on makes it go away. Guess the RTTY is often so loud that it overloads the receiver. Anyway, 
thanks for your suggestions.  I still have to build my Hilltopper 20. Will be interesting to compare the receiver 
performance in both. Have a great weekend.

Best regards,

Gary, K7EK

--



On Friday, February 8, 2019, 08:55:55 PM EST, Charles W. Powell via Groups.Io <doctorcwp@...> wrote:


Gary, I don't know how to quantify this exactly.  I found my Hilltopper radios have all had minimal background noise.  If you want to increase the audio output of the rig, you can DECREASE the value of R9.  I actually increased it because the rig to me is so boisterous, for the most part, that I wanted it a little quieter and to make the audio chip less prone to overload. I hear a fairly comfortable signal at -107 dBm, which is generally about where the noise floor sits on any given band on any given fairly quiet day.  R9 is 22K - try a 10K or what-have-you, or if you don't want to remove it, put another resistor in parallel on the bottom of the board.  Another 22K on the bottom will give you about 11K all together.  (I went up to 100K on mine, but I might end up modifying that after I use it in the field with that configuration.

I also use earbuds with this radio because they are more efficient than most headphones.

72,

Chas

WA0ITP
 

GM Gary and Chas,

It appears that you could decrease the value of C24 or increase the size of R8, or both. These should affect the sidetone volume only.  Suggest abt 100p to start for C24 and/or ~ 47k for R8.    Hope this helps.

On the screeching, I've not heard anything like this on my HT20, but it does sound like a stage is being driven into oscillation. Suggest listening at lower volume until finding a signal you want to hear better, then increasing the gain.
Also check the orientation, continuity, and solder joints of the front end diodes, they might help with the screech.

GL 

72 WAØITP
I love this radio stuff.
www.wa0itp.com
www.4sqrp.com
On 2/8/2019 11:35 PM, Gary Kohtala via Groups.Io wrote:

Hmmm.. Thanks Chas. What I would really like to do is increase receiver audio amplitude and decrease sidetone amplitude.
It sounds like both are tied to R9. The sidetone is so loud that it hurts my ears and makes my tinnitus kick up.
I did some reheating of solder joints but no noticeable change.  I did notice on some louder signals like the RTTY that's
all over 40m causes the receiver to go into a screeching mode that blows my ears out. I am not sure what that is but 
powering off and back on makes it go away. Guess the RTTY is often so loud that it overloads the receiver. Anyway, 
thanks for your suggestions.  I still have to build my Hilltopper 20. Will be interesting to compare the receiver 
performance in both. Have a great weekend.

Best regards,

Gary, K7EK

--



On Friday, February 8, 2019, 08:55:55 PM EST, Charles W. Powell via Groups.Io <doctorcwp@...> wrote:


Gary, I don't know how to quantify this exactly.  I found my Hilltopper radios have all had minimal background noise.  If you want to increase the audio output of the rig, you can DECREASE the value of R9.  I actually increased it because the rig to me is so boisterous, for the most part, that I wanted it a little quieter and to make the audio chip less prone to overload. I hear a fairly comfortable signal at -107 dBm, which is generally about where the noise floor sits on any given band on any given fairly quiet day.  R9 is 22K - try a 10K or what-have-you, or if you don't want to remove it, put another resistor in parallel on the bottom of the board.  Another 22K on the bottom will give you about 11K all together.  (I went up to 100K on mine, but I might end up modifying that after I use it in the field with that configuration.

I also use earbuds with this radio because they are more efficient than most headphones.

72,

Chas

Charles W. Powell
 

I can consistently drive all of my HTs into oscillation with my signal generator. at about -73 dBm (50 microvolts) it happens with all three.  Comes with the territory and it’s generally not a big problem.  If you turn down the RF gain for hunting it generally won’t happen.

72,

Chas.

On Feb 9, 2019, at 10:38 AM, WA0ITP <wa0itp@...> wrote:

GM Gary and Chas,

It appears that you could decrease the value of C24 or increase the size of R8, or both. These should affect the sidetone volume only.  Suggest abt 100p to start for C24 and/or ~ 47k for R8.    Hope this helps.

On the screeching, I've not heard anything like this on my HT20, but it does sound like a stage is being driven into oscillation. Suggest listening at lower volume until finding a signal you want to hear better, then increasing the gain.
Also check the orientation, continuity, and solder joints of the front end diodes, they might help with the screech.

GL 

72 WAØITP
I love this radio stuff.
www.wa0itp.com
www.4sqrp.com
On 2/8/2019 11:35 PM, Gary Kohtala via Groups.Io wrote:
Hmmm.. Thanks Chas. What I would really like to do is increase receiver audio amplitude and decrease sidetone amplitude.
It sounds like both are tied to R9. The sidetone is so loud that it hurts my ears and makes my tinnitus kick up.
I did some reheating of solder joints but no noticeable change.  I did notice on some louder signals like the RTTY that's
all over 40m causes the receiver to go into a screeching mode that blows my ears out. I am not sure what that is but 
powering off and back on makes it go away. Guess the RTTY is often so loud that it overloads the receiver. Anyway, 
thanks for your suggestions.  I still have to build my Hilltopper 20. Will be interesting to compare the receiver 
performance in both. Have a great weekend.

Best regards,

Gary, K7EK

--



On Friday, February 8, 2019, 08:55:55 PM EST, Charles W. Powell via Groups.Io <doctorcwp@...> wrote:


Gary, I don't know how to quantify this exactly.  I found my Hilltopper radios have all had minimal background noise.  If you want to increase the audio output of the rig, you can DECREASE the value of R9.  I actually increased it because the rig to me is so boisterous, for the most part, that I wanted it a little quieter and to make the audio chip less prone to overload. I hear a fairly comfortable signal at -107 dBm, which is generally about where the noise floor sits on any given band on any given fairly quiet day.  R9 is 22K - try a 10K or what-have-you, or if you don't want to remove it, put another resistor in parallel on the bottom of the board.  Another 22K on the bottom will give you about 11K all together.  (I went up to 100K on mine, but I might end up modifying that after I use it in the field with that configuration.

I also use earbuds with this radio because they are more efficient than most headphones.

72,

Chas

Dave Benson
 

Thanks, Chas!

 The AF amp (NE5532) is hitting the rails on strong signals. It does this at its specified max output current of 38 mA. When it does so, feedback conditions are no longer being met- it's unstable.  Turning the gain down stops the screech, as you point out.

Several possible fixes:   1) a beefier op-amp. I'm fond of the TLV2462 (80 mA out) but it's a 5V device and more expensive.  There may well be others- I haven't pursued it. 
2) A back-to-back Schottky diode pair across the 1M resistor in the AF final amp should prevent the screech....and introduce distortion on strong signals.

73- Dave

 

On Sat, Feb 9, 2019 at 5:43 PM Charles W. Powell via Groups.Io <doctorcwp=yahoo.com@groups.io> wrote:
I can consistently drive all of my HTs into oscillation with my signal generator. at about -73 dBm (50 microvolts) it happens with all three.  Comes with the territory and it’s generally not a big problem.  If you turn down the RF gain for hunting it generally won’t happen.

72,

Chas.

On Feb 9, 2019, at 10:38 AM, WA0ITP <wa0itp@...> wrote:

GM Gary and Chas,

It appears that you could decrease the value of C24 or increase the size of R8, or both. These should affect the sidetone volume only.  Suggest abt 100p to start for C24 and/or ~ 47k for R8.    Hope this helps.

On the screeching, I've not heard anything like this on my HT20, but it does sound like a stage is being driven into oscillation. Suggest listening at lower volume until finding a signal you want to hear better, then increasing the gain.
Also check the orientation, continuity, and solder joints of the front end diodes, they might help with the screech.

GL 

72 WAØITP
I love this radio stuff.
www.wa0itp.com
www.4sqrp.com
On 2/8/2019 11:35 PM, Gary Kohtala via Groups.Io wrote:
Hmmm.. Thanks Chas. What I would really like to do is increase receiver audio amplitude and decrease sidetone amplitude.
It sounds like both are tied to R9. The sidetone is so loud that it hurts my ears and makes my tinnitus kick up.
I did some reheating of solder joints but no noticeable change.  I did notice on some louder signals like the RTTY that's
all over 40m causes the receiver to go into a screeching mode that blows my ears out. I am not sure what that is but 
powering off and back on makes it go away. Guess the RTTY is often so loud that it overloads the receiver. Anyway, 
thanks for your suggestions.  I still have to build my Hilltopper 20. Will be interesting to compare the receiver 
performance in both. Have a great weekend.

Best regards,

Gary, K7EK

--



On Friday, February 8, 2019, 08:55:55 PM EST, Charles W. Powell via Groups.Io <doctorcwp@...> wrote:


Gary, I don't know how to quantify this exactly.  I found my Hilltopper radios have all had minimal background noise.  If you want to increase the audio output of the rig, you can DECREASE the value of R9.  I actually increased it because the rig to me is so boisterous, for the most part, that I wanted it a little quieter and to make the audio chip less prone to overload. I hear a fairly comfortable signal at -107 dBm, which is generally about where the noise floor sits on any given band on any given fairly quiet day.  R9 is 22K - try a 10K or what-have-you, or if you don't want to remove it, put another resistor in parallel on the bottom of the board.  Another 22K on the bottom will give you about 11K all together.  (I went up to 100K on mine, but I might end up modifying that after I use it in the field with that configuration.

I also use earbuds with this radio because they are more efficient than most headphones.

72,

Chas


Charles W. Powell
 

I think I will try the alternate op amp for the final audio of the radio.  I found TLV2462 x5 on ebay for $8.  Of course they may be worthless knockoffs, but I’m not out a huge amount if they don’t work.  I will report back on this.  The pin-out and voltage requirements otherwise look identical to the NE5532.

72,

Chas - NK9O

On Feb 10, 2019, at 5:18 AM, Dave Benson <davek1swl@...> wrote:

Thanks, Chas! 

 The AF amp (NE5532) is hitting the rails on strong signals. It does this at its specified max output current of 38 mA. When it does so, feedback conditions are no longer being met- it's unstable.  Turning the gain down stops the screech, as you point out.

Several possible fixes:   1) a beefier op-amp. I'm fond of the TLV2462 (80 mA out) but it's a 5V device and more expensive.  There may well be others- I haven't pursued it.  
2) A back-to-back Schottky diode pair across the 1M resistor in the AF final amp should prevent the screech....and introduce distortion on strong signals.

73- Dave

 

On Sat, Feb 9, 2019 at 5:43 PM Charles W. Powell via Groups.Io <doctorcwp=yahoo.com@groups.io> wrote:
I can consistently drive all of my HTs into oscillation with my signal generator. at about -73 dBm (50 microvolts) it happens with all three.  Comes with the territory and it’s generally not a big problem.  If you turn down the RF gain for hunting it generally won’t happen.

72,

Chas.

On Feb 9, 2019, at 10:38 AM, WA0ITP <wa0itp@...> wrote:

GM Gary and Chas,

It appears that you could decrease the value of C24 or increase the size of R8, or both. These should affect the sidetone volume only.  Suggest abt 100p to start for C24 and/or ~ 47k for R8.    Hope this helps.

On the screeching, I've not heard anything like this on my HT20, but it does sound like a stage is being driven into oscillation. Suggest listening at lower volume until finding a signal you want to hear better, then increasing the gain. 
Also check the orientation, continuity, and solder joints of the front end diodes, they might help with the screech.

GL 
 
72 WAØITP
I love this radio stuff.
www.wa0itp.com
www.4sqrp.com
On 2/8/2019 11:35 PM, Gary Kohtala via Groups.Io wrote:
Hmmm.. Thanks Chas. What I would really like to do is increase receiver audio amplitude and decrease sidetone amplitude.
It sounds like both are tied to R9. The sidetone is so loud that it hurts my ears and makes my tinnitus kick up.
I did some reheating of solder joints but no noticeable change.  I did notice on some louder signals like the RTTY that's
all over 40m causes the receiver to go into a screeching mode that blows my ears out. I am not sure what that is but 
powering off and back on makes it go away. Guess the RTTY is often so loud that it overloads the receiver. Anyway, 
thanks for your suggestions.  I still have to build my Hilltopper 20. Will be interesting to compare the receiver 
performance in both. Have a great weekend.

Best regards,

Gary, K7EK

--



On Friday, February 8, 2019, 08:55:55 PM EST, Charles W. Powell via Groups.Io <doctorcwp@...> wrote: 


Gary, I don't know how to quantify this exactly.  I found my Hilltopper radios have all had minimal background noise.  If you want to increase the audio output of the rig, you can DECREASE the value of R9.  I actually increased it because the rig to me is so boisterous, for the most part, that I wanted it a little quieter and to make the audio chip less prone to overload. I hear a fairly comfortable signal at -107 dBm, which is generally about where the noise floor sits on any given band on any given fairly quiet day.  R9 is 22K - try a 10K or what-have-you, or if you don't want to remove it, put another resistor in parallel on the bottom of the board.  Another 22K on the bottom will give you about 11K all together.  (I went up to 100K on mine, but I might end up modifying that after I use it in the field with that configuration.

I also use earbuds with this radio because they are more efficient than most headphones.

72,

Chas