I used my HTX-252 for the first time last weekend, and was
told that the audio was muffled although intelligible. Anyone know of a cure
for this muffled effect?

Cal-

I also have one of the bargain HTX-252 transceivers. I had read here about the
low audio and expected that would be a problem for me as well.

What I found was that the radio has no microphone gain adjustment, just a peak
deviation adjustment, as has been discussed here. Checking modulation, I found
that it was working well with no further adjustment needed. It is just set up
to REQUIRE close talking to the microphone, and some people prefer to hold it
several inches away. The microphone element is located at the top front of the
microphone, so holding that spot within an inch of your mouth should give good
modulation without having to shout. During my testing I tried a couple other
similar microphone elements with no increase in sensitivity.

The only reason I can think of that would cause muffled audio, would be if
someone had gone into either the microphone or the transceiver's microphone
amplifier circuits, and tried to "fix" it! If you recently purchased yours and
it was the last one in the store, it is possible that it had been returned by a
previous customer. As such, it might have a factory defect, or it might have
been returned because of the failed attempt at improving it. Either way, your
best bet may be to take it back to a Radio Shack store along with the receipt,
and have them send it in for repair. I believe their technicians have seen
most of the problems many times, and should make fast work of a repair.

Per someone's suggestion here, I found service information for the Albrecht
AE-540 at http://www.albrecht-electronic.de/se...eurfunk/AE540/ which
appears to be almost exactly the same as the HTX-252. Following the microphone
audio path, there is a 2200 Ohm resistor that leads to the push-to-talk
circuit. That circuit is AC coupled by a 0.1 microfarad capacitor, to another
2200 Ohm resister, that connects to the audio processor integrated circuit. I
believe some increase in microphone gain would be achieved if that second 2200
Ohm resistor were shorted. However, the frequency response might also be
affected. As a wild guess, I would look on the bottom side of the main circuit
board for that 2200 Ohm resistor. It is located near a shield as I recall. If
you find it has been shorted, try un-shorting it and see if the audio improves.

By the way, I also checked www.mods.dk and found a suggestion to remove a
certain one microfarad capacitor to speed-up the radio's squelch response. I
decided that it was a better idea to replace it with a 0.1 microfarad
capacitor. As far as I can tell, that is the only worthwhile modification the
radio needs.


73, Fred, K4DII

I used my HTX-252 for the first time last weekend, and was
told that the audio was muffled although intelligible. Anyone know of a cure
for this muffled effect?

Cal-

I also have one of the bargain HTX-252 transceivers. I had read here about the
low audio and expected that would be a problem for me as well.

What I found was that the radio has no microphone gain adjustment, just a peak
deviation adjustment, as has been discussed here. Checking modulation, I found
that it was working well with no further adjustment needed. It is just set up
to REQUIRE close talking to the microphone, and some people prefer to hold it
several inches away. The microphone element is located at the top front of the
microphone, so holding that spot within an inch of your mouth should give good
modulation without having to shout. During my testing I tried a couple other
similar microphone elements with no increase in sensitivity.

The only reason I can think of that would cause muffled audio, would be if
someone had gone into either the microphone or the transceiver's microphone
amplifier circuits, and tried to "fix" it! If you recently purchased yours and
it was the last one in the store, it is possible that it had been returned by a
previous customer. As such, it might have a factory defect, or it might have
been returned because of the failed attempt at improving it. Either way, your
best bet may be to take it back to a Radio Shack store along with the receipt,
and have them send it in for repair. I believe their technicians have seen
most of the problems many times, and should make fast work of a repair.

Per someone's suggestion here, I found service information for the Albrecht
AE-540 at http://www.albrecht-electronic.de/se...eurfunk/AE540/ which
appears to be almost exactly the same as the HTX-252. Following the microphone
audio path, there is a 2200 Ohm resistor that leads to the push-to-talk
circuit. That circuit is AC coupled by a 0.1 microfarad capacitor, to another
2200 Ohm resister, that connects to the audio processor integrated circuit. I
believe some increase in microphone gain would be achieved if that second 2200
Ohm resistor were shorted. However, the frequency response might also be
affected. As a wild guess, I would look on the bottom side of the main circuit
board for that 2200 Ohm resistor. It is located near a shield as I recall. If
you find it has been shorted, try un-shorting it and see if the audio improves.

By the way, I also checked www.mods.dk and found a suggestion to remove a
certain one microfarad capacitor to speed-up the radio's squelch response. I
decided that it was a better idea to replace it with a 0.1 microfarad
capacitor. As far as I can tell, that is the only worthwhile modification the
radio needs.


73, Fred, K4DII

"Fred McKenzie" wrote in message
...
I used my HTX-252 for the first time last weekend, and was
told that the audio was muffled although intelligible. Anyone know of a
cure
for this muffled effect?

Cal-

I also have one of the bargain HTX-252 transceivers. I had read here
about the
low audio and expected that would be a problem for me as well.

What I found was that the radio has no microphone gain adjustment, just a
peak
deviation adjustment, as has been discussed here. Checking modulation, I
found
that it was working well with no further adjustment needed. It is just
set up
to REQUIRE close talking to the microphone, and some people prefer to hold
it
several inches away. The microphone element is located at the top front
of the
microphone, so holding that spot within an inch of your mouth should give
good
modulation without having to shout. During my testing I tried a couple
other
similar microphone elements with no increase in sensitivity.

The only reason I can think of that would cause muffled audio, would be if
someone had gone into either the microphone or the transceiver's
microphone
amplifier circuits, and tried to "fix" it! If you recently purchased
yours and
it was the last one in the store, it is possible that it had been returned
by a
previous customer. As such, it might have a factory defect, or it might
have
been returned because of the failed attempt at improving it. Either way,
your
best bet may be to take it back to a Radio Shack store along with the
receipt,
and have them send it in for repair. I believe their technicians have
seen
most of the problems many times, and should make fast work of a repair.

Per someone's suggestion here, I found service information for the
Albrecht
AE-540 at http://www.albrecht-electronic.de/se...eurfunk/AE540/
which
appears to be almost exactly the same as the HTX-252. Following the
microphone
audio path, there is a 2200 Ohm resistor that leads to the push-to-talk
circuit. That circuit is AC coupled by a 0.1 microfarad capacitor, to
another
2200 Ohm resister, that connects to the audio processor integrated
circuit. I
believe some increase in microphone gain would be achieved if that second
2200
Ohm resistor were shorted. However, the frequency response might also be
affected. As a wild guess, I would look on the bottom side of the main
circuit
board for that 2200 Ohm resistor. It is located near a shield as I
recall. If
you find it has been shorted, try un-shorting it and see if the audio
improves.

By the way, I also checked www.mods.dk and found a suggestion to remove a
certain one microfarad capacitor to speed-up the radio's squelch response.
I
decided that it was a better idea to replace it with a 0.1 microfarad
capacitor. As far as I can tell, that is the only worthwhile modification
the
radio needs.


73, Fred, K4DII


Thanks for the tips on the 252... I'll store them for future use. I bought 2
of them brand new, never had them out of the box yet. I had set them aside
awaiting to use them for a project, then found they weren't able to be used
for it. Now too late to return them, as it was past 30 days. ALL have
extended warranty. If anyone should be interested in one of them or both,
I'll sell em for what I got in them plus shipping.

L.

muffled? Don't know about that one.
I just cranked rv2 1/2 turn then backed off the dtmf pot in the mike
so the tones were clear and all my audio reports are
"sounds Marvelous"
I use It as my Primary NCS Radio

KC*VIF

Greg Z
to thine own sound be true

greg z wrote:
: muffled? Don't know about that one.
: I just cranked rv2 1/2 turn then backed off the dtmf pot in the mike
: so the tones were clear and all my audio reports are
: "sounds Marvelous"
: I use It as my Primary NCS Radio

I have one too. I adjusted the pot on the motherboard and still got poor
audio reports. I kept asking and finally got what I hope is a better
understanding of what it sounds like.

What most folks are calling "muffled" may actually be a high bass response
(or a low high end response)

Asking hams for opionions on audio quality is dubious at best. I've heard
a mobile fade almost completely out and get a report of "You're starting
to break up" more times than I can count. The same with audio quality.
Many hams don't listen that well, and as long as they can hear and
understand you then you "sound great"

Richard in Boston, MA, USA
N1JDU

I have one too. I adjusted the pot on the motherboard and still got poor
audio reports. I kept asking and finally got what I hope is a better
understanding of what it sounds like.

Richard in Boston, MA, USA
N1JDU

------------------------------
Seriously Richard my 252 sounds great !!!!
I've listened to it myself.
The key for me was to get the pot up, hold mike 3.5'' away at a 45deg.angle and
to remember the element is near the top of the mike. The tough part is getting
used to talking on each radio a little differently. A ht with a good pair of
hi-fi cans monitoring the input or
simplex is a great tool in getting this one down. Many schematics for simple,
easy to build deviation meters are to be had on the web.
KC*VIF
Greg Z
to thine own sound be true

I'd like to thank everyone who responded to my inquiry regarding the "muffled"
transmit audio on my HTX-252! There is a lot of very useful information among
those responses. I think I'll try listening to myself first.
FWIW, I'd bought the rig used, and, not being a 2M FM guy, only used it
this past weekend on a trip to my 45th high school reunion. The report came
from a guy I'd known in high school.
Again, thank you all!
73
Cal K4JSI

I'd like to thank everyone who responded to my inquiry regarding the "muffled"
transmit audio on my HTX-252! There is a lot of very useful information among
those responses. I think I'll try listening to myself first.
FWIW, I'd bought the rig used, and, not being a 2M FM guy, only used it
this past weekend on a trip to my 45th high school reunion. The report came
from a guy I'd known in high school.
Again, thank you all!
73
Cal K4JSI

On 30 Jul 2003 05:37:41 GMT, ospam (greg z) wrote:



------------------------------
Seriously Richard my 252 sounds great !!!!
I've listened to it myself.
The key for me was to get the pot up, hold mike 3.5'' away at a 45deg.angle and
to remember the element is near the top of the mike. The tough part is getting
used to talking on each radio a little differently. A ht with a good pair of
hi-fi cans monitoring the input or
simplex is a great tool in getting this one down. Many schematics for simple,
easy to build deviation meters are to be had on the web.
KC*VIF
Greg Z
to thine own sound be true

Speaking of deviation meters, can anyone recommend a freeware Windows
sound card oscilloscope program? I'd like to be able to run the line
out audio from a scanner into the sound card and be able to display
the audio envelope. The amplitude scale wouldn't need to be calibrated
as long as I could count the number of divisions, I could compare the
peak deviation from the 252 to other signals on the air. A quick and
dirty deviation comparison checker. I use Scanner Recorder to record
the audio, and it has an input display like I want, but no graduations
to use for comparing the amplitude from different mics and radios.

I have a Turner desk mic connected to the 252 at the moment. I don't
really know if It's an improvement or not. I built a little adapter
box with 6 push button switches so I can control the radio, but I have
to do without DTMF. Not a problem locally.

On 30 Jul 2003 05:37:41 GMT, ospam (greg z) wrote:



------------------------------
Seriously Richard my 252 sounds great !!!!
I've listened to it myself.
The key for me was to get the pot up, hold mike 3.5'' away at a 45deg.angle and
to remember the element is near the top of the mike. The tough part is getting
used to talking on each radio a little differently. A ht with a good pair of
hi-fi cans monitoring the input or
simplex is a great tool in getting this one down. Many schematics for simple,
easy to build deviation meters are to be had on the web.
KC*VIF
Greg Z
to thine own sound be true

Speaking of deviation meters, can anyone recommend a freeware Windows
sound card oscilloscope program? I'd like to be able to run the line
out audio from a scanner into the sound card and be able to display
the audio envelope. The amplitude scale wouldn't need to be calibrated
as long as I could count the number of divisions, I could compare the
peak deviation from the 252 to other signals on the air. A quick and
dirty deviation comparison checker. I use Scanner Recorder to record
the audio, and it has an input display like I want, but no graduations
to use for comparing the amplitude from different mics and radios.

I have a Turner desk mic connected to the 252 at the moment. I don't
really know if It's an improvement or not. I built a little adapter
box with 6 push button switches so I can control the radio, but I have
to do without DTMF. Not a problem locally.