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- 30 Mai 2020
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Hi all
I have an earlier blue button outdoor unit which has had all sorts of issues over the few years I have owned it, but I somehow manage to keep the thing going.
Specifically the problem I had recently is the recovery time from TX to RX when the unit is cold. The unit clicks back into receive, however, the radio stays quiet for a second or 3 before the signals can be heard. As the unit warms up, it improves to almost, but not quite normal. Its been a hassle when someone comes back but I miss their callsign
Now I found this to be the case, only when the preamp is engaged. When the preamp is bypassed, it works fine, though a little deaf.
After an hour or so on the bench, I found the culprit to be one of the tiny 6 pin SKYWORKS AS179-92LF chips on the output of the RF preamp. They are available from Mouser, however, as they are simply used as a soft switch, I simply jumpered the output capacitor from the preamp to the input capacitor to the attenuator switch
Once I had removed and bypassed the switch chip thing, the slow RX recovery went away, however, the radio could not receive anything if the preamp was switched off. To get arorund that I jumpered the output from the bypass capacitor to the same input to the attenuator. Seems to work without any noticeable loss of sensitivity.
I have some replacements in an order with Mouser that I will complete and pay for this week
There are some photos of my handywork and where these chips are located.
Hope someone finds this helpful
73 dit dit
ps. I'll post the replacement and restoration work once the parts arrive
I have an earlier blue button outdoor unit which has had all sorts of issues over the few years I have owned it, but I somehow manage to keep the thing going.
Specifically the problem I had recently is the recovery time from TX to RX when the unit is cold. The unit clicks back into receive, however, the radio stays quiet for a second or 3 before the signals can be heard. As the unit warms up, it improves to almost, but not quite normal. Its been a hassle when someone comes back but I miss their callsign
Now I found this to be the case, only when the preamp is engaged. When the preamp is bypassed, it works fine, though a little deaf.
After an hour or so on the bench, I found the culprit to be one of the tiny 6 pin SKYWORKS AS179-92LF chips on the output of the RF preamp. They are available from Mouser, however, as they are simply used as a soft switch, I simply jumpered the output capacitor from the preamp to the input capacitor to the attenuator switch
Once I had removed and bypassed the switch chip thing, the slow RX recovery went away, however, the radio could not receive anything if the preamp was switched off. To get arorund that I jumpered the output from the bypass capacitor to the same input to the attenuator. Seems to work without any noticeable loss of sensitivity.
I have some replacements in an order with Mouser that I will complete and pay for this week
There are some photos of my handywork and where these chips are located.
Hope someone finds this helpful
73 dit dit
ps. I'll post the replacement and restoration work once the parts arrive
