I tried to update my posting from 2013 - 2017 but the posting had been locked 
This was the first posting:
The TK7180 service manual states that you just input fixed default values for the front end softpots?
This suggest that NO further alignment is required.
Has anybody managed to obtain better sensitivity by adjusting the default values?
With other radios I have found that front end alignment is very broad so small changes in softpot values makes no difference...I guess this must be the same for the TK7180 otherwise why have fixed default values?
With my TK3180 hand portable it appears that the radio was set up for "exactly" 119dBm for 12dB SINAD and no attempt was made by the factory to get better performance. I obtained a good improvement when I actually aligned it for better than 12dB SINAD. But the TK3180 did not use 100% fixed default values as with the TK7180!!!
So can I get better RX performance from my TK7180 be doing a careful front end alignment or is it a waste of time?
I recently acquired another TK7180 and decided to realign the front end BUT no improvement in RX sensitivity was achieved over the default values of 60, 88, 109, 159, and 192.
Alignment is very broad with a decline in sensitivity only noticed when you adjust the softpots down to around 30-40.
RX sensitivity at the default settings is very good...maybe only 1-1.5dB behind my Motorola MCS2000 which has a fantastic front end.
I'm very happy with the TK7180 performance.
The MEGA advantage is that you can scan all channels and all zones with the TK7180....unlike all my Motorola stuff which is limited to 16 channel scanning..why why why does Motorola not provide the option to scan all channel and zones!!!!
The disadvantage is that you cannot toggle between High and Low power using a front key....so you need to create separate High and Low power zones....why did Kenwood engineers not provide a H/L power toggle with the TK7180 when this feature is included with the TK2180/3180 handhelds etc!!!
The squelch threshold on the TK7180 was originally set too high on 12.5KHz narrowband channels but was OK on wideband channels. As well as missing really weak signals (the lowest user setting of "1" was still too high), stations using 5 KHz deviation on narrow band channels cause filter rattling and clipping on speech peaks. Once I lowered the SQ to the threshold level, this clipping disappeared
Adjusting the SQ is not as easy as with Motorola radios as you cannot adjust the softpots manually using service mode. You need to inject a low level signal using a sig gen (or using the local osc signal from a scanner or HT) and then press "Apply".....the original SQ settings were 177, 176 and 174 and I lowered these to 129, 128 and 129. It involves a bit of trial and error as the weak test signal results in the displayed SQ values "hovering" , say, between 127 - 132 and you get a different value each time you press Apply...BUT the settings are broad so +/- 3 units does not have much effect. At around 129 ( I was aiming for 130 but 129 is close enough) the SQ opens on really really weak signals. I will probably increase the SQ threshold to 135 - 140 as 129 is just a bit too low and you sometimes get long SQ tails when the signal drops.
This was the first posting:
The TK7180 service manual states that you just input fixed default values for the front end softpots?
This suggest that NO further alignment is required.
Has anybody managed to obtain better sensitivity by adjusting the default values?
With other radios I have found that front end alignment is very broad so small changes in softpot values makes no difference...I guess this must be the same for the TK7180 otherwise why have fixed default values?
With my TK3180 hand portable it appears that the radio was set up for "exactly" 119dBm for 12dB SINAD and no attempt was made by the factory to get better performance. I obtained a good improvement when I actually aligned it for better than 12dB SINAD. But the TK3180 did not use 100% fixed default values as with the TK7180!!!
So can I get better RX performance from my TK7180 be doing a careful front end alignment or is it a waste of time?
I recently acquired another TK7180 and decided to realign the front end BUT no improvement in RX sensitivity was achieved over the default values of 60, 88, 109, 159, and 192.
Alignment is very broad with a decline in sensitivity only noticed when you adjust the softpots down to around 30-40.
RX sensitivity at the default settings is very good...maybe only 1-1.5dB behind my Motorola MCS2000 which has a fantastic front end.
I'm very happy with the TK7180 performance.
The MEGA advantage is that you can scan all channels and all zones with the TK7180....unlike all my Motorola stuff which is limited to 16 channel scanning..why why why does Motorola not provide the option to scan all channel and zones!!!!
The disadvantage is that you cannot toggle between High and Low power using a front key....so you need to create separate High and Low power zones....why did Kenwood engineers not provide a H/L power toggle with the TK7180 when this feature is included with the TK2180/3180 handhelds etc!!!
The squelch threshold on the TK7180 was originally set too high on 12.5KHz narrowband channels but was OK on wideband channels. As well as missing really weak signals (the lowest user setting of "1" was still too high), stations using 5 KHz deviation on narrow band channels cause filter rattling and clipping on speech peaks. Once I lowered the SQ to the threshold level, this clipping disappeared
Adjusting the SQ is not as easy as with Motorola radios as you cannot adjust the softpots manually using service mode. You need to inject a low level signal using a sig gen (or using the local osc signal from a scanner or HT
) and then press "Apply".....the original SQ settings were 177, 176 and 174 and I lowered these to 129, 128 and 129. It involves a bit of trial and error as the weak test signal results in the displayed SQ values "hovering" , say, between 127 - 132 and you get a different value each time you press Apply...BUT the settings are broad so +/- 3 units does not have much effect. At around 129 ( I was aiming for 130 but 129 is close enough) the SQ opens on really really weak signals. I will probably increase the SQ threshold to 135 - 140 as 129 is just a bit too low and you sometimes get long SQ tails when the signal drops.
