Kenwood Amateur Radios

Re: SM-220 two tone adjustment

mail@... (Mike) — Sat, 05 Apr 2025 06:13:50 -0700

OK scrub that. I ve just found the pot adjustment screws underneath the bottom cover ... 🤨.

Mike G8GYW

SM-220 two tone adjustment

mail@... (Mike) — Fri, 04 Apr 2025 09:00:53 -0700

I'm checking the performance of my newly acquired SM-220 and note that the levels of the two tone generator measured at TP1 and TP2 are 5.8V p-p which is nearly double the specified 3V.

So I decided to adjust them but found this to be impossible because VR108 is inaccessible (under the CRT) and I can't see VR107 anywhere. My PCB doesn't match the drawing in the service manual.

Any ideas please?

Mike G8GYW

Re: Kenwood SM-230 Station Monitor

mail@... (Mike) — Thu, 03 Apr 2025 12:09:36 -0700

Thanks Tom.

Mike G8GYW

Re: Kenwood SM-230 Station Monitor

alnath14308@... (Tom ai4th) — Thu, 03 Apr 2025 08:34:48 -0700

I leave my 220 in line all the time, and turn it on for the first few transmissions from each transmitter so I can see what my signal looks like. (I'm one of those idiots who constantly tinkers with their audio train. Sometimes unexpected things happen...) I leave it off otherwise to save the CRT. Insertion loss is negligible as measured by VNA or watt meter (located just before the antenna).

73,

Tom ai4th

Re: TS-870S rear panel audio input

k7qt@... (David Frechette) — Thu, 03 Apr 2025 04:33:49 -0700

I believe the speech processor is only available for the microphone main connector circuit.

Re: TS-870S rear panel audio input

mail@... (Mike) — Thu, 03 Apr 2025 00:00:22 -0700

Thanks Sam that link was very informative and it has persuaded me not to go down that route. I don't need the complication of an audio rack!

Mike G8GYW

Re: Kenwood SM-230 Station Monitor

mail@... (Mike) — Wed, 02 Apr 2025 09:23:14 -0700

I couldn't find an SM-230 locally but I did get an immaculate SM-220. Not the same colour as my radio but it will do for now.

Do you guys leave the monitor in the antenna lead all the time or just connect it up when needed? Is the VSWR / insertion loss OK?

Mike G8GYW

Re: TS-870S rear panel audio input

sernstfortin@... (Samuel W7STF) — Wed, 02 Apr 2025 06:12:40 -0700

I think the main difference between the two input methods is that the mic input has a differential amplifier to cancel common-mode noise (i.e. noise imposed on both the signal and ground wires from the microphone) where that isn't the case with the ACC connector input.

Here is more discussion on the same site provided by Trevor

https://www.wz5q.net/talkvoodoo/viewtopic.php?t=133

Sam, W7STF

MONTHLY REMINDER--Our Amateur Radio Groups

@... — Tue, 01 Apr 2025 05:31:44 -0700

MONTHLY REMINDER--Our Amateur Radio Groups

Below are our amateur radio related groups. Some may be new enough there are only a few members. If one of those interests you, join it and give it some time to grow. It costs nothing and if there’s few members, it won’t be filling up your inbox while you wait for it to grow. 😊

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Re: TS-870S rear panel audio input

mail@... (Mike) — Mon, 31 Mar 2025 00:23:01 -0700

Thanks Trevor. I get the impression that the guys doing this are running external audio processing whereas I would just want to use the mic (at an appropriate level).

Mike G8GYW

Re: TS-870S rear panel audio input

trevor.baker2254@... (Trevor Baker) — Sun, 30 Mar 2025 11:39:31 -0700

Hi Mike

TS-870S rear panel audio input

mail@... (Mike) — Sun, 30 Mar 2025 09:15:34 -0700

Now that I've fixed the problem with my ACC2 socket I've been reading about the supposed benefits of using it for audio in instead of the Mic socket.

Apart from making the front panel tidier (no mic cable) is it worth doing? Is the speech quality improved without any external processing?

Mike G8GYW

Re: TS-870S no TX

mail@... (Mike) — Fri, 28 Mar 2025 10:02:09 -0700

Hello Sam

I made sure that the indent was correctly aligned, the problem was the excessive amount of force required to push the plug home. I've thrown that cable away now to avoid problems in the future.

Incidentally, on the TS-870 the ACC2 socket indent is at the bottom because the PCB is upside down in the chassis.

Mike G8GYW

Re: TS-870S no TX

sernstfortin@... (Samuel W7STF) — Thu, 27 Mar 2025 06:20:32 -0700

Mike, I don't know that you indicated the radio was mis-behaving when no cable was installed in the socket... As others indicated, the 13-pin DIN male should mate with the female socket EASILY. You have to make sure that the indent in the shield is located towards the ceiling, 12 o'clock...

And not all 13-pin DIN cables are the same.

Even if the cable had nothing plugged into the other end, likely the cable wasn't straight-through, and several conductors/pins were at the same potential as GND (the shield). This could be verified with an ohm meter. Check the resistance between each pin of the suspect cable and the shield. If any of the pin to shield resistances are low, you've found the culprit.

Glad you resolved your problem.

Sam W7STF

Re: TS-870S no TX

Outposter30@... (Jordan) — Thu, 27 Mar 2025 06:04:53 -0700

��

No problem Mike....Glad you got it sorted...73...Jordan...

Re: TS-870S no TX

mail@... (Mike) — Thu, 27 Mar 2025 05:34:35 -0700

Hi Jordan, I bought an MFJ accessory cable with a 13 pin DIN plug on one end and it goes into the ACC2 socket easily. It looks identical to the other plug that doesn't fit so I don't know where the problem was. I can wiggle the plug in the socket and it doesn't drop out of TX so I'm hoping it will be OK now.

Thanks for listening.

Mike G8GYW

Re: Kenwood SM-230 Station Monitor

kreatywny@... (GM0VEQ) — Wed, 26 Mar 2025 05:10:35 -0700

I am located in Japan, and I have SM-230 and would part with it if somebody want it. Tom

Re: Kenwood SM-230 Station Monitor

mail@... (Mike) — Tue, 25 Mar 2025 15:38:10 -0700

On Tue, Mar 25, 2025 at 04:51 PM, John Geiger AF5CC wrote:

Here is one if you can get them to ship it to the UK:

https://www.hamradio.com/detail.cfm?pid=M1-002192

73 John AF5CC

Thanks John. That's a low price, the last one I saw at a UK dealer was £699.

My PS-31 PSU came from the US, it was in immaculate condition but the courier dropped it and bent the rear panel.

Mike G8GYW

Re: Kenwood SM-230 Station Monitor

Af5cc1@... (John Geiger AF5CC) — Tue, 25 Mar 2025 09:51:07 -0700

Here is one if you can get them to ship it to the UK:

https://www.hamradio.com/detail.cfm?pid=M1-002192

73 John AF5CC

Re: Kenwood SM-230 Station Monitor

Outposter30@... (Jordan) — Mon, 24 Mar 2025 06:53:57 -0700

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The AIP function bypasses the Rx RF amplifier and feeds the Rx signal directly to the mixer, resulting in less gain on Rx...That's why you see less signal on the SM-230 when the AIP is on...

73...Jordan VE6ZT