More Chinese AM radio kits - Page 10 - UK Vintage Radio Repair and Restoration Discussion Forum

Station X · 23rd Oct 2025, 7:11 pm

Thread reopened.

Neil Purling · 23rd Oct 2025, 10:35 pm

I have been drawn back to these kits again..........

It is a victory to come up with a working radio despite none-existent instructions in your language & components of suspect quality.
Proper English instructions do exist for one of these kits. Getting the IF transformers in the right positions is not quite so hard as the Chinese characters for Red, Yellow, White & Black already exist in how to interpret resistor code on the existing instructions.You can use the Internet to see Chinese for the colours as well and look at images of completed radios.

If you have a Digital Multi Meter they may well have a transistor test socket
I verified the 9018H transistors were within the quoted range of their hfe classification. I did not test the ceramic capacitors, but I did test the electrolytic capacitors.
The second transistor (V2) in the only IF amplifier stage is a 2N3904 with a hfe 0f 300.
This improves the sound out of the speaker.
The black pocket radio has the same transistors used for mixer/osc, IF and detector as the standard HX-6B. It is weaker than the kit radio in picking up Radio Caroline
At the HF end of the band I can get a radio station that broadcasts Indian music. Not sure what that is

Neil Purling · 24th Oct 2025, 8:39 am

The station I heard is not audible during the day. It never gave an ID

Send me a Private Message if anyone knows what erp a AM Community Radio station may use. No discussion of that here, please.

Jon_G4MDC · 24th Oct 2025, 10:01 am

BBC Asian Network has a few TXs in the midlands at the high end of the band. Most are a few hundred Watts so maybe that is what you heard.

Neil Purling · 24th Oct 2025, 8:31 pm

I was sat eating an ice-cream with the HX-6BB playing minutes ago.
It is Lyca Radio on 1458Khz. A clear positive ID after the news at 21:00.
Long slow fades. No idea of the erp, but 1458 is listed as their Greater London service.
Not bad for a kit radio.

Has anyone tried a 2N3904 as the first 3 transistors? From hearing Lyca it seems the tracking is pretty good.

Jon_G4MDC · 25th Oct 2025, 7:51 am

I also thought of Lyca which is a bit loud here. I wasn't sure what their content was.

125kW from Brookmans Park at 5.5miles range.

Graham G3ZVT · 25th Oct 2025, 12:04 pm

The first "HX108-2" kit I bought had the name QIUXIN xinghad. It worked well, and I bought another, this time an "HX108-2+" BOSHI xlite.
The PCBs were quite similar a noticeable difference was the later one had smaller IFTs
but more significantly, the later kit was supplied with a low-profile 32 ohm speaker, I'm pretty sure the OPT was intended to drive an 8 ohm speaker.

The other thing that I found mildly annoying is that the position of the axis of rotation of the tuning dial did not match the half-moon tuning scale.

Neil Purling · 25th Oct 2025, 9:21 pm

I cut up two tuning scales. One of the HX108 and one of a HX-6B: See post 109.
The adhesive strip of the HX108 dial partially obscured the dial. There is something wrong with the original dial I never wondered how accurately it displayed frequency.

Re-reading this thread the HX108 would give me Manx Radio. The HX-6B does the same with the 2N3904. Has anyone used 2N3904's elsewhere in the 6 transistor radios?

Neil Purling · 3rd Nov 2025, 10:07 pm

2N3904 causes audio distortion. I cannot wind up the volume much.
Can I cut the gain of the 2N3904 by changing the collector resistor?
It is the standard 30K ohms at present.
Unless I swop the 2N3904 for a 9018 gain group I instead of the standard H.

Neil Purling · 12th Nov 2025, 4:21 pm

Can you get group I 9018 transistors?
The original 9018 H transistors supplied had a hfe figure between 110 and 120.

Right now the HX-6 has a BC147A at V2, which has a hfe measured at 172.
The 2N3904 I extracted was measured at 327.

Would using a higher gain transistor have any benefit used as the mixer/osc (V1)

Jolly 7 · 12th Nov 2025, 11:09 pm

I fished out some RF transistors from my parts box and tested them at random for beta. The lowest gain one was a BF 494B with a beta of 59. The two 9018G transistors I tested had betas of 94 and 95 respectively.. The highest of them all was a 2N3904 with a beta of 339 !

I think I used a 9018G in the oscillator mixer if my HX 108-2 kit radio which I built six years ago.

23rd Oct 2025, 7:11 pm	#181
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 22,762	Re: More Chinese AM radio kits Thread reopened. __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

23rd Oct 2025, 10:35 pm	#182
Neil Purling Nonode Join Date: Jul 2005 Location: Hull, East Yorkshire, UK. Posts: 2,115	Re: More Chinese AM radio kits I have been drawn back to these kits again.......... It is a victory to come up with a working radio despite none-existent instructions in your language & components of suspect quality. Proper English instructions do exist for one of these kits. Getting the IF transformers in the right positions is not quite so hard as the Chinese characters for Red, Yellow, White & Black already exist in how to interpret resistor code on the existing instructions.You can use the Internet to see Chinese for the colours as well and look at images of completed radios. If you have a Digital Multi Meter they may well have a transistor test socket I verified the 9018H transistors were within the quoted range of their hfe classification. I did not test the ceramic capacitors, but I did test the electrolytic capacitors. The second transistor (V2) in the only IF amplifier stage is a 2N3904 with a hfe 0f 300. This improves the sound out of the speaker. The black pocket radio has the same transistors used for mixer/osc, IF and detector as the standard HX-6B. It is weaker than the kit radio in picking up Radio Caroline At the HF end of the band I can get a radio station that broadcasts Indian music. Not sure what that is Attached Thumbnails

24th Oct 2025, 8:39 am	#183
Neil Purling Nonode Join Date: Jul 2005 Location: Hull, East Yorkshire, UK. Posts: 2,115	Re: More Chinese AM radio kits The station I heard is not audible during the day. It never gave an ID Send me a Private Message if anyone knows what erp a AM Community Radio station may use. No discussion of that here, please.

24th Oct 2025, 10:01 am	#184
Jon_G4MDC Nonode Join Date: Nov 2015 Location: Welwyn Garden City, Hertfordshire, UK. Posts: 2,344	Re: More Chinese AM radio kits BBC Asian Network has a few TXs in the midlands at the high end of the band. Most are a few hundred Watts so maybe that is what you heard.

24th Oct 2025, 8:31 pm	#185
Neil Purling Nonode Join Date: Jul 2005 Location: Hull, East Yorkshire, UK. Posts: 2,115	Re: More Chinese AM radio kits I was sat eating an ice-cream with the HX-6BB playing minutes ago. It is Lyca Radio on 1458Khz. A clear positive ID after the news at 21:00. Long slow fades. No idea of the erp, but 1458 is listed as their Greater London service. Not bad for a kit radio. Has anyone tried a 2N3904 as the first 3 transistors? From hearing Lyca it seems the tracking is pretty good.

25th Oct 2025, 7:51 am	#186
Jon_G4MDC Nonode Join Date: Nov 2015 Location: Welwyn Garden City, Hertfordshire, UK. Posts: 2,344	Re: More Chinese AM radio kits I also thought of Lyca which is a bit loud here. I wasn't sure what their content was. 125kW from Brookmans Park at 5.5miles range.

25th Oct 2025, 12:04 pm	#187
Graham G3ZVT Dekatron Join Date: May 2010 Location: Greater Manchester, UK. Posts: 19,365	Re: More Chinese AM radio kits The first "HX108-2" kit I bought had the name QIUXIN xinghad. It worked well, and I bought another, this time an "HX108-2+" BOSHI xlite. The PCBs were quite similar a noticeable difference was the later one had smaller IFTs but more significantly, the later kit was supplied with a low-profile 32 ohm speaker, I'm pretty sure the OPT was intended to drive an 8 ohm speaker. The other thing that I found mildly annoying is that the position of the axis of rotation of the tuning dial did not match the half-moon tuning scale. __________________ -- Graham. G3ZVT Last edited by Graham G3ZVT; 25th Oct 2025 at 12:20 pm.

25th Oct 2025, 9:21 pm	#188
Neil Purling Nonode Join Date: Jul 2005 Location: Hull, East Yorkshire, UK. Posts: 2,115	Re: More Chinese AM radio kits I cut up two tuning scales. One of the HX108 and one of a HX-6B: See post 109. The adhesive strip of the HX108 dial partially obscured the dial. There is something wrong with the original dial I never wondered how accurately it displayed frequency. Re-reading this thread the HX108 would give me Manx Radio. The HX-6B does the same with the 2N3904. Has anyone used 2N3904's elsewhere in the 6 transistor radios?

3rd Nov 2025, 10:07 pm	#189
Neil Purling Nonode Join Date: Jul 2005 Location: Hull, East Yorkshire, UK. Posts: 2,115	Re: More Chinese AM radio kits 2N3904 causes audio distortion. I cannot wind up the volume much. Can I cut the gain of the 2N3904 by changing the collector resistor? It is the standard 30K ohms at present. Unless I swop the 2N3904 for a 9018 gain group I instead of the standard H.

12th Nov 2025, 4:21 pm	#190
Neil Purling Nonode Join Date: Jul 2005 Location: Hull, East Yorkshire, UK. Posts: 2,115	Re: More Chinese AM radio kits Can you get group I 9018 transistors? The original 9018 H transistors supplied had a hfe figure between 110 and 120. Right now the HX-6 has a BC147A at V2, which has a hfe measured at 172. The 2N3904 I extracted was measured at 327. Would using a higher gain transistor have any benefit used as the mixer/osc (V1)

12th Nov 2025, 11:09 pm	#191
Jolly 7 Octode Join Date: Feb 2018 Location: Southampton, Hampshire, UK. Posts: 1,122	Re: More Chinese AM radio kits I fished out some RF transistors from my parts box and tested them at random for beta. The lowest gain one was a BF 494B with a beta of 59. The two 9018G transistors I tested had betas of 94 and 95 respectively.. The highest of them all was a 2N3904 with a beta of 339 ! I think I used a 9018G in the oscillator mixer if my HX 108-2 kit radio which I built six years ago.