Feeling rather smug - UK Vintage Radio Repair and Restoration Discussion Forum

cendoubleu · 16th Sep 2010, 2:23 pm

Over the last couple of days I have put together a bandpass filter for my 40m receiver. I took data from the design notes at the back of the book 'Solid State Design for the Radio Amateur'. I am revamping a transceiver based on the TCF transceiver by Drew Diamond, which I built about 6 years ago. It never worked very well on the Tx side, and as I am now more interested in receiving than transmitting I thought I would make it just a receiver.
I used the design notes to re-calc the output to match the 1500 ohms input of the NE602 used in this design. Constructed it this morning and with a quick lash-in, tried it out. With the sig-genny set at 7Mhz, and the attenuator down to -60db, a signal was still fully discernable. So feeling rather satisified with myself as I have never 'designed' any parts of a receiver, I have always used a published circuit.
I shall now box it up and install in the receiver properly.
The next job is to revamp the audio section as I always got motor-boating at highish volume levels. Bit of work required re Zobel network etc.
Following that, the VFO requires extending to cover up to 7.2 Mhz.

enquirium · 16th Sep 2010, 7:54 pm

No harm being proud of you're achievments .

.

cendoubleu · 16th Sep 2010, 9:14 pm

Thanks enquirium. Sorry if it sounded like blowing me own trumpet too much but its the first time I have designed anything 'from scratch'. I was more than suprised when it actually worked!
I just tried it now on a busy band at night time, and it is certainly better than the original design. Not getting any out-of-band interference now which I did before from broadcast stations.
Charlie

16th Sep 2010, 2:23 pm	#1
cendoubleu Tetrode Join Date: Jan 2007 Location: Lincoln, Lincs. UK. Posts: 94	Feeling rather smug Over the last couple of days I have put together a bandpass filter for my 40m receiver. I took data from the design notes at the back of the book 'Solid State Design for the Radio Amateur'. I am revamping a transceiver based on the TCF transceiver by Drew Diamond, which I built about 6 years ago. It never worked very well on the Tx side, and as I am now more interested in receiving than transmitting I thought I would make it just a receiver. I used the design notes to re-calc the output to match the 1500 ohms input of the NE602 used in this design. Constructed it this morning and with a quick lash-in, tried it out. With the sig-genny set at 7Mhz, and the attenuator down to -60db, a signal was still fully discernable. So feeling rather satisified with myself as I have never 'designed' any parts of a receiver, I have always used a published circuit. I shall now box it up and install in the receiver properly. The next job is to revamp the audio section as I always got motor-boating at highish volume levels. Bit of work required re Zobel network etc. Following that, the VFO requires extending to cover up to 7.2 Mhz.

16th Sep 2010, 7:54 pm	#2
enquirium Triode Join Date: Jan 2008 Location: Bangor, Northern Ireland, UK. Posts: 44	Re: Feeling rather smug No harm being proud of you're achievments . .

16th Sep 2010, 9:14 pm	#3
cendoubleu Tetrode Join Date: Jan 2007 Location: Lincoln, Lincs. UK. Posts: 94	Re: Feeling rather smug Thanks enquirium. Sorry if it sounded like blowing me own trumpet too much but its the first time I have designed anything 'from scratch'. I was more than suprised when it actually worked! I just tried it now on a busy band at night time, and it is certainly better than the original design. Not getting any out-of-band interference now which I did before from broadcast stations. Charlie