455kHz IF cans + MW oscillator coil - component source

I built a AM/FM 'Radio 4 receiver' I used the circuit by RA Penfold, 'Short Wave Superhet receiver Construction', I did away with the front end and used a NE602 for LW and a TDA7000 for Radio 4 VHF. I just can't tell the difference. This set up seems to be my favourite for a 'quickie build'. I have the pcb layout if required, both are 'fixed tuned.

The I.F uses  two 2n3904's, for SSB I use another NE602. For the IF's I used Mouser I.F cans and used different connections than was shown in the book.

Dave

That was really interesting.

I also found that instead of a conventional oscillator coil for the self-oscillating mixer, it is easier to use the same circuit as a mixer and feed an external oscillator into the emitter of the mixer.

The rats-nest version worked exceptionally well. A single-winding coil is all that is needed, but I also got success with a CD4046 VCO and no coils. Not exactly "traditional" but it works.

I am laying out a PCB for this at the moment (in my precious spare time) for the extra transistor/coil version.

BR Harry

Hi!

If you should need a "hi-fi" AM detector for your AM-receiver:

"High-fidelity" AM broadcast detector:
http://g3ynh.info/circuits/hi-fi_am.html
Quote: "...
I discovered "Hi-Fi AM" quite by accident too. It can rival FM to some extent and some of the venues on AM here in Idaho are not available on FM.
..."
Backup:
https://web.archive.org/web/20161113034018/http://g3ynh.info/circuits/hi-fi_am.html
http://g3ynh.info/circuits/AM_det.html
http://g3ynh.info/circuits/push-pull_det.pdf
Backup:
https://web.archive.org/web/20160623035857/http://g3ynh.info/circuits/push-pull_det.pdf

Complete "hi-fi" MW AM tuner:
http://g3ynh.info/circuits/Bob_Batey/am_hifi_shet_sch.gif
Backup:
https://web.archive.org/web/20171022023744/http://g3ynh.info/circuits/Bob_Batey/am_hifi_shet_sch.gif

Hi Harry,
I monitor this forum almost daily. I write here if I have some thought to add only.

VBR from Ivan

Hi Ivan,
So nice to hear from you again :-)

Thank you very much for the information. It was a very interesting site, and there are loads of fixed inductors that are also of particular interest. When I have finished my oscilloscope project I will place an order with them for a load of components.

A couple of years ago I was given a box of 100s of assorted cans. Nothing useable pre-wound, but they are very good for rewinding. But for the 3-band pocket SSB receiver I really want to use ready-made coils. Thanks again for the information.

Very best regards from Harry

Hi, various types of coils suitable for rewinding are here:
HADEX
Fixed inductors show first, go down through the pages.
Prices are in CZK, 1 EUR=cca 26 CZK

BR from Ivan

Update

I received my 455kHz IF cans; had them delivered to work while I was away. The product code ACS1667 does NOT include the MW oscillator coil; just a set of four IF cans.

But BG-micro did send me extra YELLOW cans FOC, since there are two variants; one with capacitor on the primary and one can with the capacitor on the secondary winding. So I received four cans in each set

I have asked BG-micro if they sell the MW oscillator coil, awaiting a reply. I will update this post with their reply.

I know the MW band is dead, but the idea was to make a 1MHz tunable IF (1MHz to 2MHz with osc = low) for SSB and cover 160m directly, 80m and 20m using a simple converter.

BR Harry - SM0VPO

Hello again,
I have been searching the web and found that www.bgmicro.com (USA) offer a set of four IF transformers for US$1.80 each. They have about 15,000 sets in stock.

They are NOT the yellow/yellow/black sets you often find, but the full red/yellow/white/black set of four.

They will dispatch worldwide :-)

best regards from Harry - SM0VPO