23-05-2012, 05:55 PM
The band conditions on 40 were really bad this afternoon so I did a prelim. comparison test with the Regenerodyne as it is so far and a Murphy B40D, both aerial inputs were connected to my temp. wire aerial, not a lot on the band but those transmissions that were were very weak and well into the noise.
I tuned the band for about 3 hours, I have to say that whatever was resolvable on the B40D was also resolvable on the regenerodyne.
The received signals were a bit clearer on the B40D as I had the xtal filter in, without the filter I would say they were about the same bearing in mind that the B40D only has a tiny speaker which cuts out a lot of the mid to low range noise, the regenerodyne speaker is a standard 6" job.
I have noticed that whatever tunable IF frequency is chosen for the receiver there are good points and bad points,
The main bug at the moment is that any strong transmission within the spectrum of the IF's passband can sometimes appear right where you don't want them even with the aerial disconected and the aerial terminals shorted out, it is probably due to direct pickup by the regen det tuning coil itself, hopefully if this receiver gets built properly then screening will sort out a lot of the problems in that department.
Lawrence
I tuned the band for about 3 hours, I have to say that whatever was resolvable on the B40D was also resolvable on the regenerodyne.
The received signals were a bit clearer on the B40D as I had the xtal filter in, without the filter I would say they were about the same bearing in mind that the B40D only has a tiny speaker which cuts out a lot of the mid to low range noise, the regenerodyne speaker is a standard 6" job.
I have noticed that whatever tunable IF frequency is chosen for the receiver there are good points and bad points,
The main bug at the moment is that any strong transmission within the spectrum of the IF's passband can sometimes appear right where you don't want them even with the aerial disconected and the aerial terminals shorted out, it is probably due to direct pickup by the regen det tuning coil itself, hopefully if this receiver gets built properly then screening will sort out a lot of the problems in that department.
Lawrence
