31-12-2016, 04:24 PM
Don't panic, Mike!
I've been looking at your crystals - I hadn't realised before that the seller had provided a list of frequencies - so here are my findings.
The vast majority are, as I'm sure you will be well aware, completely outside the MW range but there are six that are not: 820/850/908/936/960/1024kHz
I'll start with 936kHz as that is the only one which is right on a 9kHz channel. It is used by 2 low power transmitters in the UK but far enough away that they shouldn't cause you any problems. Outside the UK, the only transmitter I can find with any substantial power output is in Iran, so I don't think you need to worry about that! Should be an excellent choice for your micro Tx!
908kHz is a definite no-no! It is only 1kHz off Brookmans Park R5 (909kHz) - all 150kW of it!
820kHz looks good - virtually midway between the channels at 810 and 828kHz so any beats will be outside the IF passband. There is one high power Tx in Egypt on 819kHz, so this one looks good too.
850kHz. Authorised channels are 846kHz & 855kHz. Nothing of interest on 846, 1.5kW on 855 from Norfolk but the 5kHz beat should be outside the IF passband of most radios. High powered stations in Spain and Rumania. So, another one that looks good!
960kHz. There is a 1.5MW(!) transmitter in Qatar on 954kHz but, again, the 6kHz beat should be outside the IF passband. There are 2 UK based low power transmitters on 963kHz, the only one of interest being 950W in Lea Bridge Road. Whether this would reach Basildon at night is difficult to say and will be influenced by both terrain and the design of the transmitter's aerial. A 3kHz beat could objectionable. You'd have to suck this one and see.
1024kHz. 200kW from Iran on 1024kHz plus a couple of low power distant UK locals here. Unlikely to cause any problems, I would have thought.
So, overall, you seem to have struck lucky with your haul! Getting one that is bang on a virtually empty channel is a particular bonus!
Browsing through the list I noted a 45233.3kHz crystal. This is only 0.5% off Channel B1 vision frequency so could be useful for a Band I modulator ...
Be very careful what you do with that 2182kHz crystal - it is/was an International Distress Frequency and, although the Coastguard no longer actively monitors it, I've now idea what the current situation is.
I've been looking at your crystals - I hadn't realised before that the seller had provided a list of frequencies - so here are my findings.
The vast majority are, as I'm sure you will be well aware, completely outside the MW range but there are six that are not: 820/850/908/936/960/1024kHz
I'll start with 936kHz as that is the only one which is right on a 9kHz channel. It is used by 2 low power transmitters in the UK but far enough away that they shouldn't cause you any problems. Outside the UK, the only transmitter I can find with any substantial power output is in Iran, so I don't think you need to worry about that! Should be an excellent choice for your micro Tx!
908kHz is a definite no-no! It is only 1kHz off Brookmans Park R5 (909kHz) - all 150kW of it!
820kHz looks good - virtually midway between the channels at 810 and 828kHz so any beats will be outside the IF passband. There is one high power Tx in Egypt on 819kHz, so this one looks good too.
850kHz. Authorised channels are 846kHz & 855kHz. Nothing of interest on 846, 1.5kW on 855 from Norfolk but the 5kHz beat should be outside the IF passband of most radios. High powered stations in Spain and Rumania. So, another one that looks good!
960kHz. There is a 1.5MW(!) transmitter in Qatar on 954kHz but, again, the 6kHz beat should be outside the IF passband. There are 2 UK based low power transmitters on 963kHz, the only one of interest being 950W in Lea Bridge Road. Whether this would reach Basildon at night is difficult to say and will be influenced by both terrain and the design of the transmitter's aerial. A 3kHz beat could objectionable. You'd have to suck this one and see.
1024kHz. 200kW from Iran on 1024kHz plus a couple of low power distant UK locals here. Unlikely to cause any problems, I would have thought.
So, overall, you seem to have struck lucky with your haul! Getting one that is bang on a virtually empty channel is a particular bonus!
Browsing through the list I noted a 45233.3kHz crystal. This is only 0.5% off Channel B1 vision frequency so could be useful for a Band I modulator ...
Be very careful what you do with that 2182kHz crystal - it is/was an International Distress Frequency and, although the Coastguard no longer actively monitors it, I've now idea what the current situation is.
