I like the idea of that.
I'll try a plastic crate/basket for the mk2 model.
As they come in different sizes, is the 110 ft of wire more critical than the actual size of the frame.?
Tecsun Radios
- Thread starter rocky28965
- Start date
- Status
I like the idea of that.
I'll try a plastic crate/basket for the mk2 model.
As they come in different sizes, is the 110 ft of wire more critical than the actual size of the frame.?
majoco
Stirrer
The bigger the frame, the more sensitive the loop will be, but of course it will need more wire. The construction of a loop is a very 'experimental' thing, it's difficult to give a hard-and-fast rule. I have found that the best way is to find you tuning capacitor first, then wind on too many turns of wire - check the low frequency end against the lowest frequency station near you and make sure you can tune it with the capacitor nearly or fully meshed. If the low frequency station is too far away from fully meshed, take a turn off the loop and try again. Once you get it right then check that you can tune to the highest frequency with the capacitor open - hopefully it should come in correctly with a broadcast band capacitor -if you have a meter to measure capacitance you need a low/high ratio of about 9 to 1 or slightly less to cover 550 to 1600kHz.
I had a quick listen on the AM broadcast band last night about 2130 to 2200 local time last night and I had stations or carriers at almost every 9kHz spacing - I didn't stop to check if some were real stations or intermod but it seems strange that Rocky seems to have poor reception although his location is surrounded by some pretty large hills in most directions. This was on the internal ferrite antenna under a tin-tile roof. If time permits I'll do another test tonight against my GE Superadio ll which is a well respected AM band receiver.
Here's a pic of a loop I built for NDB low frequency bands which worked well but a bit too large!
You can zip-tie together several milk crates. I made a loop antenna with one crate, and then I built another one with two crates, which had a little more gain. Then I added two more crates to that, using zip-ties. A bit more gain. In my case, it took the same amount of wire to tune the band. I usually use my single crate loop because it is more convenient to use.
This is probably the best technique. It may seem tedious but in the end it works.
There are formulas out there giving dimensions, number of turns, etc. but in my
experience they were not very useful.
ka3jjz
Wiki Admin Emeritus
If I take the radio outside, it will pickup the two Alexandra AM stations & after dark will pick more distant ones.
I'm finding the 660 a bit fiddly to use compared with the Sangean it replaced.
I have fat fumbling fingers.
So are seriously thinking of upgrading to a S-2000
Last edited:
Are you mostly interested in MW? Or did you get the 660 for SW also.
Because if you are mostly interested in MW distance listening, you might be better off with a Sangean PR-D5 or PR-D15. Big controls, easy to use, excellent performance on MW and very good on FM also (in stereo, too). Both with a 220mm internal loopstick, no external loop needed.
Because if you are mostly interested in MW distance listening, you might be better off with a Sangean PR-D5 or PR-D15. Big controls, easy to use, excellent performance on MW and very good on FM also (in stereo, too). Both with a 220mm internal loopstick, no external loop needed.
Have the Satellit 750 version here. The advantage is that it has provision for an external antenna on all bands including AM.
The use of an external antenna makes the 750 a good AM DX radio.
Otherwise, selectivity on AM seems to be about the same as on the PL-600.
If AM DX is your thing, you may want to check out what CCrane has to offer.
Have the CCRadio-EP here and it is excellent on AM DX.
Yes thats a big advantage over the 660, having more antenna inputs
I want the same range as the 660
majoco
Stirrer
I am beginning to think that your 660 may be working as it should. Today at midday - the worst possible time - I went hunting for some weak stations and here's what I found.
The signal strengths were measured on my HP 3586A selective level meter from a 45metre/15metre ocfd through a 9:1 balun directly to the SLM. The Tecsun 600 and the GE Superadio ll were just on their internal ferrite antennas.
Frequency 567 kHz, RNZ National programme, Titahi Bay 118km away, -118dBm, say 0.5uV EMF, the 600 gave a noisy but readable signal but no "S" meter indication, my GE gave a good signal with very slight background noise. Powerful transmitter.
Frequency 594kHz, Star Radio, Wanganui, 71km away, -112dBm, 1.2uV EMF, 600 gave good signal clean audio and 2 "S" meter points, the GE radio was clean audio with no noise.
Frequency 1071kHz, Masterton, 75km, -119dBm, 0.3uV EMF, on the 600 barely audible and no "S" meter reading, the GE radio was about the same - over the Tararua Ranges so not unexpected.
Frequency 1602kHz, the Radio Reading Service in Levin, 54km, -112dBm, on the 600 noisy and unreadable, on the GE noisy but readable. Very local low power transmitter.
The weather was overcast with drizzle and low cloud.
It's 60km or so from Wanaka to Alexandra and I recall that the transmitter is up on the flat by the airport so your results would seem to be about par for the course. Still there's some hills in the way.
The signal strengths were measured on my HP 3586A selective level meter from a 45metre/15metre ocfd through a 9:1 balun directly to the SLM. The Tecsun 600 and the GE Superadio ll were just on their internal ferrite antennas.
Frequency 567 kHz, RNZ National programme, Titahi Bay 118km away, -118dBm, say 0.5uV EMF, the 600 gave a noisy but readable signal but no "S" meter indication, my GE gave a good signal with very slight background noise. Powerful transmitter.
Frequency 594kHz, Star Radio, Wanganui, 71km away, -112dBm, 1.2uV EMF, 600 gave good signal clean audio and 2 "S" meter points, the GE radio was clean audio with no noise.
Frequency 1071kHz, Masterton, 75km, -119dBm, 0.3uV EMF, on the 600 barely audible and no "S" meter reading, the GE radio was about the same - over the Tararua Ranges so not unexpected.
Frequency 1602kHz, the Radio Reading Service in Levin, 54km, -112dBm, on the 600 noisy and unreadable, on the GE noisy but readable. Very local low power transmitter.
The weather was overcast with drizzle and low cloud.
It's 60km or so from Wanaka to Alexandra and I recall that the transmitter is up on the flat by the airport so your results would seem to be about par for the course. Still there's some hills in the way.
Last edited:
RE: your earlier question Rocky: RE size of crate vs. length of wire:
The milk crate I use is about 1 ft. to 1.5 feet per side or so. 30 cm maybe? and it has a little less than 110 ft of wire (30 meters or so?). I had to cut a little to get it to tune to the 365 pf AM radio tuner cap. As said before by others, it's a process of cut to fit. Better to use a little more wire than called for, and then cut it down.
Sorry the answer is late, and can't get quotes to work on this new forum.
The milk crate I use is about 1 ft. to 1.5 feet per side or so. 30 cm maybe? and it has a little less than 110 ft of wire (30 meters or so?). I had to cut a little to get it to tune to the 365 pf AM radio tuner cap. As said before by others, it's a process of cut to fit. Better to use a little more wire than called for, and then cut it down.
Sorry the answer is late, and can't get quotes to work on this new forum.
Havent seen a milk crate in 20 years but I've got my eye on a plastic basket about that size.
Someone currently has some plants in it, so haven't got the official go ahead to use it yet.
Someone currently has some plants in it, so haven't got the official go ahead to use it yet.
majoco
Stirrer
Boombox said:
I still do it like I did on the old forum. With square brackets [ ] around "quote" and "/quote" - but not with the ".
I still do it like I did on the old forum. With square brackets [ ] around "quote" and "/quote" - but not with the ".
They are sold in a lot of stores, as storage options. (In the US, at least. It is not a stretch to believe they are in other countries, too.
Sent using Tapatalk
^^^^^ What he said. A plastic 'box', with open sides, used for storage. Like a square, plastic basket. They look just like the old school milk crates.
Here in my section of the US they cost about $10 or so. Zip ties are cheap -- I use them to secure the tuner capacitor, and a couple ends of the wire -- the wire is further secured with tape in places. Zip ties can also be used to attach two or more crates if you want.
Here in my section of the US they cost about $10 or so. Zip ties are cheap -- I use them to secure the tuner capacitor, and a couple ends of the wire -- the wire is further secured with tape in places. Zip ties can also be used to attach two or more crates if you want.
Un update on the proceedings.
Decided not to use a plastic basket as I thought it would be easier to control the wire spacing if I made a frame specifically for the purpose.
So it's finished up looking very similar to the one in post #9 except I made slots to locate the wire.
I used the table from post #25 to work out the number of turns.
Have just been testing it out & the range is almost perfect.
Tuneable from about 530 - 1630.
Dosent pull in any more stations but the 2 it does are much clearer using the loop.
Will most likely be better outside but its to hot for an old fart out there atm
Decided not to use a plastic basket as I thought it would be easier to control the wire spacing if I made a frame specifically for the purpose.
So it's finished up looking very similar to the one in post #9 except I made slots to locate the wire.
I used the table from post #25 to work out the number of turns.
Have just been testing it out & the range is almost perfect.
Tuneable from about 530 - 1630.
Dosent pull in any more stations but the 2 it does are much clearer using the loop.
Will most likely be better outside but its to hot for an old fart out there atm
Trade you... that is for the heat, -12F here presently.
- Status
