cistercian
Member
I have been very happy with my #15 wire 7 turn loop that is a bit less than 4 feet per side. It performed well.
Of course...I am never satisfied. I built a new antenna out of 1 inch schedule 40 PVC. Here in the US it is available in 5 foot lengths. Two 5 foot sections
cut in half are inserted into a 4 way 90 degree cross and each end has a 3 way 1 inch PVC tee fitting attached. I slotted the PVC fittings for 8 turns and wound
about 128 feet of #12 magnet wire for a total of 8 turns. Turn spacing is about .39 inches. Nearly 2.5 lbs of wire!
Q @ 100kc went from 95 on the old antenna to 220 on the new build. Tuning is sharp and as a crystal set the improvement was very marked.
Adding a turn really increased signal strength in the mid and lower band but it only tuned up to 1650 kc or so at the top end. Tapping at turn 7 eliminates this issue
so it covers the entire band with room to spare.
Performance is just outstanding as a signal booster for portables. The Sangean 909X2 works great because the signal meter is so responsive. The variable gain
helps when using it as a spotter radio when using the antenna as a crystal set. It is helpful when using my PR4W as well.
For you crystal set guys I use KZ AS16 balanced armature IEM's with an impedance of 39 ohms and a sensitivity of 144db/mw @ 2kc for phones and a Dynalec
100k to 150/16 ohm transformer. 15 bucks at fair radio sales and by far the best transformer I have tested by far. All of my tuning capacitors are steatite insulated
transmitting types and I use a 18 to 140 pf one for fine tuning. A 300 pf cap is the coarse tuning cap.
Increased wire diameter worked much better than I thought it would. I am frankly amazed at how well it works. I expected modest gains...at best.
I am happy to say I was wrong!
Of course...I am never satisfied. I built a new antenna out of 1 inch schedule 40 PVC. Here in the US it is available in 5 foot lengths. Two 5 foot sections
cut in half are inserted into a 4 way 90 degree cross and each end has a 3 way 1 inch PVC tee fitting attached. I slotted the PVC fittings for 8 turns and wound
about 128 feet of #12 magnet wire for a total of 8 turns. Turn spacing is about .39 inches. Nearly 2.5 lbs of wire!
Q @ 100kc went from 95 on the old antenna to 220 on the new build. Tuning is sharp and as a crystal set the improvement was very marked.
Adding a turn really increased signal strength in the mid and lower band but it only tuned up to 1650 kc or so at the top end. Tapping at turn 7 eliminates this issue
so it covers the entire band with room to spare.
Performance is just outstanding as a signal booster for portables. The Sangean 909X2 works great because the signal meter is so responsive. The variable gain
helps when using it as a spotter radio when using the antenna as a crystal set. It is helpful when using my PR4W as well.
For you crystal set guys I use KZ AS16 balanced armature IEM's with an impedance of 39 ohms and a sensitivity of 144db/mw @ 2kc for phones and a Dynalec
100k to 150/16 ohm transformer. 15 bucks at fair radio sales and by far the best transformer I have tested by far. All of my tuning capacitors are steatite insulated
transmitting types and I use a 18 to 140 pf one for fine tuning. A 300 pf cap is the coarse tuning cap.
Increased wire diameter worked much better than I thought it would. I am frankly amazed at how well it works. I expected modest gains...at best.
I am happy to say I was wrong!
