My New GE SuperRadio 2

[KB2GOM]

After more than ten years, I broke my C Crane Radio EP. It is a portable. So, I bought the EP PRO. I was not impressed.

So, I open both. Overall design and layout has not changed. However, the analog Sanyo LA 1260 AM/FM/MPX was not upgraded using the newer Sanyo LA 1823/4 but with the Silicon Labs / Skyworks Si 4730. This is a Digital RX DSP receiver with no inductors or potentiometers to adjust. Only a single mini VCO variable cap to diddle. Only analog components on the receive side is a dial string on a pot.

The 200 mm by 10 mm ferrite loop antennas are near identical. So, I’m thinking a good radio is only as good as its antenna ... why not have two. There is room after cutting out the three antenna support stanchions. So, I cable tie the two loops together then wire them IN SERIES. Yes, this doubles the ohms. Voltage is the point. Close proximity quadruples the henries and broadens the lower and upper MW BCB. After removing near 80 mm of extraneous litz wire, the dual ferrite loop assembly is rubber cemented together, assembly is soldered to the main PCB which is re-installed then the assembly is rubber cemented to the back chassis. Takes five hours. Four hours for the glue to dry.

Immediate results are impressive. There are no analog test points to measure. But, the red signal strength LED seems to light with more distant stations twice as much. So, I did some field testing in urban EMI environments and at a remote pond swamp. Wide / Narrow filter remains very good but Fine Tuning is not as effective. I’m thinking it’s the digital electronics and not the antennae. C Crane does not offer service manuals for either radio. Buy a new one. It’s a Sangean.

Rhombics and loops are most effective for AM DX. However, size and weight are issues. With this dual antenna, side lobes seem to be more suppressed but this may be due to on lobes being more sensitive. On night two, I brought out the Tecsun H-501X for side by side comps. EP PRO has more directional side lobe nulling and at higher frequencies. EP PRO has less fade and with different phases perhaps due to it being more sensitive to M than E waves than the Tecsun single ferrite loop. Proven at the pond when the EP PRO is oriented vertical and performs much like the original C Crane Twin Coil which it is not. That twin coil is a reverse phase design requiring a transformer and pre-amplification. It was quieter to EMI and CMR but fails in the market due to inductive coupling difficulties and the direct coupling impedance matches C Crane radios but not many others (5:1 balbal).

H-501X is more selective. There is no adjacent channel interference. None. AGC is very good. EP PRO is not. Its AGC will lock up and soft mute. H-501X four speaker audio has more fidelity and presence. EP PRO two speaker audio is more intelligible. This is important for crowded noisy AM reception.

On night three, I brought out both radios and a Tecsun AN-200 inductive loop antenna. Results are more impressive. With both radios inside the loop, modified EP PRO has more sensitivity, directivity and less fade than H-501X. Propagation delays have faster rise and fall times. Additional Q makes low band frequency channels more selective with AN-200 fine tuning. Side lobe nulls seem sharper. I listened to three stations in different directions on the same frequencies above 1300 kHz. Loop coupling is more effective with internal dual antennas than the H-501X single antenna. It has broad fine tune peaks while EP PRO is more narrow (Q). I have not used the direct connect method using RF cables. Tecsun does not allow for external AM antennae. C Crane may have Z and CMR issues. Later maybe.

ON VHF BCB using whip antennas only, H-501X is more selective and has better stereo audio quality on headphones. However, EP PRO has better capture and locks MPX stereo pilot sooner with 80 mm less whip. I listened to an 18 kW ERP FM station 160 miles away with no LOS (mountains) at times in stereo. H-501X needs an external antenna to achieve similar or better performance. Basic conclusion is Tecsun has better sound, C Crane has more to listen to.

This EP PRO will replace the GE SR2 (finally). Four carbon or alkaline D cells give this monster gravitas.

Only one thing will make the EP PRO and AN-200 combo better. Two AN-200s side by side with radios inside both loops. Will 3-D print the frame as soon as the second arrives from China.

And then, there is the Qudosen SR-286 dual antenna project. First attempt using a Sony ferrite loop with different coil windings fails even though the math was good (parallel series). If you enjoy analog radio the way Providence intended, this SR-286 may be the light weight portable yer lookin’ fer.

Chico Baravelli
cbaravelli@mail.com

This was my experience with the EP PRO: Sometimes simple works . . . really well! Exploring the CCrane EP PRO

 

[cbaravelli]

Props to swling.com, but the CCrane EP Pro is not an analog receiver. I found using the red LED signal strength indicator somewhat difficult. For DX broadcast MW stations, It lights up solid with no audio (50% modulation) then flickers with audio. Digital.
Wanted to 3-D print a portable loop antenna system. But college switched to Bambu Labs. There is a learning curve and I don't have the time. Hobby Lobby to the rescue. (Note to self. Parking lot and store are full at 10 AM Friday morning. Buy company stock.) Bought a wood box and heavy foam pad for $12. Circ saw a four inch half hole to access the two Tescun AN-200 tunable loop antennae knobs then mounted to the box with four short counter-sink screws and rubber cement (glue and screw). Polyuerathane the box. Cut two foam pads to fit inside the duo-loops and rubber cement together. I use felt feet to slide and rotate on tables and car roofs. Turntables work but not out in the woods.
Grab the three portable DX radios I own and went out in the field for testing. Single ferrite loop Tecsun H-601X, dual ferrite loop CCrane EP Pro and Qudosen SR-286. WOW.
In common for all radios, bi-directional figure eight patterns are broader toward the two locus points with more forward than reverse gain. Off axis side gain is less. All three radios in conjunction with the duo-loops fine tune differently. AN-200s will interact (mutual inductance) depending on radio ferrite loop number and type. Re-tweaking tuning the AN-200s may be required. In urban environments (damn those big screen TVs), slight de-tuning and radio fine tuning notch out most electrical and impulse noises. I can DX in my bed now. Sunday night, I listened to "When Radio Was" from 780 WBBM - Chicago (50kw non-directional with a north-south pattern bias) for half an hour before the station started to fade. I live near the coast.
For grins, I used the beater AN-200 in close proximity to the box. WOWWOW. Forward gain improves more but so does side gain. Three AN-200s have more selectivity (Q) to separate same and co-channel interference from stations in different directions. Special situations.
H-601X has dBu and dB meters I do not understand (Chinese standards?) nor trust. ISO standards are dBu is a relative voltage level and dB is a relative power level in watts. Remember, high MW band (1.2 mHz and above) reception is not as good as at low band for near all receivers. Longer the ferrite loop antenna, better the bandwith. Here are the numbers for two AN-200s:
Frequency dBu W/O dB W/O dBu With dB With
570 kHz 25 00 43 00
770 kHz 45 20 52 20
950 kHz 43 22 57 22
1110 kHz 42 17 55 25
1360 kHz 43 00 56 00
1520 kHz 43 17 46 22
1680 kHz 32 11 33 17
Measured stations are long distance at night. Signal strengths and noises will fluctuate. Numbers are long term averages. Average mid-band duo-loop voltae gain is near +13 dBu for 4.2 times more power at the receiving antenna. Depending on frequency, the third AN-200 adds + 3 to +5 dBu for another 1.2 to 1.8 times power gain. Note: AN-200 windings will separate with age and use. Rubber cement works.
Under $70. No batteries required. Beats using a big stationary Loop or Rhombic antenna system. Thinking about adding a rope carrying "handle".
If there a broadcast station out there. "The Box" will find it.

 

[TAC4]

Dude you should be working for NASA building satellites.🛰
Like seriously stop wasting your time in SWL hobby.

 

[KB2GOM]

Props to swling.com, but the CCrane EP Pro is not an analog receiver. I found using the red LED signal strength indicator somewhat difficult. For DX broadcast MW stations, It lights up solid with no audio (50% modulation) then flickers with audio. Digital.
Wanted to 3-D print a portable loop antenna system. But college switched to Bambu Labs. There is a learning curve and I don't have the time. Hobby Lobby to the rescue. (Note to self. Parking lot and store are full at 10 AM Friday morning. Buy company stock.) Bought a wood box and heavy foam pad for $12. Circ saw a four inch half hole to access the two Tescun AN-200 tunable loop antennae knobs then mounted to the box with four short counter-sink screws and rubber cement (glue and screw). Polyuerathane the box. Cut two foam pads to fit inside the duo-loops and rubber cement together. I use felt feet to slide and rotate on tables and car roofs. Turntables work but not out in the woods.
Grab the three portable DX radios I own and went out in the field for testing. Single ferrite loop Tecsun H-601X, dual ferrite loop CCrane EP Pro and Qudosen SR-286. WOW.
In common for all radios, bi-directional figure eight patterns are broader toward the two locus points with more forward than reverse gain. Off axis side gain is less. All three radios in conjunction with the duo-loops fine tune differently. AN-200s will interact (mutual inductance) depending on radio ferrite loop number and type. Re-tweaking tuning the AN-200s may be required. In urban environments (damn those big screen TVs), slight de-tuning and radio fine tuning notch out most electrical and impulse noises. I can DX in my bed now. Sunday night, I listened to "When Radio Was" from 780 WBBM - Chicago (50kw non-directional with a north-south pattern bias) for half an hour before the station started to fade. I live near the coast.
For grins, I used the beater AN-200 in close proximity to the box. WOWWOW. Forward gain improves more but so does side gain. Three AN-200s have more selectivity (Q) to separate same and co-channel interference from stations in different directions. Special situations.
H-601X has dBu and dB meters I do not understand (Chinese standards?) nor trust. ISO standards are dBu is a relative voltage level and dB is a relative power level in watts. Remember, high MW band (1.2 mHz and above) reception is not as good as at low band for near all receivers. Longer the ferrite loop antenna, better the bandwith. Here are the numbers for two AN-200s:
Frequency dBu W/O dB W/O dBu With dB With
570 kHz 25 00 43 00
770 kHz 45 20 52 20
950 kHz 43 22 57 22
1110 kHz 42 17 55 25
1360 kHz 43 00 56 00
1520 kHz 43 17 46 22
1680 kHz 32 11 33 17
Measured stations are long distance at night. Signal strengths and noises will fluctuate. Numbers are long term averages. Average mid-band duo-loop voltae gain is near +13 dBu for 4.2 times more power at the receiving antenna. Depending on frequency, the third AN-200 adds + 3 to +5 dBu for another 1.2 to 1.8 times power gain. Note: AN-200 windings will separate with age and use. Rubber cement works.
Under $70. No batteries required. Beats using a big stationary Loop or Rhombic antenna system. Thinking about adding a rope carrying "handle".
If there a broadcast station out there. "The Box" will find it.

Do you have any estimate of what the EP PRO performance with your DX Box might be without the second ferrite rod that you transplanted?

As it turns out, I have both the Twin Coil Ferrite antenna, the Terk indoor passive loop antenna, and an EP PRO, and your experiments have me wondering how I might combine the three. I would welcome your suggestions.

 

[cbaravelli]

Less than -3dB forward/backward gain or -0.5% voltage or -0.707% power (RMS Watts) or about half as good. More side lobes, too. Two antennae figure eight pattern is impressive with near twice the gain.
CCrane Twin Coil fails in the market place due to being difficult to use with a seperate tunable pre-amplifier. Direct antenna impedance is for CCCrane / Sangean MW recievers and may mis-match with other radios.
EP PRO ferrite bar is closer to the rear cover than the top. Duct tape the CCrane Twin Coil to the top of the rear cover. You will find the "sweet spot". The Terk is more an FM antenna, but you know that. For MW DX, I would duct tape the Terk over or along side the Twin Coil in the horizontal position. You can see the problem.
Best method is purchase an old EP on eBay, gut the ferrite antenna and screw/glue it to the EP PRO antenna then wire in series. Proximity is key.
My solution, The Box, is more for portable remote reception 'cause it's so good darm noisey in town. Your requirements may differ. For indoors, loops and rhombics (they are BIG) are the best solution. Bigger is better. But if on a budget. check out GOOZEEBOO MW tunable loops but with a vertical orientation.
There are three rules for radio antennas; elevation, elevation and elevation.

 

[cbaravelli]

TAC4: "Dude you should be working for NASA building satellites.🛰"
I am a enjineer. I are an enginner. I'm just good at math.
Wanted to prove Maxwell, Henri and Faraday were right.

 

[cbaravelli]

CLARIFICATION:
A radio with one ferrite loop bar antenna will have -3dB loss than two ferrrites or about half the power gain. Using the Tecsun H-801X numbers based on an arbitrary laboratory reference (@-25dB S/N), 13dBu minus 3dBu is 10dBu. This may not seem much of a voltage difference. But it is in watt power 4.2dBw -1.2dBw = 3.0dBw or near 1/3rd.
The Box two tunable loops and a MW receiver with a single ferrite are three antennae. With mutual inductance (mu) as high as physically possible, assembly will have near 1/3 less power gain than with a dual ferrite receiver.
Hope this helps more.

 

[TAC4]

Your speaking Greek to me. So I guess your saying more
is better ? lol

 

[KB2GOM]

CLARIFICATION:
A radio with one ferrite loop bar antenna will have -3dB loss than two ferrrites or about half the power gain. Using the Tecsun H-801X numbers based on an arbitrary laboratory reference (@-25dB S/N), 13dBu minus 3dBu is 10dBu. This may not seem much of a voltage difference. But it is in watt power 4.2dBw -1.2dBw = 3.0dBw or near 1/3rd.
The Box two tunable loops and a MW receiver with a single ferrite are three antennae. With mutual inductance (mu) as high as physically possible, assembly will have near 1/3 less power gain than with a dual ferrite receiver.
Hope this helps more.

Yes it does help.

For What It's Worth (cue Buffalo Springfield) I tried putting the ferrite element from the Twin Coil Ferrite AM Antenna (without connecting it to any of the associated electronics) next to the EP PRO on the back side above the battery hatch. I placed it in various positions around the outside with absolutely no effect whatsoever. There appeared to be NO coupling between the EP PRO internal ferrite antenna and the ferrite element from the Twin Coil antenna.

With Terk loop antenna, however, the effect was dramatic: an instant improvement in the clarity and readability of faint stations.

 

[cbaravelli]

TAC4: "So I guess your saying more is better?"
No quite. Bigger is better. A Tescun AN-200 type loop antenna with twice the circumference or twice the wire will out perform two AN-200s in close proximity.
KB2GOM: "There appeared to be NO coupling between the EP PRO internal ferrite antenna and the ferrite element from the Twin Coil antenna."
Yeah, that happens. EP PRO has a humongous internal antenna. Something should've. Is the red LED on? Depending on the Litz wire wraps around the feritte, you may wanna twist the Twin Coil around 180 degrees. Could be out of phase and null instead of an in-phase notch. Inductors will do that.
CCrane Twin Coil antennas work best with a direct wire to the EP PRO MW external antenna in. That's what it's made for. Intent was having the dual bar be in a more remote location (outside) away from all the EMI we humans generate inside. For me, the hassle is re-orientating and tuning whenever I wanna listen to a station in another direction or on another channel. Now, if CCrane had a TV remote control, then it would cost much more than $100.
Terks are good. Have you tried pasting or taping the Terk in the same horizontal orientation as the EP PRO antenna inside the back cover near the top? With the pre-amplification, I bet its an RF magnet.