Golborne Vintage Radio

Hi.

Well this is not so much a home-brew item but a home-brew solution.
Way back in 2006 I bought a Wellbrook ALA1530 Loop aerial. The loop was a godsend in my noisy area, I could receive stations that it was impossible to hear on a long wire or active rod aerial (Sony AN1)
My only gripe was the output wasn't that high, a low performance radio wasn't ideal, Wellbrook though redesigned the amp later on for higher output.
I got about 5 years out out of the loop then it went intermittent with it cutting off if it was breezy.
I discovered that the amp unit that is a plastic unit was cracked and this had compromised the loop that is a composition of alloy & ferrite, the ferrite was cracked too.
The loop was then withdrawn from use.
I then discovered this circuit on the net.
[attachment=13908]

I then added this to the loop in an external box. It worked very well, far better than the ALA1530 ever did, with the exception it ran out of steam quite early, above 15Mhz it went deaf.
I had troubles though with the original amps mounting and the whole thing was pensioned off.
Today though I have rebuilt the whole thing. I have built a second amp using 2N2222A transistors rather than the BC109's I used previously, I also used a different ferrite ring for the coupling transformer and also used a waterproof box to house the amp and feed in the ends of the loop.
The loop has been secured with jubilee clips and epoxy resin and once completed the box will be epoxy sealed.
So far a quick test has resulted in the best performance so far.
Pictures to come

[attachment=13909][attachment=13910][attachment=13911][attachment=13912]
Hi.
Here are some pics of the weather proof box, the amp board and the partially filled with epoxy in the box.
The mounting bracket and full potting will be done over the next few days.

IP67 box Trevor?

Hi Sam.
Yes it is. I will be potting the lot once I have fitted a couple of through bolts to make up a saddle for the pole its going to live on. I'm sure it will be water tight and strong too.
One thing I'll do this time is to have the top of the loop secured to a non metallic pole that will sleeve inside the main mounting pole to increase the overall strength and reduce possible damage in the high winds we get here.

Hello Trevor

Interesting to me a I bought a Wellbrook about a year ago and I'm most pleased with. As you say it will be a higher gain version than your original. I will keep your info for the future though. Any chance you could post the circuit diagram at a higher resolution please?

thanks Gary

(11-02-2016, 04:54 PM)Radio Fixer Wrote: [ -> ]Hello Trevor

Interesting to me a I bought a Wellbrook about a year ago and I'm most pleased with.  As you say it will be a higher gain version than your original.  I will keep your info for the future though.  Any chance you could post the circuit diagram at a higher resolution please?

thanks Gary

Hi  Gary.
 Unfortunately  the circuit is posted as it was on the net.  It's clear enough if you don't blow it up.

Hi.
I potted the box yesterday and left it overnight to cure.
This afternoon I have mounted the complete aerial on the pole, added a support rod (advised if using the loop outside) and gave it a good test.
Performance is now the best I have had since purchase. I did consider buying a replacement amplifier from Wellbrook but I really couldn't justify the £90 cost.
I gave the loop a good test this afternoon. Medium wave was the best its been, I suffer severe QRM here with any other aerial, It's been some time since I have been able to hear Manx radio on 1368, Tay FM 1354, Radio Ulster from Londonderry 792, amongst others.
Long wave was lively too, with my home made three valve short superhet doing very well indeed.
I'll post a picture of the final installation tomorrow when its light!

Hi Trevor,

Well done on resurrecting your Wellbrook loop - I'm sure your up-grade will last longer than the original !
Gary, the circuit is described here :- http://www.pa1m.nl/pa1m/simple-active-receive-loop/

Regards,
Andy

radioman

(13-02-2016, 11:05 AM)radioman Wrote: [ -> ]Hi Trevor,
Well done on resurrecting your Wellbrook loop - I'm sure your up-grade will last longer than the original !
Gary, the circuit is described here :- http://www.pa1m.nl/pa1m/simple-active-receive-loop/

Regards,
Andy

Thanks Andy.
The link is handy as the original has long gone.
Here is a picture of the loop erected.
[attachment=13921]

Thanks for that link.

I don't understand how it is a magnetic aerial although he uses the term. To me it has to be an aerial shielded from the E part of the received signal. So shouldn't it be a wire inside a tubes as per the Wellbrook? Wonder how they get the ferrite inside the tube and what difference that makes.

In the Den I have a large window and I could put a tube all the way around it with an inner wire, coupled to the amplifier. Any ideas if that would work? I understand that shape is not critical, it doesn't have to be round and larger presumably means more signal? With the Wellbrook, for the lounge best radio, it is on a rotator bought NOS for a very low price but for MW and LW I don't find it any advantage so having a window aerial fixed in a single plain wouldn't matter. Actually the Wellbrook started off on the window sill of the Den and worked very well for the radios in there, with large signals. This was also the case when tried with the HMV 650 just loose in the lounge. LW R4 closed the eye tube with considerable overlap but now garden mounted and 60 feet away signal is down and eye not fully closed. That just must be the loss in the RG59 coax.

thanks for ideas Gary