It's a 4 band ham radio antenna. It covers 6m (50 MHz), 4m (70MHz), 2m (145 MHz) and 70cm (430 MHz)
The reason I want to give it some publicity, is the fact that it's small, at only 1.2m in length, covers 4m, and I had some good service from the supplier....
I'd been contemplating sticking something on the roof for a while, to get better access into the local repeaters for a natter on 2m and 70cm every so often. It's got to be fairly small so as not to aggravate the neighbours or the wife....
Then I spotted a small ad in the back of RadCom magazine for a quad-band co-linear antenna. It wasn't too pricey either, having 4m is really good too. Most quad-bands are 10m, 6m,2m and 70cm. I have a magnetic loop that works well on 10m, so that doesn't really interest me.
I placed an order on the website at www.mirfield-electronics.co.uk, and very soon a cardboard tube arrived.
So, it's Sunday. The weather was looking promising, I had half a reel of RG-8 co-ax cable that would do the job, only to be thwarted. One of the radial elements didn't have a thread, and the mounting brackets seemed to be missing... :(I telephoned the number on Mirfield's website and left a message...
... and a super chap called Martin rang me back about half an hour later (on a Sunday too!). I explained the situation.
He was great, "What WAS I thinking, must have had a bad day!" He promised to post next day, and good to his word, a nice new radial, and the missing mounting brackets turned up on Tuesday.
So, It's Saturday, and once again the weather looks favourable.
I gather the parts and assemble the antenna....
The antenna is fitted with a SO259 "UHF" connector at it's base. Quite why anyone would call it UHF is beyond me. It's a pretty poor connector at VHF, let alone UHF.... anyway, it seemed good enough for Icom to put on the back of their UHF radios, so maybe it's just me... an N-type connector would have been preferable, but at this price point, I'm more than happy.
Having soldered a PL259 on to the RG-8 co-ax, slide the coax and connector through the support tube, making sure the screw hole is pointing towards the antenna. I also slid a piece of heat-shrink tubing on too... Don't do what I did, and forget to slide the mounting clamps onto the mounting tube first!
A couple of laps of self-amalgamating tape are used to give the connector some protection against the elements, and the heat-shrink makes a tidy job ....
... slide the mounting tube onto the bottom of the antenna, and do up the screw. The mounting tube is steel, and I wonder if it could have been made a little thicker for strength. Seems to work OK though...When doing up the mounting clamps, I found it helpful to keep them flat against the floor, as when you do up the screws, they tend to move about a bit....
I've left the radials off until I get the thing up on the roof...
So, a couple of hours later, and it's up....
(Glad I did it too, the TV co-ax was in an awful state!)
So how's it perform?
Gain figures are quoted as 2.5dBi on 6m, 2.5dBi on 4m, 3.5dBi on 2m, and 5.5dBi on 70cm. I've got no way of checking those, but the antenna opens up repeaters on 2m I haven't heard for years, and fully quietening on local repeaters at just 5 watts. The antenna is rated to 60 watts.
VSWR is better than 1.5:1 on all the frequencies I'm interested in.
Good points...
The service from Mirfield was superb.
It's short.
It's cheap.
It's largely well made, and looks like it will stand the test of time.
70 MHz!
Minor grumbles...
SO259 "good buddy" connector.
Mounting tube could be more robust.
Another excellent article thank you!
ReplyDeleteIf I may meander... During the CB boom I was making lots of money repairing CB sets, several a week sometimes and apart from a few FM/AM/SSB which were too much for me most were repaired in order to fund the beer and wine habit. If I may meander a little further... A good friend was into scanners as I still am but seldom took good advice. One day he bought an expensive 'Discone' antenna and boy was I jealous! he dismissed my offer of help and did a jolly good job of soldering a PL259 plug to some nice thick expensive cable. He put up the aerial, switched everything on and NOTHING, ZERO< ZILCH! Then he phoned me, we brought down the Discone I unravelled the well applied self amalgamating tape, checked the plug and all was perfect, then I glanced by the rather empty void in the socket, yup, it was N! The large pin in the PL259 had split the socket, it was integral to the hardware and the seller who I cannot remember was not interested. In this case "the less you know the worse it works".
Hi Andy, I read with interest your review on the Me 64270 Colinear, you've had your's up a few months now, whats the verdict, I was thinking of getting one at the canvey rally this weekend just for a bit of local work, is it worth the effort ? Thanks Paul G4YBI
ReplyDeleteWorks OK. Consistently opens the Salop cluster on UHF with 5 watts from here which surprises me. Played with it a bit on 2 and 4 , and it seems to be OK. Haven't tried 6. Not worked any fabulous DX on it, but I don't have much time. Hasn't fallen off yet. I'd recommend one.
DeleteOK thanks !!
ReplyDeleteI have this antenna too. SWR are poor 6/4/2m but 70cm is good.
ReplyDeleteMine did nit support 35W in fm 2m
ReplyDeleteI’m pleased I stumbled across this as I think I may have the same antenna.
ReplyDeleteDoing some research on 4m antenna options I saw the quad band colinear and then another link to this write up.
The antenna was bought second hand for £10 as an unknown (no brand name on it) “dual band” antenna but recently found out the SWR on 4m is 1:5:1.
I don’t have a transceiver that covers 6m so cannot test that but can confirm it also works on 2m and 70cm.
Quite pleased as it’s got me operating on 4m whilst I shop around for a more dedicated antenna.
Thank you for the review.
73 Frank
Very fast delivery from Mirfield Electronics. The antenna comes with explicit instructions to mount it clear of other aerials, roofs, walls etc so mine went up on a 10ft mast fixed at the gable apex. The swr is very good on 4m/2m/70cm @ around 1.3 to 1. 50mhz though is less than ideal @ 1.8 to 1 at the lower end of the band rising to 2.0 to 1 mismatch at the top (the specifications indicate to expect an swr around 1.8 to 1 on 50mhz)....as a "compromise antenna" covering so many bands I don't think this is too bad, esp as I only intend runing 10 watts RF into it. Quality and finish wise the antenna is not quite on par with similar fiberglass verticals from Diamond etc, but at under £70 quid (inc postage) its hard to fault. Initial reports from local stations are encouraging and considering its diminutive 1.2 metre size, low visual impact and it covers 4 bands, this may be ideal for anyone severely hampered by local restrictions, neighbours etc.
ReplyDeleteWould the additional bands have any negative effect if using on a dual band 2m / 70cm radio tranciever?
ReplyDelete