|
Vintage Amateur and Military Radio Amateur/military receivers and transmitters, morse, and any other related vintage comms equipment. |
|
Thread Tools |
3rd Jun 2022, 10:23 am | #1 |
Hexode
Join Date: Dec 2018
Location: Lugo, Spain
Posts: 483
|
GEM Quad Antennas
Whatever happened to GEM Quad Antennas, belive they were based in Canada, they just seemed to have disappeared ?. There were ads for their cubical quads for years in RadCom and Short wave magazine i remember someone having one years ago , it was a work of art and the F/B ratio was allegedly superior to a yagi.
|
3rd Jun 2022, 1:06 pm | #2 |
Dekatron
Join Date: Aug 2013
Location: Wigan, Greater Manchester, UK.
Posts: 9,433
|
Re: GEM Quad Antennas
A keen DXer I knew had one, i help install it and the 60 foot telescopic tilt over tower is was on top of. This was around 1976, the gem quad had gone but the tower and a 3 band Yagi was there around 2010.
Sadly he is silent key, I don’t know what happened to the radio equipment and tower.
__________________
Frank |
7th Jun 2022, 12:04 am | #3 |
Hexode
Join Date: Mar 2009
Location: Minneapolis, Minnesota, USA.
Posts: 279
|
Re: GEM Quad Antennas
Gem Quad Products were based in Manitoba in Canada. In the 1970's Western Electronics in Southampton sold their quad antenna. In the 1990's Vine Antennas sold them. Their web site was www.gemquad.com A look at www.archive.org does not show much, only that by 2007 they had ceased operations.
73 John KC0G/M0KCY |
9th Jun 2022, 5:14 pm | #4 |
Hexode
Join Date: Dec 2018
Location: Lugo, Spain
Posts: 483
|
Re: GEM Quad Antennas
Perhaps the market for quads dried up .
|
9th Jun 2022, 6:29 pm | #5 | |
Hexode
Join Date: Nov 2011
Location: Chippenham, Wiltshire, UK.
Posts: 323
|
Re: GEM Quad Antennas
Quote:
I seem to remember that the GEM Quad was discussed at the time as an advance on previous designs, which used a cross-arm at each end of a fixed boom. The element spacing of the 'boom and two crosses' design was therefore optimal for only one band. The GEM spider - made possible by aluminium welding or some other up-to-date fabrication technique (?) - permitted the nesting of loops for several bands with each at optimum spacing. Was GEM a new registered design, which others were not able to copy for a time? Peter |
|
10th Jun 2022, 7:50 pm | #6 |
Hexode
Join Date: Mar 2009
Location: Minneapolis, Minnesota, USA.
Posts: 279
|
Re: GEM Quad Antennas
It seems that the first advertisements in Short Wave Magazine were in 1971.
An online search of CQ magazine led to a full page ad. on page 119 of the May 1968 issue. The company name was Structural Glass Limited in Winnipeg. Today they are Structural Composite Technologies Ltd. According to the advertisement the spider was made from aluminum alloy and the arms from fibreglass. 73 John KC0G/M0KCY |
10th Jun 2022, 7:58 pm | #7 |
Dekatron
Join Date: Apr 2012
Location: Wiltshire, UK.
Posts: 14,010
|
Re: GEM Quad Antennas
Thinking of this, does anyone remember a 14/21/28MHz HF beam-antenna which had one simple dipole-type element [with loading-coils/capacitance-enhancing spokes at the ends] but the other element was a sort-of squashed-diamond [with similar spokes at the ends] ??
__________________
I'm the Operator of my Pocket Calculator. -Kraftwerk. |
11th Jun 2022, 1:30 am | #8 | |
Heptode
Join Date: Mar 2008
Location: Newmarket, Suffolk, UK.
Posts: 613
|
Re: GEM Quad Antennas
Quote:
Not sure who made it Fred |
|
11th Jun 2022, 6:35 am | #9 |
Dekatron
Join Date: Aug 2013
Location: Wigan, Greater Manchester, UK.
Posts: 9,433
|
Re: GEM Quad Antennas
I can confirm the arms were fiberglass, can’t remember the spider.
__________________
Frank |
11th Jun 2022, 8:20 am | #10 | |
Heptode
Join Date: Mar 2008
Location: Newmarket, Suffolk, UK.
Posts: 613
|
Re: GEM Quad Antennas
Quote:
https://www.radioworld.co.uk/mq-1_tg...d_quad_antenna Made by "TGM Antennas" Fred |
|
11th Jun 2022, 5:53 pm | #11 | ||
Dekatron
Join Date: Apr 2012
Location: Wiltshire, UK.
Posts: 14,010
|
Re: GEM Quad Antennas
Quote:
Does anyone have assessments of how effective it is? Most HF antennas boast about 'forward-facing gain but in practice I'll happily trade a few dB of forward-gain if I can get 10dB of 'null' against a local QRM-source.
__________________
I'm the Operator of my Pocket Calculator. -Kraftwerk. |
||
12th Jun 2022, 12:07 am | #12 |
Hexode
Join Date: Mar 2009
Location: Minneapolis, Minnesota, USA.
Posts: 279
|
Re: GEM Quad Antennas
The HQ-1 was made by Mini-Products Inc., of Erie , Pennsylvania. The first advert which I found was in the July 1972 issue of CQ magazine.
It was advertised by Waters Electronics in the June 1973 issue of Short Wave Magazine. It was also advertised in the March 1975 issue. By then Waters Electronics had become Waters and Stanton Electronics. Perhaps somebody can turn up a review? 73 John KC0G/M0KCY |
12th Jun 2022, 9:02 am | #13 |
Hexode
Join Date: Mar 2006
Location: Helston, Cornwall, UK.
Posts: 304
|
Re: GEM Quad Antennas
I used a HQ1 mini beam a few years ago. Sturdy construction. As you would expect it worked better on the higher bands, 10 and 15 but 20M was very compromised with narrow bandwidth and very little F/B performance. Certainly on 10 and 15 it was a fair performer with about 10 to 15dB F/B and some gain. Much better than my 260ft Doublet.
I could never get it to resonate on 6M. I think there are better options these days, a number of manufacturers are offering beams with folded elements optimised using modern software. The TGM domain is now registered to a company selling Viagra!, I doubt they are still in business Tim M0AFJ Last edited by M0AFJ, Tim; 12th Jun 2022 at 9:08 am. Reason: Updated info |
12th Jun 2022, 6:39 pm | #14 |
Hexode
Join Date: Mar 2009
Location: Minneapolis, Minnesota, USA.
Posts: 279
|
Re: GEM Quad Antennas
http://www.tgmcom.com/ seems to be the current web site.
|