HF Antenna

[Wayne Pearce]

Can anyone help with information on mounting brackets, position of brackets and general layout of HF antenna to suit C337G, where my antenna terminal post is left rear of cabin.
The reason I ask is that I am not happy with the suggestion from the radio guys here they are not familiar with 337's
Things like I would have thought that the length from terminal post to side boom should be shorter than length from terminal post to rear prop etc etc
Even with a brief description of mounting brackets and mounting position I can then have them manufactured.

Any help appreciated ....... Wayne

Oh! has anyone fitted a single point digital EGT (dual) to 337G
I would like to fit EI model EE-1P into standard hole in panel, would like more info but can't find email address for EI.

[Bob Cook]

Wayne

Is this for adf or is this a transmit antenna for low frequency radio (7 mhz)

2) Most owners have used JPI which has an stc for the 337, or at least it was approved. Sorry on EI but I think I have seen them on 337s.

Last thing is you need a piece of wire rapped around the rear pros... scary. Be sure if you do not have the approved cessna parts then get an DEA to approve the installation or a real good radio shop.


Bob

[GMAs]

Wayne you can look in the avonics book for the cessna stuff.... yep they have a avonics book that shows how to put the sunair in as well as how the antenna wire is supposed to be strung around the airplane.. but,.......

We went away from that... and also the high priced sunair and collins radios... we use the ICOM 706.. the same one that they sell for the ham bands... yep it covers all the bands and will tune from DC to daylight... the US broadcast 0Kc to 450 mhz... and will do it in sideband, FM, AM as well... so you can also get on the ham bands and go aeronautical mobile... and escape the boordum of just listening for hours after hour... it has memory channels that you can pre program... but,....

It also has this neet little antenna turner... they sell it as the AH-4... and it plugs into the back of the radio and gets everything from it... and when you change frequencies.. it remembers the settings and brings up the other automaticly so that things can't be any easier.... and ICOM will remove the one diode that will allow you to use it for the aircraft band... now I am not saying that you should use all 50 watts to contact the tower... but, if you wanted to you could.... but wait their is more....

seeings how most radios are kinda like cigar boxes these days... ICOM went one better... you can place the radio almost 12 feet away (4 meters) from the... control head... yep they have the control head which is 1 inch by 6 by 2.5... and no I am not going to change to metric you want to know.. you do the math... smile... but, it can be velcro+ed right to the dash.. your yoke.. your co-pilot forhead, etc...... and it has the avialibiltiy to tie into your audio system such as the King KMA-24... and change frequency by either dialing it in... or using a up down switch on the yoke or mic...in memory mode... One minor problem though....

It works on 12 volts.. not 24.. so we use the two power reducers that cessna used for their nav coms.. yep they were 12 volt radios... and their are two of the 24 to 12 volt converters up on the service trays... they will handle about 15 amps each... so when you transmitt with the 706... you need 25 amps... well within the limit of the converters... (but their are others out their that can be had too that handle up to 50 amps or so... some even make their own and still get a 337 form from the FAA here in the US to put it in...

but, to get back to your question... about antennas... well we mount the radio under the pilots seat.. convient place.. or up in the right wing... inboard of the last fuel tank... where their is a big space and their we also put the AH-4... or we could put it up in the ceiling of the cabin.. but, we perfer to have it in the wing so that the output antenna lead is not too long... we run RG-213 down the boom on the left... and ground the sheilding to the rudder post... and the center runs to the fishing reel... that has been jazzed up with a small 12/24 volt elect motor and a small spocket and chain.. to give it some gear reduction... this is mounted on a new rudder stike fiberglass housing... that has had the strobe light removed.. and placed on the other side... which doesn't seem to effect the marker reciever antenna.. too much.. I mean how often do you need it.. except on landings... as you pass over the markers... smile...

Now the fishing reel has some fine like No. 20 copper coated steel wire... although we have used small aircraft cable (ss) we perfer the copper... because if it gets caught on something while your landing... like you forgot to real it in... it will snap real fast....

the fishing reel has a couple of microswitches on it so that it knows when the cable is in or out... and it gives you a light on the dash... (we used LED's for the indicators) and will stop the motor from going too far...

How long a piece of wire you need.. well the antenna tuner will take care of anything from 23 ft... to a mile or more... but, wait... theirs more too...

See you need the antenna trailing out behind the plane.. you don't want the thing coming back and getting into anything... again the copper wire is good because the prop would have no problem cutting it if it somehow got into it...

Here Jon one of the mechanics came up with a simple and cheep way to make the antenna stay out back almost streight... he used a funnel... yep a plastic 3-5 incher seems to work just about right.. and keeps enough tension on the wire to keep it streight while still not enough to break it off.... smart kid... that Jon... and if you leave it out while landing... well hey for 39 cents u.s. you can get another one...

As to the strike mount... it has a little bludge in it where the reel goes... and a little door on the side so you can get to it... make sure you use one that has the little winder that goes back and forth across the reel.. as it also is what makes contact with the wire for the antenna...

the motor we got from C&H sales... its a gear reduced 50 rpm surplus motor... about 1 inch in dia and 3 inches long... but, any motor would work so long as the funnel would not be able to pull the wire out unless you wanted it to...

And one thing more we found that if you mount it out in the wing... don't plan on using it in freezing weather... as them electronic things don't like being real cold... otherwise...

How do they work... well the last one that we put in cost about 900 for the radio and another 300 for the tuner... and that was back 3 months ago.. I think they have come down since then even.. and give you the mounts and extender from the control head to radio... for free... from ICOM.. the same people who bring you the hand helds for avation...

We took it up and first tired it on the UHF bands... it worked great.. about 400 miles... then we tried it on the vhf bands... again not bad... about 200 miles ... we tried calling the tower and got a immediate response even though we were.... and then we went to the ham bands on 40 meters.. 7 mc... and we made contact with both a australan station.. as well as one in japan.... both said it was getting out quite well... and we talked for several min..... then we went to the HF bands for avation and again it seemed to work better than even the sullair stuff or collens....by the reports from commercial aircraft way out in the pacific... (it puts out 100 watts so it should)... so it seems to be a good way to go... and by the way... it meets the mill specs for the US... and FCC in both frequency control and drift... and we had no problems putting it in without drilling a lot of holes.. and it can be taken out at any time by removing the parts made... and putting the plane back the way it was...

Hope this gives you some food for thought as to what you can do... we had no problems getting approval for it from our FAA so I would think you shouldn't either...

Good luck... 73's (ham stuff).. GMAs

[Wayne Pearce]

Thanks for response guys, prize goes to GMAS the best clue was the "Cessna Avionics Installation Book" it gave all the information needed to complete the installation.
Interesting that the Cessna distributor here (for 40 years or more) would not give a definitive answer, hence my call for help on the board.

Don't suppose we have reconsidered Tasmania as a meeting place ?

Regards ........ Wayne

[rick bell]

HAD MY ADF ANTENNA BREAK AT THE ATTACHMENT POINT ON THE RIGHT HORZ. STABL. WHILE IN FLIGHT, THE PROP DIDN'T CUT IT AND THE BACK PASSENGER WAS A LITTLE CONCERNED WITH IF WHIPPING AROUND. ONLY DAMAGED IT CAUSED WAS TO THE INSIDE OF THE BOOM AND HORZ. STABL., MADE A LOT OF LITTLE DENTS LIKE HAIL DAMAGED.

[Kevin McDole]

Wayne,

Electronics International's website is:

&nbsp&nbsp&nbsp&nbsp&nbsphttp://www.buy-ei.com/

JPI is at:

&nbsp&nbsp&nbsp&nbsp&nbsphttp://www.jpinstruments.com/

Insight is at:

&nbsp&nbsp&nbsp&nbsp&nbsphttp://www.insightavionics.com/

When I was working with a DEA group in Belize and we installed a Icom 706 HF radio with a Auto tuner using the ADF ant. this was in 1995. The radio was not even in the US yet, it was used on 6,8,10 MHZ Icom cut a few wires to make it do this. I also used it on the Ham bands (where it is appoved). A photo of it in the Belize O2 can be found in the Dec 1996 QST page 20, QST is a ham radio news pub, see arrl.com This setup works very good I used it on many Gulf crossings talking to New Your Radio on HF giving reports. I now have one in my P 337 with the newer tuner. This is a 100 watt HF radio and also works on VHF and UHF. The radio will rec the "FM broadcast" band and 120Mhz aircraft. We used the VHF/UHF all the time.
General Walz V31KW

[rick bell]

small world, we also lived in belize for a while 79/80